MESOSCALE PRECIPITATION DISCUSSION 0319
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
154 AM EDT TUE JUL 07 2015
 
AREAS AFFECTED...WESTERN TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 070554Z - 071154Z
 
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BECOME A
BIT MORE CONCENTRATED OVER THE NEXT FEW HOURS ACROSS WEST TEXAS.
THE SLOW MOVEMENT AND INTENSE RAINFALL RATES WILL LIKELY RESULT IN
FLASH FLOODING.

DISCUSSION...DESPITE THE GENERAL TREND FOR CONVECTION ON THE
LARGER SCALE TO WEAKEN OVER THE LAST COUPLE OF HOURS OVER WEST
TEXAS...THERE IS EVIDENCE TO SUGGEST THAT CONVECTION WILL BE
REGENERATING AND TENDING TO BECOME MORE CONCENTRATED THROUGH THE
EARLY MORNING HOURS. THE LATEST GOES-RGB AIRMASS IMAGERY SHOWS
EVIDENCE OF A SHORTWAVE MOVING SLOWLY EAST THROUGH EASTERN
NM...AND THIS ENERGY WILL CROSS INTO WESTERN TX BETWEEN 09Z AND
12Z.

THE SHORTWAVE WILL BE INTERACTING WITH A FRONTAL ZONE ACROSS WEST
TEXAS WHICH IS ALSO WHERE A SIGNIFICANT AMOUNT OF LOW LEVEL
MOISTURE TRANSPORT/CONVERGENCE IS SEEN. INSTABILITY IS NOT THAT
GREAT WITH MUCAPE VALUES RATHER MODEST BETWEEN 1500 TO 2000
J/KG...BUT VAD WIND PROFILER DATA IS SHOWING 40 KT SOUTHERLY 850MB
FLOW AIMED INTO THE BOUNDARY. SUFFICIENT LARGE SCALE ASCENT FROM
THE SHORTWAVE ENERGY IS EXPECTED TO WORK WITH THE AVAILABLE
MOISTURE AND INSTABILITY FOR CONVECTION TO EXPAND IN COVERAGE AND
ORGANIZATION OVER THE NEXT FEW HOURS.

STEERING FLOW RATHER WEAK AND SO THE CONVECTION WILL BE SLOW
MOVING...AND AS SUCH THIS WILL FOSTER HEAVY RAINFALL TOTALS...AND
ESPECIALLY WITH GPS-DERIVED PWATS OVER 1.75 INCHES IN WESTERN
TEXAS ALONG THE FRONT SUPPORTING INTENSE RAINFALL RATES OF OVER 2
INCHES/HR.

THE LAST COUPLE OF RUNS OF THE HRRR HAVE BEEN QUITE IMPRESSIVE
WITH THEIR RAINFALL TOTALS. THE 04Z HRRR SUGGESTS RAINFALL AMOUNTS
OF AS MUCH 4 TO 8 INCHES BETWEEN 06Z AND 12Z. WITH LOCALLY HEAVIER
AMOUNTS. THE 00Z ARW SIMILARLY SUGGESTS HEAVY CONCENTRATED RAINS
OF LOCALLY OVER 5 INCHES. THESE RAINS ARE LIKELY TO CAUSE FLASH
FLOODING.

ORRISON

ATTN...WFO...FWD...LUB...MAF...OUN...SJT...

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

LAT...LON   34260002 34099902 33289859 32859887 32379963 
            31950076 31920190 32030272 32410301 32880297 
            33470257 34040142