MESOSCALE DISCUSSION 0155
   NWS STORM PREDICTION CENTER NORMAN OK
   0758 AM CST TUE FEB 12 2013
   
   AREAS AFFECTED...TX PANHANDLE TO WESTERN/NORTH-CENTRAL OK
   
   CONCERNING...HEAVY SNOW 
   
   VALID 121358Z - 121800Z
   
   SUMMARY...MODERATE/HEAVY SNOW WILL CONTINUE TO DEVELOP
   EAST-NORTHEASTWARD FROM THE TX PANHANDLE INTO WESTERN/NORTH-CENTRAL
   OK THROUGH 18Z. SNOWFALL RATES SHOULD CONTINUE TO REACH 1 IN/HR
   THROUGH EARLY AFTERNOON...WITH LOCALLY HIGHER RATES POSSIBLE FOR
   RELATIVELY SHORT DURATIONS.
   
   DISCUSSION...IN ASSOCIATION WITH AN EAST-NORTHEAST ADVANCING UPPER
   TROUGH OVER NM/APPROACHING FAR WEST TX EARLY THIS MORNING...DEEP
   LAYER ASCENT VIA UPPER JET EXIT REGION/WARM ADVECTION CONTINUES TO
   CONTRIBUTE TO AN EAST-NORTHEASTWARD DEVELOPMENT OF PRECIPITATION
   ACROSS FAR NORTH TX/TX PANHANDLE INTO WESTERN/SOUTHERN OK. AS OF
   13Z...ZERO/SUB-ZERO SURFACE WET BULB TEMPERATURES ARE EVIDENT ACROSS
   THE MAJORITY OF THE TX PANHANDLE AND INTO NORTHWEST OK /AREAS NORTH
   OF I-40/. THESE COLDER TEMPERATURES CONTINUE TO ROUGHLY COINCIDE
   WITH AREAS THAT ARE ALONG AND NORTH-NORTHWEST OF A WEAK SURFACE
   INVERTED TROUGH/ZONE OF LOW-LEVEL CONFLUENCE. 
   
   ALTHOUGH THE 12Z OBSERVED SOUNDING FROM NORMAN WAS INDICATIVE OF AN
   ABOVE-FREEZING WET BULB PROFILE BELOW 850 MB...THE ONSET OF STRONGER
   FORCING FOR ASCENT/HIGHER PRECIPITATION RATES AND LOW-LEVEL COLD
   ADVECTION SHOULD CONTINUE TO LEAD TO A GENERAL WEST TO EAST
   TRANSITION OF RAIN TO SNOW INTO WEST-CENTRAL/NORTH-CENTRAL OK
   THROUGH MIDDAY. THIS ASIDE...SOME SLEET WILL BE POSSIBLE WITH
   PRECIPITATION ONSET AND/OR EXISTING CONVECTIVE ELEMENTS ACROSS
   SOUTH-CENTRAL OK.
   
   DEEP FORCING/SATURATION ASIDE...MID-LEVEL FRONTOGENESIS /800-600
   MB/...ALONG WITH WEAK UPRIGHT INSTABILITY AND/OR SLANTWISE
   INSTABILITY...WILL LIKELY ENHANCE SNOWFALL WITH RATES OF 1+ IN/HR
   POSSIBLE INTO EARLY AFTERNOON. THIS WILL ESPECIALLY BE THE CASE
   ACROSS THE EASTERN TX PANHANDLE INTO WEST-CENTRAL OK AND PERHAPS
   NORTH-CENTRAL OK BY EARLY AFTERNOON.
   
   ..GUYER.. 02/12/2013
   
   
   ATTN...WFO...OUN...LUB...AMA...
   
   LAT...LON   35030123 35900146 36659920 36249804 35479801 35089917
               34640016 35030123