MESOSCALE DISCUSSION 2342
   NWS STORM PREDICTION CENTER NORMAN OK
   0105 PM CST SAT NOV 19 2011
   
   AREAS AFFECTED...NRN WI...WRN/CNTRL PORTIONS OF THE UPPER PENINSULA
   OF MI
   
   CONCERNING...HEAVY SNOW 
   
   VALID 191905Z - 192300Z
   
   SNOWFALL RATES COULD LOCALLY REACH 1 IN/HR INTO THE EVENING HOURS
   ACROSS NRN WI AND WRN/CNTRL PORTIONS OF THE UPPER PENINSULA OF MI.
   
   A 25-MILE-WIDE SNOW BAND EXTENDING WSWWD FROM FAR WRN SECTIONS OF
   THE MI UPPER PENINSULA ACROSS EXTREME NWRN WI INTO CNTRL/SRN MN IS
   IN ASSOCIATION WITH A ZONE OF LOW-TO-MID-LEVEL FRONTOGENESIS. THE
   FRONTOGENESIS IS BEING ENHANCED BY /1/ MID-LEVEL ASCENT ATTENDANT TO
   AN APPROACHING IMPULSE INTERACTING WITH A NWWD-SLOPING BAROCLINIC
   ZONE DRAPED ACROSS THE AREA...AND /2/ STRENGTHENING LOW-LEVEL
   CONVERGENCE AHEAD OF A LOW DEVELOPING NEWD ALONG THE INTERSECTION OF
   THE BAROCLINIC ZONE AND THE SFC. AS THE IMPULSE AND SFC LOW ADVANCE
   EWD AND NEWD...RESPECTIVELY...LOW/MID-LEVEL FRONTOGENESIS WILL
   INCREASE ACROSS THE DISCUSSION AREA...ALLOWING THE SNOW BAND TO
   DEVELOP ENEWD NEAR THE COAST OF LAKE SUPERIOR. FRICTIONAL
   CONVERGENCE OWING TO MERIDIONAL SPEED DIFFERENCES INVOF THE SOUTH
   SHORE WILL ALSO AID IN FOCUSING MESOSCALE ASCENT OVER THE MI UPPER
   PENINSULA. ADDITIONAL FRONTOGENETICALLY ENHANCED SNOW BANDS COULD
   OCCUR FARTHER SOUTH INTO NRN WI IN THE PRESENCE OF SLANTWISE CAPE
   VALUES OF 100-150 J/KG PER EXPERIMENTAL NAM OUTPUT. THOUGH NOT
   PARTICULARLY STRONG...THE AFOREMENTIONED ASCENT IS EXPECTED TO
   LOCALLY SUPPORT SNOWFALL RATES REACHING 1 IN/HR AFTER 21Z.
   
   WHILE AREAS IN CLOSER PROXIMITY TO THE SFC FRONT IN THE CNTRL UPPER
   PENINSULA OF MI AND NRN WI MAY INITIALLY EXPERIENCE RAIN...RUC/NAM
   FORECAST SOUNDINGS SUGGEST THAT /1/ ADIABATIC COOLING OWING TO
   FORCED ASCENT.../2/ STRENGTHENING LOW-LEVEL COLD ADVECTION...AND /3/
   NOCTURNAL COOLING WILL SUPPORT SNOW AS THE PREDOMINANT PRECIP TYPE
   AREA-WIDE AFTER 00Z...AS AFFIRMED BY EXPERIMENTAL SPC SSEO GUIDANCE.
   THIS GUIDANCE ALSO INDICATES PRECIP GENERALLY TAPERING OFF FROM WSW
   TO ENE AFTER 03Z...THOUGH COASTAL CONVERGENCE COULD MAINTAIN
   ENHANCED SNOW BANDS FROM NEAR MARQUETTE TOWARD BARAGA FOR A FEW
   HOURS THEREAFTER.
   
   ..COHEN.. 11/19/2011
   
   
   ATTN...WFO...MQT...GRB...DLH...ARX...MPX...
   
   LAT...LON   45729212 46609164 46869106 46769043 46898947 47388840
               47298792 46948777 46578696 46528616 45928651 45338815
               45128971 45159154 45729212