MESOSCALE PRECIPITATION DISCUSSION 0455
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
835 PM EDT MON JUL 11 2016
 
AREAS AFFECTED...WESTERN/CENTRAL IA...EASTERN NE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 120035Z - 120600Z
 
SUMMARY...THUNDERSTORMS ARE EXPECTED TO EXPAND AND ORGANIZE OVER
THE NEXT FEW HOURS ACROSS ERN NE/WRN IA. 1 TO 3 INCHES OF RAIN ARE
POSSIBLE THROUGH 06Z. FLASH FLOODING IS POSSIBLE.

DISCUSSION...A SURFACE COLD FRONT AND MID/UPPER-LEVEL SHORTWAVE
ARE ADVANCING INTO A PREVIOUSLY CAPPED AIR MASS, AND CONVECTION IS
NOW FIRING ALONG A SLOWLY ADVANCING COLD FRONT. A HIGHLY MOIST
(850 MB DEWPOINTS NEAR 20 DEG C) AND UNSTABLE (MLCAPE OF 2000-4000
J/KG) AIR MASS WILL SUPPORT CONTINUED DEVELOPMENT AND EXPANSION OF
DEEP CONVECTION THROUGH THE NEXT SEVERAL HOURS. PWAT VALUES ARE IN
THE 2-2.2 INCH RANGE ACROSS THE OUTLINED AREA, WHICH COMBINED WITH
THE IMPRESSIVE INSTABILITY VALUES AND MODEST UPPER-LEVEL WIND
SHEAR, SHOULD SUPPORT INSTANTANEOUS RAIN RATES OF 2-3 IN/HR.

CONVECTION IS FORECAST BY THE HRRR AND HRRR-PARALLEL TO BECOME
MORE ORGANIZED OVER THE NEXT SEVERAL HOURS, EVENTUALLY BECOMING
MORE QUICKLY FORWARD PROPAGATING AS A COLD POOL DEVELOPS BY
04-05Z. THE MAIN FLASH FLOODING THREAT WILL BE BEFORE THIS OCCURS,
WHEN TRAINING OF CELLS MAY OCCUR DUE TO 850-300 MB MEAN FLOW
ORIENTED NEARLY PARALLEL TO THE SURFACE COLD FRONT. AS A RESULT, 1
TO 3 INCHES OF RAIN ARE POSSIBLE, WITH LOCALLY HIGHER AMOUNTS.
GIVEN THE POTENTIAL FOR HIGH RATES AND SOME TRAINING, FLASH
FLOODING IS POSSIBLE.

RYAN

ATTN...WFO...ARX...DMX...FSD...MPX...OAX...

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

LAT...LON   43919441 43549348 42819272 41839300 41229379 
            40849511 40739594 41009688 41859713 42879639 
            43579564 43799519