638
AWUS01 KWNH 270404
FFGMPD
MSZ000-LAZ000-ARZ000-TXZ000-271000-
MESOSCALE PRECIPITATION DISCUSSION 1128
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1203 AM EDT THU AUG 27 2026
AREAS AFFECTED...LOWER MISSISSIPPI VALLEY
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 270402Z - 271000Z
SUMMARY...HIGH RAINFALL RATES WITH 2 TO 3+ INCH HOURLY TOTALS AND
15 MINUTE RAINFALL LOCALLY IN EXCESS OF 1 INCH ARE EXPECTED TO
IMPACT PORTIONS OF THE LOWER MS VALLEY THROUGH 10Z. PEAK RAINFALL
TOTALS IN EXCESS OF 4 INCHES WILL BE POSSIBLE ON AN ISOLATED BASIS
ALONG WITH POSSIBLE FLASH FLOODING.
DISCUSSION...GOES EAST INFRARED IMAGERY AT 0345Z SHOWED POCKETS OF
COLDER CLOUD TOPS FROM THE WESTERN AR/LA BORDER INTO CENTRAL AND
SOUTHERN MS, ASSOCIATED WITH THUNDERSTORMS CONTAINING A GENERAL
MOTION TOWARD THE SOUTH TO SOUTHEAST. PRECEDING THE THUNDERSTORMS,
REGIONAL RADAR IMAGERY AND SURFACE OBSERVATIONS FROM 03Z SHOWED AN
ELONGATED SOUTHWARD PROPAGATING OUTFLOW BOUNDARY FROM NORTHEASTERN
TX INTO FAR NORTHERN LA AND CENTRAL MS, WHERE IT MET WITH A
WESTWARD PROPAGATING OUTFLOW ACROSS CENTRAL/SOUTHERN MS. THE
ENVIRONMENT AHEAD OF THE COMPOSITE OUTFLOW WAS VERY MOIST WITH PWS
OF 1.9 TO 2.2 INCHES AND MLCAPE OF 1000 TO 2000+ J/KG (VIA AREA
00Z SOUNDINGS AND 03Z SPC MESOANALYSIS DATA). NORTHERN PORTIONS OF
THE REGION ALSO CONTAINED ADDED LIFT WITHIN THE RIGHT-ENTRANCE
REGION OF A STRENGTHENING 70-90 KT UPPER LEVEL JET MAX EXTENDING
EASTWARD FROM THE CONFLUENCE OF THE MO AND OH RIVERS, WITH
DIFFLUENT FLOW TO THE SOUTH ACROSS THE LOWER MS VALLEY.
EXPECTATIONS ARE FOR THUNDERSTORMS TO CONTINUE ADVANCING SOUTH TO
SOUTHEAST OVER THE NEXT 3-6 HOURS, CONTAINING HOURLY RAINFALL OF 1
TO 2 INCHES. HOWEVER, THE UNSTABLE AND MOIST ENVIRONMENT WILL
FAVOR EFFICIENT RAINFALL PRODUCTION WITH 15 MINUTE RAINFALL
LOCALLY OVER 1 INCH AND THE POTENTIAL FOR 2 TO 3+ INCH HOURLY
TOTALS WHERE CELLS LOCALLY MERGE AND BRIEFLY TRAIN. WHILE PEAK
RESIDENCE TIME OF HEAVY RAIN OVER ANY GIVEN LOCATION IS NOT
EXPECTED TO EXCEED MUCH MORE THAN 60-90 MINUTES, THE POTENTIAL FOR
LOCALIZED FLASH FLOODING WILL EXIST, ESPECIALLY ACROSS URBAN OR
OTHER LOCATIONS OF POOR DRAINAGE. DUE TO A MAJORITY OF THE REGION
CONTAINING HIGH FFG (MANY AREAS OF 4+ INCHES IN 3 HOURS), THE
COVERAGE OF ANY FLASH FLOODING THAT OCCURS SHOULD REMAIN LOCALIZED.
OTTO
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...JAN...LCH...LIX...LZK...MOB...SHV...
ATTN...RFC...ALR...FWR...ORN...NWC...
LAT...LON 33498992 33428916 32788881 32188880 31158868
30578960 30699235 31159353 32099399 33029386
33279343 33189208 33369122 33459040
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