MESOSCALE PRECIPITATION DISCUSSION 0026
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
944 AM EDT TUE APR 07 2015
 
AREAS AFFECTED...CENTRAL AND EASTERN MO...SOUTHERN IL 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 071340Z - 071740Z
 
SUMMARY...SLOW-MOVING MCS WILL FOSTER SOME FLASH FLOOD POTENTIAL
OVER THE NEXT FEW HOURS DUE TO POTENTIAL FOR INTENSE AND REPEATING
CELLS.

DISCUSSION...MORNING IR SAT IMAGERY SHOWS COLD-TOPPED CONVECTION
WITH OCCASIONAL OVERSHOOTING TOPS IMPACTING PORTIONS EAST-CENTRAL
MO. THE ACTIVITY IS SOMEWHAT ELEVATED IN NATURE JUST TO THE
NORTHEAST OF A WEAK SURFACE COLD POOL OVER NORTH-CENTRAL MO...AND
IS BEING ASSISTED BY THE NOSE OF AN ACTIVE SOUTHWESTERLY LOW LEVEL
JET ON THE ORDER OF 40 KTS. THE ATMOSPHERE IS MODERATELY UNSTABLE
TOO WITH MUCAPE VALUES EXCEEDING 2000 J/KG IN VICINITY OF THE
LEADING EDGE OF THE COLD POOL AND THIS IS SUPPORTING THE REPEAT
NATURE OF SOME OF THE CONVECTIVE CELLS ALONG THE SOUTHERN FLANK OF
THE MCS.

THE 06Z NAM-CONEST...00Z WRF-ARW AND 00Z WRF-NMMB ALL APPEAR TO
HAVE A RELATIVELY GOOD HANDLE ON THE CURRENT ACTIVITY.
HOWEVER...THE MODELS MAY BE PROPAGATING THE MCS A BIT TOO
PROGRESSIVELY TO THE SOUTHEAST...AS THE LATEST RADAR/SAT IMAGERY
WOULD SUGGEST ADDITIONAL POTENTIAL FOR BACK-BUILDING AND REPEATING
OF CELLS. GIVEN THE INSTABILITY POOL OVER SOUTHWEST MO ADVANCING
NORTHEAST INTO THE AFOREMENTIONED FRONT...IT WOULD APPEAR LIKELY
FOR CONVECTION TO SUSTAIN ITSELF ALONG THE SOUTHERN FLANK OF THE
MCS. ALTHOUGH GRADUALLY THE CONVECTION SHOULD EXTEND FARTHER
SOUTHEAST AND ADVANCE INTO SOUTHERN IL WHERE A BIT STRONGER
FORWARD PROPAGATION IS EXPECTED.

HEAVY RAINFALL RATES OF 1 TO 2 INCHES/HR ARE POSSIBLE...AND WITH
POTENTIAL FOR REPEATING CELLS OVER THE NEXT FEW HOURS...SO CONCERN
FOR AT LEAST LOCALIZED FLASH FLOODING EXISTS.

ORRISON

ATTN...WFO...EAX...ILX...LSX...PAH...SGF...

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

LAT...LON   39309265 38909098 38788978 38538825 37398842 
            37188987 37839180 38479299 38999325