MESOSCALE PRECIPITATION DISCUSSION 0363
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
206 AM EDT SUN JUL 19 2015
 
AREAS AFFECTED...CNTRL-NRN MISSOURI INTO W-CNTRL ILLINOIS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 190605Z - 191115Z
 
SUMMARY...TRAINING CONVECTION WITHIN A VERY MOIST AND UNSTABLE
AIRMASS MAY LEAD TO A FEW FLASH FLOOD CONCERNS FROM CNTRL-NRN
MISSOURI INTO W-CNTRL ILLINOIS THROUGH 09Z. A GRADUAL PUSH TOWARD
THE SOUTH IS EXPECTED NEAR THE MISSISSIPPI RIVER VALLEY BUT
ACTIVITY MAY HOLD ON LONGER ACROSS NWRN MISSOURI IN A REGION OF
LOW FFG.

DISCUSSION...RADAR IMAGERY OVER THE PAST FEW HOURS HAS SHOWN AN
EXPANDING REGION OF THUNDERSTORMS FROM NRN MISSOURI INTO W-CNTRL
ILLINOIS. IT APPEARS THIS REGION HAS FORMED WITHIN A REGION OF LOW
LEVEL CONFLUENT FLOW AND LARGE INSTABILITY AS NOTED ON KILX AND
KTOP 00Z RAOBS. AT 05Z...BLENDED TPW IMAGERY SHOWED AN AXIS OF
PRECIPITABLE WATER BETWEEN 1.75 AND 2.25 INCHES EXTENDING FROM
CNTRL KANSAS INTO NRN MISSOURI AND W-CNTRL ILLINOIS...WHICH MAY
ALLOW FOR LOCALLY VERY HEAVY RAINFALL RATES...IN EXCESS OF 2 IN/HR.

GIVEN LOW LEVEL FLOW IS 20-30 KTS FROM THE WSW PER AREA VAD WIND
PROFILE PLOTS...WHICH IS SIMILAR TO THE CLOUD BEARING LAYER MEAN
WIND...TRAINING CELLS APPEAR LIKELY ACROSS THE REGION AND IS
ALREADY CONFIRMED IN REGIONAL RADAR IMAGERY. 00Z HI-RES MODELS AND
RECENT RUNS OF THE HRRR AND HRRR_EXPERIMENTAL ARE MIXED WITH THE
MAGNITUDE OF RAINFALL THROUGH THE NIGHT...HOWEVER...GIVEN THE
THERMODYNAMIC ENVIRONMENT IN PLACE...AND THE PRESENCE OF THE RIGHT
ENTRANCE REGION OF A JET STREAK FORECAST TO REACH NRN MISSOURI BY
10Z...ALONG WITH DIFFLUENT UPPER LEVEL FLOW...SIGNS ARE POINTING
TOWARD THE WETTER MODELS. AS RAINFALL COVERAGE INCREASES...AND A
COLD POOL DEVELOPS...CELLS MAY SINK SOUTHWARD TOWARD 10-11Z...BUT
THERE ARE HINTS THAT A CONVECTION MAY CONTINUE TO REGENERATE ALONG
THE WEST SIDE OF THE COMPLEX PROMOTING POSSIBLE FLASH FLOODING.
FFG VALUES ARE LOWEST ACROSS THE WRN AND NRN PORTIONS OF THE
THREAT AREA...GENERALLY 1.5-2.0 IN/HR AND LESS THAN 3 INCHES IN 3
HOURS.

OTTO

ATTN...WFO...DMX...DVN...EAX...ILX...LSX...

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

LAT...LON   40679459 40579244 39918940 39058849 38399048 
            38919379 40009506 
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