MESOSCALE DISCUSSION 0073
   NWS STORM PREDICTION CENTER NORMAN OK
   1214 PM CST TUE JAN 16 2007
   
   AREAS AFFECTED...FAR NWRN INDIANA
   
   CONCERNING...HEAVY SNOW 
   
   VALID 161814Z - 162215Z
   
   NARROW LM LAKE EFFECT SNOW BAND EXPECTED TO PERSIST FOR AN
   ADDITIONAL 2-4 HOURS ACROSS FAR NWRN IND.  PORTER AND LAKE COUNTIES
   ARE EXPECTED TO BE AFFECTED THROUGH AT LEAST 21Z...WITH THE
   POTENTIAL FOR AN EWD SHIFT IN THE BAND TOWARD LA PORTE COUNTY DURING
   THE MID-LATE AFTERNOON.  LOCAL SNOWFALL RATES UP TO 1 INCH PER HOUR
   REMAIN POSSIBLE.
   
   REGIONAL RADARS INDICATED LES BAND HAS SHIFTED WWD DURING THE LAST 2
   HOURS...AND HAS BEEN AFFECTING MUCH OF NRN PORTER COUNTY SINCE 16Z. 
   THIS WWD SHIFT IS LIKELY DUE TO THE EXIT OF THE UPPER TROUGH INTO
   THE LOWER GREAT LAKES REGION AS A RIDGE BUILDS INTO THE WRN GREAT
   LAKES...RESULTING IN A MORE NLY SHIFT IN LOW LEVEL WINDS AS
   INDICATED BY REGIONAL VADS...WCL WIND PROFILER AND ACARS DATA. 
   
   12Z NAM/15Z RUC SUGGEST LOW LEVEL WINDS WILL LIKELY SHIFT TO NWLY
   THIS AFTERNOON AS CENTER OF SURFACE HIGH PRESSURE TRANSLATES INTO
   THE LOWER MO/MID MS VALLEYS.  THIS NW WIND SHIFT SHOULD ALLOW LES
   BAND TO SHIFT EWD TOWARD LA PORTE COUNTY DURING THE MID-LATE
   AFTERNOON TIME FRAME.  INTENSITY OF THE SNOW BAND SHOULD DECREASE
   DURING THE LATE AFTERNOON AS THE INVERSION HEIGHT IS FORECAST TO
   LOWER WITH THE RIDGE BUILDING EWD PER 12Z NAM/15Z RUC FORECAST
   SOUNDINGS.
   
   ..PETERS.. 01/16/2007
   
   
   ...NOTICE...
   SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A
   SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR
   TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC
   FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS.
   
   ATTN...WFO...IWX...LOT...
   
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