FXUS63 KLBF 220957
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
357 AM CST TUE DEC 22 2009
.DISCUSSION...
SFC ANALYSIS SHOWING ARCTIC FRONT HAS PROGRESSED OUT OF CENTRAL
SANDHILLS INTO NW KS AND WESTERN PANHANDLE WITH STRATUS MOVING
SLOWLY MOVING SOUTHWESTWARD AS WELL. LITTLE BIT OF FZDZ/FZFG AT KLBF
ATTM BUT MOST AREAS UP IN THE 3 TO 6 MILE RANGE. SYSTEM TO MAKE
LARGE IMPACT TO CENTRAL PLAINS WAS SHOWN NEAR NW WASHINGTON COAST AT
00Z WITH GREATEST HGHT FALLS SOUTH OF THE SYTEM ALONG THE WEST COAST
AND AS A RESULT MAJORITY OF MODELS THROUGH NEXT 36HR CONISTENT IN
DIGGING THIS CYLCONE TO THE 4 CORNERS AREA. GOES DPI/WATER VAPOR
SHOWING STRONG...WELL TAPPED...SUB TROP JET BISECTING THE SOCAL/BAJA
COAST...WITH GULF MOISTURE ALSO BEGINNING TO MAKE A RETURN TO THE
SOUTH TX COAST LINE. THIS MOISTURE SOURCES LOOK TO COMBINE...FEED
INTO THE CYCLONE AS IT EJECT FORM ROCKIES AND DEEPENS OVER PLAINS
UNDER FAVORABLE COUPLED JET DYNAMICS. NEEDLESS TO SAY WCB WILL BE IN
FULL FORCE AND LOOKING AT PW PLOTS...MAJORITY OF PLAINS ALREADY WELL
ABOVE NORMAL PERCENTAGE WISE. WITH ALL THIS COMING TOGETHER
WEDNESDAY NIGHT INTO FRIDAY...A MAJOR WINTER STORM LOOKS INEVITABLE
AND ALL WARNINGS LOOK ON TRACK. MAIN OBJECTIVE TO FORECAST IS TO
TWEAK QPF/SNOWFALL AMOUNTS AND MADE A FEW ADJUSTMENTS. AN UPGRADE TO
BLIZZARD WARNING STILL LOOKS WARRANTED DURING THE WED NITE AND INTO
THURSDAY EVENING TIME FRAME AS GUIDANCE NUMBERS RESPONDING TO THE
INCREASING PRESSURE GRADIENT AND STRONG 500M WINDS.
WINDS...ESPECIALLY DURING THE DAYLIGHT HOURS THURSDAY...WILL MOST
LIKELY BE IN THE 25 TO 35 MPH RANGE. STRONG CAA WITH FALLING TEMPS
THROUGH THE DAY SHOULD HELP MIX DOWN HIGHER GUSTS AS WELL. PRIOR TO
THE ONSET OF THE WINDS MAIN CONCERN WILL BE MODERATE TO HEAVY SNOW
BEGINNING LATE TONIGHT. UNSATURATED DENDRITIC PROFILES AND THREAT OF
FREEZING DRIZZLE WILL SLOWLY GIVE WAY TO SNOW ACROSS SOUTHERN AND
WESTERN AS STRONGER LIFT ARRIVES WITH H7 WARM FRONT LIFTING
NORTHWARD. MODELS MOST LIKELY NOT DONE CHANGING WITH SYSTEM STILL
DIGGING WELL TO THE WEST...BUT GEM AND EURO SEEM TO BE THE MOST
SIMILAR AND HAVE CONSISTENCY HAS BEEN THE THE PAST FEW DAYS. THIS
TAKES THE BULK OF THE PRECIPITATION ACROSS SOUTHERN AND CENTRAL CWA
ON WEDNESDAY...THEN ROTATES THIS ACROSS EASTERN HALF OF CWA WED
NIGHT INTO THURSDAY WHILE SFC LOW DEEPENS SIGNIFICANTLY ACROSS LOWER
MO VALLEY. TROWAL SIGNATURE ALSO PRESENT AND AIDS IN THE HEAVY SNOW
FORECAST...ESPECIALLY EAST OF A BBW TO ANW LINE WHERE SPECIFIC
HUMIDITY IS RUNNING 3-4 G/KG IN STRONG UPGLIDE SITUATION. MODELS
SEEM TO BE IN AGREEMENT OF ONE MORE WESTWARD MOVING BAND OF SNOW
THURSDAY NIGHT INTO FRIDAY MORNING...THOUGH EURO/GEM SLIGHLY
FASTER.
&&
.AVIATION...
STRATUS TO STAY FIRMLY ENTRENCHED OVER WESTERN AND NORTH CENTRAL
NEBRASKA TODAY WITH LIFR-IFR CONDITIONS CEILINGS AND VISIBILITIES.
LOW LEVEL MOISTURE TO 850 MB WITH ICING CONDITIONS EXPECTED. DRY
LAYER ABOVE 850MB AND WEAK UPSLOPE LIFT WILL CREATE AREAS OF FZDZ
OVER MOST OF FORECAST AREA TODAY AND TONIGHT CHANGING TO SNOW EARLY
WEDNESDAY MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING FROM 5 PM
THIS AFTERNOON TO 11 PM MST THURSDAY FOR
NEZ004-022>024-035-056>058-094.
WINTER STORM WARNING FROM MIDNIGHT CST /11 PM MST/ TONIGHT TO 6
AM CST /5 AM MST/ FRIDAY FOR NEZ005>010-025>029-036>038-059-
069>071.
&&
$$
13/POWER
