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000
FXUS65 KSLC 062354
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
454 PM MST FRI DEC 6 2013

.SYNOPSIS...A COLD STORM SYSTEM WILL CROSS THE GREAT BASIN TONIGHT
THROUGH SATURDAY NIGHT THEN MOVE OFF TO THE EAST ON SUNDAY. A COLD
NORTHERLY FLOW WILL FOLLOW FOR MONDAY. HIGH PRESSURE WILL BUILD
OVER THE AREA THROUGH MID WEEK.

&&

.SHORT TERM (THRU 00Z TUE)...A BROAD COLD UPPER TROF EXTENDS FROM
THE GREAT LAKES TO THE PAC NORTHWEST THIS AFTERNOON. A WELL
DEFINED SHORT WAVE IS DEEPENING OVER THE PACNW AND THE FLOW IS
STARTING TO BACK OVER THE GREAT BASIN.

THE PACNW SHORT WAVE SWEEPS ACROSS THE GREAT BASIN SAT THRU EARLY
SUN BRINGING WIDESPREAD PRECIP FOR OUR CWA THAT WILL FALL EVERYWHERE
AS SNOW. HAVE UPGRADED THE WINTER STORM WATCH TO A WARNING FOR
ALL AREAS. SOME LOCATIONS MAY NOT QUITE GET WARNING AMOUNTS BUT THE
EXISTING COLD SURFACES WILL ALLOW SNOW TO ACCUMULATE RIGHT FROM THE
START...INCLUDING ON ROADS...CREATING HAZARDOUS TRAVEL CONDITIONS.
SO WE CONSIDER THIS SIGNIFICANT IMPACT JUSTIFIES THE WARNING
ISSUANCE.

LIGHT SNOW HAS ALREADY STARTED IN THE PRICE AREA AND EXPECT THIS TO
BECOME STEADY AND HEAVIER BY MIDNIGHT...CONTINUING THRU EARLY AFTN.
SNOW SHOULD ALSO BEGIN IN THE DIXIE AREA BEFORE SUNRISE WITH THE
BEST PERIOD FOR ACCUMULATION THERE IN THE MID MORNING THRU MID
AFTERNOON.

SNOW SHOULD DEVELOP ACROSS THE REMAINDER OF THE CWA FROM WEST TO
EAST SAT MORNING WITH SOUTHERLY FLOW FAVORED AREAS DOING THE BEST.
THE SURFACE LOW TRACKS ACROSS CENTRAL UT DURING THE DAY WITH THE
GRADIENT SWITCHING TO NWLY OVER WRN UT BY 00Z AND ACROSS THE EASTERN
CWA BY 06Z.

THIS SHOULD SHUT DOWN THE SNOW FOR THE SOUTHERN AND ERN VALLEYS BUT
IT SHOULD REMAIN HEAVY ALONG THE I-15 CORRIDOR PAST MIDNIGHT.

THE GREAT SALT LAKE WILL LIKELY GET INVOLVED WITH SNOW LINGERING
INTO SUNDAY MORNING DOWNWIND OF THE LAKE AND POTENTIALLY BRINGING
SOME LARGE SNOW TOTALS TO SALT LAKE AND DAVIS CO BENCHES.

SNOW SHOWERS LINGER OVER THE NRN MTNS INTO THE AFTN THEN TAPER
OFF. IT IS LOOKING LESS LIKELY THAT A WEAK TRAILING SHORT WAVE IN
THE COLD NORTHERLY FLOW WILL GENERATE ANY SNOW SUN NIGHT INTO MON
AND THE VERY COLD AIRMASS TRAILING THIS SYSTEM SHOULD ALLOW TEMPS
TO GET BITTER COLD ONCE AGAIN BY MON MORNING IN AREAS WHERE SKIES
CLEAR.

&&

.LONG TERM (AFTER 00Z TUESDAY)...A STABLE NORTHWESTERLY FLOW
TRANSITIONS TO A DRY ZONAL MIDLEVEL FLOW AS A RIDGE SLIDES OVER
THE GREAT BASIN ON WEDNESDAY. MOUNTAIN TEMPERATURES SHOULD CLIMB
TUESDAY AND WEDNESDAY WITH GOOD WARM ADVECTION ALOFT...BUT VALLEY
INVERSIONS WILL SLOW THE WARMING IN THESE AREAS. THE GFS AND THE
ECMWF AGREE ON A WINDSHIFT TO SOUTHWEST BY LATE WEDNESDAY AHEAD OF
THE NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST. MODELS LACK
AGREEMENT ON TIMING AND INTENSITY OF THIS NEXT SYSTEM...THUS WILL
SAVE DISCUSSION OF THIS FEATURE UNTIL BETTER MODEL CONFIDENCE IS
SEEN.

&&

.AVIATION...SURFACE WINDS AT THE SLC TERMINAL ARE EXPECTED TO REMAIN
SOUTHERLY THROUGH THE TAF PERIOD. CEILINGS ARE BEGINNING TO LOWER
UPSTREAM OF THE TERMINAL AND ARE EXPECTED TO DROP TO 6000 FT AGL AT
THE TERMINAL AREA AFTER 12-14Z...WITH A 30 PERCENT CHANCE THAT
THIS DROP OCCURS SOONER. SNOW WILL LIKELY CREATE MVFR CONDITIONS
BY 17Z SATURDAY LOWERING TO IFR DURING THE AFTERNOON.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 10 AM MST SUNDAY
     FOR UTZ011>013-019>021.

     WINTER STORM WARNING FROM 5 AM SATURDAY TO 6 PM MST SUNDAY FOR
     UTZ002>004-006>010.

     WINTER STORM WARNING FROM 5 AM SATURDAY TO NOON MST SUNDAY FOR
     UTZ001-005-014>016-517-518.

WY...WINTER STORM WARNING FROM 5 AM SATURDAY TO 6 PM MST SUNDAY FOR
     WYZ021.

&&

$$

WILENSKY/VERZELLA/STRUTHWOLF

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

FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)