MESOSCALE PRECIPITATION DISCUSSION 0438
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
547 PM EDT MON JUL 03 2017

AREAS AFFECTED...TX/OK PANHANDLES...NORTHWEST/CENTRAL OK

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

VALID 032145Z - 040245Z

SUMMARY...DEVELOPING CLUSTERS OF VERY INTENSE SHOWERS AND
THUNDERSTORMS WILL BECOME A BIT MORE EXPANSIVE AND ORGANIZED
THROUGH THE LATE-AFTERNOON WHILE SHIFTING SOUTHEAST IN TIME GOING
THROUGH THE EVENING HOURS. SOME FLASH FLOODING IS POSSIBLE.

DISCUSSION...VERY IMPRESSIVELY COLD-TOPPED CONVECTION IS IMPACTING
HARPER COUNTY IN NORTHWEST OK...WHICH IS PART OF A GRADUALLY
ORGANIZING AND EXPANDING CLUSTER OF THUNDERSTORMS. THE ACTIVITY IS
DEVELOPING IN A VERY UNSTABLE AIRMASS GIVEN CONTINUED STRONG
DIURNAL HEATING AND ALSO A MOISTENING BOUNDARY LAYER. IN
FACT...THE LATEST MLCAPE VALUES ACROSS AREAS OF NORTHWEST OK ARE
ON THE ORDER OF 3500 TO 4000 J/KG.

SURFACE OBSERVATIONS ARE ALSO SUGGESTING AN AREA OF IMPROVING
SURFACE CONVERGENCE ACROSS THE OK/TX PANHANDLE REGION WITH
PROXIMITY OF A WAVE OF LOW PRESSURE AND ALSO EXTENDING
EAST-SOUTHEAST TOWARD CENTRAL OK ALONG A WEAK SURFACE TROUGH.
ADDITIONAL ASCENT IS ALSO NOTED ON THE LARGE SCALE COURTESY OF A
MID LEVEL SHORTWAVE TROUGH EJECTING OUT ACROSS THE CENTRAL KS AND
EXTENDING SOUTHWEST BACK DOWN ACROSS THE TX PANHANDLE.

GIVEN THE AFOREMENTIONED FACTORS...THE CONVECTION SHOULD TEND TO
GROW UPSCALE OVER THE NEXT SEVERAL HOURS WITH AN ORGANIZATION
FAVORING SLOW-MOVING AND INTENSE THUNDERSTORMS WITH VERY HEAVY
RAINFALL RATES. PWATS ARE NEAR 1.5 INCHES ACROSS THE REGION...BUT
INCREASE ACROSS AREAS FARTHER SOUTHEAST TOWARD CENTRAL OK WHERE
THE CONVECTION IS LIKELY TO PROPAGATE TOWARD LATER IN THE EVENING.

SOME FLASH FLOODING WILL BE POSSIBLE WITH RAINFALL RATES OF 2.5
INCHES/HR AND STORM TOTAL OF 3 TO 6+ INCHES CONSIDERING THE RATHER
SLOW CELL MOTION. WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...AMA...DDC...ICT...OUN...TSA...

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

LAT...LON   37389832 36999729 36329656 35479655 34829735
            34739864 35210011 35690061 36390080 37050028
            37359938