145 
FXUS65 KSLC 211537
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
937 AM MDT THU MAR 21 2013

.SYNOPSIS...A COLD UPPER TROUGH WILL BE OVER THE AREA THROUGH THE
WEEKEND WITH EMBEDDED DISTURBANCES ROTATING THROUGH THE PATTERN
AND BRINGING UNSETTLED WEATHER TO THE NORTHERN PORTION OF UTAH AND
SOUTHWEST WYOMING.

&&

.DISCUSSION...SURFACE COLD FRONT AT 15Z STRETCHED FROM AROUND
VERNAL TO MILFORD. A COUPLE OF THUNDERSTORMS HAVE BEEN NOTED ALONG
THE SURFACE BOUNDARY OVER EASTERN UTAH. THE UPPER TROUGH AXIS AT
500 MB IS A FEW HOURS BEHIND THE SURFACE FRONT AND WAS RESPONSIBLE
FOR A PERIOD OF INTENSE SNOWFALL AS IT MOVED THROUGH THE WASATCH FRONT.

LAKE EFFECT SNOW HAS DEVELOPED OVER SALT LAKE AND DAVIS COUNTIES BEHIND
THE TROUGH AXIS. OTHERWISE STRONG SUBSIDENCE AND A RAPIDLY DRYING
AIRMASS IS BRINGING CLEARING SKIES TO MOST OF WESTERN UTAH. 

AT THE SURFACE A STRONG ISSALLOBARIC RISE CENTER OF 6 MB IN 3
HOURS BROUGHT GUSTY NORTHWEST WINDS TO MANY AREAS BEHIND THE
SURFACE COLD FRONT. AT 15Z THIS CENTER WAS NEAR DELTA...SO STRONG
GUSTY WINDS ARE LIKELY ACROSS CENTRAL AND EASTERN UTAH THROUGH MID
DAY BEHIND THE FRONT....OVER THE NORTH WINDS WILL BE DECREASING
BUT WILL STILL FEEL BRISK GIVEN THE COLD AIR.

SNOW CONTINUES AT THIS TIME IN THE NORTHERN MOUNTAINS...MAINLY DUE
TO LAKE EFFECT...BUT EXPECT THIS TO WIND DOWN IN THE NEXT 2 HOURS
AS A BIT OF SOLAR HEATING WILL LEAD TO UNFAVORABLE MOUNTAIN/VALLEY
CIRCULATIONS FOR MAINTAINING ORGANIZED LAKE BANDS. WILL ALLOW THE
WINTER WEATHER ADVISORIES FOR THE MOUNTAINS TO EXPIRE AT 18Z.

COLD UPPER TROUGH REMAINS OVER THE NORTHERN ROCKIES THROUGH THE
WEEKEND. MODELS INDICATE A COLDER SHORT WAVE FRIDAY ROTATING
THROUGH THE PATTERN AND ANOTHER ON SUNDAY. EXPECT THESE TO PRODUCE
WIDESPREAD SNOW SHOWERS BUT GENERALLY LITTLE ACCUMULATION IN THE
NORTHERN VALLEYS WITH A FEW INCHES OF LOW DENSITY SNOW POSSIBLE
IN THE MOUNTAINS...MAINLY FROM MID DAY THROUGH SUNSET AS DIRUNAL
HEATING DRIVES SHOWER ACTIVITY.

COLD AIR EXTENDS ALL THE WAY TO THE UT/AZ BORDER SATURDAY NIGHT
AND SUNDAY...DRY BUT UNSEASONABLY COOL EVEN IN DIXIE.

NO CHANGES TO FORECASTS AT THIS TIME.

&&

.AVIATION...SNOW SHOWERS WILL CONTINUE IN THE VICINITY OF THE SLC 
TERMINAL THROUGH ABOUT 17-18Z. THERE IS A 20 PERCENT CHANCE THAT A 
LIGHT SNOW SHOWER WILL ROLL IN OFF THE GREAT SALT LAKE AND LOWER 
CEILINGS AND VISIBILITIES INTO THE HIGH END IFR/LOW END MVFR RANGE 
THROUGH 18Z AS WELL. OTHERWISE EXPECT VFR CONDITIONS. CEILINGS 
SHOULD RAPIDLY RISE ABOVE 6000 FT AGL OVER THE NEXT FEW HOURS. WINDS 
WILL BE GENERALLY LIGHT NORTHWESTERLY WITH OCCASIONAL GUSTS TO 20 
MPH POSSIBLE UNTIL 21Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER WEATHER ADVISORY UNTIL NOON MDT TODAY FOR UTZ007>009. 

WY...NONE.
&&

$$

PUBLIC...DUNN
AVIATION...YOUNG

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)