FXUS65 KSLC 071150
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
450 AM MST MON DEC 7 2009

.SYNOPSIS..A STORM SYSTEM WILL SLIDE SOUTH ACROSS CALIFORNIA AND 
ENTER THE GREAT BASIN TODAY. THIS STORM WILL INTENSIFY AS IT MOVES 
ACROSS THE AREA TONIGHT THROUGH TUESDAY. A COOL AIRMASS WILL THEN 
REMAIN IN PLACE UNDER A WESTERLY FLOW THROUGH LATE WEEK.

&&

.DISCUSSION...AN UPPER LEVEL TROUGH CONTINUES TO PIVOT AROUND OREGON 
AND WILL DIVE SOUTH OVER CALIFORNIA TODAY. MEANWHILE OVER 
UTAH...ISENTROPIC UPGLIDE HAS RESULTED IN THE CONTINUATION OF LIGHT 
SNOW ACROSS PORTIONS OF NORTHERN UTAH. THIS SNOW IS EXPECTED TO 
TAPER OFF LATER THIS MORNING AS WARM ADVECTION WEAKENS. ALTHOUGH 
ACCUMULATION FROM THIS SNOWFALL WILL REMAIN RATHER LIGHT...COLD 
TEMPERATURES WILL ALLOW THIS SNOW TO ACCUMULATE ON ROAD SURFACES AND 
CONTRIBUTE TO SLICK ROADS FOR THE MORNING COMMUTE. 

THE FOCUS WILL BEGIN TO SHIFT TOWARDS SOUTHERN AND CENTRAL UTAH THIS 
MORNING AS THE STORM SYSTEM APPROACHES THE AREA. THE STORM WILL 
INTENSIFY THROUGH TONIGHT AS IT MOVES ACROSS SOUTHERN UTAH. A STREAM 
OF MOISTURE FROM A WEAKENING PACIFIC STORM HAS BEEN TAPPED BY THE 
STRONG WEST TO SOUTHWEST FLOW ACROSS SOUTHERN CALIFORNIA/NEVADA AND 
THIS MOISTURE IS ALREADY STREAMING INTO UTAH THIS MORNING. THE STORM 
WILL INTERACT WITH THIS MOISTURE TO PRODUCE SIGNIFICANT SNOWFALL 
ACROSS SOUTHERN AND CENTRAL UTAH THROUGH TOMORROW. THIS STORM HAS 
THE POTENTIAL TO PRODUCE SNOWFALL DOWN TO THE VALLEY FLOORS ACROSS 
ALL AREAS...INCLUDING UTAHS DIXIE. BECAUSE STRONG SOUTHWEST FLOW 
WILL BE IN PLACE ACROSS SOUTHERN AND CENTRAL UTAH TODAY...THE MOST 
SIGNIFICANT SNOWFALL WILL LIKELY OCCUR IN AREAS OF SOUTHERN UTAH 
FAVORED BY SOUTHWEST FLOW. THE STRONG WINDS WILL ALSO RESULT IN 
REDUCED VISIBILITIES DUE TO BLOWING SNOW...ESPECIALLY IN THE HIGHER 
ELEVATIONS. NORTHWEST FLOW WILL DEVELOP EARLY TOMORROW MORNING AS 
THE TROUGH AXIS MOVES ACROSS THE AREA. THIS WILL BRING A GREATER 
CHANCE FOR ACCUMULATING SNOWFALL ALONG THE WASATCH FRONT FROM THE 
SALT LAKE VALLEY NORTH TO AROUND OGDEN. FOR NOW...HAVE MADE NO 
CHANGES TO EXISTING WINTER WEATHER HEADLINES. 

PRECIPITATION SHOULD TAPER OFF WEDNESDAY BUT A COLD AIRMASS WILL 
REMAIN IN PLACE. WARM ADVECTION WILL DEVELOP FOR THURSDAY...BUT THIS 
WILL ONLY RESULT IN VALLEY INVERSIONS. MODELS HAVE BECOME DRIER FOR 
THE LATTER PART OF THE WORK WEEK...SO HAVE LOWERED POPS FOR THIS 
TIMEFRAME. NEXT BEST CHANCE FOR SIGNIFICANT PRECIPITATION WILL BE 
NEXT WEEKEND.

&&

.AVIATION...THE SLC TERMINAL WILL SEE LIGHT NORTHWESTERLY WINDS 
THROUGHOUT THE DAY. SNOW IS EXPECTED TO DEVELOP AT THE TERMINAL BY 
15Z...RESULTING IN LOW-END MVFR TO HIGH-END IFR CONDITIONS. THE SNOW 
IS EXPECTED TO BECOME MORE WIDESPREAD BY TONIGHT...RESULTING IN 
IFR/LIFR CONDITIONS. 

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER STORM WARNING UNTIL 4 PM TUESDAY FOR UTZ517-UTZ518.

     WINTER STORM WARNING UNTIL NOON TUESDAY FOR UTZ014-
     UTZ015-UTZ016.

     WINTER STORM WARNING UNTIL 6 AM TUESDAY FOR UTZ011-
     UTZ012-UTZ013-UTZ019-UTZ020-UTZ021.

     WINTER STORM WARNING UNTIL 4 PM TUESDAY FOR 
     UTZ008-UTZ009-UTZ010.

     WINTER WEATHER ADVISORY UNTIL 4 PM TUESDAY FOR 
     UTZ003-UTZ004-UTZ006.

WY...NONE.

&&

$$

PUBLIC...CHENG
AVIATION...TRAPHAGAN

FOR MORE INFORMATION FROM NOAA/S NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY (ALL LOWER CASE)