MESOSCALE DISCUSSION 0029
   NWS STORM PREDICTION CENTER NORMAN OK
   0427 PM CST SUN JAN 13 2013
   
   AREAS AFFECTED...N-CNTRL INDIANA NEWD INTO NERN LOWER MI
   
   CONCERNING...FREEZING RAIN 
   
   VALID 132227Z - 140230Z
   
   SUMMARY...AREAS OF FREEZING RAIN WITH RATES OF 0.05-0.10 INCH PER 3
   HOURS WILL IMPACT AN APPROXIMATELY 50-MILE-WIDE CORRIDOR CENTERED
   FROM JUST E OF LAF NEWD TO THE LAKE HURON COAST 25 NNW APN INTO THE
   EVENING HOURS.
   
   DISCUSSION...ELEVATED WAA/ISENTROPIC ASCENT ASSOCIATED WITH A WARM
   CONVEYOR BELT EXTENDING NWD INTO THE GREAT LAKES REGION WILL
   CONTINUE TO SUPPORT THE NEWD TRANSLATION OF A SHIELD OF GENERALLY
   LIGHT PRECIPITATION ACROSS NRN INDIANA AND THE LOWER PENINSULA OF
   MI. THIS PRECIPITATION WILL INTERACT WITH SUBFREEZING WET-BULB SFC
   TEMPERATURES WITHIN THE AFOREMENTIONED CORRIDOR TO SUPPORT FREEZING
   RAIN...AS THE ELEVATED WAA SUPPORTS MELTING OF DESCENDING
   HYDROMETEORS. AS AFFIRMED BY RECENT SFC OBSERVATIONS...FREEZING RAIN
   IS ONGOING FROM PARTS OF SRN LOWER MI INTO N-CNTRL INDIANA...AND THE
   FREEZING-RAIN THREAT WILL LIKELY SPREAD NEWD INTO NERN PARTS OF THE
   LOWER PENINSULA OF MI DURING THE NEXT FEW HOURS...GENERALLY
   REMAINING W/NW OF SAGINAW BAY. HOURLY PRECIPITATION RATES
   UPSTREAM...ALONG WITH RADAR DATA...SUGGEST THAT FREEZING RAIN RATES
   OF 0.05-0.10 INCH PER 3 HOURS MAY OCCUR.
   
   FREEZING RAIN MAY BRIEFLY TRANSITION TO SLEET/SNOW OWING TO THE
   INFLUX OF DEEPER COLD AIR FROM THE WEST. HOWEVER...MOISTURE CHANNEL
   IMAGERY DEPICTS A DRY SLOT ALIGNING WITH A SW/NE-ORIENTED MID-LEVEL
   JET MAX THAT IS APPROACHING THE MCD AREA FROM THE SW. AS THIS
   OCCURS...ICE CRYSTAL NUCLEATION ALOFT WILL BECOME LESS LIKELY AS THE
   PRECIPITATION GROWTH ZONE BECOMES INCREASINGLY SHALLOW AND CONFINED
   TO RELATIVELY WARMER TEMPERATURES IN THE LOWER TROPOSPHERE. THIS MAY
   REINFORCE THE THREAT FOR FREEZING RAIN/DRIZZLE THROUGH THE EVENING
   HOURS AS PRECIPITATION RATES DECREASE FROM SW TO NE BETWEEN 00Z AND
   04Z.
   
   ..COHEN.. 01/13/2013
   
   
   ATTN...WFO...DTX...APX...IWX...GRR...IND...
   
   LAT...LON   44328467 43018538 42278582 41298641 40738681 40418674
               40608619 41248563 41698533 41998514 43108441 43878397
               44648367 44898359 45168358 45338366 45308357 45458381
               45458398 45358415 45028434 44328467