MESOSCALE PRECIPITATION DISCUSSION 0177
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
148 AM EDT FRI JUL 26 2013
 
AREAS AFFECTED...CENTRAL OK...NORTH-CENTRAL TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 260547Z - 260947Z
 
SUMMARY...BUILDING THUNDERSTORM ACTIVITY ACROSS CENTRAL OK IS
EXPECTED TO PERSIST FOR SEVERAL HOURS, WHICH SHOULD BRING HEAVY
RAINFALL TO AN AREA WITH SOMEWHAT LOWER FLASH FLOOD GUIDANCE
VALUES -- FFGS.  FLASH FLOODING WILL BE POSSIBLE IN THIS REGION.

DISCUSSION...AN UPPER-LEVEL SHORTWAVE MOVING ACROSS CO COMBINED
WITH BROAD DIVERGENCE ALOFT BETWEEN TWO STREAMS OF THE WESTERLIES
IS ALLOWING FOR A GOOD UPPER LEVEL ENVIRONMENT FOR THUNDERSTORM
ACTIVITY.  A LOW-LEVEL BOUNDARY ACROSS WESTERN OK IS ACTING AS A
SURFACE FOCUS, THOUGH CIN IN ITS VICINITY IS LEADING TO THE
CONVECTION'S ELEVATED NATURE FARTHER TO THE EAST ACROSS
WEST-CENTRAL OK.  MUCAPE VALUES IN THE REGION ARE IN THE 500-1000
J/KG RANGE.  INFLOW AT THE 850 HPA LEVEL IS AROUND 30 KNOTS, WHICH
COMBINED WITH PRECIPITABLE WATER VALUES OF AROUND TWO INCHES --
NEAR THE 80TH PERCENTILE FOR LATE JULY -- SHOULD ALLOW FOR SOME
CONTINUED ORGANIZATION TO THE CONVECTIVE ACTIVITY OVER THE NEXT
SEVERAL HOURS. THE DEVELOPING BAND IS ABOUT TO MOVE INTO AN AREA
WITH FFGS ON THE ORDER OF 2.5-3 INCHES IN THREE HOURS.  RADAR
TRENDS ARE SHOWING SOME SIGNS OF BACKBUILDING TO THE THUNDERSTORM
ACTIVITY, ADDING TO THE FLASH FLOOD RISK.   A QUICK 2-4 INCHES OF
RAINFALL COULD CAUSE REGIONAL FLASH FLOODING.
 
ROTH

ATTN...WFO...TSA...FWD...OUN...

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

LAT...LON   33649788 34429876 35839933 36979908 36439710 34799615
            33689669 33649788