MESOSCALE PRECIPITATION DISCUSSION 0276
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
510 PM EDT FRI JUN 26 2015
 
AREAS AFFECTED...CNTRL ILLINOIS AND EWD ACROSS INDIANA AND OHIO 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 262110Z - 270310Z
 
SUMMARY...VERY EFFICIENT RAINFALL RATES EMBEDDED WITHIN A LARGE
AREA OF LARGELY STRATIFORM RAIN WILL CONTINUE A FLASH FLOOD THREAT
THROUGH 03Z GIVEN WET ANTECEDENT CONDITIONS ACROSS PORTIONS OF THE
MIDWEST. 

DISCUSSION...AT 21Z...A LARGE REGION OF STRATIFORM RAIN WITH
EMBEDDED CONVECTIVE ELEMENTS EXTENDED EWD FROM N-CNTRL ILLINOIS
INTO MUCH OF OHIO. DESPITE INSTABILITY BEING RATHER LIMITED ACROSS
THE REGION...POCKETS OF RAINFALL WITH RATES OF 1-3 IN/HR HAVE BEEN
OBSERVED ACROSS THE MIDWEST SUCH AS 2.56 INCHES IN 45 MIN FROM
DELAWARE COUNTY INDIANA...1.5 INCHES IN 40 MIN FROM GRUNDY COUNTY
ILLINOIS AND 1 INCH IN 15 MIN FROM CLINTON COUNTY OHIO. THESE
IMPRESSIVE RAINFALL AMOUNTS ARE EVIDENCE OF VERY EFFICIENT...WARM
TOPPED RAIN PRODUCERS OUT AHEAD OF AN APPROACHING NNE-SSW ORIENTED
MID-UPPER LEVEL TROUGH AXIS CURRENTLY CENTERED OVER IOWA.
DIFFLUENT AND DIVERGENT UPPER FLOW TIED TO THE RIGHT ENTRANCE
REGION OF THE ASSOCIATED UPPER JET ARE HELPING TO SUPPORT STRONG
VERTICAL MOTIONS.

GIVEN THE STRONG DYNAMIC FORCING IN PLACE FOR LATE JUNE...SOME
FRONTOGENETIC FORCING IN THE 850-700 LAYER TIED TO THE SURFACE
BOUNDARY DRAPED ACROSS THE REGION...AND SUFFICIENT MOISTURE...WE
EXPECT THE FLASH FLOOD THREAT TO SLOWLY SHIFT EWD WITH TIME THIS
EVENING INTO THE EARLY OVERNIGHT HOURS. BROAD SUPPORT IS SEEN FOR
THIS SCENARIO IN BOTH THE GLOBAL AND HI-RES MODELS THROUGH 03Z.

OTTO

ATTN...WFO...CLE...ILN...ILX...IND...IWX...LOT...PBZ...RLX...

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

LAT...LON   41278601 41068407 40858302 40558181 39978088 
            39188111 39028265 39278528 39388704 39498847 
            39718879 40158888 40798852 41028764