MESOSCALE DISCUSSION 0019
   NWS STORM PREDICTION CENTER NORMAN OK
   0913 PM CST SAT JAN 12 2013
   
   AREAS AFFECTED...A LARGE PART OF THE LOWER PENINSULA OF MI...A SMALL
   PART OF N-CNTRL INDIANA
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 130313Z - 130915Z
   
   SUMMARY...WINTER MIXED PRECIPITATION...INCLUDING FREEZING RAIN RATES
   OF 0.05-0.10 IN/HR...WILL OVERSPREAD THE AREA AFTER 0430Z AND
   CONTINUE INTO THE OVERNIGHT HOURS.
   
   DISCUSSION...RADAR MOSAIC IMAGERY DEPICTS A LARGE SHIELD OF
   WARM-CONVEYOR-RELATED PRECIPITATION EXTENDING ACROSS MO NEWD INTO
   WRN LOWER MI. THIS ACTIVITY WILL CONTINUE TO OVERSPREAD LOWER MI AND
   NRN INDIANA DURING THE NEXT FEW HOURS. AN INCREASE IN PRECIPITATION
   RATES WILL OCCUR AS ELEVATED WARM ADVECTION INCREASES AND A SFC LOW
   TRACKS NEWD FROM THE OH VALLEY TO THE W END OF LAKE ERIE. ASCENT
   ACCOMPANYING A FRONTOGENETIC CIRCULATION WILL ALSO EXTEND NEWD
   ACROSS THE AREA...PROVIDING A MESOSCALE ENHANCEMENT TO PRECIPITATION
   RATES.
   
   OBS FROM THE NSSL PRECIPITATION IDENTIFICATION NEAR THE GROUND
   /PING/ PROJECT AND OFFICIAL SFC OBS SUGGEST AN APPROXIMATELY
   40-70-MILE-WIDE CORRIDOR OF FREEZING RAIN LYING FROM CNTRL MO NEWD
   INTO NERN IL -- CENTERED ROUGHLY FROM COU TO AURORA IL. THIS
   CORRIDOR IS FLANKED BY REPORTS OF SLEET AND SNOW WITHIN THE DEEPER
   COLD AIR TO THE W...AND RAIN WHERE SFC TEMPERATURES ARE ABOVE
   FREEZING TO THE E.
   
   THIS OVERALL PRECIPITATION REGIME WILL GRADUALLY TRANSLATE NEWD INTO
   AND ACROSS THE MCD AREA DURING THE NEXT SEVERAL HOURS.
   MEANWHILE...THE LEADING EDGE OF SUBFREEZING SFC TEMPERATURES WILL
   CONTINUE TO SHIFT SEWD ACROSS THE AREA AND UNDERCUT AN ELEVATED WARM
   LAYER FEATURING 850-MB TEMPERATURES AOA 3C PER FORECAST SOUNDINGS
   AND UPSTREAM 00Z RAOBS.
   
   THE AFOREMENTIONED FACTORS WILL SUPPORT FREEZING RAIN WITH RATES OF
   0.05-0.10 IN/HR -- PERHAPS LOCALLY HIGHER WITH MODEST CONVECTIVE
   ENHANCEMENTS. THE MOST PERSISTENT AREA OF FREEZING RAIN IS EXPECTED
   TO EXTEND FROM THE LAKE MI SHORELINE FROM FAR NWRN INDIANA TO
   MBL...NEWD TO THE LAKE HURON SHORELINE FROM E OF PLN TO OSC. TO THE
   SE OF THIS AREA...RAIN WILL BE SLOWER TO TRANSITION TO FREEZING RAIN
   OWING TO /1/ THE LATER ONSET OF SUBFREEZING SFC TEMPERATURES AND /2/
   SENSIBLE HEAT FLUXES FROM ANTECEDENT LIQUID PRECIPITATION. TO THE NW
   OF THE LIKELY/PERSISTENT FREEZING-RAIN AREA...THE INFLUX OF DEEPER
   COLD AIR WILL LIMIT/PRECLUDE MELTING OF DESCENDING
   HYDROMETEORS...WITH SLEET AND LIGHT TO OCCASIONALLY MODERATE SNOW
   BECOMING MORE LIKELY THROUGH THE NIGHT.
   
   ..COHEN.. 01/13/2013
   
   
   ATTN...WFO...DTX...APX...IWX...GRR...
   
   LAT...LON   43828646 44128641 44678628 45178601 45238559 45558512
               45718477 45688444 45428378 45338343 44998328 44568326
               44378332 44178351 44018371 43958382 43828392 43338410
               42688469 41618599 41488667 41698680 42038651 42588621
               43178629 43438643 43828646