Flash Flood Guidance
Issued by NWS

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000
AWUS01 KWNH 191551
FFGMPD
TXZ000-NMZ000-192110-

MESOSCALE PRECIPITATION DISCUSSION 0392
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1150 AM EDT FRI SEP 19 2014

AREAS AFFECTED...ERN NM...SW TX

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

VALID 191550Z - 192110Z

SUMMARY...VARIOUS FACTORS WILL CONSPIRE TOWARD A CONTINUED RISK OF
FLASH FLOODING THROUGH MID-AFTERNOON IN ERN NM AND SW TX.
ORGANIZATION WILL TEND TO OCCUR ON SMALL SCALES...BUT DEEP
MOISTURE AND INCREASING INSTABILITY WILL SUPPORT LOCALLY INTENSE
RAIN RATES.

DISCUSSION...IN THE NEAR TERM...A WELL- FORMED MCV WAS APPROACHING
MIDLAND TX. STRATIFORM RAIN RATES NEAR THE CENTER MAY ONLY REACH
0.75"/HOUR...BUT MUCH HEAVIER RAIN IS POSSIBLE IN SPIRAL BANDS
DIRECTED SOUTH AND EAST TOWARD GREATER INSTABILITY. MEANWHILE...
THE RAP SHOWS A CIRCULATION LOOSELY INTERPRETED AS THE REMNANTS OF
ODILE BEING BEST DEFINED AT 850 MB...AND DRIFTING ALONG NORTH OF
THE MCV. THOUGH INSTABILITY IS LACKING...SOME FORCED ASCENT OF
UNUSUALLY MOIST AIR MAY YIELD HEAVY RAIN IN THE FOOTHILLS WEST
THROUGH NORTHWEST OF ROSWELL. A CONSERVATIVE ESTIMATE ON
RATES...USING TWO-THIRDS OF WHAT HAS BEEN OBSERVED FROM LONG
DISTANCE AT KFDX...SUGGESTS MORE THAN AN INCH PER HOUR.

IN HANDLING THE MCV...THE HRRR MAY BE TOO QUICK TO TRANSITION
CONVECTION TOWARD A MORE SURFACE-BASED CHARACTER WITH STRONGER
COLD POOLS AND FORWARD PROPAGATION. CLOUD COVER SHOULD SLOW
HEATING...BUT AT THE SAME TIME THE VERTICAL PROFILES THROUGHOUT SW
TX ARE SO MOIST AS TO ALLOW A MORE RAPID TRANSITION TOWARD
SFC-BASED CONVECTION COMPARED TO YESTERDAY. CONSECUTIVE RUNS OF
THE HRRR ARE VERY CONSISTENT IN EXPANDING CONVECTION ALONG THE
SOUTHERN FLANK OF THE MCV...WHICH GRADUALLY OVERTAKES SLOW-MOVING
CELLS FORMING FROM THE HILL COUNTRY NW TOWARD SAN ANGELO.

THESE EVENTS ARE MOVING AWAY FROM THE VERY LOW FLASH FLOOD
GUIDANCE WEST OF MIDLAND...BUT GUIDANCE VALUES ARE RELATIVELY
LOW...WITH FLOODING PREDICTED AT 1.5" IN AN HOUR...OVER ALL OF SW
TX. RICH MOISTURE AND SLOW INDIVIDUAL CELL MOVEMENT SHOULD LOCALLY
SUPPORT THESE RATES AND A RISK OF FLASH FLOODING.

BURKE

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

ATTN...WFO...ABQ...EWX...LUB...MAF...SJT...

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

LAT...LON   33950421 33870293 33550183 32870083 31859984
            30479904 29719932 30040120 30390373 30700457
            31380458 32140429 32840487 33450507 33800486




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