MESOSCALE PRECIPITATION DISCUSSION 0313
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
326 AM EDT SAT AUG 23 2014
 
AREAS AFFECTED...FAR EASTERN NE...CENTRAL AND SOUTHERN
IA...NORTHERN MO 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 230715Z - 231200Z
 
SUMMARY...REPEATING SHOWERS AND THUNDERSTORMS ARE ANTICIPATED OVER
THE NEXT FEW HOURS. SOME FLASH FLOODING IS POSSIBLE GIVEN THIS AND
THE EXPECTATION OF INTENSE RAINFALL RATES.

DISCUSSION...THE LATEST SAT TRENDS INDICATE THE SERN FLANK OF THE
LARGE MCS OVER NEB TENDING TO BECOME MORE ACTIVE AS THERE APPEARS
TO BE AN EXPANSION OF COLD CONVECTIVE TOPS OVER SERN NEB AND INTO
FAR SWRN IA. THIS AREA OF INTENSIFYING CONVECTION APPEARS TO BE
HEAVILY CONNECTED TO THE NOSE OF A 30 TO 40 KT SWLY LOW LVL JET
INTERSECTING A STALLED FRONTAL ZONE.

THE ATMOS IS VERY MOIST WITH PWATS AS PER THE LATEST GOES-SOUNDER
DATA AOA 2 INCHES. THE LATEST RAP ANALYSIS SHOWS A FAIR AMT OF
INSTABILITY...2000 J/KG TO 3000 J/KG...NEAR THE FRONT AND ESP OVER
NRN MO. GIVEN THE INCREASE LOW LVL JET ENERGY/WARM AIR ADVECTION
AND THE THERMODYNAMICALLY FAVORABLE ENVIRONMENT FOR
CONVECTION...THE ONGOING ACTIVITY MAY TEND TO EXPAND IN COVERAGE
OFF TO THE EAST ACROSS SRN IA INVOF THE FRONT. THE ACTIVITY IS
ALSO EXPECTED TO TEND TO BACK BUILD AND REPEAT OVER THE SAME AREA
WHERE THE NOSE OF THE LOW LVL JET INTERACTS WITH THE FRONT. THIS
SOLN IS SUPPORTED BY THE 06Z HRRR AND MATCHES THE LATEST RADAR
TRENDS.

SOME AREAS IN CNTRL AND SRN IA HAVE ALREADY SEEN HVY RAINFALL OVER
THE LAST 24 HOURS...AND SO ADDITIONAL HVY RAINS WILL ENHANCE THE
POTENTIAL FOR RUNOFF PROBS AND ELEVATE THE RISK OF FLASH FLOODING.
WILL CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...LSX...DVN...DMX...EAX...FSD...OAX...

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

LAT...LON   40119395 40199505 40489609 40969677 41729720 42489697
            42759573 42469391 41859218 41249142 40669144 40139212
            40119395