MESOSCALE PRECIPITATION DISCUSSION 0047
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
934 PM EDT SUN MAY 11 2014
 
AREAS AFFECTED...EASTERN IL...CENTRAL IN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 120130Z - 120530Z
 
SUMMARY...STRONG TO SEVERE THUNDERSTORMS WILL CONTINUE TO PRODUCE
VERY HEAVY RAINFALL. ADDITIONAL FLASH FLOODING CONCERNS ARE
EXPECTED FOR THE NEXT FEW HOURS

DISCUSSION...LATEST IR SAT IMAGERY SHOWS A VERY COLD-TOPPED MCS
ADVANCING ACROSS PORTIONS OF ERN IL AND N CNTRL IN. THE MOTION OF
THE BROADER CONVECTIVE CLUSTER IS GENERALLY ESE AT 10 TO 20
KTS...BUT THERE IS EVIDENCE OF THE SWRN FLANK OF THE CONVECTIVE
LINE SLOWING DOWN AND BEGINNING TO PARALLEL THE MEAN LYR FLOW
SOMEWHAT. MEANWHILE...OUT AHEAD OF THE MCS...THERE IS SOME
MULTI-CELLULAR CONVECTION LIFTING GENERALLY NWD.

OVER THE NEXT 2 TO 3 HOURS...THERE SHOULD BE SEVERAL CELL MERGERS
AND THERE IS A GROWING RISK OF CELL TRAINING GIVEN THE MCS
BECOMING MORE PARALLEL TO THE MEAN FLOW. PROPAGATION VECTORS
SHOULD REMAIN RATHER WEAK...AND A SUSTAINED SRLY TRANSPORT OF
MOIST/UNSTABLE AIR UP ACROSS CNTRL/SRN IL AND SRN IN...THE
CONVECTION SHOULD CONTINUE TO BE SUSTAINABLE.

LATEST HI-RES MODELS ARE NOT AT ALL HANDLING THIS CONVECTION
WELL...BUT WITH A FAVORABLE THERMODYNAMIC ENVIRONMENT AND
INCREASING STRONG WARM AIR ADVECTION AHEAD OF A DEEP TROUGH
EXITING THE ROCKIES...CONVECTION SHOULD PERSIST WELL INTO THE
NIGHT.

RAINFALL RATES OF UP TO 2 INCHES/HR ARE EXPECTED AND WITH CELL
MERGERS/TRAINING...LOCALLY VERY HVY RAINFALL TOTALS ARE
EXPECTED...AND THIS WILL ELEVATE THE RISK FOR FLASH FLOODING.

ORRISON

ATTN...WFO...ILN...IWX...IND...LOT...ILX...DVN...

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

LAT...LON   39428558 39598686 39968820 40368900 40828935 41378919
            41728842 41518680 41028552 40418493 39708491 39428558