738
AWUS01 KWNH 250432
FFGMPD
TXZ000-251000-
MESOSCALE PRECIPITATION DISCUSSION 1210
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1231 AM EDT SAT OCT 25 2025
AREAS AFFECTED...EASTERN & SOUTH-CENTRAL TEXAS...
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 250430Z - 251000Z
SUMMARY...UPSTREAM QLCS HAVE SLIGHTLY FAVORABLE TRAINING
ENVIRONMENT TO MAINTAIN LONGER RAINFALL DURATION FOR SPOTS OF 2-4"
TOTALS AND SCATTERED POSSIBLE INCIDENTS OF FLASH FLOODING THROUGH
LATE OVERNIGHT PERIOD.
DISCUSSION...REGIONAL RADAR MOSAIC SHOWS A MATURE QLCS RAPIDLY
ADVANCING ACROSS NORTH TEXAS INTO THE HEART OF TEXAS INCREASING IN
FORWARD SPEED, WHILE STRONG INFLOW VECTOR BECOMES PARALLEL TO THE
LINE REDUCING OVERALL CONVERGENCE. HOWEVER, GOES-E WV SUITE
DENOTES MAIN SOUTHERN STREAM SHORTWAVE LIFTING NORTHEAST THROUGH
THE RED RIVER VALLEY WITH TRAILING MID-LEVEL TROUGH AXIS BACK
TOWARD THE BIG BEND OF THE RIO GRANDE VALLEY. STRONG
DIFFLUENT/SPLIT FLOW FROM 80KT SUB-TROPICAL JET STREAK, GENERALLY
ALIGNED ALONG SOUTH TEXAS AND THROUGH THE UPPER TEXAS COAST
COMBINED WITH RIGHT ENTRANCE TO 70KT SOUTH TO NORTH POLAR JET
STREAK ACROSS THE BIG COUNTRY ALLOWS FOR INCREASING DIVERGENCE IN
PROXIMITY TO THE TRAILING CONVECTIVE OUTFLOW (SOUTHERN EDGE OF
STRONG 1015 MESO-HIGH).
STRONG SURFACE TO 925 SOUTH-SOUTHEASTERLY FLOW AT 10-20KTS IS
PUMPING LOW 70S TDS AND INCREASINGLY UNSTABLE AIR OFF THE WESTERN
GULF GENERALLY ORTHOGONAL TO THE ORIENTATION OF THE
TROUGH/CONVERGENCE AXIS. THIS IS PROVIDING MORE THAN AMPLE STRONG
MOISTURE FLUX CONVERGENCE FOR A STRENGTHENING CLUSTER ALONG THE
UPWIND EDGE WITH OVERSHOOTING TOPS TO -70C. POOLED MOISTURE IS UP
TO 1.5" THROUGH DEPTH, THOUGH MAXIMIZED IN THE LOWEST PORTION OF
THE COLUMN ALLOWING FOR EFFICIENT RAINFALL PRODUCTION WITH
1.75-2"/HR RATES. DOWNSTREAM ALONG THE NORTHEAST EDGE, ISENTROPIC
WAA IS PROVIDING SOME SCATTERED TOWERS PRE-WETTING THE SOILS AS
THE PEAK CORES RAPIDLY ADVANCE. WHILE FORWARD SPEED WILL LIMIT
OVERALL TOTALS, THE COMBINATION OF PROLONGED MODERATE RAINFALL
WITH PEAK RATES UP TO 2" (WITH 03Z HRRR SUGGESTING 1.25"/15
MINUTES) MAY BE INTENSE ENOUGH TO OVERCOME THE REGIONALLY HIGH FFG
VALUES. A FEW URBAN LOCATIONS ALONG THE PATH WOULD BE MORE PRONE
TO THESE RATES FOR SCATTERED FLASH FLOODING CONCERNS PARTICULARLY
SAN ANTONIO METRO.
OF NOTE, BUT A BIT LESS CERTAIN, IN THE WAKE OF THE CLUSTER THERE
IS A SOLID UPSTREAM REMAINING POCKET OF 1000-1500 J/KG OF MUCAPE
THROUGH THE BIG BEND/LOWER PECOS VALLEY. WHILE MID-LEVEL
SHORTWAVE AND IDEAL JET DIFFLUENCE WILL BE DOWNSTREAM, LOW LEVEL
FLOW INTERSECTING THE FLANKING OUTFLOW HAS SOME SOLID POTENTIAL
FOR REDEVELOPMENT. WHILE NOT LIKELY AS STRONG AS THE INITIAL
CLUSTER ANY TOTALS OF 1-2" ADDITIONAL WOULD FURTHER EXPAND THOSE
AREAS THAT WERE CLOSE TO EXCEEDING WITH THE INITIAL ROUND AND
MAINTAIN A RISK OF LOCALIZED FLASH FLOODING FOR A FEW ADDITIONAL
HOURS.
GALLINA
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...CRP...EWX...FWD...HGX...
ATTN...RFC...FWR...NWC...
LAT...LON 30869829 30849640 29899569 28839627 28649903
28880036 29250109 30000129 30189935
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page