MESOSCALE PRECIPITATION DISCUSSION 0089
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
304 PM EDT SAT MAY 16 2015
 
AREAS AFFECTED...TX PANHANDLE...NORTHWEST OK...SOUTHERN KS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 161900Z - 170000Z
 
SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BECOME
MORE ORGANIZED AND EXPAND IN COVERAGE THIS AFTERNOON. GIVEN RECENT
HEAVY RAINS...AND THE POTENTIAL FOR CELL-TRAINING AND
BACK-BUILDING...FLASH FLOODING WILL BE A CONCERN.

DISCUSSION...MULTIPLE CLUSTERS OF INCREASINGLY SURFACE-BASED
COLD-TOPPED CONVECTION IS SEEN IN THE LATEST RADAR AND SATELLITE
IMAGERY ACROSS THE TX PANHANDLE AND INTO PORTIONS OF NORTHERN OK
AND SOUTHERN KS. THE ACTIVITY IN PARTICULAR OVER THE TX PANHANDLE
HAS BECOME BETTER ORGANIZED OVER THE LAST HOUR...AND THE LATEST
EXPERIMENTAL LIGHTNING DENSITY PRODUCT COUPLED WITH THE GOES
OVERSHOOTING TOP ALGORITHM CONFIRM THIS UPTICK IN
ORGANIZATION/GROWTH.

ALL OF THE ACTIVITY IS DEVELOPING OUT AHEAD OF A DEEP UPPER TROUGH
OVER THE WESTERN U.S. AND WILL BE STRONGLY INFLUENCED THIS
AFTERNOON AND EVENING BY THE ARRIVAL OF A VERY STRONG VORT CENTER
MOVING EAST ACROSS NM CURRENTLY. THIS ENERGY WILL LIFT NORTHEAST
INTO THE HIGH PLAINS LATER THIS AFTERNOON AND WILL FOSTER STRONGLY
DIVERGENT FLOW ALOFT AND THUS ROBUST DEEP LAYER ASCENT.
MEANWHILE...THE LATEST GOES-SOUNDER DATA SHOWS AN INCREASINGLY
UNSTABLE AIRMASS POOLING ACROSS THE CENTRAL AND SOUTHERN PLAINS
WITH A NOTABLE N/S AXIS OF LI/S DOWN AS LOW AS -5 TO -8...AND
MUCAPE VALUES OF 2000 TO 3000 J/KG. A COMBINATION OF STRONG UPPER
SUPPORT AND INSTABILITY WILL RESULT IN WIDESPREAD ORGANIZED
CONVECTION THIS AFTERNOON AND EVENING. ALREADY THERE IS A
WELL-DEFINED COLD POOL SITUATED NOW OVER PORTIONS OF NORTHWEST OK
AND SOUTHERN KS IN ASSOCIATION WITH SOME OF THE ONGOING
CONVECTION...BUT THIS COLD POOL IS EXPECTED TO FOSTER ADDITIONAL
CELL DEVELOPMENT AS SOMEWHAT STRONGER 850 FLOW DEVELOPS AHEAD OF
THE TROUGH AND INSTABILITY INTERACTS WITH AND OVERRUNS IT.

THE 12Z WRF-ARW/12Z WRF-NMM AND ESPECIALLY THE 12Z WRF-NSSL ALL
FAVOR A WELL-DEFINED SW/NE AXIS OF HEAVIER RAINS THIS AFTERNOON
AND EVENING ASSOCIATED WITH THE EXPANDING CLUSTERS OF CONVECTION.
RAINFALL AMOUNTS OF 2 TO 4 INCHES WITH ISOLATED HEAVIER AMOUNTS
CAN BE EXPECTED. WHILE THERE WILL OVERWHELMINGLY BE A SEVERE MODE
TO THE CONVECTION...THERE WILL BE A GRADUAL INCREASE IN THE
POTENTIAL FOR FLASH FLOODING DUE TO CELL-TRAINING AND
BACK-BUILDING. FURTHERMORE...THE RAINS WILL BE OCCURRING OVER
AREAS THAT HAVE SEEN SIGNIFICANT RAINFALL OVER THE LAST COUPLE OF
WEEKS. 

ORRISON

ATTN...WFO...AMA...DDC...ICT...LUB...OUN...TOP...

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

LAT...LON   38719709 38299625 37469643 36489750 35709860 
            34740011 34170132 34270192 34620221 35230199 
            35950136 36820036 37729912 38369805