240
AWUS01 KWNH 170412
FFGMPD
TXZ000-170811-
MESOSCALE PRECIPITATION DISCUSSION 0749
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1212 AM EDT FRI JUL 17 2026
AREAS AFFECTED...PORTIONS OF CENTRAL/SOUTH TEXAS
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 170411Z - 170811Z
SUMMARY...SCATTERED THUNDERSTORMS HAVE REDEVELOPED ACROSS PORTIONS
OF CENTRAL/SOUTH TEXAS AND WILL MOVE THROUGH THE HILL COUNTRY OVER
THE NEXT 2-4 HOURS. LOCAL IMPACTS FROM EARLIER FLOODING CONTINUE
AND COULD BE AGGRAVATED BY ADDITIONAL RAINFALL.
DISCUSSION...THE INCREASE OF THE LOW-LEVEL JET ACROSS SOUTH TEXAS
HAS AIDED IN DEVELOPMENT OF SCATTERED THUNDERSTORMS PARTICULARLY
ACROSS UVALDE AND REAL COUNTIES IN THE PAST HOUR. THE STORMS ARE
EMBEDDED WITHIN A CONTINUED MOIST/UNSTABLE AIRMASS (2 INCH PW,
1500 J/KG MLCAPE), FAVORING HEAVY RAINFALL. SPOTS OF 1 INCH/HR
RAIN RATES HAVE ALREADY BEEN ESTIMATED PER MRMS, WITH RAINFALL
OCCURRING OVER AREAS THAT ARE EXTREMELY SENSITIVE (NEAR ZERO FFG)
FROM THE NEARLY 10-30 INCHES OF RAINFALL THAT HAVE OCCURRED OVER
THE PAST 72 HOURS. IMPACTS ARE LIKELY ONGOING, AND THE ADDITIONAL
RAINFALL COULD EXACERBATE THEM OVER THE NEXT 2-4 HOURS (THROUGH
08Z/3A CENTRAL).
THE LONGER TERM EVOLUTION OF CONVECTION ACROSS THIS REGION IS A
BIT UNCLEAR. WHILE WIDESPREAD CONVECTION IS NOT EXPECTED, SUBTLE
INFLUENCES FROM 1) CONVERGENCE ASSOCIATED WITH THE LOW-LEVEL JET,
2) WEAK MID-LEVEL WAVES NOTED ACROSS WEST TEXAS PROVIDING ASCENT,
AND 3) WEAK CAPPING/INHIBITION COULD FOSTER A FEW AREAS OF
CONVECTION TO BE SUSTAINED AND PROVIDE AREAS OF 1-2 INCH RAINFALL
TOTALS IN A SHORT AMOUNT OF TIME. GIVEN ONGOING LOCAL
SENSITIVITIES AND POOR RECOVERY/RUNOFF, ADDITIONAL INSTANCES OF
FLASH FLOODING APPEAR POSSIBLE -- ESPECIALLY IF ANY LOCALLY
BACKBUILDING STORMS CAN BE MAINTAINED.
COOK
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...EWX...FWD...SJT...
ATTN...RFC...FWR...NWC...
LAT...LON 31870023 31759859 30769819 29039895 28900025
29780099 30930105
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