MESOSCALE PRECIPITATION DISCUSSION 0700...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1138 PM EDT SAT SEP 24 2016
 
CORRECTED FOR CATEGORY USED

AREAS AFFECTED...SOUTH-CENTRAL OK & NORTHWEST TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 250333Z - 250703Z
 
SUMMARY...A THUNDERSTORM COMPLEX WITH COOLING CLOUD TOPS IS
EXPECTED TO CONTINUE PRODUCING HOURLY RAIN RATES TO 2.5" AS IT
MOVES EAST ~15 KTS.  WITH LOCAL AMOUNTS IN THE 3-6" RANGE
EXPECTED, FLASH FLOODING REMAINS POSSIBLE.

DISCUSSION...A LINE OF THUNDERSTORMS HAS BEEN MOVING EAST AT ~15
KTS ACROSS THE REGION DURING THE PAST SEVERAL HOURS, WELL AHEAD OF
A WEAK FRONTAL BOUNDARY/DRY LINE-LIKE FEATURE LOCATED OVER THE
PANHANDLE, PERMIAN BASIN, AND TRANS-PECOS REGIONS OF TX.  IN THIS
AREA, THUNDERSTORM PROGRESSION HAS BEEN SOMEWHAT HELD UP BY A
MESOSCALE WAVE ALONG THE QLCS/LEWP TO THE SOUTHWEST.  CLOUD TOPS
HAVE BEEN COOLING THE LAST FEW HOURS, AND ARE AT AROUND -80C NEAR
THE TX/OK BORDER, TAKING ON A VAGUE WEDGE-SHAPED PATTERN NORMALLY
SEEN IN HEAVY RAIN EVENTS.  PRECIPITABLE WATER VALUES OF 1.75-2"
LIE ACROSS THE REGION, WHICH HAS BEEN ALLOWING HOURLY RAIN TOTALS
TO REACH 2.5" PER RADAR ESTIMATES.  INFLOW AT 850 HPA IS 25-35
KTS, ABOVE THE MAGNITUDE OF THE MEAN 850-400 HPA WIND, WHICH IS
LIKELY AIDING PRECIPITATION PRODUCTION.  MUCAPES AHEAD OF THE LINE
ARE 1000-2000 J/KG.

AN EASTWARD MOTION AT ~15 KTS IS EXPECTED TO CONTINUE OVER THE
NEXT SEVERAL HOURS.  THE TX PORTION IS ALSO WORRISOME IN THAT THE
OUTFLOW BOUNDARY IS ORIENTED AT MORE OF AN ANGLE TO THE LOW-LEVEL
INFLOW AND MEAN WIND AND WHERE THE VEERING IN THE 850 HPA WINDS IS
EXPECTED TO BE SMALLER IN SCOPE -- RAINFALL MAGNITUDE IS EXPECTED
TO BE GREATER IN NORTHWEST TX THAN SOUTHERN OK.  THE SOLUTION
PREFERRED IS A SLIGHTLY QUICKER VARIATION OF THE 12Z WRF NSSL AND
12Z ARW GUIDANCE -- RECENT HRRR AND EXPERIMENTAL HRRR RUNS WERE OF
SOME UTILITY HERE.  LOCAL AMOUNTS OF 3-5", WITH HOURLY AMOUNTS UP
TO 2.5", SHOULD BE ABLE TO OVERCOME RECENT DRY SOIL CONDITIONS AND
COULD CAUSE ADDITIONAL FLASH FLOODING.

ROTH

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

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

LAT...LON   35139766 34989680 34399611 33009700 32429767 
            32399875 32939910 33579900 34729832