MESOSCALE DISCUSSION 2316 NWS STORM PREDICTION CENTER NORMAN OK 0651 AM CST FRI DEC 29 2006 AREAS AFFECTED...SWRN NEB / FAR ERN CO / WRN KS INTO THE OK PNHDL CONCERNING...WINTER MIXED PRECIPITATION VALID 291251Z - 291845Z THROUGH 18Z...PERIODS OF HEAVY SNOW WITH HOURLY RATES APPROACHING 1 INCH /LOCALLY HIGHER IN CONVECTIVE BURSTS/ WILL BECOME INCREASINGLY LIKELY ACROSS FAR ERN CO INTO WRN KS ALONG AND W OF KS HWY 27. A MIX OF SNOW...FREEZING RAIN AND PERHAPS SLEET WILL BE MORE LIKELY FROM E OF KS HWY 27 TO U.S. HWY 83. A SLOW EWD CHANGE OVER TO ALL SNOW WILL OCCUR TODAY AS COLD AIR GRADUALLY DEEPENS. 11Z MESOANALYSIS INDICATED PRIMARY SURFACE LOW NE OF LBB WITH A SECONDARY LOW CENTER OVER THE NRN TX PNHDL /S OF GUY/. ATTENDANT QUASI-STATIONARY FRONT EXTENDED NEWD FROM THIS NRN LOW TO JUST E OF GCK TO RSL TO N OF CNK. LARGE SHIELD OF PRECIPITATION IS ONGOING THIS MORNING OVER MUCH OF ERN CO/WRN KS INTO THE TX/OK PNHDLS...DRIVEN BY A COMBINATION OF DPVA ASSOCIATED WITH SHORT WAVE TROUGH LIFTING NWD THROUGH REGION...850-700 MB FRONTOGENESIS AND LOW-LEVEL WAA ALONG NOSE OF 30-40 KT SELY LLJ. 12Z SURFACE OBSERVATIONS INDICATE MAINLY SNOW ACROSS FAR ERN CO WITH A MIX OF SNOW AND LIGHT FREEZING RAIN ACROSS ERN PORTION OF DISCUSSION AREA. LATEST SHORT RANGE MODEL GUIDANCE SUGGESTS THAT 850 MB BAROCLINIC ZONE WILL INTENSIFY WHILE BECOMING PROGRESSIVELY MORE ORIENTED N-S ACROSS WRN KS TODAY. AS THIS OCCURS...A MESOSCALE BAND OF PRECIPITATION /WITH SIMILAR N-S ORIENTATION/ WILL LIKELY BECOME BETTER DEFINED WITHIN ZONE OF INTENSIFYING FRONTOGENETIC FORCING. THIS FORCING IS EXPECTED TO BE ENHANCED BY THERMODYNAMIC ENVIRONMENT EXHIBITING CONDITIONALLY UNSTABLE MID-LEVEL LAPSE RATES /PER 12Z AMA/DDC SOUNDINGS/ WHICH ARE SUPPORTING N-S LINE OF ELEVATED TSTMS FROM THE TX S PLAINS INTO SWRN KS. FREEZING RAIN RATES OF .01-.05"/HR WILL BE POSSIBLE THIS MORNING FROM NEAR AND W OF GCK NWD TO MCK. SNOW AND PERHAPS SLEET WILL PERIODICALLY MIX WITH THE FREEZING RAIN. FARTHER TO THE W...OVER FAR WRN KS INTO ERN CO...FORECAST SOUNDINGS SUGGEST THAT THERMODYNAMIC PROFILES WILL BE LARGELY SUPPORTIVE OF SNOW...WITH RATES APPROACHING 1"/HR. LOCALLY HEAVIER RATES UP TO 1.5"/HR WILL BE POSSIBLE WITH CONVECTIVE BURSTS. TRANSITION LINE BETWEEN SNOW AND SNOW-FREEZING RAIN MIX WILL GRADUALLY SHIFT EWD TODAY. ..MEAD.. 12/29/2006 ...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...LBF...DDC...GLD...AMA...PUB... 36660215 37230239 39430229 40410185 40590100 40230024 39280053 38570071 37570095 36710164
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