MESOSCALE PRECIPITATION DISCUSSION 0166
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
803 PM EDT WED JUN 03 2015
 
AREAS AFFECTED......SOUTHEAST NE/NORTHEAST KS/NORTHWEST MO... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 040003Z - 040600Z
 
SUMMARY...CONVECTION EXPANDING IN COVERAGE THIS EVENING WILL TAP
MOISTURE AND INSTABILITY TO POSE THE THREAT FOR FLASH FLOODING IN
AREAS THAT RECEIVED HEAVY RAINFALL EARLIER TODAY.

DISCUSSION...CONVECTION IS EXPECTED TO DEVELOP ALONG A SURFACE
BOUNDARY EXTENDING FROM SOUTHEAST NE THROUGH NORTHEAST KS INTO
NORTHWEST MO. THIS IS CLOSE TO A 2000-3000 J/KG MLCAPE AXIS JUST
TO THE SOUTH OF THE SURFACE BOUNDARY. AN INCREASING LOW LEVEL
SOUTHERLY FLOW TRANSPORTS INSTABILITY AND HIGH MOISTURE CONTENT
AIR UP AND OVER THE SURFACE BOUNDARY DURING THE EVENING
HOURS...WITH CONVECTIVE COVERAGE EXPECTED TO EXPAND PRIOR TO 03Z.

RAP MODEL SOUNDINGS INITIALLY SHOW DRY AIR IN THE MID LEVELS...AND
THE COMBINATION OF DRY MID LEVEL AND HIGH CAPE VALUES SUGGESTS
THAT THE CONVECTION IS INITIALLY COLD POOL DRIVEN. HOWEVER...AS
THE LOW LEVEL INFLOW BACKS AHEAD OF THE CONVECTIVE CLUSTER...THE
COLUMN MOISTENS...AND THE CONVECTIVE MODEL SHIFTS TO MORE OF A
FLASH FLOOD THREAT... WITH BACKBUILDING POSSIBLE. 

THERE IS A STRONG HIGH RESOLUTION MODEL SIGNAL THAT THE BEST
CONVECTIVE COVERAGE OCCURS BETWEEN 03Z AND 06Z ACROSS THE MPD
AREA. THERE IS SOME SPREAD ON WHERE THE AXIS OF HEAVIEST RAINFALL
OCCURS. THE NAM/WRF BASED GUIDANCE (INCLUDING THE 12Z ARW/NMMB)
PLACE THE AXIS OF HEAVIEST RAINFALL FURTHER NORTH TOWARD THE
SOUTHEAST NE/SOUTHWEST IA BORDER. CONVERSELY...THE LATEST HRRR IS
FURTHER SOUTH...CLOSER TO THE KS/NE BORDER INTO NORTHWEST MO.

WHILE THERE IS SOME NORTH/SOUTH MODEL DIFFERENCE IN THE PLACEMENT
OF THE HEAVIEST QPF...THERE IS CONSENSUS THAT LOCAL 2 TO 4 INCH
RAINFALL ARE POSSIBLE. FLASH FLOOD GUIDANCE VALUES WERE LOWERED
ACROSS MUCH OF THE REGION BY THE HEAVY RAIN EARLIER TODAY.

THE THREAT FOR HEAVY RAIN COULD EXTEND PAST 06Z...ESPECIALLY
ACROSS THE SOUTHEAST PORTION OF THE MPD AREA.

HAYES

ATTN...WFO...EAX...GID...LBF...OAX...TOP...

ATTN...RFC...MBRFC...

LAT...LON   41229887 41069690 40739593 39559313 38429373 
            39239682 39829915 40270003 40839990 40859993