MESOSCALE PRECIPITATION DISCUSSION 0144
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
341 AM EDT FRI JUN 20 2014
 
AREAS AFFECTED...FAR S TX...SW TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 200740Z - 201140Z
 
SUMMARY...A SMALL BUT INTENSE HEAVY RAIN EVENT HAS POTENTIAL TO
PERSIST...OWING TO NEARLY STEADY STATE INFLOW...LIFT...AND
INSTABILITY. A GRADUAL MIGRATION TO THE NORTHWEST WILL BRING THIS
EVENT INTO THE MORE POPULATED AREA ALONG HIGHWAY 90 INCLUDING
IN/AROUND DEL RIO TX.

DISCUSSION...EVEN THE HIGH RESOLUTION MODELS WOULD HAVE A
DIFFICULT TIME CAPTURING THE MCV WHICH MAY BE ROUGHLY 30 MILES
ACROSS. LIFT IS STRONG NEAR THIS FEATURE AS EVIDENCED BY FLEDGLING
RADAR ECHOES BLOSSOMING AND ACCELERATING INTO THE CORE...SOMETIMES
TAKING ON SPIRAL BANDED STRUCTURE. STILL...DESPITE ERRORS IN THE
MODEL PLACEMENT AND EVOLUTION...THE NSSL WRF...WRF-ARW...AND HRRR
ALL FORECAST CONTINUED CONVECTION THROUGH 12Z AND PERHAPS BEYOND.
GIVEN LIGHT SOUTHEASTERLY STEERING WINDS IN THE LAYER OF MAXIMUM
LATENT HEAT RELEASE / LAYER OF THE MCV / WOULD EXPECT A SLOW
NORTHWEST DRIFT OF THE FEATURE. PREFERRED DEVELOPMENT OF FEEDER
CELLS SHOULD CONTINUE ALONG THE SE AND S FLANK WHERE 850 MB INFLOW
EMANATES FROM A REGION OF 500-1000 J/KG MUCAPE WHICH THE HRRR
FORECASTS TO MIGRATE NORTHWEST WITH THE SYSTEM.

RECENT OBS OF 5.25 INCH RAIN AT BRACKETVILLE MATCHES CLOSELY TO
THE DUAL POL RADAR ESTIMATES...WHICH SHOULD BE PERFORMING WELL
THIS CLOSE TO KDFX. RADAR SUGGESTS MORE THAN A FOOT OF RAIN HAS
LIKELY FALLEN OVER RURAL KINNEY/MAVERICK COUNTIES....WITH HOURLY
RATES OVER 3 INCHES. RATES MAY DECREASE WITHIN THE COOLER MORNING
HOURS...BUT ALL ELSE REMAINS FAVORABLE FOR 2-3 INCH/HR RATES
MOVING INTO MORE HEAVILY POPULATED AREAS WHERE FLASH FLOOD IMPACTS
COULD BECOME MORE SEVERE.

BURKE

ATTN...WFO...EWX...SJT...MAF...

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

LAT...LON   28600070 28470028 28889988 29799999 30300099 30380230
            30010307 29330339 28800292 28970197 28870127 28600070