FXUS65 KSLC 062330
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
430 PM MST SUN DEC 6 2009

.SYNOPSIS..A STORM SYSTEM DEVELOPING ALONG THE WEST COAST LATE
THIS AFTERNOON WILL TURN EAST TOWARDS THE GREAT BASIN MONDAY. THIS
STORM WILL RAPIDLY GAIN STRENGTH AS IT MOVES ACROSS THE BASIN MONDAY
NIGHT THROUGH TUESDAY. COLD TEMPERATURES AND LINGER SHOWERS ARE
EXPECTED MIDWEEK.

&&

.DISCUSSION...THE WEST-TO-EAST COLD CORE UPPER TROUGH ALONG THE
OREGON/CALIFORNIA BORDER WILL CONTINUE TO ELONGATE WEST-TO-EAST
OVERNIGHT...THEN TURN EAST INTO THE WRN GREAT BASIN MONDAY. THE
INGREDIENTS ARE THERE TO MAKE THIS A SIGNIFICANT WINTER STORM FOR
MONDAY NIGHT/TUESDAY...ESPECIALLY ACROSS SRN/CNTRL UTAH. COLD
TEMPERATURES AND LINGERING SHOWERS WILL REMAIN MIDWEEK IN THE WAKE
OF THE TROUGH....WITH A MOIST WESTERLY FLOW ALOFT PUNCHING INTO
THE BASIN BY NEXT WEEKEND.

THE APPROACHING SYSTEM WILL BRING GOOD DYNAMIC LIFT/MOISTURE/COLD
AIR ALOFT ALONG WITH A STRONG UPPER JET ACROSS ARIZONA MONDAY
NIGHT. THE RAPID INTENSIFICATION OF THE LEE SIDE SURFACE LOW OFF
THE CNTRL SIERRAS MONDAY INDICATIVE OF THE STRONG LIFT GENERATED
BY THIS STORM. HEAVY SNOW EXPECTED ACROSS MUCH OF THE SRN HALF OF
UTAH...WITH EVEN THE LOWEST ELEVATIONS NEAR THE ARIZONA BORDER
PICKING UP MEASURABLE SNOW. NRN UTAH WILL SEE MOST OF ITS SNOW
GENERATED IN THE MOIST SW FLOW ALOFT...FOLLOWED BY A PERIOD OF 
INSTABILITY SNOWS IN THE WAKE OF THE TROUGH. AMOUNTS ARE EXPECTED
TO BE LESS THAN DOWN SOUTH DUE IN PART TO LESS FAVORABLE DYNAMICS
AND A SHORTER DURATION OF HEAVY PRECIP.

CYCLONIC NORTHERLY FLOW ALOFT MIDWEEK WILL KEEPS TEMPS VERY COLD
WITH SPOTTY LIGHT PRECIP POSSIBLE OVER THE FAR NORTH. EXTREME COLD
POSSIBLE WHERE DEEP SNOW COVER EXISTS. THE WESTERLIES WILL FINALLY
CUT UNDER THE ERN PACIFIC RIDGE AND RACE ACROSS THE CONUS BY NEXT WEEKEND.
THE WESTERLIES DO LOOK TO BE MOIST...WITH AN INCREASING THREAT OF
SNOW AND SPOTTY LOWER VALLEY RAIN LATE IN THE FORECAST PERIOD.

&&

.AVIATION...LIGHT SOUTHEAST WINDS HAVE DEVELOPED AND ARE EXPECTED TO 
CONTINUE THROUGH THE NIGHT. A 20 PERCENT CHANCE OF CALM OR LIGHT 
NORTHWEST WINDS OFF THE LAKE IS POSSIBLE THROUGH 02Z. CLOUDS WILL 
INCREASE ONCE AGAIN OVERNIGHT WITH LIGHT SNOW SHOWERS DEVELOPING 
BETWEEN 10-12Z. 

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER STORM WARNING FROM 11 PM SUNDAY TO 4 PM TUESDAY FOR 
     UTZ517-UTZ518.

     WINTER STORM WARNING FROM 3 AM MONDAY TO NOON TUESDAY FOR UTZ014-
     UTZ015-UTZ016.

     WINTER STORM WARNING FROM 6 AM MONDAY TO 6 AM TUESDAY FOR UTZ011-
     UTZ012-UTZ013-UTZ019-UTZ020-UTZ021.

     WINTER STORM WARNING FROM MIDNIGHT MONDAY TO 4 PM TUESDAY FOR 
     UTZ008-UTZ009-UTZ010.

     WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO 4 PM TUESDAY FOR 
     UTZ003-UTZ004-UTZ006.

WY...NONE.

&&

$$

PUBLIC...CONGER
AVIATION...YOUNG

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