MESOSCALE PRECIPITATION DISCUSSION 0228
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
854 PM EDT THU AUG 29 2013
 
AREAS AFFECTED...E-CNTRL MN INTO NRN WI AND THE WRN U.P. OF MI 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 300053Z - 300553Z
 
SUMMARY...TRAINING CONVECTION WITH RAINFALL RATES OF 1-2 IN/HR TO
THE NORTH OF A WARM FRONT AND OUTFLOW BOUNDARY WILL POSE A FLASH
FLOOD RISK ACROSS NRN WISCONSIN AND PORTIONS OF THE MICHIGAN U.P.
INTO THE EARLY OVERNIGHT HOURS BEFORE ENDING FROM WEST TO EAST.

DISCUSSION...00Z SOUNDING DATA FROM GRB AND MPX...APPEARED TO
MATCH THE SPC MESOANALYSIS PAGE INDICATING MIXED LAYER CAPE OF
1000-2000 J/KG WITHIN THE THREAT AREA. CLUSTERS OF CONVECTION HAVE
BEEN OCCURRING TO THE NORTH OF A WARM FRONT / OUTFLOW BOUNDARY
COMBINATION WITH IR SATELLITE TRENDS SHOWING
COOLING/INTENSIFICATION WITH A CLUSTER OF STORMS ORGANIZING JUST
WEST OF DLH. THESE STORMS ARE OCCURRING IN ASSOCIATION WITH A
POTENT SHORTWAVE VISIBLE ON WV IMAGERY ALONG THE NRN MN BORDER
WHICH IS TRACKING EAST...FOLLOWED BY STRONG SUBSIDENCE IMMEDIATELY
BEHIND THE SHORTWAVE AS SEEN BY DRYING ON THE WV IMAGERY. 

SOUTHWESTERLY 850 MB WINDS HAVE INCREASED TO 30 KT PER DLH/MPX VAD
WIND PROFILE AND ARE OCCURRING WITHIN AN AIRMASS CHARACTERIZED BY
PRECIPITABLE WATER VALUES OF 1.5 TO 2.0 INCHES PER BLENDED TPW
PRODUCT. SHORT TERM RAP FORECASTS SUGGEST THESE WINDS WILL
MAINTAIN INTENSITY WITH SLIGHT VEERING WHICH WOULD BE PARALLEL TO
THE CLOUD BEARING MEAN LAYER WIND...CONTINUING TO RUN ATOP
RELATIVELY COOLER OUTFLOW ENHANCED AIR. RAINFALL RATES OF 1-2
IN/HR ARE EXPECTED WHICH MAY EXCEED FFG VALUES OF 1.5-2.5 IN/HR
AND 1.5-3.0 IN/3HR. DRYING BEHIND THE PROGRESSIVE SHORTWAVE IS
EXPECTED TO BRING AN END TO HEAVY RAIN FROM WEST TO EAST ACROSS
THE THREAT AREA.

OTTO

ATTN...WFO...MQT...GRB...DLH...ARX...MPX...

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

LAT...LON   45278744 44878873 45079146 46279386 46799400 47189324
            47089174 47019014 46788893 46078759 45278744