MESOSCALE PRECIPITATION DISCUSSION 0144
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1050 AM EDT MON JUL 01 2013
 
AREAS AFFECTED......OHIO VALLEY... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 011449Z - 011849Z
 
SUMMARY...FLASH FLOODING IS LIKELY ACROSS PORTIONS OF THE OHIO
VALLEY DUE TO NEARLY STATIONARY OR SLOW-MOVING HEAVY RAIN AND WET
ANTECEDENT CONDITIONS.

DISCUSSION...A DEEP PLUME OF MOISTURE...WITH PRECIPITABLE WATER
VALUES NEAR 1.5 INCHES... CONTINUES TO EXPERIENCE DEEP ASCENT
WITHIN PROXIMITY OF 2 DISTINCT ZONES OF CONVERGENCE OVER THE OHIO
VALLEY DENOTED AS MID-LEVEL TROUGHS ON THE MAP...WHICH ARE
ROTATING SLOWLY AROUND DUAL-MID LEVEL CENTERS OVER WESTERN
KENTUCKY AND TENNESSEE.  REGIONAL VAD WIND PROFILE DATA AND 12Z
RAOBS INDICATE LIGHT AND NEARLY UNIDIRECTIONAL FLOW THROUGH 300
MB...WITH RADAR LOOPS CONFIRMING NEARLY STATIONARY CONVECTIVE CELL
MOTION DUE TO THE PROPAGATION COMPONENT OFFSETTING THE ADVECTION
COMPONENT.  CLOSE EXAMINATION OF WATER VAPOR IMAGERY SHOWS A
SUBTLE BUT POTENTIALLY SIGNIFICANT LOBE OF ASCENT LIFTING SLOWLY
INTO PORTIONS OF SOUTHERN INDIANA AND ILLINOIS WITH VISIBLE
IMAGERY DISPLAYING POCKETS OF STRONGER INSOLATION CONTRIBUTING TO
FURTHER DESTABILIZATION.  RADAR LOOPS ARE CONFIRMING THE
ATMOSPHERIC RESPONSE THROUGH MORE VIGOROUS CONVECTIVE CELLS.

RADAR RAINFALL ESTIMATES OF 0.5 TO 1.0 INCHES PER HOUR...WITH
LOCAL VALUES OF 1.0 TO 1.75 INCHES PER HOUR...ARE EASILY
ATTAINABLE GIVEN THE DESCRIBED ANALYSIS.  GIVEN THAT HOURLY FLASH
FLOOD GUIDANCE VALUES AVERAGE 1.5 TO 2.0 INCHES ACROSS A BROAD
PORTION OF THE OHIO VALLEY...WITH EMBEDDED BUT SMALLER AREAS OF
0.75 TO 1.5 INCHES...THE PROBABILITY OF EXCEEDING FLASH FLOOD
GUIDANCE IS ESTIMATED TO BE ABOVE 80 PERCENT.

JAMES 

ATTN...WFO...CLE...ILN...LMK...IWX...IND...PAH...LOT...ILX...
MEG...LSX...

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

LAT...LON   37848954 39758870 40938690 41378515 41058383 40018348
            39128418 38018669 37168786 35738855 36238929 37848954 
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