MESOSCALE PRECIPITATION DISCUSSION 0032...CORRECTION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
906 AM EDT FRI MAY 03 2013
 
AREAS AFFECTED...NORTHEAST AR...WESTERN TN...WESTERN
KY...SOUTHEAST MO...NORTHERN MS...SOUTHERN IL
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 031250Z - 031850Z
 
SUMMARY...RAINFALL EXPECTED TO INCREASE IN MAGNITUDE ACROSS
PORTIONS OF THE MID-MISSISSIPPI VALLEY INTO THIS AFTERNOON, WHICH
COULD LEAD TO FLASH FLOODING.

DISCUSSION....LOW-LEVEL FRONTOGENESIS IS EXPECTED TO INCREASE
TODAY IN PROXIMITY TO A SLOWLY PROGRESSIVE -- AND WELL-DEFINED --
COLD FRONT MOVING THROUGH THE MISSISSIPPI VALLEY, WITH CONVECTION
MOVING NORTH TO NORTHWESTWARD INTO THE COLD SECTOR PER
PROPAGATION/CORFIDI VECTORS.  FLASH FLOOD GUIDANCE VALUES (FFGS)
ARE QUITE LOW -- BELOW AN INCH WITHIN THREE HOURS -- ACROSS
NORTHEAST AR DUE TO HEAVY RAINS LAST NIGHT, AND THEY REMAIN LOW --
JUST UNDER TWO INCHES WITHIN THREE HOURS -- ACROSS NORTHERN AND
CENTRAL MS AND PORTIONS OF ILLINOIS DUE TO RAINFALL FROM THE PAST
FEW DAYS.  THE 850 HPA INFLOW IS SLIGHTLY CONVERGENT INTO THE
FRONT, WITH WINDS AT THAT LEVEL RISING TO ABOVE 50 KNOTS AT TIMES.
 PRECIPITABLE WATER VALUES ARE EXPECTED TO REMAIN STEADY BETWEEN
1.25 AND 1.50 INCHES.  HOWEVER, INCREASING LOW-LEVEL FRONTOGENSIS
COMBINED WITH A STRENGTHENING UPPER LEVEL TROUGH/DEVELOPING CLOSED
LOW WHICH IS BECOMING NEGATIVELY TILTED SHOULD INCREASE DIVERGENCE
ALOFT OVER THIS AREA.  AMONGST THE MESOSCALE GUIDANCE, THE 00Z ARW
APPEARS TO BE DOING THE BEST JOB (OUTSIDE OF THE IL/IA BORDER) IN
DEPICTING THE ONGOING PRECIPITATION.  PRECIPITATION IS EXPECTED TO
TRAIN INTO THIS AFTERNOON DUE TO THE SLOW MOVEMENT OF THE SYSTEM,
WHICH COULD LEAD TO LOCAL AMOUNTS OF 2-4 INCHES WITHIN THE
SCALLOPED AREA.

ROTH


ATTN...WFO...PAH...MEG...JAN...LSX...LZK...

LAT...LON   32819030 33089073 34049118 35299126 37029091 38779022
            39208898 37238869 35248885 33498942 32978990 32819030