000 FXUS63 KGLD 100850 AFDGLD AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 150 AM MST FRI FEB 10 2012 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 144 AM MST FRI FEB 10 2012 04Z WATER VAPOR IMAGERY INDICATED SHORT WAVE TROUGH MOVING TO THE EAST ACROSS CENTRAL KANSAS AND OKLAHOMA...WITH SECOND SHORT WAVE TROUGH DIGGING INTO NORTHERN NORTH DAKOTA. AREA OF DRYING/SUBSIDENCE NOTED MOVING INTO THE CWA HELPING TO BREAK UP CLOUD COVER. SFC OBSERVATIONS INDICATE LEADING EDGE OF COLD FRONT ASSOCIATED WITH NORTH DAKOTA SHORT WAVE TROUGH WAS DRAPED ACROSS EASTERN NEBRASKA INTO THE NORTHEAST PORTION OF THE CWA...ALTHOUGH THE MUCH COLDER SINGLE DIGIT TEMPS LAGGED BEHIND FROPA AS THEY REMAINED IN NORTH DAKOTA AND NORTHERN MINNESOTA. MAIN FORECAST CONCERNS IN THE SHORT TERM WILL BE SNOW/FREEZING DRIZZLE CHANCES AND AMOUNTS OVERNIGHT FRIDAY AND HOW COLD TEMPERATURES WILL BE THROUGH THE WEEKEND. TODAY-TONIGHT...INITIAL CONCERN FOR THE PERIOD WILL BE HOW QUICKLY STRATUS BUILDS OVER THE AREA AS FAIRLY WIDESPREAD MVFR DECK NOTED ACROSS MUCH OF SOUTH DAKOTA AND NORTHEAST NEBRASKA. SHORT TERM MODELS SEEM TO HOLD OFF ON BRINGING LOWER CLOUDS INTO THE AREA UNTIL AROUND 18Z...BUT NOT SURE I AM THAT CONFIDENT IN THAT TIMING. WITH SOUTHERN EDGE OF STRATUS DECK ALREADY TO KBBW WOULD NOT BE SURPRISED TO SEE IT ENTER NORTHEAST CWA IN THE 12-15Z TIME RANGE. TEMPERATURES WILL BE CHALLENGING TODAY AS TIMING OF DEEPER COLD AIR AND CLOUD COVER WILL HAVE A LARGE IMPACT ON HOW MUCH POTENTIAL WARMING THERE IS...BUT EXPECT SEVERAL LOCATIONS IN NORTHEASTERN CWA TO ALREADY BE AT THEIR HIGH TEMPS...WITH TEMPS FALLING THROUGH THE DAY. OVERNIGHT PROVIDES AN EVEN TOUGHER CHALLENGE AS WIDESPREAD CLOUD COVER IS EXPECTED...BUT SFC HIGH WITH MUCH DRIER AND COLDER TEMPS WILL SETTLE OVER THE REGION. WHILE CLOUDS SHOULD HOLD TEMPS UP A BIT...900 MB TEMPS ONLY AROUND 1-3 DEGREES F BY 12Z. EVEN WITH CLOUDS TO HOLD UP TEMPS...THINK AT THE VERY LEAST LOWS WILL BE ISOTHERMAL TO THIS LEVEL IF NOT SLIGHTLY COOLER WITH AN INVERSION SETTING UP. WHILE NOT READY TO GO WELL BELOW ZERO LIKE SOME GUIDANCE SUGGESTS...LOWERED TEMPERATURES TO AROUND ZERO ACROSS THE EASTERN CWA. CHANCES FOR PRECIPITATION WILL BEGIN TO INCREASE ACROSS THE AREA AFTER 00Z TONIGHT AS STRONG AREA OF H75-H65 FRONTOGENESIS DEVELOPS DURING THE EVENING AND OVERNIGHT PERIODS. LATEST SUITE OF NUMERICAL GUIDANCE ALONG WITH SREF AND GEFS MEAN HAVE SHIFTED BEST FORCING TO THE WEST SIGNIFICANTLY WITH BEST FORCING...COMBINED WITH LOW LEVEL UPSLOPE/OROGRAPHIC COMPONENT ACROSS EASTERN COLORADO AND HAVE ADJUSTED PROBABILITIES ACCORDINGLY. MODELS STILL SUGGESTING POTENTIAL FOR RELEASE OF CSI...WITH LAYER OF NEGATIVE EPV* AND POSITIVE THETA E LAPSE RATES ABOVE FRONTAL ZONE...WHICH IF REALIZED COULD RESULT IN A FAIRLY STRONG BAND OF PRECIPITATION BEFORE COLDER AIR MASS DEEPENS AND STABILIZES THINGS. THE POTENTIAL INSTABILITY...IN ADDITION TO SNOW RATIOS CLIMBING IN IN EXCESS OF 20 TO 1 OVERNIGHT AS NEARLY ENTIRE SOUNDING BELOW H5 BECOMES DENDRITIC LEADS ME TO THINK THERE MAY BE A NARROW BAND OF SNOWFALL IN EXCESS OF 3 INCHES OVERNIGHT...BUT CONFIDENCE IS TOO LOW IN EXACTLY WHERE FOR ANY KIND OF HIGHLIGHT ATTM. OTHER CONCERN WILL BE FOR -FZDZ AS FRONT BACKS ACROSS WESTERN CWA AND LOW LEVEL FLOW BECOMES MORE EASTERLY/UPSLOPE. WITH MORE WESTERLY POSITION OF DEEP LAYER FORCING/SATURATED CONDITIONS...THINK THE WINDOW FOR -FZDZ PRIOR TO SNOW FALLING HAS GOTTEN A LITTLE SMALLER AND MORE CONFINED TO WESTERN CWA. ONCE COLD AIR DEEPENS GREATLY AFTER 06Z...THINK THREAT WILL PRETTY MUCH BE OVER ACROSS THE AREA ALTHOUGH FREEZING FOG WILL BE A PROBLEM THROUGH THE NIGHT. SATURDAY-SUNDAY...FAIRLY ACTIVE WEATHER PATTERN WILL CONTINUE ACROSS THE AREA THROUGH THE PERIOD AS FLOW ALOFT TRANSITIONS FROM SHORT WAVE RIDGING EARLY IN THE PERIOD...TO HAVING ANOTHER TROUGH BECOME ESTABLISHED ACROSS THE CENTRAL PLAINS ON SUNDAY AND SUNDAY NIGHT. LIGHT SNOW SHOULD BE ONGOING ACROSS EASTERN COLORADO DURING THE MORNING HOURS...BUT AS SHORT WAVE RIDGE SHIFTS TO THE EAST DURING THE AFTERNOON EXPECT FRONTAL CIRCULATION TO WEAKEN GREATLY BRINGING AN END TO PRECIPITATION. DO HAVE SOME CONCERNS THAT PRECIP COULD LINGER INTO THE AFTERNOON...AS SUBSIDENCE DOES NOT SEEM ALL THAT STRONG BUT HAVE DECIDED TO STICK WITH MOST LIKELY SOLUTION. AS SHORTWAVE RIDGE SHIFTS TO THE EAST OVERNIGHT...STRONG LOW LEVEL WARM AIR ADVECTION EXPECTED TO OCCUR THROUGH SATURDAY MORNING. HAVE SOME CONCERNS THAT TEMPS ABOVE THE SFC WILL WARM ENOUGH TO LIMIT ICE POTENTIAL IN SOUNDINGS AND PERSISTENT WEAK ASCENT WILL BE ENOUGH FOR SOME PATCHY FREEZING DRIZZLE TO DEVELOP OVERNIGHT SATURDAY AND SUNDAY MORNING. MAIN SHORT WAVE TROUGH AND ASSOCIATED PV ANOMALY WILL DRIFT ACROSS THE AREA SUNDAY AFTERNOON AND EARLY SUNDAY EVENING. DEEP LAYER STABILITY RATHER WEAK...SO WILL NOT BE SURPRISED TO SEE A SNOW SHOWER OR TWO DEVELOP AND WENT WITH LOW POPS FOR THE PERIOD SIMILAR TO ENSEMBLE DATA. WARM LAYER ALOFT DOES CONCERN ME A BIT FOR PRECIP TYPE...BUT LOOKS LIKE IF PRECIP DOES OCCUR THINGS SHOULD WETBULB ENOUGH FOR SNOW TO BE DOMINANT TYPE. WITH PERSISTENT CLOUD COVER AND SFC HIGH ANCHORED OVER MUCH OF THE AREA...EXPECT SATURDAY TO BE COLDEST DAY OF THE WEEKEND...WITH LOCATIONS STRUGGLING TO REACH THE TEENS. TEMPS WILL WARM THROUGH THE REST OF THE WEEKEND...CLIMBING ABOVE FREEZING IN A FEW LOCATIONS SUNDAY. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 144 AM MST FRI FEB 10 2012 PERIOD STARTS OUT WITH SLIGHT CHANCES FOR PRECIPITATION ACROSS THE NORTHEAST AND WEST PARTS OF THE TRI-STATE AREA AS THE UPPER LEVEL TROUGH MOVES THROUGH MONDAY. AM NOT TOO EXCITED ABOUT THE SLIGHT CHANCES SINCE LIFTING FROM THE 500MB JET IS FURTHER SOUTH OVER TEXAS WHERE THE STRONGER JET WINDS ROUND THE BASE OF THE TROUGH. HOWEVER BOTH GFS AND ECMWF SHOW WEAK 700-500MB FRONTOGENESIS OVER THE AREA...SO CANNOT COMPLETELY RULE OUT SOME PRECIPITATION FROM FALLING AS THE UPPER LEVEL TROUGH MOVES THROUGH THE AREA. MEANWHILE THE NEXT UPPER LEVEL TROUGH MOVES OVER THE WEST COAST ON MONDAY. THE GFS AND PREVIOUS ECMWF QUICKLY FALL OUT OF AGREEMENT WITH THE SPEED OF THE TROUGH AS IT PROGRESSES EASTWARD. THE GFS ENSEMBLE MEMBERS SUPPORT THE FASTER OPEN WAVE GFS...WHICH TRACKS OVER SOUTHWEST KANSAS WEDNESDAY AFTERNOON...AS APPOSED TO THE SLOWER CLOSED LOW OF THE PREVIOUS ECMWF THAT STAYS OVER NORTHERN MEXICO. THE LATEST ECMWF ALSO HAS A CLOSED LOW...BUT FALLS MORE IN LINE WITH THE GFS SOLUTION. HOWEVER IT IS STILL A BIT SLOWER THAN THE GFS AS IT LIFTS THE TROUGH NORTHEAST OVER THE 4 CORNERS AREA. SINCE THE LATEST ECMWF IS MORE IN LINE WITH THE GFS AM A BIT MORE CONFIDENT WITH THE GFS SOLUTION. THE BEST CHANCES FOR PRECIPITATION CONTINUE TO BE ALONG AND SOUTH OF I-70 AS THE TROUGH TRACKS EAST-NORTHEAST ACROSS THE STATE. && .AVIATION... 937 PM MST THU FEB 9 2012 FOR THE 06Z TAFS...VFR AT BOTH TERMINALS THROUGH FRIDAY MIDDAY. AFTERWARDS...EASTERLY UPSLOPE WINDS WILL LEAD TO MVFR STRATUS FORMATION FIRST AT KMCK THEN AT KGLD. AFT 00Z...MID LEVEL FORCING INCREASES AND WITH SATURATED LOW/MID LEVELS...LIGHT SNOW WILL BECOME POSSIBLE...ESPECIALLY AT KGLD. IF LIGHT SNOW MATERIALIZES...EXPECT POSSIBLE IFR CIGS/VIS THROUGH END OF TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...NONE. KS...NONE. NE...NONE. && $$ SHORT TERM...JRM LONG TERM....JTL AVIATION.....BAS