AWUS01 KWNH 072015
FFGMPD
PAZ000-WVZ000-OHZ000-INZ000-080100-

Mesoscale Precipitation Discussion 0717
NWS Weather Prediction Center College Park MD
414 PM EDT Mon Sep 07 2020

Areas affected...Central IN...Northern OH...Western PA

Concerning...Heavy rainfall...Flash flooding possible

Valid 072003Z - 080100Z

Summary...Multiple rounds of heavy showers and storms are expected
to persist through the early evening hours across portions of the
northern Ohio Valley region. Some instances of flash flooding
will be possible with the most persistent convection through 9 pm
local time.

Discussion...An outflow boundary oriented west to east is
continuing to generate convection from central Indiana to western
Pennsylvania. Regional Doppler radars are indicating ongoing
instances of convective training about 50 miles north of
Interstate 70, and GOES-16 visible satellite imagery depicts a
well-developed anvil canopy with generally clear skies and
unstable conditions south of the outflow boundary. This is
supported by the latest SPC mesoanalysis depicting a corridor of
1000-2000 J/kg of mixed layer CAPE and PWs in the 1.6 to 1.9
range. Furthermore, 850 mb inflow of 20-30 mph is being lifted
over this boundary with a subtle mid-level vortmax over the
region. Model forecast soundings indicate a veered boundary layer
wind profile and nearly unidirectional westerly flow in the
800-300 mb layer, which will support additional training
convection with rainfall rates approaching 2 inches per hour.

The latest suite of high-res model guidance is indicating the
potential for patchy areas of 2-4 inch rainfall totals through 9
pm within the outlook area. However, it does appear that the most
recent HRRR is underdone with it QPF through this time based on
ongoing radar trends. HREF probabilities of 1 inch per hour rates
are up to 50 percent, and up to 25 percent for 2 inch per hour
rates. In addition, portions of northern Ohio have already
received over two inches of rain over the past 12 hours, and those
areas are more vulnerable to any additional rainfall.

Hamrick

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...CLE...CTP...ILN...IND...IWX...PBZ...RLX...

ATTN...RFC...MARFC...OHRFC...NWC...

LAT...LON 41508006 41407911 40787885 40367935 40158034
40008138 39838275 39708412 39678528 39818605
40028638 40208647 40468641 40668618 40788546
40878469 41028372 41178274 41278217 41398147
41468077
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 081836
FFGMPD
ILZ000-MOZ000-OKZ000-KSZ000-082355-

Mesoscale Precipitation Discussion 0720
NWS Weather Prediction Center College Park MD
236 PM EDT Tue Sep 08 2020

Areas affected...Northeast OK...Southeast KS...Southwest to
East-Cent MO...

Concerning...Heavy rainfall...Flash flooding possible

Valid 081835Z - 082355Z

SUMMARY...Slow moving thunderstorms along stationary front

DISCUSSION...18z Observations and GOES-Visible loop depicts a
stationary front extending from western OK across southeast KS and
just north of I-44 across MO into STL and Central IL. CIRA LPW
suite along with regional sounding denote moisture pooled along
and just north of the frontal boundary though the North-South
boundary layer "feeder" band is demarcated across the eastern half
of OK, with low to mid-70s Tds highlighted, though 850-7H also
depicts a solid .75" values along the same axis. This is
supporting TPW values over 1.5". Weakly veered to unidirectional
flow of 15-20kts through 7H is not perfectly orthogonal to the
boundary, but given angle, provides solid deep moisture
convergence and solid flux (particulary further west) to increase
moisture loading to help with rainfall efficiency. Solar
insolation has supported a stark gradient of instability due to
clouds north of the front, with 60s Ts rapidly changing to near 90
across N OK/SW MO, supporting MLCAPEs over 2500 J/kg across the
area of concern.

GOES-WV suite and AMVs denote a upper level speed max and
shortwave moving away from the area across WI, with a fairly
stationary shortwave near the low-level moisture inflection point
across central OK. The stationary wave will provide continued
maintenance of the flow with broad divergence in the 500-1000mb
thickness field across the MO/KS/OK tri-state region. So solid
upglide over the front has already supported sufficient moisture
convergence to break out convection across much of the line, deep unidirectional flow will support northeast cell moitions; yet,
persistent upstream flow suggested by the weakness in the
thickness fields suggests back-building flow regime with
propagation potentially southwest with time or nearly stationary
downdraft cores. The weakness of the flow is likely to keep the
overall coverage more scattered than a solid line, to support
longer duration of thunderstorms with rates up to 1.5"/hr initially...increasing flux/saturating profiles may increase
efficiencies locally toward 2"/hr later into the evening. While
the ground conditions are drier than normal, and hourly FFG values
are generally higher and not to be exceeded. However, given the
possible relatively stationary nature, isolated spots of 3-4"
totals may be possible and lead to possible flash flooding.

Further east (central to eastern MO), further from the upstream
shortwave, low level flow may reduce the propagation vectors have
more of an easterly component. This may reduce the duration
potential compared to further west, though orientation near the
boundary may support some repeat nature, but the FFG values are
also a tad lower too, so there is an isolated threat for flash
flooding across this area as well through 00z.

Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...EAX...ICT...LSX...OUN...SGF...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC...

LAT...LON 39259132 39169028 38359024 37689132 36959324
36369581 36199693 36649735 37139715 37729592
38029501 38799297


* SLMR 2.1a * Answers: $1 æ Correct answers: $5 æ Dumb looks: Free! Ã
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 091618
FFGMPD
MDZ000-VAZ000-NCZ000-092030-

Mesoscale Precipitation Discussion 0727
NWS Weather Prediction Center College Park MD
1217 PM EDT Wed Sep 09 2020

Areas affected...Southern Central MD...Eastern/Southeastern
VA...ext North-Central NC...

Concerning...Heavy rainfall...Flash flooding possible

Valid 091615Z - 092030Z

SUMMARY...Flash flooding threat to continue, upstream
redevelopment possible.

DISCUSSION...Strong early morning warm advection off the Atlantic
produced strong convection within the 9-8H confluence axis that
extends from a weak 7H shortwave near RAH. CIRA LPW denotes very
deep moisture even above 7H with this WAA regime presenting very
moist environment with coastal RAOBs of 2.1" at WAL and 2.4" at
MHX indicative of this environment. Surface temps have been high
enough throughout the morning to support MLCAPES over 1500 J/kg
even with near moist adiabatic lapse rates, providing the
convective vigor needed for highly efficient shallow tropical
thunderstorms. GOES-E Visible shows the cauliform nature of this
development with recent uptick noted as the cells continue to
advance slowly westward, particularly nearer the shortwave. The
WV suite shows an ideally anticyclonically arched jet streak
across the Mid-Atlantic with the right entrance to the 50-60kt 3H
jet ideally oriented over the VA Coastal Plain, providing solid
outflow to maintain/enhance the updrafts. As such, cells will
continue to be capable of 2.5-3"/hr rates, these rates continue to
produce localized flash flooding concerns eclipsing even the
hourly FFG.

Weak surface wedge over the Piedmont is eroding a bit, to allow
for slight westward increase in propagation of the cells, which
may reduce some extreme totals as noted in Isle Wight and Surry
counties this morning. However, continued strong onshore flow
remains with frictional convergence from 20-25kts to 5-10kts and
some increased solar insolation to support additional upstream
development. As such flash flooding is considered likely more of
a continuation for areas affected earlier this morning. With
time, the right entrance of the jet will continue to lift north
and then northeast, expanding the risk further north into S MD by mid-afternoon.

Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...AKQ...LWX...RAH...

ATTN...RFC...MARFC...SERFC...NWC...

LAT...LON 38827660 38257635 37917616 37147615 36727649
36457698 36027748 35997838 36427861 37147832
37757808 38487736
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 101649
FFGMPD
NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-DCZ000-102248-

Mesoscale Precipitation Discussion 0736
NWS Weather Prediction Center College Park MD
1248 PM EDT Thu Sep 10 2020

Areas affected...Mid-Atlantic to New Jersey and NYC area

Concerning...Heavy rainfall...Flash flooding possible

Valid 101648Z - 102248Z

Summary...Tropical moisture in place across the region will result
in heavy downpours at times through the afternoon. Hourly rain
totals up to 2" will be possible with localized 3-5" amounts. This
could lead to flash flooding, particularly over urban and other
sensitive areas.

Discussion...The surface trough associated with the tropical
moisture/wave that has been slowly moving inland today now is
draped along the I-95 corridor from near Richmond to DC/Baltimore
to west of Philadelphia. This is along an instability gradient and
differential heating boundary likely associated with early morning
convection that moved through portions of MD/DE/NJ/NY. With
instability now building into the 2000-2500 J/kg range from
daytime heating, deeper convection has developed per recent radar
imagery and cooling clouds seen in IR. The deep, anomalously high
tropical moisture remains in place with PWs as high as 2.3-2.5"
across portions of the region.

The latest hi-res guidance including the last few runs of the HRRR
are signaling for the highest rainfall this afternoon to fall
along the highly urban corridor from near DC to Baltimore to
central NJ. This is where the HREF prob for 5" is the highest
(20-50 perecent) and matches up well with a weak vort max that is
working through eastern VA right now. So the expectation is for a
blossoming of convection this afternoon that will be capable of
producing hourly totals up to 2" at times and generally will be
slow-moving (mean flow parallel to storm motions) or repeating in
places. Localized 3-5" totals will be possible given the
environment and storm motions. With the potential for this type of
rainfall over a highly urban corridor and other sensitive areas
including those with low FFG due to recent rainfall, some
localized flash flooding will be possible into the afternoon.

Taylor

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...AKQ...CTP...LWX...OKX...PHI...

ATTN...RFC...MARFC...NERFC...NWC...

LAT...LON 41187446 40727333 39117503 37697584 37307620
37587687 38887748 39817683 40817533
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 110018
FFGMPD
VAZ000-NCZ000-110300-

Mesoscale Precipitation Discussion 0739
NWS Weather Prediction Center College Park MD
818 PM EDT Thu Sep 10 2020

Areas affected...Eastern North Carolina and Far Southeast Virginia

Concerning...Heavy rainfall...Flash flooding possible

Valid 110016Z - 110300Z

Summary...Tropical moisture in place across the region will allow
for torrential downpours from storms which develop throughout the
evening. Hourly rain totals up to 2" will be possible with
localized 2-4" amounts. This could lead to flash flooding,
particularly over urban and other sensitive areas.

Discussion...Thunderstorms were developing over from eastern North
Carolina into far southeast Virginia as of 00Z in a region where
surface dewpoint temperatures were generally in the upper 70s, and
where moisture flux convergence was maximized within an axis of
maximum instability (as shown by MU/ML CAPE values of 2000 J per
kg to 3000 J per kg). This environment has supported isolated
rainfall rates in excess of 2 inches earlier in the day and should
still be able to produce some 2 to 4 inch rainfall amounts until
the atmosphere becomes worked-over later this evening.

HREF probability of 3-hour rainfall amounts exceeding 3 inches was
maximized in northern/northeaster North Carolina through 03Z and
then weakens and translates northeast later tonight. The RAP also
was suggestive of the current up-scale growth losing momentum
followed by a decrease in both the areal coverage of convection
and in the maximum rainfall rates.

This indicates that flash flooding will be possible through the evening...especially in highly urbanized areas and in areas with
low Flash Flood Guidance due to recent heavy rainfall.

Bann

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...AKQ...ILM...MHX...RAH...

ATTN...RFC...MARFC...SERFC...NWC...

LAT...LON 37327640 36847612 35607633 34197782 34217836
35347821 36657780 37227710
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 121146
FFGMPD
FLZ000-121745-

Mesoscale Precipitation Discussion 0741
NWS Weather Prediction Center College Park MD
745 AM EDT Sat Sep 12 2020

Areas affected...Florida Keys and Ext. Southern Peninsular
Florida...

Concerning...Heavy rainfall...Flash flooding possible

Valid 121145Z - 121745Z

SUMMARY...Tropical Depression 19L relatively stationary southeast
band.

DISCUSSION...Current GOES-E satellite and regional RADAR trends
continue to depict TD 19 developing as the circulation begins to
roll southwestward within the parent wave through Florida Bay.
This is enhanced by diurnal enhancement of offshore convective
development particularly along the SE quadrant of the circulation
which is generally aligned with the chain of the Florida Keys.
CIRA LPW loops show with this vortex roll up increased moisture
flux convergence through a solid vertical depth (tilted ever so
slightly toward the SE) currently focused at the apex of the
Florida Bay and Key Largo. This is accounting for over 2.5" of
total precipitable water but with solid directional flux
convergence, there has been recent uptick in convective activity
along and southeast of the Keys with a new band of shallower
convection forming on the inside as well. While instability is
limited to about 500-750 J/kg given deep moist adiabatic lapse
rates, it is sufficient to develop deep convection to -70C and
-80C tops with some lightning present. Given this and the flux,
hourly rain rates of 2.5-3"/hr are likely with higher sub-hourly
rates likely. While the Keys do not flash flood per se, the
intense rate will lead to inundation flooding particularly along
culverts and streets enough to be hazardous. The uncertainty is
as it is always in the thunderstorms being able to pinpoint the
narrow strips that are the Keys.

Hi-Res CAMs including the rapidly refreshing RAP, HRRR and HRRRv4
all generally strong in depicting the development of the outside
(southeast) rainband. Given the westward, maybe south of due
westward in the development phase of the surface circulation to
the natural flow along the SW FL coast, there is strong signal
from nearly all (particularly the HRRR, 00z ARW2 to have the band
set up close enough to the islands with persistent rates for
pockets of 4-6" with some suggestion of even higher totals to 8"
through 18z. Normally, this kind of consensus and rainfall
rate/total would yield likely flash flooding conditions; however,
as mentioned above, the nature of flash flooding in the Keys as
well as the precision of hitting such a small target.

Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...KEY...MFL...

ATTN...RFC...SERFC...NWC...

LAT...LON 25728092 25678048 25418024 24898040 24508129
24388186 24418216 24648230 24748192 24878147
25028127 25388126 25618129
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 121822
FFGMPD
TNZ000-ALZ000-MSZ000-122330-

Mesoscale Precipitation Discussion 0743
NWS Weather Prediction Center College Park MD
221 PM EDT Sat Sep 12 2020

Areas affected...Northern MS...Western/Central TN...Far Northwest
AL...

Concerning...Heavy rainfall...Flash flooding possible

Valid 121820Z - 122330Z

SUMMARY...Slow moving, highly efficient cells pose a flash
flooding risk through evening hours. Some potential for
back-building and training environments locally further enhance
this potential.

DISCUSSION...WV suite depicts south-southwest to north-northeast
corridor of fairly unidirectional flow, across the Southern Plains
to the Great Lakes, a narrow stripe of dry air demarcates the
western edge of return deeper tropical moisture air around the
sub-tropical ridge axis. CIRA LPW shows the slug of increasing
moisture through the 850-5H layers along this periphery where
confluence continues to tighten the corridor. Given proximity
from the deeper closed low, the flow is very weak (less than 20kts
through the bulk of the troposphere) resulting in slow cell motion
environment. With that stated, the right entrance to the
northward moving jet axis has provided peripheral favorable
ascent. Given the strong 7H moisture gradient over NW TN, there
is an effective warm front that has been the focus of increased
convergence to spark convection in this weak flow environment.
Given the lower profile is also saturated enough resulting to
2-2.25" total PWAT values and FGZ levels AoA 16Kftm, suggesting
deep warm cloud layer and efficient rainfall generation processes.
Given cell motions are 5-10kts but with weak propagation vectors
(0-5kts) toward the east, duration of heavy rainfall is likely
suggesting localized pockets of 3-4" are possible. This would
near the 3hr FFG values in the region, suggesting flash flooding
is possible, particularly further north and east in the area of
concern (given lower FFG values).

Currently there is some additional concerns that the orientation
of convection across NW MS into SW TN is oriented favorably for
training even though the cell motions are slow. However, some
upper-level dry air entrainment may help for cold pool generation,
and similar to this morning's weaker cells along the MS River,
there appears to be some outflow boundaries generating and should
result in eastward propagation to help reduce the flash flooding
threat a tad.

Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...HUN...JAN...MEG...OHX...

ATTN...RFC...LMRFC...OHRFC...SERFC...NWC...

LAT...LON 36508734 36468645 35498669 34188855 33458997
33519090 34329061 34929008 35418930 35888827
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 130958
FFGMPD
FLZ000-131500-

Mesoscale Precipitation Discussion 0748
NWS Weather Prediction Center College Park MD
558 AM EDT Sun Sep 13 2020

Areas affected...South Florida and the Florida Keys

Concerning...Heavy rainfall...Flash flooding possible

Valid 130957Z - 131500Z

Summary...Heavy rainfall associated with Tropical Storm Sally will
continue to advect into South Florida and the Florida Keys.
Rainfall rates of 2-3"/hr at times are likely. Some locations have
already received in excess of 5" of rain this morning. Additional
heavy rain may lead to flash flooding.

Discussion...Tropical Storm Sally clearly evident on GOES-E WV
imagery this morning is lifting northwest away from the Central
Florida Gulf Coast. Despite Sally's motion away from Florida,
heavy rainfall continues to plague parts of the Southern
Peninsula. The Lower Keys, Everglades, and Sun Coast are beneath
the central dense overcast (CDO) according to satellite and radar
imagery, while the Gold Coast has experienced several rounds of
convergent spiral bands moving onshore. While Sally moves further
away this morning, the overall setup across South Florida will
change little.

Rainfall rates have been estimated as high as 2-3"/hr from local
radars, but are likely higher than that in some of the stronger
convective cores. These heavy rain rates are occurring in an
environment characterized by PWs of 2.25-2.5" as measured by
recent GPS observations, and MUCape analyzed by the RAP to be
1000-1500 J/kg, highest along the coasts. This environment is
expected to persist through the late morning as deep SE flow east
of T.S. Sally continues to advect high low-level PW towards
Florida. This is evident on LPW fields with a PW max east of the
Peninsula between 850-700mb which will allow convective bands to
develop within any modest convergence, and advect onshore.

There are likely to be two focused areas of heavy rainfall which
may lead to flash flooding. The most persistent rainfall is likely
within the CDO on the SW coast where continuous rain rates of
1-2"/hr are likely, and HREF hourly probabilities indicate a
chance for 3+"/hr at times. While the heaviest rain axis may pivot
just offshore in the region of greatest instability and as Sally
pulls away, but an additional 2-3" of rainfall with locally higher
amounts is possible. This will fall atop soils that have received
an estimated 1-4" overnight, and flash flooding will be possible.
The other area of concern is along the Gold Coast where the
periodic feeder bands move onshore. While these will likely be
strongest just offshore and on the immediate coast due to a lack
of instability across the central peninsula, they may have
excessive rain rates of 3"/hr as well, with training along the
bands likely. This occurred earlier near Miami, when more than 5"
of rain fell in just 2-3 hours. While the placement and timing of
these bands is uncertain, any band which moves onshore could
produce excessive rainfall and renewed flash flooding through late
morning.


Weiss

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...KEY...MFL...TBW...

ATTN...RFC...SERFC...NWC...

LAT...LON 27728234 27688204 27398158 27128119 26908093
26768063 26608035 26388011 26108003 25798006
25428024 25028047 24788078 24618118 24538150
24498175 24528196 24758189 24858167 25008140
25288131 25538146 25828173 26118199 26438228
27088260 27368271 27648275
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 131903
FFGMPD
TNZ000-ALZ000-MSZ000-LAZ000-ARZ000-140100-

Mesoscale Precipitation Discussion 0753
NWS Weather Prediction Center College Park MD
303 PM EDT Sun Sep 13 2020

Areas affected...portions of Lower MS Valley into south-central TN

Concerning...Heavy rainfall...Flash flooding possible

Valid 131901Z - 140100Z

SUMMARY...Slow moving thunderstorms with rainfall rates of 2-3
in/hr will continue a flash flood threat from portions of the
Lower MS Valley into south-central TN. Storm coverage is expected
to decrease toward the southwest, closer to the MS River.

DISCUSSION...GOES-E visible imagery and surface observations
showed an elongated outflow boundary at 18Z extending from
east-central TN, southwestward into north-central MS. The outflow
boundary was sinking slowly to the south and east, with
overrunning thunderstorms producing high rainfall rates from TN
into northern MS/AL with average cell motions of 10 kt or less.
Recent observations from northwestern AL showed rainfall rates of
1.4 inches in 30 minutes, supporting the potential for 2-3 in/hr
rates. Mostly clear skies to the south of the outflow boundary
have allowed MLCAPE to increase into the 1000-2000 J/kg range from
northeastern LA into northern AL, which appeared to be uncapped
given adjusted 12Z soundings at BMX and JAN, as well as RAP
analysis soundings from 17Z. Deeper layer flow is weakest, less
than 10 kt, within the instability axis and precipitable water
values ranged from 1.75 to 2.25 inches.

While weak shear is present which will limit storm residence time,
the environment is supportive of efficient rainfall production
which could be capable of 2-3 inches in an hour where storm core
repeating is maximized. Low level convergence focused on southward
sagging outflow is expected to continue numerous thunderstorm
development from eastern MS into northwestern AL and south-central
TN with 2-4 inch totals expected in the next few hours. Farther
south and west toward the MS River, storm coverage is more
uncertain, but moisture and instability are maximized near the
LA/MS border into west-central MS with potential for a quick
falling 2-4 inches given the slow storm movement. Portions of
central to northern MS received heavy rain within the past 24
hours which has left soils more susceptible to runoff, but
overall, flash flood guidance values are higher to the south and
west. Therefore, the flash flood threat should be limited for
locations closer to the MS River, while coverage is expected to be
a bit higher toward northern AL/TN.

Otto

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...BMX...HUN...JAN...MEG...OHX...

ATTN...RFC...LMRFC...SERFC...NWC...

LAT...LON 35528606 35418590 34898614 34048676 33528783
32888925 32538981 32269039 32289093 32559136
33059144 33519109 33959020 34218949 34458861
34688792 35058726 35498643
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 141639
FFGMPD
FLZ000-142030-

Mesoscale Precipitation Discussion 0755
NWS Weather Prediction Center College Park MD
1238 PM EDT Mon Sep 14 2020

Areas affected...Eastern Florida Panhandle

Concerning...Heavy rainfall...Flash flooding possible

Valid 141547Z - 142030Z

Summary...A narrow outer band of Sally will continue to spread
inland over eastern portions of the Florida Panhandle from
Apalachee Bay through the afternoon making for a heavy rainfall
and localized flash flooding threat.

Discussion...Three inches of rain have been estimated in northern
Franklin as well as southern Liberty and Calhoun counties on the
FL Panhandle from KTLH from a persistent outer band of Sally
spreading in from the Apalachee Bay. This band is drifting north
with southern Wakulla county now experiencing heavy rain. Ample
moisture is spreading in with the band with 2.3" PWs (about 2.5
standard deviations above normal) confirmed by GPS sensors. There
is an instability gradient along the shore with about 2500 J/kg
SBCAPE over the Apalachee Bay and 1500 J/kg over much of the FL
Panhandle which is contributing to diminishing rain rates as the
band shifts inland.

Rainfall of generally 1.5"/hr, but up to 2"/hr have been estimated
by KTLH and given the slow northward advancement, local areas have
received just about 3" which can be expected to continue going
forward this afternoon. Flash flood guidance is generally 3 to 4"
in 3 hours, so local exceedance of these guidance values is
possible through the rest of the afternoon as the band continues
to re-form and spread inland before slowing diminishing farther
inland (by about Washington and Jackson Co). Given the trajectory
and inflow from Apalachee Bay this band looks to remain south of
I-10 through the afternoon, but is expected to get into at least
southern portions of the Tallahassee metro where drainage issues
are anticipated.


Jackson

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...TAE...

ATTN...RFC...SERFC...NWC...

LAT...LON 30598540 30518478 30268416 29988389 29858416
29818459 30138520 30508571
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 161442
FFGMPD
FLZ000-GAZ000-ALZ000-162025-

Mesoscale Precipitation Discussion 0762...Corrected
NWS Weather Prediction Center College Park MD
1042 AM EDT Wed Sep 16 2020

Corrected for Typo

Areas affected...Southern AL...FL Panhandle...Southwest GA

Concerning...Heavy rainfall...Flash flooding likely

Valid 161425Z - 162025Z

Summary...As Hurricane Sally continues to drift to the northeast,
very heavy rains are expected near and east of the center across
the western Florida Panhandle and Lower Alabama. Meanwhile,
feeder bands east of the center continue to produce locally heavy
rains across portions of the central Florida Panhandle.
Additional catastrophic and life-threatening flooding is likely.

Discussion...Near the center, GOES imagery shows cooling cloud
tops just east and north of the center, with rainfall rate
estimates increasing across Escambria and Santa Rosa counties in
Florida. With the trends expected to continue as Sally drifts to
the northeast, additional very rainfall is likely over the next
few hours across the far western Florida Panhandle into Lower
Alabama. Operational and experimental runs of the HRRR show the
potential for additional amounts of 3-5 inches across this area
over the next 6-hrs. This of course will impact some of the areas
that have already been inundated with heavy rains.

Farther east, two significant feeder bands -- one extending north
from near Panama City and another near Apalachicola -- continue to
impact the Florida Panhandle. Eglin AFB radar (KEVX) continues to
show rainfall rates upward of 2.5 inches/hr within the core of
these rainbands as they shift slowly east across the central
Florida Panhandle. Recent runs of the operational and
experimental HRRR have shown the potential for localized 6-hr
accumulations of 3-6 inches within these bands. Here also, these
bands will continue to impact areas already impacted by heavy
amounts -- further exacerbating ongoing flooding.

Elsewhere across the highlighted region, there is a good model
signal for heavy rains extending farther north and east across
southern southern Alabama and southwestern Georgia -- with 6/hr
amounts upward of 3-inches possible.

Pereira

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...BMX...MOB...TAE...

ATTN...RFC...SERFC...NWC...

LAT...LON 32108674 31878524 30608417 29548500 30098575
30178655 30308726 30678760 30898788 31528777
31768748
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 181708
FFGMPD
ORZ000-WAZ000-182107-

Mesoscale Precipitation Discussion 0771
NWS Weather Prediction Center College Park MD
107 PM EDT Fri Sep 18 2020

Areas affected...Western Oregon

Concerning...Heavy rainfall...Flash flooding possible

Valid 181707Z - 182107Z

Summary...Showers and thunderstorms this afternoon will be capable
of producing hourly rain totals 0.5 to 1.0" at times and this
could cause flash flooding, particularly over recent burn scar
areas.

Discussion...Visible satellite imagery as of 1700Z off the
southern Oregon coast with towering cumulus seen across the
terrain areas of western Oregon. After early morning elevated
convection passed through, the approach of the stacked low
pressure system will help generate a second round of showers and
thunderstorms through this afternoon. The moisture profile is
seasonably high with recent blended TPW product showing values of
1.2 to 1.4 inches, which is about 2 STD above the climo mean. The
moist inflow of 20-25 kts is expected out of the south/southwest
through the afternoon and as the low pressure system moves
onshore, the increasing lapse rates should help yield upwards of
1500 J/kg of instability.

The 12Z HREF supports hourly totals in the 0.5-1.0" range starting
after 18Z through the late afternoon hours. Hi-res guidance
including the most recent HRRR shows isolated maximum hourly
totals of 1 to 1.5" in the strongest cores after about 20-21Z. The
drier air above 700 mb that is advecting in will likely limit the
coverage but could help with intensity (steeper lapse rates,
greater instability) and with some of the storm motions remaining
parallel to the mean flow, backbuilding or regeneration on the
south flanks of storm clusters is possible.

The greatest risk for flash flooding due to this rainfall will be
over recent burn scar areas across the Cascades, including the
Riverside, Beachie Creek, Lionshead, and Holiday Farm fires.
Elsewhere outside of burn scars, intense rain rates could still
cause issues, particularly for any urban or other sensitive area.

Taylor

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...MFR...PDT...PQR...

ATTN...RFC...CNRFC...NWRFC...NWC...

LAT...LON 45792263 45702182 45082153 43972187 42772186
42172256 42312419 44042365 44732355 45732327
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 191706
FFGMPD
FLZ000-192200-

Mesoscale Precipitation Discussion 0773
NWS Weather Prediction Center College Park MD
105 PM EDT Sat Sep 19 2020

Areas affected...Northeast Florida...

Concerning...Heavy rainfall...Flash flooding possible

Valid 191700Z - 192200Z

SUMMARY...Very efficient rain-rates up to 3"/hr possible and slow
cell motions (backbuilding) suggest rapid inundation flooding
possible through this afternoon.

DISCUSSION...16Z Surface analysis denotes a very weak surface wave
in the wind field and very tight pressure gradient at the
intersection of an old secondary cold front and the FL coast
between SGJ and DAB. Strong onshore flow behind the front
(15-20kts) with very deep moisture (over 2.25" TPW) is converging
with nearly zero flow, perhaps even weak SSWly winds. RAP
analysis suggests at this inflection deeper surface temps along
the Gulf Stream are setting low level profiles well enough for
solid instability profile (even though it is generally
saturated/moist adiabatic) with 2000-2500 SBCAPE J/kg estimated.
The combination is sparking a few very shallow convective towers
(-35C) that are now crossing the coastal zone and west of I-95.
Localized 'backyard' gauges measured .5-1" hourly totals with this
cell. Further solar insolation south of the cloud boundary from
Marion to Flagler county would suggest further vertical growth and
potential for extreme rain rates (over 3"/hr) are becoming
possible.

The concern here even along/north of the boundary where
insolation/surface temps are lower, continued/strong upstream
convergence enhanced due to friction at the coast line will keep a
potential for back-building/regeneration upstream with very slow
southward drift of the old frontal boundary southward. Steering
winds above the boundary layer are quite weak with southwesterly
flow above 7H, combine this with backbuilding may keep downdrafts
very slow moving allowing for compounding totals. Rainfall
gradients should be very tight, so areal coverage of excessive
rainfall should be limited but within those smaller areas, rapid inundation/flash 'ponding' conditions are possible which is of
great concern along the urbanized core along I-95, though concerns
eastward into the more rural central peninsula is not without risk
but higher FFG values suggest threat may be a bit less.

The HRRR and HRRRv4 seem to be handling the evolution of the
current convective pattern though this is very early toward the
expected deeper convection development in the next hour or so.
While the HRRR has been hinting at localized totals of greater
than 6" through 21z, the overall suite is more suggestive of 3-4"
totals, denoting the nearly permanent uncertainty of small
thunderstorms and slow/stationary cell motions and hitting very
sensitive urban centers/watersheds.


Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...JAX...MLB...

ATTN...RFC...SERFC...NWC...

LAT...LON 30078145 29998129 29628113 29268097 29058090
28908131 28958184 29228218 29658215 29958177
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 202115
FFGMPD
FLZ000-210300-

Mesoscale Precipitation Discussion 0775
NWS Weather Prediction Center College Park MD
514 PM EDT Sun Sep 20 2020

Areas affected...Central FL

Concerning...Heavy rainfall...Flash flooding possible

Valid 202110Z - 210300Z

SUMMARY...Scattered bands of very heavy showers and thunderstorms
may result in at least some localized flooding concerns going
through the evening hours.

DISCUSSION...The afternoon GOES-16 visible satellite imagery,
along with surface observations and radar, shows a rather
well-defined area of low pressure west of Lake Okeechobee that is
focused along a frontal zone that is gradually settling down to
the south. Meanwhile, there is a rather well-organized narrow band
of convection seen wrapping around the northern and eastern flanks
of the low center as the low moves generally off to the west.
Elsewhere, additional clusters of cold-topped convection are seen
west of Melbourne and also over the offshore Atlantic waters east
of Melbourne.

The low center and proximity of the front are collectively
fostering an axis of rather strong low-level moisture convergence
and forcing, which in part is being aided by a strong surge of
northeasterly low-level flow dropping down across central and
northern FL. PWs across the region are very high and indicative of
a tropical airmass with values of 2.3 to 2.5 inches, and the
airmass pooled along the front is moderately unstable with MLCAPE
values of 2000+ j/kg.

Rainfall rates with the associated shower and thunderstorm
activity are consequently very high given the favorable
thermodynamic environment, and even though the convection coming
into the east coast of FL has been quite progressive, there have
been some very efficient rainfall processes resulting in hourly
rainfall amounts of 1.5 to 2 inches. Meanwhile, with the
aforementioned convective band closer into the low center, there
has been some training of this activity over the same area which
has already resulted in some dual-pol QPE amounts of 3 to 4 inches
over the last couple of hours.

Overall, the experimental HRRR appears to have a reasonably good
handle of the ongoing activity, and this guidance tends to support
some additional rainfall amounts of 3 to 4+ inches going through
03Z (11pm EDT). In time the front should settle further south
which will generally favor the convection focusing farther south
as well going into the overnight hours. The gradual loss of
daytime heating/instability should at least allow for the coverage
of convection to also decrease some after 00Z.

Nevertheless, given such high short-term rainfall rate potential
and also localized training concerns, some pockets of flooding
cannot be ruled out.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...MFL...MLB...TBW...

ATTN...RFC...SERFC...NWC...

LAT...LON 28278067 27758031 27308033 27018059 26998107
26978190 27158235 27498251 27908234 28258160
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 211601
FFGMPD
TXZ000-212100-

Mesoscale Precipitation Discussion 0778
NWS Weather Prediction Center College Park MD
1201 PM EDT Mon Sep 21 2020

Areas affected...Middle Texas Coast

Concerning...Heavy rainfall...Flash flooding possible

Valid 211600Z - 212100Z

Summary...Heavy rainfall associated with Tropical Storm Beta is
spreading onshore the Middle Texas Coast. Rain rates of 1-1.5"/hr
have been estimated by local radars, and training of these heavier
echoes are likely through the morning. The heaviest rainfall is
expected along the immediate coast where 2-3" of rain with locally
higher amounts is possible. This may produce flash flooding.

Discussion...Tropical Storm Beta is rotating near the Middle Texas
Coast this afternoon, with a slow northwest motion analyzed by
NHC. GOES-E visible imagery shows expansive cloud cover
enshrouding much of the Texas Coast and into LA, with the central
dense overcast (CDO) just southeast of Matagorda Bay. This CDO is
being somewhat interrupted by dry air rotating all the way around
Beta from the NW, evident both on 700-300mb LPW fields, and also
as a clearing in the visible imagery approaching the TX/LA border.
On the NE periphery of this CDO, bands of rain have been
developing with embedded convective elements, likely due to local
enhancement in instability and forcing along the differential
heating boundary. These convective elements have produced rainfall
rates estimated above 1.5"/hr from KHGX WSR-88D, lifting onshore
south of Galveston Bay. While rainfall this morning has been
generally light, 1-2" in the last 12 hours according to MRMS,
heavier rain has developed recently offshore and is likely to
spread inland this aftn.

PWs across the region are anomalously high, measured by GPS to be
2.25-2.5", with similar observations on the local 12Z U/A
soundings. These values are well above the 90th percentile
according to SPC sounding climatology, and approaching the 99th
percentile on NAEFS ensemble tables. Although very dry air is
evident above 400mb in the U/A soundings, the lower 2/3 of the
profile is indicative of tropical rain processes with deep
saturation, freezing levels above 16000 ft, weak moist adiabatic
lapse rates, and LI's of -4 or less. The limiting factor to heavy
rain has been a relative dearth of instability due to widespread
cloud cover, and RAP MUcape above 500 J/kg has so far been
confined to just the immediate coast. However, 850mb winds around
T.S. Beta have increased to 35-45 kts, which will continue to
transport moisture and instability onshore. These strengthening
winds combined with increasing upper diffluence within the RRQ of
a 50kt jet streak, and the likelihood that drier air rotating
around Beta will enhance instability to the E/NE, suggests that
rainfall rates will intensify through the aftn, and spread more
efficiently inland.

HREF probabilities indicate that 2"/hr rain rates may spread
onshore during the next few hours. Although individual cell
motions will be quick to the W/NW, Corfidi vectors opposed to the
mean wind and at slow speeds suggest backbuilding of the more
intense reflectivity into the better instability, with training
then occurring onshore. The high-res CAMs depict a narrow corridor
of 2-3" of rain is likely, with isolated higher amounts. FFG
across this area is relatively high, 2.5-3.5"/3hrs, but where
training of these 2"/hr rain rates can occur, flash flooding will
be possible.

Weiss

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...CRP...HGX...

ATTN...RFC...WGRFC...NWC...

LAT...LON 29649536 29619505 29509487 29319487 29159501
29079515 28939534 28799562 28649588 28519612
28429630 28379651 28479665 28689667 28939657
29199642 29399619 29529595 29629567
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 222314
FFGMPD
TXZ000-230430-

Mesoscale Precipitation Discussion 0783
NWS Weather Prediction Center College Park MD
714 PM EDT Tue Sep 22 2020

Areas affected...Greater Houston Metro and around Galveston Bay

Concerning...Heavy rainfall...Flash flooding likely

Valid 222138Z - 230430Z

Summary...Rain bands spiraling onshore east of the center of T.D.
Beta will continue to redevelop over the greater Houston Metro
Area and to the east of Galveston Bay. This will likely exacerbate
ongoing flash flooding across parts of Houston where 5 to 15" have
fallen in the past 36 hours as well as possibly cause new flash
flooding elsewhere. Rainfall rates of 1.5"/hr should continue
through the evening.

Discussion...The center of Beta is apparent in visible satellite
and 23Z surface obs as just northeast of Matagorda, TX moving ENE.
Along and east of the center, PWs were analyzed by GPS sensors to
be 2.1 to 2.3" east of the storm center along the upper TX coast.
A gradient is noted in SBCAPE from about 2000 J/kg near Beaumont
to about 1500 J/kg over Houston. Onshore low level flow of 20 to
25 kt per Houston area VPSs are supporting a few spiral bands in
greater the Houston area with localized one hour rainfall up to
1.5". A few cells have redeveloped in the immediate Houston urban
area over the past couple hours as they passed over a warm front
over the southern Houston metro which is also where 5 to 15" rain
fell over the past 36 hours with ongoing flooding.

As Beta slowly shifts ENE just inside the coast, the environment
is likely to remain favorable for at least locally heavy rainfall.
Rainfall locally reaching 1.5"/hr and 6hr rainfall locally
exceeding 3" through the rest of the evening is progged by recent
HRRRs and the 18Z 3kmNAM to be over Houston and areas a little
east of Galveston Bay which is in agreement with recent radar
trends and the presence of this warm front. This is likely to
expand or enhance ongoing flash flooding across this region with
the potential for repeating activity in the bands to form new
areas of flash flooding.

Jackson

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...HGX...LCH...

ATTN...RFC...WGRFC...NWC...

LAT...LON 30209531 30209483 29729421 29449460 29209503
29099534 29599600 29989585
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 250927
FFGMPD
ORZ000-WAZ000-251500-

Mesoscale Precipitation Discussion 0795...Corrected
NWS Weather Prediction Center College Park MD
526 AM EDT Fri Sep 25 2020

Corrected for Jet Level/Strength in Discussion/Graphic.

Areas affected...Western Washington...Northwest Oregon...

Concerning...Heavy rainfall

Valid 250820Z - 251500Z

SUMMARY...Fast moving slug of moisture at nose of deep moisture
plume along with strong dynamic forcing pose quick-hitting heavy
rainfall (3-5") threat across the Olympic Range into the Northern
Cascades through daybreak.

DISCUSSION...CIRA Layered PW shows nose of deep, laminar moisture
plume nosing across 130W at this time, with the 850-7H nose
preceding ever so slightly the surface to 850mb and even upper
level layers. Core moisture is running about 1.5" total though
that core is not likely to reach the NW coast until later morning,
as dynamic forcing will flux the moisture northward along/ahead of strengthening height-falls. GOES-WV suite denotes this very well
with lead stronger shortwave near 49N130W starting to anchor and
pivot with strong broad (about 75-90 degrees) of diffluent flow.
The core of the 100kt 3H jet is anticyclonically arched west of
140W and is digging to sharpen the base of the trailing
shortwave/trof axis. This accelerating/amplifying inflection will
rapidly increase low level cyclonic response and low level flow.

Strong Southwesterly flow with rapidly increase from 30kts at
850mb to around 50-60kts near 12-13z, providing that strong isentropic/orographic ascent across the Olympic range. But given
positive to neutral to possibly negative tilting of the inflection
of the trof in diffluent flow will rapidly increase divergence
aloft and support very strong vertical ascent. This will be
maximized with as sharp veering convergence flow to come ashore in
the 13-14z time frame. Combined with total PWATs increasing from
1.25 to near 1.5", flux convergence is likely to support .75"/hr
rates along this north-northeast to south-southwest axis, this
without thermal instability fields with less than 100 J/kg
forecast in this warm conveyor belt surge. Adding favorable SW
to W orographic ascent in the Olympics at 50-60kts may add .5"/hr
rates as suggested by the broad suite of Hi-Res CAMs including the
RAP/HRRR. While this area is not typically prone to flash
flooding (due to limited infrastructure in the frequently
inundated flow channels), rapid rises should be expected though
due to 3-5" totals across the Olympics by 15z (1.5-2.5" for lower
coastal ranges of SW WA into NW OR). HREF Probabilities are
running about 80-90% of 3" exceedance by 15z providing solid
confidence in timing/rainfall totals. Due to the orientation of
the forcing, the wave will also start to affect the Northern WA
Cascade Range by 15z as well with the start of .5-.75"/hr rates,
with HREF 2" totals reaching 60-75% by 15z as well.

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...PQR...SEW...

ATTN...RFC...NWRFC...NWC...

LAT...LON 49112206 49032130 48172135 47472176 47382234
46852289 45812275 45062308 44902379 45162420
46212429 47222453 47882479 48392496 48422420
48282367 48392337 48622325 48942310 49082270
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 281916
FFGMPD
FLZ000-290100-

Mesoscale Precipitation Discussion 0801
NWS Weather Prediction Center College Park MD
315 PM EDT Mon Sep 28 2020

Areas affected...Southern and Central Florida Peninsula

Concerning...Heavy rainfall...Flash flooding possible

Valid 281915Z - 290100Z

Summary...Increasing coverage of showers and thunderstorms across
the Florida Peninsula will create a flash flood risk into the
evening. Rainfall rates may exceed 2"/hr at times. Slow motion of
these rain rartes to the E/NE could produce 2-4" of rainfall with
locally higher amounts. Flash flooding is possible.

Discussion...GOES-E 10.35 micron IR imagery this aftn indicates
pockets of rapidly cooling cloud tops across the southern and
central Peninsula of Florida. These cooling tops are associated
with expanding and deepening thunderstorms evident on the regional
radar mosaic. The environment across much of FL is extremely
favorable for heavy rainfall. PWs as measured by GPS observations
are approaching 2.25", above the 90th percentile according to the
NAEFS ensemble table, and SBCape as analyzed by the 18Z RAP has
eclipsed 3500 J/kg across much of the southern half of the state.
This environment are being impinged upon by a 50kt jet streak
across N FL developing ahead of a deepening and eastward advecting
long wave trough, producing modest height falls and a weak
divergence maxima overhead to drive deep layer ascent.

The extremely favorable thermodynamics are allowing for heavy
rainfall rates despite overall modest forcing. Recent rain rate
estimates from KMLB and KAMX are exceeding 1.5"/hr, and the HREF
hourly probabilities indicate these may climb above 2"/hr at times
this aftn. Although 850mb inflow is weak at 5-10kts from the Gulf
of Mexico, this is roughly equal to the 0-6km mean wind, and with
synoptic flow out of the W/SW, a pinned east coast sea breeze is
likely where storm mergers may occur. Propagation vectors aligned
with the mean flow indicate the likelihood for cell training, and
with slow motions expected, and cell mergers likely near the east
coast, heavy rainfall amounts of 2-4" are forecast by many of the
available CAMs.

During the past week, much of this area has seen below normal
rainfall, although a few pockets have received >200% of normal.
This has led to FFG which is generally 3"/1hr and 4"/3hrs. With
rain rates rising above 2"/hr and slow storm motions of 5-10 kts
to the E/NE likely, some exceedance of these values are possible
as echoed by the HREF indicating a 50% chance for the 3-hr FFG.
Flash flooding will be most likely should this heavy rainfall
occur atop the pockets of higher antecedent soil moisture or in
any urban areas, but anywhere along the pinned sea breeze where
storms may briefly stall or regenerate in place could produce
flash flooding.


Weiss

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...JAX...MFL...MLB...TBW...

ATTN...RFC...SERFC...NWC...

LAT...LON 29688123 29158089 28588060 28178054 27628032
27228016 26978007 26708009 26498015 26288030
26218043 26198058 26258079 26358102 26568113
26798145 26988157 27488173 28048186 28528191
29108176 29508158
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 011550
FFGMPD
FLZ000-012045-

Mesoscale Precipitation Discussion 0806...Corrected
NWS Weather Prediction Center College Park MD
1149 AM EDT Thu Oct 01 2020

Corrected for Description of the MPD area

Areas affected...Southeast and east central FL

Concerning...Heavy rainfall...Flash flooding possible

Valid 011545Z - 012045Z

Summary...Thunderstorms tracking onshore across southeast FL this
afternoon could produce hourly rainfall rates of 2.00 inches over
areas that saw heavy rainfall earlier this morning. This could
pose a flash flood threat through this afternoon hours.

Discussion...Regional radars over southeast FL are showing a slow
increase in convective coverage along the coast from Fort Pierce
to just east of Miami late this morning. The storms are developing
in an area of 1500/2500 J/KG of SBCAPE (per 12z soundings/most
recent RAP analysis), with a sharp cutoff to the instability north
of the Space Coast. While the GOES-16 clean IR loop showed little
in the way of cooling with the developing storms, the visible loop
showed towers lining up east Fort Pierce.

Deep moisture in place (with precipitable water values between
2.00/2.25 inches, which is about two standard deviations above the
mean) is capable of supporting hourly rainfall rates in excess of
2.00 inches, though the KMLB radar is showing rates closer to 1.50
inches north of White City. The storms are tracking westward
toward the coast with the low level flow, with storm motions
generally less than 10 knots.

The areal coverage of the storms is expected to increase as short
wave energy over the eastern Gulf of Mexico moves slowly eastward,
providing weak synoptic scale ascent over the region. Mid level
flow ahead of the short wave could allow storms to train or
backbuild during the afternoon, and where this occurs, hourly
rainfall rates could exceed 2.00 inches (per the most recent HRRR
runs).

Recent HRRR runs (supported by the experimental HRRR) showed local
6.00 inch rainfall amounts from south of Vero Beach to near Palm
Beach through 01/2000z. Portions of this area (especially from
Fort Pierce to north of West Palm Beach) saw local 3.00/5.00 inch
rainfall amounts with storms earlier this morning, and the
additional rainfall could cause flash flooding.

The limiting factor here could be overall convective coverage, as
the low level push could bring storms further inland away from
areas that got hit hard this morning. Given the deep moisture
plume in place, and the early morning heavy rainfall, flash
flooding is considered possible this afternoon.

Hayes

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...MFL...MLB...

ATTN...RFC...SERFC...NWC...

LAT...LON 27888061 27788039 27738037 27238014 26808002
26538003 26308004 26038012 26288044 26568061
26918076 27248082 27508092 27698088 27858079
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 092046
FFGMPD
MSZ000-LAZ000-TXZ000-100245-

Mesoscale Precipitation Discussion 0815
NWS Weather Prediction Center College Park MD
446 PM EDT Fri Oct 09 2020

Areas affected...eastern TX...southwestern to northeastern LA

Concerning...Heavy rainfall...Flash flooding likely

Valid 092045Z - 100245Z

SUMMARY...The core of the heaviest rain associated with Hurricane
Delta will move inland across southwestern into central LA over
the next 3-6 hours along with likely flash flooding. Some flash
flooding could be significant given an additional 4-8 inches
through 03Z, overlapping with heavy rain which fell over the past
24 hours near Alexandria.

DISCUSSION...NHC estimated Hurricane Delta to be roughly 50 miles
south of Cameron, LA at 20Z, with a movement off toward the NNE at
12 kt. GOES East 10.3 micron imagery showed the coldest cloud tops
over the TX and LA coasts with values ranging between -75 C and
-90 C. This region of coldest cloud tops, stretching from near
Winnie, TX to Lafayette, LA, has been associated with observed
rain rates between 0.5 and 1.5 in/hr ending at 20Z. KHGX and KPOE
reflectivity indicated the northern eyewall of Delta was just
starting to make landfall into Cameron and Vermilion parishes.

The current track and speed of Delta will take its center toward
Alexandria through 06Z. Expect rainfall rates with, and just north
of, Delta's eyewall to be in the 2-3 in/hr range. Rainfall rates
up to 1-2 in/hr can be expected to the immediate west and east of
Delta's inner core. Delta's forecast track places the highest
rainfall over the next 6 hours along a swath that overlaps with a
region of heavy rainfall (4-6 inches) which fell over the past 24
hours just southwest of Alexandria. Widespread flash flooding,
some of which could be significant, is expected into the early
overnight hours as Delta moves inland across southwest to central
LA. Some local enhancement to rainfall will also be possible from
southwest to northeast across the central TX/LA border in
association with a forecast low level convergence axis expected to
set up between 00Z-03Z.

Farther east, just northeast of Baton Rouge, 5 to 10 inches of
rain was reported through this morning. While this area is
certainly sensitive to flash flooding from added rainfall, it
appears the track and heaviest rainfall from Delta will pass west
of the 5 to 10 inch area, with additional forecast rainfall in the
1-2 inch range in the vicinity of Baton Rouge.

Otto

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...HGX...JAN...LCH...LIX...SHV...

ATTN...RFC...LMRFC...WGRFC...NWC...

LAT...LON 32729171 32649142 32429127 32169117 32049108
31719100 31489098 31279096 30989089 30719087
30509083 30389100 30479137 30199168 29479241
29559321 29479426 29939437 30809427 31619379
32019344 32279291 32479250 32719203
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 281651
FFGMPD
TNZ000-ALZ000-MSZ000-282245-

Mesoscale Precipitation Discussion 0833
NWS Weather Prediction Center College Park MD
1250 PM EDT Wed Oct 28 2020

Areas affected...Northeast MS...Northwest AL...South-Central TN

Concerning...Heavy rainfall...Flash flooding possible

Valid 281645Z - 282245Z

SUMMARY...Heavier showers and thunderstorms may tend to become a
bit more concentrated this afternoon well north of Hurricane
Zeta's approach on the north-central Gulf Coast. There will be a
gradual increase in runoff concerns and the potential for some
flash flooding.

DISCUSSION...The latest surface analysis shows a quasi-stationary
front draped down across the TN Valley and into the lower MS
Valley. Meanwhile, the latest GOES-WV imagery suite shows a very
well-defined closed mid-level low center and associated trough
slowly ejecting east out across the southern High Plains.

Downstream of this energy is an increasingly favorable zone of
right-entrance region upper-jet dynamics that is covering much of
the lower MS Valley at this point and is gradually overspreading
the TN Valley. This is generating an uptick in large scale ascent
over the region which coupled with a gradual increase in very
moist and relatively unstable low-level flow intersecting the
front is resulting in a broken axis of locally heavy showers and
thunderstorms. Radar imagery shows some of the heaviest/focused
areas of convection lifting north across east-central to northeast
MS within a zone of relatively enhanced low-level convergence.

Over the next several hours, there will likely be a tendency for
the convection to become a bit more widespread and focused along
the aforementioned front as the southerly low-level jet increases
ahead of Hurricane Zeta's approach on the north-central Gulf
Coast. Strengthening speed convergence near the front, a continued destabilization of the boundary layer through modest solar
insolation, and also additional strengthening of upper-level jet
dynamics all point to convection becoming a bit more robust and
organized with a trend toward heavier rainfall rates.

The PW environment, with values of 2 to 2.25 inches, will favor
efficient rainfall processes, with rates likely reaching as high
as 1.5+ inches/hr given the uptick in instability and moisture
transport. The last couple of runs of HRRR suggest additional
rainfall amounts of as much as 3 to 4 inches of rain going through
21Z, with some of the heaviest focus across areas of northeast MS
and perhaps brushing up across far northwest AL and near the
border with south-central TN.

In general, there has locally been as much as 2 to 4 inches of
rain over the last 12 hours, and the additional rainfall this
afternoon will increase the concerns for runoff problems and
potentially some flash flooding.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...BMX...HUN...JAN...MEG...MRX...OHX...

ATTN...RFC...LMRFC...OHRFC...SERFC...NWC...

LAT...LON 35868536 35578519 35238563 34618688 34068764
33608798 33338841 33368881 33888918 34298936
34878919 35208862 35438808 35618739 35858634
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 281846
FFGMPD
MSZ000-LAZ000-290043-

Mesoscale Precipitation Discussion 0834
NWS Weather Prediction Center College Park MD
244 PM EDT Wed Oct 28 2020

Areas affected...South-Central to Southeast LA...Southern MS

Concerning...Heavy rainfall...Flash flooding likely

Valid 281843Z - 290043Z

SUMMARY...Hurricane Zeta approaching southeast LA with very heavy
rainfall. The threat of flash flooding will increase this
afternoon and evening leading up to and just after landfall.

DISCUSSION...The latest GOES-16 IR 1-minute satellite imagery
shows a rather well-defined eye associated with CAT-2 Hurricane
Zeta as the storm accelerates north-northeast toward southeast LA.
Some very cold cloud tops are seen with the northern eyewall of
Zeta, and the New Orleans (KLIX) radar confirms some very intense
convection.

Heavy rainfall and embedded bands of convection north of Zeta are
beginning to advance onshore across southeast LA, and conditions
will be rapidly deteriorating over the next few hours as more
concentrated heavy rains associated with Zeta's central core begin
to arrive. A 1627Z AMSU pass captured some of the heavier rainfall
rates evolving in Zeta's northern eyewall and showed hourly rates
of near 1.75 inches/hr. However, since then the hurricane has
become even better organized with colder cloud tops, and most
likely heavier rainfall rates that are exceeding 2 inches/hr.

Zeta will continue to quickly advance north-northeast toward
southeast LA this afternoon and should make a landfall in between
21Z and 00Z. The latest HRRR-based guidance supports rainfall
amounts of 2 to 4 inches with isolated heavier amounts going
through 00Z, and while they heaviest rainfall over the next
several hours will be over southeast LA, the heavier rains will be
quick to advance into southern MS near and just after 00Z.

The threat for areas of flash flooding will increase as a result
as Zeta approaches and makes landfall, but fortunately the
accelerating nature of the storm will tend to mitigate the storm
totals somewhat and the resulting magnitude of runoff problems and
flash flooding. However, the more urbanized areas, especially
around New Orleans, will ultimately have the greatest sensitivity
and concerns for locally more significant flash flooding.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...JAN...LIX...MOB...

ATTN...RFC...LMRFC...NWC...

LAT...LON 31098958 31078914 30698883 30208907 29598965
29119005 28959053 29029098 29289114 30009093
30759032
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 031004
FFGMPD
ORZ000-WAZ000-032202-

Mesoscale Precipitation Discussion 0842
NWS Weather Prediction Center College Park MD
503 AM EST Tue Nov 03 2020

Areas affected...Pacific Northwest

Concerning...Heavy rainfall

Valid 031002Z - 032202Z

SUMMARY... A steady stream of Pacific moisture is set to usher in
a wet and unsettled pattern to the Pacific Northwest today. Heavy
rainfall is likely to occur particularly in the higher terrain of
the Olympic and Cascade ranges.

DISCUSSION... A longwave trough with embedded shortwave vorticity
maximums over the northeast Pacific is ushering moist
southwesterly flow ahead of a cold front inching its way towards
the Northwest U.S. coast. CIMSS MIMIC imagery shows an atmospheric
river (AR) originating from just east of Hawaii sending high
levels of TPW into Vancouver Island. PWATs offshore within the AR
range between 2.5-3.0 STDs above normal. WAA within the 925-700mb
layer becomes situated over the Olympics early this morning,
followed by the Puget Sound and the front range of the Cascades
later today.

As WAA advection increases, so are low level wind speeds with
850mb flow as high as 50 knots coming ashore between 10-12Z. As
the trough continues to head east, the LLJ with 35-45 knot SW
winds race over the I-5 corridor and intercept the Cascades late
morning. Ascent is favored aloft as the region is located under
the right-entrance region of a ~130 knot 250mb jet in western
Canada and up-sloping low level flow favors more robust ascent
within the low-mid levels of the atmosphere.

Along with the aforementioned rich subtropical moisture this setup
supports the development of heavy rainfall later today, especially
for the Olympics and Cascades. Hourly rainfall rates up to 0.50"
per hour are possible in the higher elevations this morning and
into the early afternoon. Rainfall totals during the span of this
MPD may range between 1-2" with locally higher amounts found in
the tallest peaks of the Olympics today.

Mullinax

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...PDT...PQR...SEW...

ATTN...RFC...NWRFC...NWC...

LAT...LON 49042118 48362124 47662134 47002152 46202211
45652302 45512336 45662402 47012445 47802469
48382474 48232429 48022333 47152294 47232235
47932197 49022224
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 071623
FFGMPD
CAZ000-072145-

Mesoscale Precipitation Discussion 0843
NWS Weather Prediction Center College Park MD
1120 AM EST Sat Nov 07 2020

Areas affected...Southern CA

Concerning...Heavy rainfall...Flash flooding possible

Valid 071615Z - 072145Z

SUMMARY...Brief heavy showers may result in concerns for runoff
problems and some localized flash flooding in and around the burn
scar areas of the San Gabriel and San Bernadino mountains.

DISCUSSION...The latest GOES-17 GeoColor satellite imagery shows a
very well-defined and strong mid-level vort center dropping
east-southeast toward the coastal ranges of southern California as
a broader upper low digs down across the state. Strong forcing
associated with the leading edge of this energy is resulting in
some locally heavy convective showers that are overspreading
portions of Los Angeles, Orange, San Bernadino and Riverside
counties.

The moisture transport into the terrain including the San Gabriel
and San Bernadino mountains is not particular strong, but there is
at least an onshore low-level jet of 30 to 40 kts aimed into these
ranges. Additionally, and perhaps more importantly in this case,
is the nose of modest instability advancing down the coast across
the coastal ranges around the southern flank of the aforementioned
vort center. The latest RAP analysis shows a nose of 500+ j/kg of
MUCAPE nosing into the aforementioned block of counties where
convection has been tending to increase in coverage over the last
hour. The instability is being fostered in large part due to
strong mid-level lapse rates settling southeast with time in
conjunction with the deeper layer height falls associated with the
upper low.

There are several burn scar areas that will need to be closely
monitored in the San Gabriel and San Bernadino mountains over the
next several hours, including those associated with the Lake,
Bobcat, Ranch, El Dorado and Apple fires.

Rainfall amounts over these areas going through 21Z (1pm PST) may
reach up as high as 1 to 1.5 inches given the repeated nature of
some of these showers going through the late morning and early
afternoon hours. This is generally consistent with the latest
hires CAM model guidance. Some 15-minute rainfall rates of as much
as a 0.25 inch will be possible where these brief, but heavy
showers occur. This may be enough to result in some locally
enhanced runoff concerns and flash flooding in and around these
sensitive terrain-focused burn scar areas as a result.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...LOX...SGX...

ATTN...RFC...CNRFC...NWC...

LAT...LON 34621748 34391698 33921671 33451689 33371737
33531774 33911806 34301819 34561803
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 072024
FFGMPD
FLZ000-080220-

Mesoscale Precipitation Discussion 0844
NWS Weather Prediction Center College Park MD
322 PM EST Sat Nov 07 2020

Areas affected...Southeast FL and the FL Keys

Concerning...Heavy rainfall...Flash flooding possible

Valid 072020Z - 080220Z

SUMMARY...Bands of heavy showers and thunderstorms will be on the
increase this evening across southeast FL and the FL Keys. Very
heavy rainfall rates and some localized training of these bands
may result in some flooding concerns and especially for the urban
corridors.

DISCUSSION...The latest GOES-16 IR satellite imagery shows T.S.
Eta advancing northeast across the northwest Caribbean Sea to the
south of Cuba. Bands of heavy showers and thunderstorms have been
tending to become better organized north of Eta across areas of
the Bahamas and also extending west through the FL Straits and
adjacent areas of the FL Keys and southeast FL. This is suggested
by the increase in colder convective tops and increasing expanse
of ice clouds overall as seen by the IR and Day Cloud Phase RGB
data. Some of the bands have become aligned in a manner with the
low to mid-level steering flow enough to pose a convective
training threat as they advance in an east to west fashion around
the northern periphery of Eta.

The increasing easterly flow north of Eta and associated moisture
convergence, along with a pool of moderate instability given
MLCAPE values of near 1500 j/kg nosing into southeast FL from the
Bahamas suggests that convection should at least maintain its
current character or perhaps organize a bit further in coverage
and intensity. PWs across southeast FL and the FL Keys are on the
order of 2.0 to 2.25 inches and gradually increasing with time.
Given this and the instability transport, the rainfall rates will
be quite high, and may reach as high as 2.5+ inches/hr within the
more organized/stronger and deeper convective bands going into the
evening hours.

Overall, the latest hires model guidance appears to be
undercutting the short-term rainfall potential considering the
increase in convective banding, heavier rainfall rates, and
concerns for cell-training north of Eta's circulation. Some
portions of Broward County have already picked up over 2 inches of
rain since this morning. Going through the mid-evening hours,
expect locally an additional 3 to 5 inches of rain where any
focused bands set up.

Concerns for runoff problems, and especially urban flooding along
and adjacent to the I-95 urban corridor of southeast FL will be on
the increase with time as these heavier rains arrive ahead of T.S.
Eta.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...KEY...MFL...

ATTN...RFC...SERFC...NWC...

LAT...LON 26678004 26357985 24988024 24308175 24628195
24988165 25168102 25778061 26548058
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 101922
FFGMPD
FLZ000-110115-

Mesoscale Precipitation Discussion 0852
NWS Weather Prediction Center College Park MD
222 PM EST Tue Nov 10 2020

Areas affected...southern FL

Concerning...Heavy rainfall...Flash flooding possible

Valid 101916Z - 110115Z

Summary...Small scale heavy rain bands with rain rates of 1 to 1.5
inches in 30 minutes will be possible across portions of
southeastern FL through 01Z. Given heavy rain across the region
over the past 2 days, flash flooding will be possible.

Discussion... 12Z RAOB data continued to show a very moist
environment over southern FL with precipitable water values
ranging from 1.9 to 2.4 inches. These values, combined with over
1000 J/kg MLCAPE are supportive of high rainfall rates with near 1
inch in 30 minutes observed earlier this morning along the
southeastern FL coast at several locations. However, the CIRA
layered PW product through 17Z indicated a distinct gradient in
the surface-700 mb layer oriented from near Charlotte Harbor to
Card Sound to the north-central coast of Cuba, with higher
moisture to the south. Over the past few hours, a broken axis of
showers and thunderstorms has been found near the moisture
gradient, tracking with the mean flow from southeast to northwest.
In addition, a mesoscale vorticity maximum was noted roughly 75
miles west of Andros Island in visible satellite imagery at 19Z,
with a nearby burst of convection to its northwest.

Deep-layered steering flow is from the southeast at 20-30 kt and
850 mb winds of 30-40 kt from the southeast are supportive of
training and back building of storms if convective bands align
with the mean flow. While short term forecasts from the RAP
indicate that the low level moisture gradient will translate
northward this afternoon, deep-layered southeasterly steering flow
will support the the low level vorticity max located west of
Andros Island, to track toward the southeastern FL coastline
between 20Z and 23Z. Short periods of training will support
locally very heavy rain with rainfall of 1 to 1.5 inches in 30
minutes as storm motions align with the deeper-layer mean winds.
Overall movement of convective rain bands should limit 6 hour
rainfall totals to 3 inches or less, but confidence in this is low
given potential for mesoscale boundary interactions. Given
especially high rainfall over the past 2 days across portions of
southeastern FL, especially across sections of the Miami and Fort
Lauderdale metro areas, flash flooding will be possible.

Otto

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...KEY...MFL...MLB...

ATTN...RFC...SERFC...NWC...

LAT...LON 27498072 27498009 26357976 25697986 25337994
25118016 25288042 25568063 26068089 26408104
27088094
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 112006
FFGMPD
FLZ000-120200-

Mesoscale Precipitation Discussion 0855
NWS Weather Prediction Center College Park MD
305 PM EST Wed Nov 11 2020

Areas affected...west coast of FL

Concerning...Heavy rainfall...Flash flooding possible

Valid 112002Z - 120200Z

Summary...Heavy rain in advance of, and with, the approaching
eyewall of Tropical Storm Eta is expected to produce an additional
3-5 inches of rain through 02Z across the Tampa Bay metro area.
Given antecedent rainfall since midnight, flash flooding will be
possible

Discussion...Tropical Storm Eta was located about 115 miles
southwest of Tampa, FL as of 18Z via NHC, moving north northeast
at 9 kt. Three hour rainfall totals ending 19Z of 1 to 2 inches
from Tampa Bay to near Sarasota have contributed to as much as 3
inches of rain since early this morning across the region. Radar
imagery from 1945Z showed a temporary lull in heavy rain along the
coast, located between a rain band north of Tampa and an
approaching band just offshore of the Cultural Coast. The
approaching band corresponded with a surge of higher moisture
located between the surface and 700 mb, stretching from just west
of Key West to the Lee Island Coast, as seen in the Layered PW
imagery product. There was some relatively drier air in the
500-300 mb layer above the low level moisture surge.

Another round of heavy rain with peak rainfall rates of 1-2 in/hr
will likely impact coastal sections from Charlotte to Pasco
counties over the next 60 to 90 minutes. Beyond that time frame,
the current track of Eta will take the eastern eyewall...currently
visible in KTBW reflectivity...into the Sarasota to St. Petersburg
to Tampa metropolitan areas near 00Z. Expect peak rainfall rates
to increase from 1-2 in/hr into the 2-3 in/h range near and beyond
00Z. An additional 3-5 inches of rain is expected through 02Z
across the west coast of FL which may lead to flash flooding given
antecedent rainfall since early this morning.

Otto

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...TBW...

ATTN...RFC...SERFC...NWC...

LAT...LON 28468281 28298255 27888229 27318234 27098257
27328283 27928304 28298305
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 121531
FFGMPD
VAZ000-NCZ000-SCZ000-122130-

Mesoscale Precipitation Discussion 0862
NWS Weather Prediction Center College Park MD
1030 AM EST Thu Nov 12 2020

Areas affected......Central to eastern Carolinas and far southeast
Virginia...

Concerning...Heavy rainfall...Flash flooding likely

Valid 121530Z - 122130Z

SUMMARY...Clusters of heavy showers and embedded thunderstorms are
expected to move across central to eastern South Carolina and
North Carolina to southeast Virginia. Pockets of heavy rain are
expected to occur that will likely lead to flash flooding.

DISCUSSION...The latest radar imagery shows widespread showers
and thunderstorms moving across the Carolinas and Virginia.
Activity is moving off to the northeast at a steady rate, but
training of cells is leading to episodes of flash flooding.

Inflow of anomalously deep tropical moisture is expected to
persist east of a cold front moving east across Virginia and the
Carolinas today. Additional moisture is moving onshore in advance
of the circulation of Eta in South Carolina. The ECMWF shows a
plume of 2.25-2.4 inches of precipitable water in the eastern
Carolinas this afternoon, supporting heavy rain. The models show
well defined couplets of upper divergence/lower convergence that
lifts the soggy airmass. Instability is modest with pockets of
mixed layer CAPE values of 1000-1500 J/KG.

2-4.5 inches of rain has occurred in the last several hours from
the western Carolinas to southern Virginia. 2 to 4 inches of rain
is expected through 21z with isolated maxima of 5 inches possible
in central to eastern South Carolina/North Carolina.

There is a strong signal out of the latest hires multi-model
consensus for an additional 2 to 4 inches of rain through 21Z,
with better than usual agreement among the 00-06z Nam Conus Nest,
with the 00z NSSL WRF, 13z HRRR, and 00z WRF ARW/ARW2/NMMB showing
2-4 inches of rain. The HREF probability of 3 inches of rain is
90 percent, which is unusually high.

The flash flood guidance is variable across the Carolinas to
southeast Virginia. The most vulnerable areas for flash flooding
are where guidance is down to near a quarter to half an inch near
the southeast VA/NC border and near the northeast SC/southeast NC
border. Because of these low values where additional rain is
expected to exceed flash flood guidance values, I have indicated
flash flooding is likely.

Petersen

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...AKQ...CAE...CHS...GSP...ILM...MHX...RAH...

ATTN...RFC...MARFC...SERFC...NWC...

LAT...LON 36957512 36367471 35077512 34017747 33437882
33087939 32718017 33438134 34108146 34528105
34938045 35927868 36377752 36807624
#
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 141858
FFGMPD
ORZ000-150656-

Mesoscale Precipitation Discussion 0864
NWS Weather Prediction Center College Park MD
157 PM EST Sat Nov 14 2020

Areas affected...Northwest Oregon

Concerning...Heavy rainfall

Valid 141856Z - 150656Z

Summary...A quick burst of heavy rain is expected in northwest
Oregon between 21-06Z (1 PM to 10 PM local time) as an atmospheric
river reaches the coast. Rainfall totals should reach 1 to 3
inches with locally higher amounts by the end of that time frame,
and hourly amounts could exceed 0.5 inches in some locations.

Discussion...An atmospheric river is poised off the Oregon coast
as of 18Z, and is expected to begin delivering heavy rain to
northwest Oregon in several hours. The time window for impacts is
constrained to about 6 hours or so, as the core of the strongest
onshore flow is forecast by NWP models to shift south and rapidly
weaken. However, prior to arrival on the coast, the LLJ should
actually strengthen and may reach 70-75 knots at 850mb based on
the preponderance of model guidance. Therefore, a short period of
strong orographic ascent is expected, and PW values over 1 inch
(around the 90th percentile) should compensate for a lack of
instability to produce hourly rainfall rates in excess of 0.5
inches in favored upslope areas. These rain rates may be sustained
for a couple consecutive hours in some areas before quickly
ending, and thus a significant fraction of the total rainfall may
be largely delivered in a few hours. Right now the core of the LLJ
appears to be centered around 132W, just behind a region of
enhanced cold cloud tops in GOES-17 IR imagery channels. This
enhancement is likely due to a coupling of low-level WAA on the
nose of the LLJ with the exit region of a jet streak aloft, and
extrapolating trends forward in time suggests an arrival of the
LLJ (and thus enhanced ascent) around 21-23Z. That timing is
closely matched by hi-res models including the latest runs of the
HRRR.

The discussion area was outlined to include both the Coastal and
Cascade Ranges in northwest Oregon. Although the 12Z HREF does
show much higher probabilities of 0.5 in/hr rain rates in the
Coastal Ranges, there are still substantial (over 50 percent in
some areas) probabilities in the Cascades where several large
recent burn scars are situated. Overall, the rainfall totals and
rates are not expected to be high enough for significant impacts
or widespread flooding. However, there are two exceptions. First,
in the favored upslope regions of the Coastal Ranges (where some
stream gauges are close to the 90th percentile), enhanced runoff
is more likely and could lead to a few minor flooding issues. And
second, as always, burn scars will need to be monitored even for
temporary increases in the localized rain rate as they would be
more susceptible to flash flood impacts. The lack of instability
may keep rain rates relatively suppressed, but the very strong
low-mid level flow pushing onshore can't be ignored and could
briefly boost rain rates high enough to cause some issues. Areas
further to the south in Oregon were not included in this
discussion as there is widespread severe drought ongoing, and the
low-mid level flow is expected to weaken with time as it pivots
further south, thus reducing orographic ascent.

Lamers

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...PDT...PQR...

ATTN...RFC...NWRFC...NWC...

LAT...LON 46162367 46112304 45612274 45482202 45012167
44092184 43922233 44172297 44142358 44192414
45182404 45932406
#
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 271532
FFGMPD
MSZ000-LAZ000-TXZ000-272030-

Mesoscale Precipitation Discussion 0865
NWS Weather Prediction Center College Park MD
1031 AM EST Fri Nov 27 2020

Areas affected...Southeast TX... Central LA... Southwest MS

Concerning...Heavy rainfall...Flash flooding possible

Valid 271530Z - 272030Z

SUMMARY... Heavy thunderstorms capable of producing ~2" per hour
rainfall rates or higher to train over portions of eastern TX,
central LA, and southwest MS, potentially resulting in flash
flooding.

DISCUSSION... Doppler radar around 15Z shows large cluster of
thunderstorms from eastern TX stretching into central LA and will
soon enter southwest MS. The 12Z surface analysis showed a
stationary front from western LA to southeast TX that is still in
the general area as of 14Z. To get an idea of how saturated the
nearby environment is, the 12Z sounding out of Lake Charles had
PWs of 1.91". Farther southwest, the 12Z sounding from Corpus
Christi showed a ~35 knot LLJ at ~925mb advecting rich low level
moisture towards the highlighted area. This has resulted in a
3-hour increase in CAPE along and just south of the frontal
boundary from far east TX across central LA. Aloft, the region is
located under diffluent upper level flow ahead of an upper trough
over the Southwest.

Mean layer flow aloft is out of the SW and may lead to some
training of intense cells from east TX and central LA into
southwest MS. MLCAPE in these areas are averaging 1000-1500 J/Kg
as well, which combined with the well saturated air-mass and low
level warm cloud layer as evident on the 12Z Lake Charles
sounding, could support hourly rainfall rates of ~2" per hour or
more.

One limiting factor to flash flooding is much of the highlighted
region has been abnormally dry for weeks with very dry soil
moisture, most notably in eastern TX where there is also ongoing
areas of moderate-to-severe drought. Flash flood guidance is high,
resulting in the more urbanized areas to be most at risk for
excess runoff. That said, soils across portions of central LA are
a little more saturated and given current radar trends, may have a
better chance to witness areas of flash flooding late morning into
the early afternoon. Expect areas farther west of the highlighted
region to see a break in the action by early afternoon while
eastern locations may see heavy thunderstorms persist into late
afternoon hours.

Mullinax

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...HGX...JAN...LCH...LIX...SHV...

ATTN...RFC...LMRFC...WGRFC...NWC...

LAT...LON 32089115 31589034 31019032 30759105 30559213
29889377 29369477 29639586 30579573 31419468
31839299
#
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 271950
FFGMPD
ALZ000-MSZ000-LAZ000-280048-

Mesoscale Precipitation Discussion 0866
NWS Weather Prediction Center College Park MD
249 PM EST Fri Nov 27 2020

Areas affected...Eastern LA... Southern MS... Southwest AL

Concerning...Heavy rainfall...Flash flooding possible

Valid 271948Z - 280048Z

SUMMARY... Precipitation shield with embedded heavy thunderstorms
to track towards southern MS and AL this afternoon. Rainfall rates
around 2" per hour could occur within the strongest areas of
convection and pose a threat for flash flooding.

DISCUSSION...Doppler radar shows a swath of moderate-to-heavy rain
stretching from southeast TX to southwest MS with stronger cells
embedded within the area of precipitation. The environment remains
favorable for fostering periods of rain as the region lies beneath
the right-entrance region of a 300-250mb jet streak over the
mid-MS Valley. At lower levels, a southwesterly fetch of rich Gulf
of Mexico moisture is being transported by a brisk 925-850mb jet.
Surface dew points have also been on the rise over the last 3 to 6
hours and SPC mesoanalysis indicates a modest increase in MUCAPE
to as much as ~600 J/kg over the last 3 hours to the south of the
warm front.

Latest MUCAPE levels within the warm sector are anywhere from
750-1500 J/Kg with further destabilization possible over southern
MS and AL. In addition, PWs are steadily rising to levels between
1.5-1.8" thanks to the aforementioned low level moisture fetch.
Mean level wind flow just south of due west is helping to not only
funnel current convection over southwest MS and central LA towards
the area, but also may lead to training of additional cells should
they develop this afternoon. While FFG does remain relatively
high, urbanized areas could deal with excess runoff and locations
along creeks and streams may see water levels rise quickly in
spots.

Mullinax

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...BMX...JAN...LIX...MOB...

ATTN...RFC...LMRFC...SERFC...NWC...

LAT...LON 32318768 32058716 31628712 31018771 30678955
30919042 31449046 31808999 32278854
#
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 301736
FFGMPD
MEZ000-MAZ000-NHZ000-RIZ000-VTZ000-CTZ000-NYZ000-302330-

Mesoscale Precipitation Discussion 0867
NWS Weather Prediction Center College Park MD
1236 PM EST Mon Nov 30 2020

Areas affected...New England

Concerning...Heavy rainfall...Flash flooding possible

Valid 301730Z - 302330Z

SUMMARY... Strengthening low pressure system with strong low level
winds and rich atmospheric moisture to foster periods of rain
across New England. Rainfall rates could be heavy at times and may
lead to localized areas of flash flooding this afternoon.

DISCUSSION... GOES-16 water vapor imagery depicted an intense
upper level trough diving into the eastern half of the U.S. and a
potent vorticity maximum swinging northeast through the central
Appalachians. To the north, a ~130 knot jet streak is located over
central Quebec with the diffluent right-entrance region of the jet
streak positioned over the Northeast. 17Z RAP analysis indicated
700mb Q-vector convergence which is supportive of ascent within
the atmospheric column over the interior Northeast. To the south,
another jet streak with the diffluent left exit region is
positioned over the Mid-Atlantic. The resulting strong low-mid
level WAA and abundance of upper level divergence has forced a
surface low to strengthen quickly over the central Appalachians
and a classic baroclinic leaf signature on WV imagery resides over
the Northeast and eastern Canada.

Doppler Radar as of 17Z showed a shield of precipitation tracking
through the Northeast, just ahead of a warm front positioned over
the northern Mid-Atlantic. The warm sector ahead of an approaching
cold front has led to additional convection forming from Virginia
and Maryland on south into the Carolinas. There is no shortage of
atmospheric moisture as the storm system contains PWs that are 2-3
STDs above normal. This rich moisture source, with origins
extending as far south as the Gulf of Mexico, is being transported
northward thanks to a roaring 70-80 knot low level jet (LLJ).

By early afternoon, the nose of the LLJ will be aimed directly at
southern New England. As the warm front comes ashore, atmospheric
conditions will become increasingly unstable, fostering an
environment more supportive for convection. Showers and
thunderstorms forming within the considerably moist environment
are likely to contain moderate to even at times heavy rainfall
rates. In fact, GFS model guidance shows PWs by this evening could
be between 3-4 STDs above normal over New England. In addition,
southerly winds upsloping into the higher terrain of central New
England supports the potential for heavier rainfall rates
transpiring farther inland.

Much of New England remains mired in moderate to severe drought,
which does limit the extent of the flash flood threat throughout
the region. However, given the moistening soils within the first
batch of precipitation this morning, and the combination of an
increasingly unstable environment in southern New England and
upsloping flow further inland, heavy downpours or prolonged
moderate-to-heavy rainfall could lead to localized flash flooding.
Urbanized areas where excess run-off is possible and the highest
elevations, where upslope flow is maximized, are locations most
vulnerable for potential flash flooding this afternoon and
evening.

Mullinax

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...ALY...BGM...BOX...BTV...GYX...OKX...

ATTN...RFC...MARFC...NERFC...NWC...

LAT...LON 43997092 43777020 42657021 41306966 41027121
41087357 41667454 42317437 42857366 43217273
43497157
#
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)

AWUS01 KWNH 192206
FFGMPD
ORZ000-WAZ000-200400-

Mesoscale Precipitation Discussion 0871
NWS Weather Prediction Center College Park MD
505 PM EST Sat Dec 19 2020

Areas affected...Cascade Mtns of Southern WA and Northwest OR...

Concerning...Heavy rainfall...Flash flooding possible

Valid 192200Z - 200400Z

SUMMARY...Subtropical moisture plume with ample 850-7H orographic
ascent for solid rainfall through this evening. Some hourly rain
totals of .25-.5" for a 1-3 hour across fresh 2020 burn scars pose
some flash flooding/debris flow concerns in the Cascade ranges
particularly after 02z.

DISCUSSION...CIRA Layered PW and NESDIS Blended TPW products
depicts a solid sub-tropical moisture connection under a fairly
linear subtropical cloud shield from 35N160W toward Vancouver
Island. A strong cyclone is moving through/sharpening across the
SW Gulf of AK which as pumped some mid to upper level ridging just
coming ashore across NW WA at this time. GOES-W SWIR and 89GHz
AMSU mosaic suggests warm front is advancing quickly toward the
coast line at this time though dry air remains in place at the
surface per local observations and LPW sfc-850mb layer. Still
850-7H moisture is starting to advect over the region with showers
starting to develop in the WAA regime.

This will bring the 1" TPW line to the WA coast by about 00z. Low
level southwesterly flow in the warm sector will increase from
45kts at 85H to 60-70kts by 03z before veering with the
advancement of the height-falls and cold front. Southwest facing
orographics of the Olympics are likely to have a hour or so of
.5-.75"/hr rates and totals nearing 2" by 06z, and given dry
conditions over the last few months, per AHPS anomalies, this
should be a welcome rain if there may be some increased run-off
but not likely posing any flooding concerns.

The flooding concerns will begin to manifest as plume flattens,
with forcing/shortwave lifting more north but the strong IVT plume
remains directed at NW Oregon, and the orographic ascent is
favored on west facing terrain. Stronger moisture flux
convergence by 02z across the southern WA into the northern Oregon
Cascades should start to reach rain-rates of .25-.33"/hr at longer
duration, perhaps locally reaching .5"/hr totals. These rates,
particularly at longer duration, are in the realm of inducing
debris/mud flows across the 2020 burn scars especially, the larger
areas such as the Big Hallow, Riverside, Lionshead/Beachie Creek
where more volume of run-off may impact multiple
watersheds/drainage basins. As such, flash flooding is considered
possible, but only in these burn scar and downstream locations.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!DZ3fjg!veZIlpmdIoGooUKRAKEn_n2X7E1gsVYOxbSmO_MIRnFCTWxWXEp4qh-Hu8PfrlGCWKmnT6Rs$
for graphic product...

ATTN...WFO...PQR...SEW...

ATTN...RFC...NWRFC...NWC...

LAT...LON 48202449 48082389 47422342 46592296 46592237
46552183 45502171 44092201 43972261 44412286
45102280 45862269 46112320 45342364 45502403
46432397 47382433 47962463
#
--- SBBSecho 3.11-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (21:1/175)