MESOSCALE PRECIPITATION DISCUSSION 0114
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
759 PM EDT TUE APR 12 2016
 
AREAS AFFECTED...SOUTH CENTRAL TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 122358Z - 130558Z
 
SUMMARY...INCREASING CONVECTION COVERAGE AND TRAINING CELLS MAY
PRODUCE LOCALLY HEAVY AMOUNTS...RAISING THE POTENTIAL FOR FLASH
FLOODING.

DISCUSSION...DURING THE LATE EVENING INTO THE OVERNIGHT HOURS
MODELS SHOW A MID-UPPER LEVEL SOUTHERN STREAM TROUGH DRIFTING EAST
ACROSS THE SOUTHERN ROCKIES INTO THE HIGH PLAINS.  DOWNSTREAM OF
THE TROUGH AXIS...GUIDANCE SHOWS INCREASING DIFFLUENT FLOW ALOFT
WITH NUMEROUS EMBEDDED SHORTWAVES EJECTING EAST ACROSS THE
SOUTHERN PLAINS.  MEANWHILE PERSISTENT BROAD
SOUTHERLY-SOUTHEASTERLY LOW LEVEL INFLOW IS EXPECTED TO SUPPORT
INCREASING PWS AND INSTABILITY ACROSS SOUTH TX.  THE 22Z RAP SHOWS
PWS OF 1.5 INCHES AND ABOVE PUSHING NORTH FROM SOUTH TX INTO THE
HILL COUNTRY. WHILE STRONG 0-6 KM BULK SHEAR VALUES SUGGEST
INDIVIDUAL CELLS WILL PROGRESS STEADILY DOWNSTREAM...FAVORABLE
UPPER LEVEL DYNAMICS AND LOW LEVEL INFLOW WILL ENHANCE THE
POTENTIAL FOR RE-DEVELOPING CELLS ALONG AND TO THE NORTH OF A SLOW
MOVING SURFACE BOUNDARY EXTENDING FROM THE NORTHERN GULF OF MEXICO
BACK INTO THE BIG BEND REGION.  MULTIPLE ROUNDS OF
CONVECTION...RESULTING IN LOCALLY HEAVY ACCUMULATIONS...ARE
POSSIBLE BEFORE THE AFOREMENTIONED UPPER TROUGH PUSHES EAST EARLY
WED.

THE OUTLOOK AREA GENERALLY OUTLINES AN AREA WHERE THE 12Z NSSL AND
SPC WRFS...THE 18Z  CANADIAN GEM REGIONAL...AS WELL AS THE LAST
FEW RUNS OF THE OPERATIONAL AND EXPERIMENTAL RUNS OF THE HRRR SHOW
HEAVIER AMOUNTS...WITH WIDESPREAD 1-2 INCHES AND LOCALLY HEAVIER
TOTALS THROUGH 06Z.  3-HOUR FLASH FLOOD GUIDANCE VALUES OF 3-4
INCHES ACROSS THE REGION...ALONG WITH MODEST INSTABILITY...SUGGEST
ONLY A MARGINAL THREAT FOR FLASH FLOODING AT FIRST.  HOWEVER THE
THREAT MAY INCREASE AS THE NIGHT PROGRESSES...ESPECIALLY ACROSS
AREAS IMPACTED BY MULTIPLE ROUNDS OF CONVECTION.
 
PEREIRA

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

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

LAT...LON   30239900 30229815 30099720 29839662 29369636 
            29069665 28779842 28779924 28930039 29450100 
            29900014