MESOSCALE PRECIPITATION DISCUSSION 0597
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
830 PM EDT TUE AUG 23 2016
 
AREAS AFFECTED...NORTHEAST KS...EASTERN NE....NORTHWEST
MO...WESTERN AND CENTRAL IA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 240030Z - 240500Z
 
SUMMARY...CONVECTION INCREASING IN COVERAGE ON THE NOSE OF A
STRENGTHENING LOW JET WILL EXPAND INTO COVERAGE... AFFECTING
PORTIONS OF EASTERN NE/NORTHEAST KS/NORTHWEST MO AND WESTERN IA.
THE MCS COULD PRODUCE A FLASH FLOOD THREAT THROUGH THE LATE
EVENING HOURS.

DISCUSSION...CONVECTION WAS SLOWLY INCREASING IN COVERAGE ACROSS
NORTHEAST KS...EASTERN NE AND WESTERN NE LATE THIS AFTERNOON. THE
CONVECTION IS FORMING IN A RIBBON OF 2000-3000 J/KG OF MLCAPE 
STRETCHING FROM EASTERN KS INTO EASTERN NE...WHICH HAS RECENTLY
OVERCOME LOW LEVEL BASED CIN. THE CONVECTION LIES ON THE WESTERN
EDGE OF THE PRECIPITABLE WATER GRADIENT...WITH VALUES CLOSE TO
2.00 INCHES (PER THE LATEST BLENDED TPW PRODUCT). THUS FAR...THE
FLEDGLING CONVECTION HAS BEEN PRODUCE HOURLY RAINFALL RATES
BETWEEN 1.00 AND 1.50 INCHES. 

AS THE LOW LEVEL JET INCREASES ACROSS EASTERN KS INTO EASTERN NE
AND WESTERN IA (WHERE REGIONAL VWP SHOWED 25 TO 35 KNOTS OF LOW
LEVEL SOUTHERLY FLOW...IT CONTINUES TO TRANSPORT 2.00 INCH
PRECIPITABLE WATER AIR INTO THE DEVELOPING CONVECTION. THE
CONVECTION TO THIS POINT HAS BEEN FAIRLY DISCRETE...BUT THE 00Z
OAX SOUNDING SHOWED THE COLUMN MOISTENING...SUGGESTING THAT WARM
PROCESSES COULD BECOME MORE IMPORTANT WITH TIME. THIS COULD RESULT
IN HIGHER HOURLY RAINFALL RATES...ESPECIALLY OVER EASTERN NE AND
WESTERN IA...WHERE HOURLY RATES COULD APPROACH 2.00 INCHES.

THE 23Z HRRR SHOWED A MAXIMUM OF 2.00 TO 4.00 INCHES OF QPF ACROSS
PORTIONS OF EASTERN NE AND NEARBY SOUTHWEST IA. AS THE LOW AND MID
LEVEL WINDS VEER AHEAD OF A WEAK SHORT WAVE APPROACHING WESTERN
IA... THE MAXIMUM QPF AXIS COULD SHIFT INTO CENTRAL IA.
HOWEVER...THERE IS SOME SPREAD IN THE PLACEMENT OF THE MAXIMUM QPF
AXIS AMONG THE HIGH RESOLUTION GUIDANCE SOLUTIONS...SO THE MPD
AREA WAS EXPANDED TO INCLUDED THIS SPREAD.   

HAYES

ATTN...WFO...ARX...DMX...EAX...FSD...GID...OAX...TOP...

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

LAT...LON   43439390 43239236 42519229 40569293 39959444 
            39599703 40999756 42269678 43349528