Flash Flood Guidance
Issued by NWS

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657
AWUS01 KWNH 242305
FFGMPD
TXZ000-250510-

MESOSCALE PRECIPITATION DISCUSSION 0602
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
704 PM EDT WED AUG 24 2016

AREAS AFFECTED...WEST CENTRAL TX

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 242310Z - 250510Z

SUMMARY...CONVECTION TRAINING IN A HIGH MOISTURE ENVIRONMENT ALONG
A SURFACE TROUGH COULD RESULT IN FLASH FLOODING INTO THE LATE
EVENING HOURS.

DISCUSSION...CONVECTION IS INCREASING ALONG A SURFACE TROUGH
EXTENDING FROM JUST SOUTH OF KCDS INTO K6R6...IN AN AXIS OF 1.40
TO 1.60 INCH PRECIPITABLE WATER AIR (PER THE LATEST RAP ANALYSIS
AND BLENDED TPW PRODUCT). THE MOISTURE FEED ACROSS WEST CENTRAL TX
HAS ITS ORIGINS NEAR THE SOUTHERN BAJA PENINSULA (AND THIS
CONNECTION SHOWS UP WELL IN THE LATEST HIGH LEVEL LAYERED
PRECIPITABLE WATER PRODUCT. THE KMAF RADAR HAS SHOWN STREAKS OF
HOURLY RAINFALL RATES NEAR 1.50 INCHES ACROSS HOWARD COUNTY.

THE CONVECTION HAS BEEN SCATTERED ALONG THE LINE SO FAR...AS LOW
LEVEL CIN HAS SUPPRESSED MORE EXTENSIVE ACTIVITY. IN
ADDITION...OUTFLOW FROM EARLIER CONVECTION SUPPRESSED CONVECTION
FROM SOUTH OF KSNK TO JUST NORTH OF K6R6. THE LATEST VISIBLE
IMAGES SHOWED MORE IN THE WAY OF CONVECTION FORMING ALONG THE
SURFACE TROUGH ACROSS COAHUILA IN NORTHERN MEXICO...WHERE THE MRMS
PRODUCT SHOWED HOURLY RAINFALL RATES BETWEEN 1.25 AND 2.00 INCHES.


THE MID LEVEL FLOW BETWEEN SHORT WAVE ENERGY OVER NORTHERN NM AND
RIDGING OVER THE GULF OF MEXICO SHOULD GUIDE THIS ACTIVITY INTO
WEST CENTRAL TX IN THE NEXT 2-4 HOURS. THE LATEST RAP SUGGEST THAT
THE MUCAPE VALUES REMAIN IN THE 2000 J/KG RANGE...BUT LOW LEVEL
CIN COULD KEEP THE ACTIVITY MORE SCATTERED IN NATURE.

THE LATEST HRRR/EXPERIMENTAL HRRR ARE NOT QUITE AS BULLISH AS
PREVIOUS RUNS WITH RAINFALL. HOWEVER...ONE HOUR FLASH FLOOD
GUIDANCE VALUES ARE AS LOW AS 1.50 INCHES ACROSS PORTIONS OF WEST
CENTRAL TX...AND THE HIGH MOISTURE CONTENT AIR COULD PRODUCE
HOURLY RAINFALL RATES THIS HIGH. THE COMBINATION OF HIGH RAINFALL
RATES AND TRAINING ALONG THE SURFACE TROUGH COULD RESULT IN FLASH
FLOODING THROUGH THE EVENING HOURS.

HAYES

...PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LUB...MAF...SJT...

ATTN...RFC...WGRFC...

LAT...LON   33490039 31360094 29270275 30460316 31930237
            33290134



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