099
AWUS01 KWNH 252306
FFGMPD
TXZ000-OKZ000-260503-
MESOSCALE PRECIPITATION DISCUSSION 0131
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
704 PM EDT SAT APR 25 2026
AREAS AFFECTED...NORTHEAST TX INTO SOUTHEAST OK
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 252303Z - 260503Z
SUMMARY...A LOCALIZED FLASH FLOOD RISK EXISTS THROUGH THE EVENING
HOURS ACROSS PORTIONS OF NORTHEAST TX INTO SOUTHWEST OK.
SUPERCELLS WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL RESULTING
IN AN URBAN FLASH FLOOD RISK. ADDITIONALLY, LOCALIZED CELL MERGERS
NEAR THE WARM FRONT MAY ALSO RESULT IN ISOLATED FLASH FLOODING.
DISCUSSION...SUPERCELL ACTIVITY IS EXPECTED THROUGH THE EVENING,
WITH DEVELOPMENT NEAR A DRYLINE AND A WARM FRONT NEAR THE RED
RIVER. THE ENVIRONMENT IS CHARACTERIZED BY EXTREME INSTABILITY
(MLCAPE AROUND 4000 J/KG) AND STRONG SHEAR (EFFECTIVE BULK SHEAR
AROUND 50KTS). THIS OVERLAP OF INGREDIENTS SUPPORTS SUPERCELLS
WITH VERY LARGE HAIL AND HEIGHTENED TORNADO POTENTIAL (SEE SPC
TORNADO WATCH 144). WHILE THESE ARE LIKELY THE PRIMARY HAZARDS
ASSOCIATED WITH THIS CONVECTION, AN ISOLATED FLASH FLOOD RISK
COULD ALSO EVOLVE.
LIMITING FACTORS FOR HEAVY RAINFALL WILL BE THE VERY STEEP LAPSE
RATES AND SOME DRY AIR IN THE MID LEVELS KEEPING PWS AROUND
1.4-1.6". HOWEVER, STRONG MESOCYCLONES WITHIN THESE SUPERCELLS
WILL ENHANCE LIFT AND HELP INCREASE RAINFALL EFFICIENCY. THIS WILL
RESULT IN HEAVY RAINFALL RATES, THOUGH FORECAST SUPERCELL MOTIONS
OFF TO THE EAST-SOUTHEAST AT 10-20 KTS SHOULD LIMIT DURATION.
CONSEQUENTLY, THE FLASH FLOOD RISK WILL PRIMARILY DEPEND ON
SUPERCELL MERGERS OR CLUSTERS EXTENDING DURATION. THIS IS
CERTAINLY A POSSIBILITY, ESPECIALLY NEAR THE WARM FRONT WHERE
PERSISTENT CONVERGENCE AND STORM TRACKS ALONG THE FRONT COULD
YIELD SOME TRAINING AND LOCAL RAINFALL OVER 3". EVEN WITHOUT CELL
TRAINING A LOCALIZED URBAN FLASH FLOOD RISK EXISTS AS THESE CELLS
CAN DROP 2" OF RAIN QUICKLY.
RECENT HRRR RUNS SEEMINGLY HAVE A DECENT HANDLE ON THE EXPECTED
CONVECTIVE EVOLUTION THROUGH THE EVENING HOURS. THE HRRR DEPICTS
AN UPTICK IN 850MB MOISTURE TRANSPORT LATER THIS EVENING INTO
TONIGHT, WHICH WILL HELP SUSTAIN ACTIVITY AS CONVECTION
INCREASINGLY FORWARD PROPAGATES. HOWEVER, WITH MOISTURE TRANSPORT
PERSISTING OVER NORTHEAST TX TOWARDS THE RED RIVER, WE WILL NEED
TO MONITOR FOR ADDITIONAL DEVELOPMENT OVERNIGHT DEPENDING ON HOW
THIS EVENINGS SUPERCELLS IMPACT THE INSTABILITY FIELD. IF
ADDITIONAL DEVELOPMENT OCCURS, THE PATTERN WOULD SUPPORT SOME
NORTHWEST TO SOUTHEAST TRAINING.
CHENARD
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...FWD...OUN...SHV...TSA...
ATTN...RFC...FWR...ORN...TUA...NWC...
LAT...LON 34809731 34729657 33959509 33499446 32589480
32489608 32769762 33269827 33829861 34169838
34509800
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