MESOSCALE DISCUSSION 0258
   NWS STORM PREDICTION CENTER NORMAN OK
   0733 AM CST SAT MAR 09 2013
   
   AREAS AFFECTED...PORTIONS OF ERN CO AND SERN WY
   
   CONCERNING...HEAVY SNOW 
   
   VALID 091333Z - 091730Z
   
   SUMMARY...AREAS OF SNOW WITH RATES OF 1.0-1.5 IN/HR WILL DEVELOP
   THROUGH THE MORNING OVER PARTS OF THE CO/WY FRONT RANGE...AS WELL AS
   THE ADJACENT FOOTHILLS AND HIGH PLAINS. OCCASIONAL NEAR-BLIZZARD
   CONDITIONS WILL BECOME MORE LIKELY AFTER 15Z...ESPECIALLY OVER THE
   HIGH PLAINS.
   
   DISCUSSION...CYS VWP DATA INDICATE THAT A BARRIER JET HAS BEEN
   STEADILY STRENGTHENING DURING THE PAST COUPLE OF HOURS TO THE E OF
   THE FRONT RANGE OF THE ROCKIES...WITH NLY FLOW REACHING OVER 30 KT
   BELOW 1 KM AGL. SUBTLE STRENGTHENING OF THE BARRIER JET HAS ALSO
   BEEN NOTED FARTHER S INTO CO DURING THE PAST HOUR PER FTG VWP DATA.
   DURING THE NEXT FEW HOURS...THE BARRIER JET WILL CONTINUE TO
   STRENGTHEN E OF THE CO/WY FRONT RANGE...WHILE SFC CYCLOGENESIS
   OCCURS OVER ERN CO AND WRN KS.
   
   THE STRENGTHENING CIRCULATION AROUND AN INTENSIFYING SFC LOW OVER
   THE CNTRL HIGH PLAINS...SUPERIMPOSED ON A BACKGROUND NE/SW-ORIENTED
   LOW-LEVEL BAROCLINIC ZONE...WILL SUPPORT STRENGTHENING 850-700-MB
   FRONTOGENESIS THIS MORNING. THE ASCENDING BRANCH OF THE
   FRONTOGENETIC CIRCULATION WILL BE AUGMENTED BY ISENTROPIC LIFT ATOP
   THE COLD DOME ACCOMPANYING THE BARRIER JET. AND...WITH A
   SUFFICIENTLY DEEP LAYER OF SUBFREEZING TEMPERATURES AND A DENDRITIC
   GROWTH ZONE EXTENDING FROM AROUND 590 MB TO 530 MB PER THE DNR 12Z
   RAOB...SNOW WILL INCREASE IN COVERAGE AND INTENSITY THIS MORNING.
   SNOWFALL RATES OF 1.0-1.5 IN/HR WILL BECOME INCREASINGLY COMMON
   AFTER 15Z...SPREADING FROM N TO S...AS AFFIRMED BY THE CONSENSUS
   AMONGST HIGH-RESOLUTION WRF GUIDANCE AND EXPERIMENTAL SPC SSEO
   GUIDANCE. THE HIGHEST SNOWFALL RATES WILL OCCUR WITH CONVECTIVELY
   ENHANCED PRECIPITATION OWING TO MEAGER ELEVATED BUOYANCY PER
   FORECAST SOUNDINGS. AN ISOLATED LIGHTNING STRIKE OR TWO CANNOT BE
   RULED OUT...ESPECIALLY OVER THE HIGH PLAINS.
   
   FURTHERMORE...THE STRENGTHENING SFC PRESSURE GRADIENT/BARRIER JET
   WILL BE ACCOMPANIED BY INCREASING WINDS. NLY WINDS OF 15-25 MPH WITH
   OCCASIONAL GUSTS REACHING 30-35 MPH -- PERHAPS LOCALLY 
   STRONGER -- WILL YIELD VISIBILITIES AOB ONE-HALF MILE ALONG WITH
   OCCASIONAL NEAR-BLIZZARD CONDITIONS. THE MOST LIKELY AREA FOR THESE
   CONDITIONS WILL BE OVER THE HIGH PLAINS -- E OF INTERSTATE 25 --
   AFTER 15Z.
   
   ..COHEN.. 03/09/2013
   
   
   ATTN...WFO...GLD...PUB...BOU...CYS...
   
   LAT...LON   41430572 41790523 41880438 41700406 40960392 40910225
               40520221 39660332 38340414 38230507 38890546 40580571
               41430572