Graphic for MPD #0240

MESOSCALE PRECIPITATION DISCUSSION 0240
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
841 PM EDT FRI MAY 19 2017

AREAS AFFECTED...CENTRAL TX

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

VALID 200040Z - 200455Z

SUMMARY...TWO CLUSTERS OF CONVECTION MAY MERGE WITHIN CENTRAL TX
OVER THE NEXT SEVERAL HOURS.  WITH HOURLY RAIN RATES UP TO 2",
WITH ADDITIONAL AMOUNTS UP TO 4", COULD LEAD TO CONTINUED ISSUES.

DISCUSSION...A SMALL THUNDERSTORM CLUSTER HAS BEEN STUCK IN THE
VICINITY OF SAN ANGELO TX FOR ABOUT FIVE HOURS NEAR A WEAK SURFACE
LOW.  NEW CONVECTION IS FORMING OFF TO THE EAST ALONG A WEAK
THERMAL BOUNDARY.  PRECIPITABLE WATER VALUES OF 1.25-1.75" LIE IN
THE AREA.  INFLOW AT 850 HPA IS 20-40 KTS PER VAD WIND PROFILES. 
MUCAPES OF 2000-4000 J/KG LIE NEARBY, WHICH DESPITE CIN, IS LIKELY
WHY CONVECTION IS OCCURRING AT THESE LOCATIONS.

THE NAM CONEST AND HRRR/RAP HAVE BEEN THE ONLY PIECES OF GUIDANCE
USEFUL IN THIS REGION.  SO FAR, FORWARD PROPAGATION HAS NOT
OCCURRED IN CENTRAL TX, BUT AT SOME POINT, STORMS SHOULD MOVE EAST
TO EAST-NORTHEAST AT 30 KTS.  THIS IS IMPLIED BY THE RAP 850 HPA
WINDS, WHICH SHOW SOME VEERING WITH TIME.  IT IS POSSIBLE THAT THE
TWO CONVECTIVE AREAS COULD MERGE WITH TIME, WHICH WOULD HEIGHTEN
THE RISK FOR HEAVY RAINFALL.  HOURLY RAIN RATES UP TO 2", WITH
LOCAL AMOUNTS TO 4", COULD LEAD TO OR CONTINUE FLASH FLOOD ISSUES.

ROTH

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

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

LAT...LON   32729786 32699692 31539745 31069839 30930000
            31240035 32129909


Last Updated: 841 PM EDT FRI MAY 19 2017