MESOSCALE DISCUSSION 2567
   NWS STORM PREDICTION CENTER NORMAN OK
   0618 PM CST WED DEC 22 2004
   
   AREAS AFFECTED...FAR SERN MO...NWRN/WRN TN...SRN IL...CENTRAL/SRN
   IND...CENTRAL/WRN KY...MUCH OF OH...NWRN PA...AND FAR WRN NY
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 230018Z - 230515Z
   
   A MAJOR WINTER STORM WILL CONTINUE FROM THE MID-MS RIVER VALLEY NEWD
   ACROSS THE OHIO VALLEY AND INTO THE SERN GREAT LAKES REGION THROUGH
   THE OVERNIGHT PERIOD. AXIS OF VERY HEAVY SNOW...WITH LOCAL RATES OF
   1-2"/HR...IS EXPECTED FROM THE IL/KY BORDER...NEWD ACROSS
   S-CENTRAL/CENTRAL IND...CENTRAL/NERN OH...AND INTO FAR SWRN NY
   THROUGH 06Z. ZONE OF FREEZING RAIN AND SLEET WILL AFFECT A 50-60NM
   WIDE ZONE FROM 25N MEM TO 30S SDF TO 30SE CMH. PRECIP RATES WILL
   TAPER OFF FROM SW TO NE ACROSS SERN MO AND WRN TN BETWEEN 03-06Z.
   
   STRONG UPPER TROUGH ACROSS THE SRN PLAINS AT 2330Z IS EXPECTED TO
   LIFT NEWD ALONG PRE-EXISTING STRONG FRONTAL ZONE REACHING THE MID-MS
   RIVER VALLEY BY 06Z. SYSTEM HAS TAPPED AMPLE GULF
   MOISTURE...RESULTING IN AN IMPRESSIVE PRECIPITATION SHIELD ON MOSAIC
   RADAR IMAGERY FROM THE CENTRAL GULF COAST STATES NWD ACROSS THE OH
   VALLEY. 
   
   NERN QUADRANT OF SYSTEM APPEARS TO BE EVOLVING INTO MORE OF A
   TRADITIONAL OVERRUNNING STRUCTURE. ZONE OF MIXED PRECIPITATION
   ACROSS WRN TN/CENTRAL AND NRN KY AND SWRN/SRN OH HAS WIDENED DURING
   THE PAST FEW HOURS AS WARM ADVECTION CONTINUES TO INCREASE IN
   COVERAGE WITHIN 850-700MB LAYER. LOCATION OF SURFACE WET-BULB ZERO
   LINE AND DISTINCT BRIGHT BANDING DENOTING MIXED PRECIPITATION ZONE
   HAS BECOME QUASI-STATIONARY AND MAY RETREAT SLOWLY NWWD OVERNIGHT
   ACROSS SERN IND/SWRN OH IN RESPONSE TO STRENGTHENING WARM ADVECTION.
   THE 18Z ETA MODEL SOUNDINGS INDICATE PROFILES FAVORING SLEET AT
   CMH...CVG...AND SDF AT 06Z. 
   
   JUST NORTH AND NW OF THIS AXIS...IMPRESSIVE SNOWFALL RATES ARE
   LIKELY GIVEN DEEP DENDRITE GROWTH LAYERS COMBINED WITH STRONG
   SYNOPTIC-SCALE ASCENT. JUXTAPOSITION OF FRONTOGENETIC FORCING WILL
   RESULT IN EXTENDED DURATION OF 1-2"/HR SNOWFALL BETWEEN 00-06Z
   ACROSS S-CENTRAL/CENTRAL IND...CENTRAL/NERN OH...AND INTO FAR NWRN
   PA/FAR WRN NY. STRENGTHENING PRESSURE GRADIENT AS SURFACE LOW
   DEEPENS ACROSS THE TN VALLEY MAY RESULT IN NEAR BLIZZARD CONDITIONS
   ACROSS THE ABOVE MENTIONED AREAS AT TIMES LATE THIS EVENING INTO THE
   OVERNIGHT HOURS AS SURFACE GUSTS INCREASE TO 30-35KT.
   
   ..BANACOS.. 12/23/2004
   
   
   ...NOTICE...
   SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A 
   SCHEDULED BASIS...FOUR TIMES A DAY...BETWEEN 00-01 UTC...
   06-07 UTC...12-13 UTC...AND 18-19 UTC AS SIGNIFICANT SHORT
   RANGE WINTER WEATHER EVENTS UNFOLD.  THIS SCHEDULE WILL BE
   USED FROM DECEMBER 1 THROUGH FEBRUARY 28.
   
   ATTN...WFO...BUF...CTP...PBZ...RLX...CLE...JKL...ILN...LMK...IWX...OHX...IND...PAH...ILX...MEG...LSX...
   
   37138575 36558653 35478819 35058882 34818947 34778994
   35848974 37808975 38588914 39848626 40998384 41628189
   42268035 42717925 42797864 42527835 42147862 40668055
   38228405 37488505 37118574