Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Nov 29 2022 21:35:51

AWUS01 KWNH 292135
FFGMPD
FLZ000-ALZ000-MSZ000-LAZ000-300334-

Mesoscale Precipitation Discussion 1136
NWS Weather Prediction Center College Park MD
434 PM EST Tue Nov 29 2022

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

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

Valid 292134Z - 300334Z

Summary...Repeat rounds of eastward translating supercells
containing 2" per hour rainfall rates could cause flash flooding
through this evening.

Discussion...Two persistent clusters of supercell thunderstorms
with estimated 1.5-2" per hour rainfall rates continue over the MS
Pine Belt and southwest Alabama this afternoon. Over the last hour
or so, these storms prompted a quick, localized uptick in FLASH
CREST responses (100-250 cfs/smi) over parts of the Louisiana
Bootheel and southwest Alabama. Additional updraft development was
 noted on the southern flank of these clusters within a regime of
strong southerly inflow.

The moist Gulf of Mexico inflow in conjunction with broken
insolation supports SPC mesoanalysis estimates of 1000-2500 J/kg
SBCAPE and PWATS of 1.5-1.6" in the vicinity of the convection,
with a noted sharp N-S cutoff in SBCAPE residing over central AL.
Kinematic fields remain very supportive of organized supercells
(50 kts of effective bulk shear and 200 m2/s2 effective inflow
SRH). However, in contrast with areas further north outlined in
MPD 1134 and 1135, Bunkers storm motions estimated by SPC
mesoanalysis to the south are noticeably weaker (easterly at 25-30
kts). This would allow for lengthened residence times of easterly
translating supercells containing rainfall rates exceeding 2" per
hour at times. The aforementioned instability gradient will likely
cap the eastward extent of excessive rainfall from this activity.

Much of the hi-res guidance has underdone the coverage and timing
of rainfall so far this afternoon. However, the continued
development of new updrafts within the inflow region of these
supercells suggests a flash flood threat continuing through this
evening.

Asherman

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!-DmD7pWSO2X3ElnJRUwN8XjRp2InbhbzRmcOu6_OK4qt20eXAW1JlBl1cApqKo_qUNAw=
mhXXi2wInN56Se2OJqzL4h4$  for graphic product...

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

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

LAT...LON   32598881 32078712 30748747 30299063 30789187=20
            32169155=20

=3D =3D =3D
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