MESOSCALE PRECIPITATION DISCUSSION 0432
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
159 AM EDT SUN AUG 09 2015
 
AREAS AFFECTED...CENTRAL AND EASTERN IA...NORTHWEST IL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 090550Z - 090945Z
 
SUMMARY...AREAS OF TRAINING AND BACKBUILDING CONVECTION WILL
CONTINUE TO PRODUCE VERY HEAVY RAINFALL AND POSSIBLE FLASH
FLOODING. ADDITIONAL CONVECTIVE ORGANIZATION IS EXPECTED.

DISCUSSION...IR SATELLITE IMAGERY SHOWS SOME INCREASED CONVECTIVE
ORGANIZATION ACROSS CENTRAL IA WITH A NOTABLE W/E AXIS OF STRONG
CONVECTION SITUATED FROM NEAR KSLB TO KEBS AND JUST TO THE NORTH
OF KMIW. SEVERAL OTHER CONVECTIVE CLUSTERS APPEAR TO BE ORGANIZING
NEAR AND TO THE EAST OF KDSM AS WELL. THIS ACTIVITY IS ALL
ELEVATED IN NATURE AND IS SOMEWHAT SEPARATED FROM THE MORE
ORGANIZED CONVECTIVE DEVELOPMENT ONGOING ACROSS FAR SOUTHEAST
NEB...NORTHWEST MO AND SOUTHWEST IA WHERE MCS DEVELOPMENT IS WELL
UNDERWAY.

THE CONVECTION FARTHER NORTH IS BEING FACILITATED BY INCREASING
WARM ADVECTION/ISENTROPIC LIFT ASSOCIATED WITH THE NOSE OF A 30 TO
40 KT SOUTHWESTERLY LOW LEVEL JET...AND IS OCCURRING ALONG AN
ELEVATED INSTABILITY GRADIENT. MEANWHILE...SHORTWAVE ENERGY IS
QUICKLY EJECTING OUT INTO THE NORTHERN/CENTRAL HIGH PLAINS AND IS
FOSTERING INCREASINGLY DIVERGENT FLOW ALOFT DOWNSTREAM OVER
NEB/IA/MO. SOME ADDITIONAL ORGANIZATION OF CONVECTION OVER
CENTRAL/EASTERN IA IS EXPECTED AND THIS MAY ADVANCE DOWNSTREAM
INTO NORTHWEST IL AS WARM ADVECTION INCREASES. THE MITIGATING
FACTOR FOR DOWNSTREAM DEVELOPMENT IS A LACK OF INSTABILITY WHICH
IS POOLED IN A MUCH GREATER FASHION OVER NORTHEAST KS/NORTHERN MO
AND SOUTHWEST IA AS PER GOES-SOUNDER LI/CAPE DATA.

REGARDLESS...THE THREAT FOR FLASH FLOODING EXISTS AT LEAST LOCALLY
GIVEN PWATS APPROACHING 2 INCHES...AND AS CONVECTIVE CELLS DEVELOP
IN AN ENVIRONMENT CONDUCIVE FOR TRAINING AND BACKBUILDING.

ORRISON

ATTN...WFO...DMX...DVN...ILX...

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

LAT...LON   42629337 42419174 42119032 41618966 40868955 
            40678960 40399047 40669171 41079304 41539394 
            41929476 42419495 42609460