MESOSCALE PRECIPITATION DISCUSSION 0122
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
901 AM EDT SUN APR 17 2016
 
AREAS AFFECTED...CENTRAL TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 171300Z - 171700Z
 
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS WILL CONTINUE THIS
MORNING OVER CENTRAL TX. SLOW FORWARD PROPAGATION AND A FEW CELL
MERGERS WILL ENHANCE THE POTENTIAL FOR SOME FLASH FLOODING.

DISCUSSION...VERY COLD-TOPPED CONVECTION CONTINUES TO DEVELOP AND
SLOWLY SHIFT EAST ACROSS THE CENTRAL TX THIS MORNING AS A DEEP
UPPER TROUGH AND ASSOCIATED CLOSED LOW LIFTS SLOWLY NORTH ACROSS
THE CENTRAL ROCKIES AND HIGH PLAINS. A COLD FRONT ASSOCIATED WITH
THE SYSTEM IS ALSO VERY SLOWLY PUSHING EAST ACROSS THE CENTRAL AND
SOUTHERN PLAINS...WITH MOST OF THE CONVECTION FOCUSED JUST OUT
AHEAD OF IT OWING TO THE PRESENCE OF A CONVECTIVELY ENHANCED COLD
POOL. 

HEAVY RAINS ARE EXPECTED TO BE FOCUSED ACROSS PORTIONS OF CENTRAL
TX THROUGH THE EARLY AFTERNOON HOURS AS A WELL-DEFINED AND MOIST
LOW LEVEL JET REACHING 40 TO 50 KTS CONTINUES TO SURGE UP THR0UGH
THE  SOUTHEAST TX COASTAL PLAIN AND INTO THE LEADING EDGE OF THE
CONVECTION. PWATS ARE ON THE ORDER OF 1.3 TO 1.4 INCHES AS PER
GPS-DERIVED DATA...BUT THE CONVECTION HAS BEEN TAKING ADVANTAGE OF
AN INSTABILITY AXIS NOSED UP THROUGH THE TX HILL COUNTRY ALBEIT
RELATIVELY MODEST.

ALTHOUGH THE THERMODYNAMIC PROFILES ARE NOT EXACTLY SUGGESTIVE OF
VERY HEAVY RAINFALL RATES...THE SLOW FORWARD PROPAGATION AND
THREAT OF CELL-MERGES WILL TEND TO COMPENSATE FOR THIS GOING
THROUGH MIDDAY. RAINFALL AMOUNTS OF 2 TO 4 INCHES ARE EXPECTED
OVER THE NEXT SEVERAL HOURS WITH ISOLATED HEAVIER AMOUNTS...AND
SOME FLASH FLOODING WILL BE POSSIBLE AS A RESULT.

ORRISON

ATTN...WFO...EWX...FWD...SJT...

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

LAT...LON   33139645 32719605 32089618 31169705 30709797 
            30619857 30989894 31329891 32209798 32889722