MESOSCALE PRECIPITATION DISCUSSION 0209
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
527 PM EDT SAT MAY 14 2016
 
AREAS AFFECTED...SOUTH TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 142126Z - 150126Z
 
SUMMARY...A FLASH FLOOD THREAT IS EXPECTED TO CONTINUE ACROSS
PORTIONS OF SOUTH TEXAS THROUGH THE AFTERNOON.

DISCUSSION...CONVECTION CONTINUES TO FIRE IN A HIGHLY UNSTABLE
AIRMASS ACROSS SOUTH TEXAS AHEAD OF A WEAK SHORTWAVE IMPULSE.
PRECIPITABLE WATER VALUES ARE AS HIGH AS 1.8" PER RECENT RAP RUNS
AND GPS OBSERVATIONS. CONVECTION IS BEGINNING TO ORGANIZE ALONG A
WEST TO EAST ORIENTED OUTFLOW BOUNDARY. WHILE INFLOW INTO THE
SYSTEM IS GENERALLY WEAK...IT IS OUT OF THE
SOUTH/SOUTHEAST...ALLOWING FOR CONTINUED CONVECTIVE DEVELOPMENT ON
THE SOUTH SIDE OF THE CONVECTIVE CLUSTER. MEANWHILE STORM
PROPAGATION VECTORS ARE SLOWLY OFF TO THE EAST PARALLEL TO THE
OUTFLOW BOUNDARY. THUS AS THE OUTFLOW CONTINUES TO SLOWLY PUSH
SOUTH...CAN EXPECT A PERIOD OF TRAINING CONVECTION ALONG IT...WITH
CONVECTIVE INTENSITY SLOWLY DECREASING BEHIND THE OUTFLOW BOUNDARY
AS INSTABILITY IS USED UP. LESS CONFIDENCE NEAR BROWNSVILLE AS
UNSURE HOW FAR SOUTH THE OUTFLOW BOUNDARY PROGRESSES...BUT WOULD
SEE A CONDITIONAL FLASH FLOOD THREAT. ALSO...FURTHER NORTH NEAR
CORPUS CHRISTI THE OUTFLOW SHOULD BE MORE PROGRESSIVE...GENERALLY
RESULTING IN A LOWER FLASH FLOOD RISK.

THE 12Z ARW AND RECENT RUNS OF THE EXPERIMENTAL ESRL HRRR APPEAR
TO HAVE A DECENT HANDLE ON CURRENT CONVECTION. DUAL POL RADAR
CONTINUES TO ESTIMATE HOURLY RAINFALL AMOUNTS AS HIGH AS
2-3"...AND EXPECT ISOLATED TO SCATTERED AMOUNTS OF THIS MAGNITUDE
TO SLOWLY SHIFT SOUTH THROUGH SOUTH TEXAS THIS AFTERNOON...WITH
TOTAL AMOUNTS AS HIGH AS 3-5" THROUGH THE AFTERNOON IN SPOTS.

CHENARD 

ATTN...WFO...BRO...CRP...

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

LAT...LON   28789734 28619675 28349667 27719700 26929729 
            26069710 25739730 25819809 26109877 26109877 
            26729978 27349898 27719833 28249793 28709764