FXUS65 KSLC 061705
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1005 AM MST SUN DEC 6 2009

.SYNOPSIS..THE UPPER LEVEL LOW PRESSURE SYSTEM OVER NORTHERN UTAH
WILL SHIFT EAST OUT OF THE AREA THIS AFTERNOON. THE NEXT UPPER
LOW CURRENTLY OVER THE PACIFIC NORTHWEST WILL TURN EAST MONDAY...
THEN MOVE ACROSS UTAH LATE MONDAY THROUGH TUESDAY.

&&

.DISCUSSION...THE UPPER LOW OVER EXTREME NRN UTAH THIS MORNING
WILL LIFT E-NE OUT OF THE AREA THIS AFTERNOON. LIGHT SNOW ALONG
THE E-NE FLANKS OF THE LOW WILL EXIT NE UTAH/EXTREME SW WY BY
EARLY AFTERNOON. SUBSIDENCE IN THE WAKE OF THE EXITING UPPER LOW
WILL KEEP SUNNY MOSTLY CLEAR OVER WRN/SRN UTAH TODAY. 

THE ONLY REMAINING AREA OF HAZARDOUS WEATHER THIS MORNING REMAINS
ACROSS SW WYOMING. STRONG SURFACE HIGH PRESSURE BUILDING SE ALONG
THE CONTINENTAL DIVIDE HAS CREATED A TIGHT SURFACE GRADIENT ACROSS
WRN WY. STRONG E-NE WINDS COMBINED WITH LIGHT SNOW DID CREATE
POCKETS OF BLOWING/DRIFTING SNOW OVERNIGHT. WINDS WILL REMAIN
FAIRLY STRONG THIS AFTERNOON...BUT WITH SNOW ENDING WILL ALLOW THE 
ADVISORY TO END AS SCHEDULED LATE THIS MORNING.

FOCUS EARLY THIS WEEK WILL TURN TO THE UPPER LOW SETTLING INTO SW
OREGON THIS MORNING. THIS FEATURE WILL LINGER OVER SW OREGON/NRN
CA THROUGH TONIGHT...THEN TURN EAST INTO THE WRN GREAT BASIN
MONDAY. A RATHER ENERGETIC VORTICITY MAX ROTATING THROUGH THE SRN
FLANK OF THE UPPER LOW ON MONDAY SEEMS TO BE THE FEATURE OF MOST
INTEREST FOR MONDAY NIGHT/TUESDAY. STRONG SURFACE CYCLOGENESIS IN
THE LEE OF THE CNTRL SIERRAS REFLECTS STRONG UPWARD MOTIONS
GENERATED BY DYNAMIC LIFT AND A STRENGTHENING UPPER JET ACROSS SRN
CA/WRN AZ. THIS SURFACE LOW IS EXPECTED TO DEEPEN FURTHER AS IT
TRACKS EAST ALONG THE UT/AZ...THEN REACH ITS LOWEST PRESSURE OVER
SW COLORADO EARLY TUESDAY. EVERY INDICATION WOULD HAVE A
SIGNIFICANT STORM ACROSS THE SRN HALF OF UTAH...WITH LIGHT SNOW
BEGINNING TONIGHT/EARLY MONDAY...THEN PERIODS OF HEAVY SNOW LATE
MONDAY THROUGH EARLY TUESDAY AFTERNOON. 

NRN UTAH WILL BE A TOUGH CALL AS TO HOW FAR THE HEAVY SNOW
REACHES INTO THE AREA. THE LOW-LEVEL LOW PRESSURE WILL CLOSE OFF
INTO A TIGHT FEATURE...BUT THE MID-LEVEL SYSTEM IS PROGGED TO
REMAIN AS MORE OF AN OPEN TROUGH AS IT MOVES THROUGH ON TUESDAY.
THE THREAT OF PRECIP UP NORTH WILL MORE LIKELY BE DRIVEN BY THE
TROUGH IN THE ABSENCE OF ANY WARM ADVECTION WRAP-AROUND WITH THIS
SYSTEM. THE CURRENT WINTER STORM WATCH LOOKS FINE FOR NOW...
THROUGH THE SALT LAKE/TOOELE VALLEYS MAY BE A BIT OF A STRETCH IN
THIS PATTERN.

HAVE ISSUED AN UPDATE EARLIER TO ACCOUNT FOR DECREASING
CLOUDS/PRECIP THIS AFTERNOON.

&&

.AVIATION...LIGHT SNOWFALL IS EXPECTED TO WANE AT THE KSLC 
TERMINAL BETWEEN 16-17Z...ALLOWING CONDITIONS TO IMPROVE TO VFR 
BY THE AFTERNOON HOURS...BUT A 30 PERCENT CHANCE EXISTS THAT 
SNOWFALL WILL CONTINUE AS LATE AS 20Z. RUNWAY ACCUMULATIVE CONCERNS 
ARE GENERALLY LOW...BUT POTENTIAL EXISTS FOR CONTINUED LIGHT AND 
PATCHY ACCUMULATIONS THIS MORNING DUE TO THE COLD SURFACE TEMPS. AS 
SNOW WANES...CIGS ARE EXPECTED TO LIFT...BUT A 40 PERCENT CHANCE 
EXISTS THAT THEY WILL REMAIN BELOW 6000FT AGL AT TIMES THROUGH 
SUNSET TONIGHT.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER STORM WATCH FROM 11 PM SUNDAY TO 4 PM TUESDAY FOR UTZ003-
     UTZ004-UTZ006-UTZ008-UTZ009-UTZ010-UTZ011-UTZ012-UTZ013-
     UTZ014-UTZ015-UTZ016-UTZ019-UTZ020-UTZ021-UTZ517-UTZ518.

WY...WINTER WEATHER ADVISORY UNTIL 11 AM SUNDAY FOR WYZ021.

&&

$$

PUBLIC...CONGER
AVIATION...MERRILL

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