MESOSCALE PRECIPITATION DISCUSSION 0136
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
534 AM EDT WED JUN 26 2013
 
AREAS AFFECTED...EASTERN IA...SOUTHERN WI...NORTHERN AND CENTRAL
IL...WESTERN IN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 260932Z - 261232Z
 
SUMMARY...A DEVELOPING MESOSCALE CONVECTIVE VORTEX -- MCV -- IS
DEVELOPING BANDS OF CONVECTION IN ITS SOUTHERN AND NORTHEASTERN
QUADRANTS.  THIS SYSTEM IS EXPECTED TO MOVE SOUTHEAST, AND COULD
CAUSE FLASH FLOODING.

DISCUSSION...A DEVELOPING MCV ACROSS EASTERN IA SHOULD BEGIN
PUSHING SOUTHEASTWARD OVER THE NEXT FEW HOURS.  THIS CONVECTIVE
CLUSTER HAS BEEN SLOW-MOVING OVER THE PAST FEW HOURS, DEPOSITING
FIVE INCHES OF RAIN IN NORTH INDEPENDENCE IA.  A NEGATIVELY-TILTED
TROUGH JUST TO ITS SOUTHWEST APPEARS TO HAVE LEFT IT IN A
RELATIVELY NON-SHEARED ENVIRONMENT, WHICH HAS ALLOWED THIS SYSTEM
TO FORM CHARACTERISTICS SIMILAR TO ITS WARM CORE COUSINS OVER THE
TROPICS, IN THIS CASE BANDING FEATURES SURROUNDING THE MCV. 
PRECIPITABLE WATER VALUES REMAIN IN THE 1.75-2 INCH RANGE, WHICH
IS WELL ABOVE NORMAL FOR JUNE.  THE 00Z GFS INDICATES THAT ANY
BACKBUILDING ACROSS THE AREA SHOULD END SHORTLY, AND THAT AN
EAST-SOUTHEAST TO SOUTHEAST PROPAGATION SHOULD BEGIN.  THE 850-250
MEAN LAYER FLOW IS JUST NORTH OF DUE EAST IN THIS REGION. 
HOWEVER, THE DEVELOPMENT OF A COOL POOL SHOULD ALLOW THE COMPLEX
TO MOVE OR REDEVELOP SOUTHEASTWARD IN THE NEAR FUTURE.  LOW-LEVEL
INFLOW OF 40-55 KNOTS INTO THE MESOSCALE STATIONARY FRONT --
THROUGH 12Z -- TO ITS SOUTHEAST AND ATMOSPHERIC INSTABILITY
INDICATED BY SATELLITE-DERIVED CAPE VALUES IN CENTRAL IL OF
2500-3500 J/KG SHOULD CAUSE NEW ACTIVITY TO BREAK OUT IN THE FORM
OF A CONVECTIVE LINE OR BAND ACROSS PORTIONS OF IL AND WESTERN
INDIANA IN ADVANCE OF THIS COMPLEX OVER THE NEXT FEW HOURS.  

CONFIDENCE IS NOT HIGH IN THIS SEQUENCE OF EVENTS SINCE THE
COMPLEX HAS NOT BEEN WELL BEHAVED OVERNIGHT, AS PART OF ITS INFLOW
MAY HAVE BEEN CUT OFF BY A SMALL ORGANIZED THUNDERSTORM CLUSTER
OVER MISSOURI.  HOWEVER, LOCAL AMOUNTS OF 2-4 INCHES REMAIN IN THE
CARDS, WITH ITS EXPECTED PROGRESSIVE NATURE CUTTING DOWN AMOUNTS
FROM WHAT HAS BEEN EXPERIENCED OVERNIGHT IN IOWA.  UNCERTAINTY IN
EXPECTED PROGRESSION AND HEAVIEST RAINFALL PLACEMENT HAS LED TO A
SLIGHTLY LARGER AREA THAN DEPICTED ON MESOSCALE PRECIPITATION
DISCUSSION #134 AND POSSIBLE OVER LIKELY WORDING IN REGARDS TO
FLASH FLOODING.

ROTH

ATTN...WFO...IWX...IND...LOT...ILX...MKX...LSX...DVN...ARX...
DMX...

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

LAT...LON   38868730 39148957 40719147 40979191 41879289 42679247
            43299125 43338828 41428601 38868730