FXUS63 KLBF 021003
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
403 AM CST WED DEC 2 2009

.DISCUSSION...
UPPER AIR HAND ANALYSIS SHOWING THREE MAIN AREAS OF LOW PRESSURE 
ACROSS NOAM THIS MORNING. THE FIRST LOW IS ASSOC WITH LARGER VORTEX 
OVER H.BAY REGION WITH ASSOC TROF SWINGING THROUGH PLAINS THIS 
MORNING. SECOND LOW IS THE SLOW MOVING SYSTEM THAT HAS BEEN 
LINGERING ACROSS THE SOUTHWEST CONUS BORDER THE PAST FEW DAYS...BUT 
SHOULD GET A GOOD KICK EASTWARD BY PLAINS TROF. THIRD LOW IS JUST 
NOW ENTERING RAOB DATA ACROSS THE ALUETIANS. BETWEEN THE AK LOW AND 
PLAINS TROF IS FAIRLY AMPLIFIED RIDGE ACROSS WESTERN CONUS ALLOWING 
DIRECT ACCESS TO ARCTIC AIRMASS WHICH WILL BE RESPONSIBLE FOR WELL 
BELOW NORMAL TEMPS THE NEXT FEW DAYS. MED RANGE MODELS HANDLING 
SCENARIO LATE WEEK INTO THE WEEKEND SLIGHTLY DIFFERENT WITH RESPECT 
TO HOW THE ALUETIAN LOW AND H.BAY LOW INTERACT BUT BASIC IDEA IS FOR 
THE WESTERN LOW TO BE FORCED INTO NORTHWEST CONUS BY STRONGLY 
AMPLIFYING E.PAC/AK RIDGE AND H.BAY LOW TO RETROGRADE BACK TOWARD 
THE NORTHERN PLAINS. EURO/GFS/CANADIAN HAVE SLIGHTLY DIFFERING 
SCENARIOS HOW THESE TWO SYSTEM INTERACT THROUGH LATE WEEKEND...AND 
SOME RATHER BIG DIFFERENCES THROUGH EARLY NEXT WEEK. ONE THING 
REMAINING SIMILAR IS PIECE OF ENERGY EJECTING FROM WESTERN LOW AND 
MOVING OVER ARCTIC AIRMASS IN PLACE ON SUNDAY INTO SUNDAY NIGHT AND 
PROBABLY LOOKING LIKE BEST CHANCE FOR MEASUREABLE PRECIPITATION OVER 
THE NEXT 5 DAYS OR SO AND RAISED POPS FOR CWA. AS FOR THE NEXT FEW 
DAYS...COLD AIR WILL CONTINUE TO FILTER DOWN PLAINS BRINGING IN 
DRASTIC CHANCE FROM THE PAST MONTH OR SO. ARCTIC FRONT MOVING INTO 
SOUTHERN PLAINS ATTM WITH STRONG HIGH BULDING DOWN ACROSS THE 
NORTHERN HIGH PLAINS. WATER VAPOR SHOWING PV LOBE/LOWERED TROP HGHTS 
MOVING ACROSS NORTHERN WY AND LEADING TO LIGHT SNOW ACROSS NEB 
PANHANDLE...WHICH ARE LINGERING INTO FAR SW THIS MORNING BUT SHOULD 
BE DONE BY SUNRISE SO MOST LIKELY KEEP OUT OF FORECAST THIS MORNING. 
MAIN CONCERN THE NEXT 24-48 HOURS...BESIDES TEMPERATURES...WILL BE 
SNOW SHOWER CHANCES. ANOTHER PV LOBE/WAVE...NOW SEEN SPINNING INTO 
FAR NW NORTH DAKOTA THIS MORNING...WILL ROTATE THROUGH REMAINDER OF 
CENTRAL DAKOTAS INTO MID MO VALLEY OVERNIGHT THEN EASTWARD ON 
THURSDAY...SLIGHTY NORTHEAST THE EXPECTED YESTERDAY. SNOW SHOWERS AT 
KISN ATTM AND THIS SHOULD BE THE CASE ACROSS NORTHEAST CWA TONIGHT 
INTO MID THUR MORNING AS FEATURE ROTATES THROUGH WHERE SOUNDINGS 
INDICATE BEST LLVL MOISTURE COUPLING WITH LIFT THROUGH DENDRITIC 
LAYER. TWO CONCERNS ARE DECREASING THICKNESS OF THIS DENDRITIC 
LAYER...BUT THIS IS OVERCOME BY THE INCREASE IN INSTABILITY...SO 
KEPT SCT SNOW SHOWERS. FARTHER SOUTH MOISTURE PROFILES JUST NOT AS 
SUPPORTIVE OF SNOW COVERAGE WITH VERY DRY LOW LAYERS SO LOWERED TO 
ISOLATED SHOWERS BUT SUSPECT FLURRIES MAY BE MORE LIKELY IF BULK OF 
SNOW CAN NOT MAKE IT TO THE SURFACE. SOUNDING SHOW LIFT QUICKLY 
ENDING THROUGH THURSDAY MORNING...THOUGH DENDRITIC LAYER REMAINS 
SATURATED...SO KEPT SMALL POPS FOR FLURRIES OR LIGHT SNOW SHOWERS. 
DRY RETURNS THROUGH EARLY WEEKEND WITH MINIMAL WARMUP INTO SATURDAY 
AS MEAGER REMINANT OF AMPLIFIED RIDGE ACROSS WEST ATTM QUICKLY MOVES 
THROUGH PLAINS BY DEVELOPING MID LEVEL CYCLONE IN THE PAC NW. 

&&

.AVIATION...
VFR CIGS TO PREVAIL THROUGH 06Z TAF CYCLE. SFC HIGH PRESSURE WILL 
REMAIN IN CONTROL WITH NORTHERLY WINDS TODAY. WINDS WILL REMAIN 
34015G21KT TODAY FROM 15Z TIL 00Z....THEN DIMINISH. SOME CURRENT 
GUSTINESS TO 25KTS REMAINS AT LBF SHOULD DIMINISH TOWARD 12Z THEN 
INCREASE AGAIN BY 15Z. BKN-OVC080 AT KLBF SHOULD SCATTER OUT THIS 
MORNING WITH KVTN SCT050 BKN150 ALSO TO SCATTER OUT. SKIES TO BECOME 
BKN050 TOWARD END OF 06Z TAF CYCLE WITH SCT -SHSN POSSIBLE FOR 
KVTN.  

&&

.LBF WATCHES/WARNINGS/ADVISORIES...NONE

$$

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