MESOSCALE PRECIPITATION DISCUSSION 0383
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1054 PM EDT SAT JUN 25 2016
 
AREAS AFFECTED...BIG BEND REGION OF TEXAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 260255Z - 260655Z
 
SUMMARY...HIGH MST FLUX INTO DEVELOPING THUNDERSTORM COMPLEX THAT
WILL BE SLOW TO MOVE...ALLOWING FOR COMPOUNDING RAINFALL TOTALS
AND AN ISOLATED FLASH FLOOD THREAT. 

DISCUSSION...WV LOOP SHOWS ENHANCED DARKENING SHORTWAVE ALONG
PECOS RIVER BETWEEN TERRELL/CROCKETT/PECOS COUNTIES ON SW
PERIPHERY OF LARGER TUTT CIRCULATION THAT DOMINATES WEST TEXAS BIG
BEND REGION. AT THE SURFACE INITIAL LINE OF CONVECTION DEVELOPED
AND KICKED AN OUTFLOW BOUNDARY THROUGH S VAL VERDE AND NORTHERN
COAHUILA...THIS COMBINED WITH INCREASED PVA AND MILD DIFFLUENCE IN
THE UL FROM S/W ROTATING THROUGH HAS SUPPORTED CONVECTIVE
DEVELOPMENT THAT IS ALREADY SUPPORTING TOPS TO -65C.  ADDITIONALLY
WITH THE S/W STRENGTHENING LL MOISTURE ADVECTION IS INCREASED
ALONG THE RIO GRANDE VALLEY AND IS PROVIDING AMPLE FLUX TO MOISTEN
LOW LEVEL ENVIRONMENT WITH DRT TD RISING NEARLY 5 DEGREES TO THE
LOW 70S IN THE LAST FEW HOURS.  MODIFYING THE 00Z DRT SOUNDING
INDICATES INCREASED CAPE AND REDUCED LOW LEVEL DRYING THAT HAVE
SUPPORTED MORE OUTFLOW DOMINANT CELLS ARE MODIFIED ENOUGH TO ALLOW
FOR STRONG RAIN RATES IN EXCESS OF 2.5"/HR WITH LESS COLD POOL
GENERATION. GIVEN PROXIMITY TO S/W AND SOUTHWARD EXTENDING UL
TROF...CLOUD BEARING STEERING FLOW WILL BE SLOW...AROUND 10-20 TO
THE NORTH AND WITH PROPAGATION VECTORS NEARLY OPPOSITE TO
EFFECTIVE CELL MOTION WHICH ALLOWS FOR TOTALS TO COMPOUND LOCALLY.
LIMITING FACTORS SEEM TO BE AREAL
THREAT...COVERAGE...DURATION...AND MAINTAINED FORCING AS S/W
BEGINS TO LIFT N AWAY FROM BEST MOISTURE POOL. 

HI-RES CAMS THAT SUPPORT THIS SCENARIO WERE RECENT NCEP PARALLEL
HRRR AND ESRL EXPERIMENTAL HRRR OR HRRR VERSION 3...THESE RUNS
PRODUCED 4-6" BUT WERE DISPLACED TOWARD EAST WITH BETTER MOISTURE
AVAILABILITY.    

GALLINA

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

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

LAT...LON   30790146 30690104 30220052 29710038 28990073 
            28570120 28480169 28830178 29340171 29710191 
            29840211 30080223 30390222 30710192