MESOSCALE PRECIPITATION DISCUSSION 0370
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
912 PM EDT TUE JUN 21 2016
 
AREAS AFFECTED...PORTIONS OF IA, MO, & IL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 220111Z - 220711Z
 
SUMMARY...THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND
ALIGN INTO TRAINING SEGMENTS OVER THE NEXT SEVERAL HOURS.  WITH
HOURLY RAIN RATES UP TO 2.5" POSSIBLE, FLASH FLOODING IS POSSIBLE.

DISCUSSION...WIDELY SCATTERED SHOWERS AND THUNDERSTORMS HAVE BEEN
SLOWLY DEVELOPING IN AN ELEVATED MANNER ON THE POLEWARD SIDE OF A
SYNOPTIC SCALE WARM FRONT AND NORTHEAST-MOVING OUTFLOW BOUNDARY,
VERY NEAR THE APPARENT EDGE OF A CAPPING INVERSION AND THE 850 HPA
SLICE OF THE FRONTAL BOUNDARY.  INFLOW INTO THE REGION IS 25-35
KTS AT 850 HPA PER RECENT VAD WIND PROFILES.  MUCAPES TO THE
SOUTHWEST ARE SIGNIFICANT, IN THE 4000-5500 J/KG RANGE. 
PRECIPITABLE WATER VALUES ARE 1.75-2" IN THE AREA, PER RAP
FORECASTS, SATELLITE-BASED BLENDED TPW IMAGERY, AND THE OAX/VALLEY
NE SOUNDING.

RAP FORECASTS OVER THE PAST SEVERAL HOURS HAVE BEEN INSISTENT ON
INCREASING THE LOW-LEVEL INFLOW BOTH IN AREAL EXTENT AND INTENSITY
THROUGH 07Z, WITH THE MAGNITUDE ULTIMATELY REACHING 50 KTS. 
ORGANIZED THUNDERSTORM MOVEMENT IS EXPECTED TO BE EAST-SOUTHEAST
NEAR 40 KTS -- CELL TRAINING WOULD BE THE MOST LIKELY CULPRIT FOR
HEAVY RAINFALL.  WITH THIS DEGREE OF INSTABILITY AND INFLOW
PRESENT, IT IS POSSIBLE THAT WHAT STARTS OUT AS A WEST-NORTHWEST/
EAST-SOUTHEAST BAND OF CONVECTION COULD EVOLVE INTO A SERIES OF
CONVECTIVE BOWS/ARCS WITH TIME OVERNIGHT.  ALSO, THERE WILL BE
BATTLE BETWEEN THE EDGE OF THE CAPPING INVERSION AND THE EVOLVING
THUNDERSTORM COMPLEX, AS THE AVAILABLE INSTABILITY WILL TRY TO
MINIMIZE ELEVATED CONVECTION (ATTEMPTING TO FORM IT CLOSER TO THE
SURFACE BOUNDARY), WHILE THE CAP EDGE WILL ATTEMPT TO MAINTAIN
SOME ELEVATION.  THE MESOSCALE/CAM GUIDANCE SUGGESTS LOCAL AMOUNTS
OF 2-4" ARE POSSIBLE. THIS COULD FALL QUICKLY, AS HOURLY RAIN
RATES UP TO 2.5" ARE POSSIBLE.  FLASH FLOODING IS CONSIDERED
POSSIBLE.

ROTH

ATTN...WFO...ARX...DMX...DVN...EAX...FSD...ILX...LSX...MPX...

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

LAT...LON   44169655 43549343 41459069 39759007 40539241 
            41329378