FXUS65 KGJT 241306
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
605 AM MST THU DEC 24 2009

.UPDATE...HEADLINES REMOVED FOR EXPIRED WINTER WEATHER PRODUCTS.

&&

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT

COLD NORTHERLY FLOW WAS KEEPING BANDS OF CLOUDS AND SNOW ACROSS
WESTERN CO EARLY THIS MORNING WHILE MOSTLY CLEAR SKIES PREVAILED
OVER MUCH OF ERN UT. SNOW OBSERVED AT MT WERNER AUTOMATED STATION...
ABOVE STEAMBOAT SPGS...MUCH OF THE NIGHT AND SUPPORTED BY SNOTEL OBS.
AIR TEMP AT MT WERNER HAS EBEN IN THE FAVORABLE SNOW GROWTH REGION AS
WELL. WEB CAMS NOT SHOWING SNOW TO WIDESPREAD ACROSS THE NRN AND
CENTRAL MTNS...HOWEVER. WILL LET THE CURRENT ADVISORIES RUN THEIR
NORMAL COURSE TO EXPIRATION AT 600 AM.

FORECAST AREA TO REMAIN IN NWLY FLOW THROUGH FRI NIGHT...WITH THE
CHANCE OF SNOW PERSISTING MAINLY FOR THE NORTHERN CO MTNS. COLD UPPER
TROUGH OVER ERN MT/WY THIS MORNING WILL MOVE TO KS BY FRI...AS
UPPER JET OVER ID-UT SHIFTS OVERHEAD. MODEL INDICATE ONLY WEAK
FORCING WITH THIS. AS THE UPPER TROUGH DEVELOPS AN LARGE AND INTENSE
LOW IN THE NATION/S MID-SECTION...A LOBE OF ENERGY ROTATES DOWN
ACROSS OUR FORECAST AREA FRI WITH A REINFORCING SHOT OF COLD AIR.
TIME-HEIGHT SECTION AT CRAIG AND BUFKIT VERTICAL SOUNDING AT HAYDEN
INDICATE MOIST LOW LEVELS IN FAVORABLE SNOW GROWTH TEMP REGIME ALOFT
FRI AFTN/EVE ACROSS NW CO....SO WILL KEEP THE CHANCE OF PRECIP
HIGHEST FOR THE NRN MTNS.

WHILE THE COLDEST AIR REMAINS EAST OF THE DIVIDE...ENOUGH GETS
WESTWARD FOR CONTINUED CHILLY TEMPS. COLDEST THU NIGHT AND FRI
NIGHT WHERE SKIES STAY MOSTLY CLEAR FOR RADIATIONAL HEAT LOSS. AS
THE STORM DEVELOPS IN THE CENTRAL PLAINS...PRESSURE GRADIENT
INCREASES SO ANTICIPATE AN INCREASE IN WINDS OVER THE HIGHER
TERRAIN. WIND CHILLS COULD BE CONCERN OVER THE HIGHER ELEVS AT
NIGHT AS A RESULT.

.LONG TERM...SATURDAY THROUGH WEDNESDAY...

BY SATURDAY A MASSIVE LOW WILL BE CENTERED OVER WISCONSIN AND NEARLY
STATIONARY. IT WILL DOMINATE WEATHER ACROSS THE CENTRAL USA. WESTERN
CO WILL BE BENEATH THE WESTERN PERIPHERY OF THE STORM WITH MODERATE
NORTHWEST FLOW AT THE SURFACE AND ALOFT. MOISTURE FROM THE STORM WILL
BE ERODING TO THE EAST. EASTERN UT AND SW CO SHOULD BE SEE DECREASING
CLOUDS THROUGHOUT THE DAY AND WESTERN CO SHOULD SEE CLOUD COVER
DIMINISH THROUGH THE AFTERNOON. ONLY ISOLD SNOW SHOWERS OVER THE
NORTHERN AND CENTRAL CO MTS ARE EXPECTED. TEMPS WILL BE QUITE COLD
SAT AND SAT NIGHT.

SUNDAY AND MONDAY...THE CENTRAL U.S. STORM MOVES NORTHEAST THROUGH
THE GREAT LAKES STATES AND HIGH PRESSURE DEVELOPS OVER UT AND CO.
LESS CLOUD COVER WILL ALLOW COLD MIN TEMPS TO CONTINUE...BUT WARMER
TEMPS DURING THE DAY...ESPECIALLY OVER SE UT AND SW CO WHICH WILL SEE
THE HIGHER THICKNESS AND 700 MB TEMP INCREASES. LATE IN THE DAY...
HIGH CLOUDS INCREASE FROM THE SOUTH AS THE NEXT PACIFIC STORM
APPROACHES AND WINDS ALOFT BEGIN SHIFTING TO THE SOUTHWEST.

TUESDAY-WEDNESDAY...THE MORE SPLIT EC IS FAVORED FOR THESE PERIODS.
MOISTURE AND MILDER TEMPS ALOFT BEGIN TO ADVECT IN FROM THE
SOUTHWEST. THIS WILL BEGIN A TREND TOWARDS MILDER TEMPERATURES AND A
CHANCE OF SHOWERS FAVORING THE SOUTH.

&&

.AVIATION...

AREAS OF LOW CLOUDS AND PATCHY FOG CAN BE EXPECTED THROUGH MID-
MORNING POTENTIALLY AFFECTING KHDN...KSBS...KMTJ...KGUC. CIGS AND
VSBY OVER THE MTS WILL IMPROVE BY MIDDAY AS HIGH ELEV SNOWFALL
DECREASES. CIGS AND VSBY ARE EXPECTED TO LOWER AGAIN TONIGHT OVER
THE CENTRAL AND NRN CO MTS. PATCHY FOG COULD AFFECT AIRPORTS
TONIGHT.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE
UT...NONE.

$$

UPDATE.......CJC
SHORT TERM...JAD
LONG TERM....CJC/JOE
AVIATION.....JAD

$$