MESOSCALE DISCUSSION 2380
   NWS STORM PREDICTION CENTER NORMAN OK
   0556 PM CST MON DEC 19 2011
   
   AREAS AFFECTED...MUCH OF WRN/NRN/CNTRL KS
   
   CONCERNING...HEAVY SNOW 
   
   VALID 192356Z - 200400Z
   
   SNOW RATES OF 1 IN/HR WILL OCCUR DURING THE EVENING/OVERNIGHT HOURS
   ACROSS MUCH OF WRN/NRN/CNTRL KS...WHILE MIXED PRECIP WITHIN A NARROW
   CORRIDOR OVER CNTRL/NERN KS TRANSITIONS TO SNOW. BLIZZARD CONDITIONS
   ARE ANTICIPATED OVER PARTS OF WRN KS...MAINLY ALONG AND WEST OF U.S.
   HIGHWAY 281.
   
   LOW/MID-LEVEL WAA IS SUPPORTING A BROAD SHIELD OF PRECIP OVER MUCH
   OF KS...WHICH WILL BE MAINTAINED THROUGH THE OVERNIGHT HOURS AS
   STRONG DEEP-LAYER ASCENT OVERSPREADS THE AREA AHEAD OF A CLOSED
   MID/UPPER-LEVEL LOW CURRENTLY LOCATED OVER THE WRN TX
   PANHANDLE/SOUTH PLAINS. SFC OBS INDICATE SNOW AS THE PREDOMINANT
   PRECIP TYPE OVER MUCH OF WRN AND PARTS OF N-CNTRL KS...WITH A MIX OF
   PRECIP TYPES WITHIN 25-30 MILES EITHER SIDE OF A LINE FROM JUST SE
   OF DODGE CITY TO JUST WEST OF ST. JOSEPH MO. OVER TIME...COLUMNAR
   COOLING OWING TO FORCED ASCENT...MELTING PROCESSES ALOFT /AS
   EVIDENCED IN WIDESPREAD BRIGHT-BANDING AT 0.5 DEGREES PER TOPEKA
   RADAR/...AND NOCTURNAL COOLING WILL ALLOW PRECIP WITHIN THIS
   TRANSITION ZONE TO BECOME MAINLY SNOW FROM WSW TO ENE THROUGH 07Z
   PER SPC EXPERIMENTAL SSEO GUIDANCE. REGARDLESS...A PERIOD OF SLEET
   OR POSSIBLY FREEZING RAIN /WITH LOCAL RATES OF 0.05-0.10 IN PER
   HOUR/ WILL BE POSSIBLE OWING TO AN ELEVATED WARM NOSE FEATURING
   850-750-MB TEMPERATURES OF 1-3C AND SFC TEMPS FALLING BELOW
   FREEZING.
   
   WHILE RUC SOUNDINGS INDICATE THE DENDRITIC GROWTH ZONE WILL BE
   FAIRLY ELEVATED /CENTERED AROUND 500 MB/ AND ABOVE THE LAYER OF
   STRONGEST ASCENT...A MODESTLY DEEP ISOTHERMAL LAYER /TEMPS OF 0 TO
   -5C/ FROM 850 TO 700 MB WILL SUPPORT EFFICIENT SNOWFLAKE
   AGGREGATION. AND...WITH SUFFICIENTLY STRONG DEEP-LAYER ASCENT...SNOW
   RATES OF 1 IN/HR WILL BE COMMON ACROSS THE DISCUSSION AREA OVERNIGHT
   TONIGHT. ADDITIONALLY...ACROSS WRN KS...MAINLY ALONG AND WEST OF
   U.S. HIGHWAY 281...THE TIGHT PRESSURE GRADIENT NORTH OF A SFC LOW
   OVER THE TX PANHANDLE WILL SUPPORT NNELY TO NELY WINDS OF 25-35 MPH
   WITH GUSTS REACHING 40-45 MPH. THESE WINDS WILL COMBINE WITH THE
   SNOW TO REDUCE VISIBILITIES BELOW ONE-QUARTER MILE...CAUSING
   BLIZZARD CONDITIONS.
   
   ..COHEN.. 12/19/2011
   
   
   ATTN...WFO...EAX...TOP...ICT...GID...DDC...GLD...
   
   LAT...LON   39179558 38339695 37649912 37130093 37350159 38050195
               38900185 39400110 39619883 39829534 39179558