Graphic for MPD #0729

MESOSCALE PRECIPITATION DISCUSSION 0729
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
435 PM EDT FRI AUG 25 2017

AREAS AFFECTED...MIDDLE TX COAST

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 252045Z - 260045Z

SUMMARY...BANDING ASSOCIATED WITH HURRICANE HARVEY ARE EXPECTED TO
COME ASHORE ALONG THE MIDDLE TX COAST INTO THE EARLY EVENING
HOURS. THE ADDITIONAL RAINFALL IS EXPECTED TO PRODUCE FLASH
FLOODING...ESPECIALLY OVER URBAN AREAS.

DISCUSSION...THE LATEST GOES-16 CLEAN IR LOOP AND KCRP RADAR LOOP
SHOWED THE NEXT BANDS ASSOCIATED WITH HURRICANE HARVEY APPROACHING
THE MIDDLE TX COAST THIS AFTERNOON. THE OUTER BANDS HAVE BEEN
PRODUCING HOURLY RAINFALL RATES BETWEEN 1.00 AND 1.50 INCHES...AS
THE BEST INSTABILITY AND DEEP MOISTURE (WITH THE LATEST RAP
ANALYSIS SHOWING 2.25/2.50 INCH PRECIPITABLE WATER VALUES WITH THE
BANDING) BECOMES FOCUSED BY THE STRONG LOW LEVEL CONVERGENCE FLOW
ALONG THE FRONTAL BOUNDARY EXTENDING ALONG THE MID AND UPPER TX
COAST.

RAINFALL RATES ARE EXPECTED TO INCREASE AS THE WESTERN EYEWALL
BEGINS TO APPROACH THE MIDDLE TX COAST THIS EVENING. CURRENTLY...
THE KCRP IS SHOWING HOURLY RAINFALL RATES BETWEEN 2.50 AND 3.00
INCHES FURTHER OFFSHORE...AND AS THE BANDS COME CLOSER TO THE
COAST...FLASH FLOODING BECOMES MORE OF A CONCERN... ESPECIALLY
OVER URBAN AREAS.

THE MOST RECENT HRRR SHOWED LOCAL 3.00 TO 6.00 INCH RAINFALL
AMOUNTS BETWEEN KCRP AND AND KPKV THROUGH ABOUT 26/02Z. THESE
AMOUNTS MAY BE TOO HIGH GIVEN THE HRRR TIMING IS INCORRECT...BUT
REGARDLESS...THE THREAT FOR FLASH FLOODING INCREASES TOWARD 01Z AS
HIGHER RAINFALL RATES ASSOCIATED WITH EYEWALL OF HARVEY APPROACHES
THE MIDDLE TX COAST.

HAYES

ATTN...WFO...BRO...CRP...EWX...HGX...

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

LAT...LON   29669547 29539525 29009520 28549619 27829705
            27159722 26959757 27659785 28369751 29109707
            29509644


Last Updated: 435 PM EDT FRI AUG 25 2017