Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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FXUS65 KSLC 281253
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
553 AM MST SAT FEB 28 2015

.SYNOPSIS...AN UPPER TROF WILL LINGER OVER THE GREAT BASIN TODAY
THROUGH MONDAY THEN SHIFT EAST TUESDAY.

&&

.SHORT TERM (THRU 00Z TUE)...FIRST SPOKE OF ENERGY FROM THE
DEVELOPING LOW OVER CA AND THE WRN GREAT BASIN IS LIFTING THRU SRN
UT AT THIS TIME BRINGING A BAND OF SNOW SHOWERS. THIS BAND
CONTINUES TO LIFT NORTH THRU THE DAY AND ENDS UP AS A DEFORMATION
FROM W-CENTRAL TO NERN UT THIS EVE.

HAVE SOME CONCERNS THAT THE PRECIP WILL BECOME TOO SHOWERY AND
DISORGANIZED ACROSS THE FAR SOUTH BY MID MORNING TO KEEP A THREAT
OF WIDESPREAD SNOW GOING TODAY AND THE AIRMASS WARMS UP AS WELL SO
MAY NEED TO CANCEL THE ADVISORY FOR THE SRN UT VALLEY ZONE THIS
MORNING IF CURRENT TRENDS CONTINUE.

FARTHER NORTH...THE SNOW SHOWERS SHOULD BRING SOME ACCUMULATION
THIS MORNING TO THE SRN AND CENTRAL MTNS AND THE ERN BASINS ALTHO
HERE TOO THE SHOWERY NATURE OF THE PRECIP COULD LIMIT AMOUNTS AND
IMPACT. ALSO WARMING TEMPS SHOULD LIMIT IMPACT IN ERN UT TO THE
HIGHER ELEVATIONS OF I-70 ACROSS THE SWELL.

MODELS INDICATE PRECIP TONIGHT SHOULD PRETTY MUCH BE LIMITED TO
THE VICINITY OF THE DEFORMATION ZONE AND TAPERS OFF ACROSS SRN UT.
THIS SHOULD BE SNOW TO THE VALLEY FLOORS AND COULD BRING SOME
IMPACT THE WESTERN VALLEYS FROM ABOUT SALT LAKE SOUTH TO DELTA AND
ACROSS THE EAST IN THE UINTA BASIN AND NEAR PRICE.

MODEST CANYON WINDS HAVE DEVELOPED ALONG THE WASATCH FRONT THIS
MORNING AND COULD STRENGTHEN SOMEWHAT TONIGHT BUT SHOULD ONLY
REACH MARGINAL ADVISORY LEVELS AT BEST. THIS SHOULD REDUCE THE
THREAT OF PRECIP TONIGHT FROM SALT LAKE NORTH TONIGHT.

THE DEFORMATION ZONE WEAKENS SUN AND ANY ASSOCIATED PRECIP
BECOMES SPOTTY AND LIGHT. HOWEVER...THE UPPER LOW OVER CA BECOMES
MORE N-S ORIENTED AND STARTS TO SEND A PLUME OF MOISTURE NWD INTO
SRN UT BY LATE IN THE DAY. THIS BECOMES A STRONG SURGE OF MOISTURE
SUN NIGHT THRU MON INTO THE CWA BUT IS ALSO FAIRLY WARM SO ANY
SNOW IMPACT WOULD BE LIMITED TO ELEVATIONS ABOVE ABOUT 6500 FEET
ACROSS THE WEST AND 7500 FEET OR HIGHER EAST. THIS WOULD ALSO
WARRANT EXTENDING THE WINTER WEATHER HIGHLIGHT FOR THE MTNS.

QUITE A BIT OF WATER IS FORECAST TO FALL OUT OF THIS SYSTEM AND
WE WILL NEED TO WATCH FOR THE POSSIBILITY OF HEAVY RUNOFF IN SERN
UT.

THIS TROF STARTS TO SHIFT EAST BY LATE MON AND PRECIP BEGINS TO
TAPER OFF.

&&

.LONG TERM (AFTER 00Z TUESDAY)...THE FIRST TROUGH IS PROGGED TO MOVE
ACROSS UTAH AND SOUTHWEST WYOMING MONDAY NIGHT AS A SECOND TROUGH
DIVES SOUTH ALONG THE PACIFIC COAST. AS IT PASSES THROUGH...MODELS
INDICATE BEST PRECIP OVER THE FORECAST AREA WILL BE IN SOUTHEAST
UTAH...WITH THE BEST MOISTURE AND INSTABILITY SOUTH OVER ARIZONA.

THERE MAY BE A BRIEF LULL BEHIND THE FIRST EXITING SYSTEM ON TUESDAY
MORNING...BUT THE SECOND STORM SYSTEM IS PROGGED TO MOVE ACROSS THE
AREA TUESDAY AFTERNOON THROUGH EARLY WEDNESDAY. EC/GFS BOTH TRENDING
WEAKER WITH THIS SYSTEM...SHOWING IT SPLITTING SHARPLY AS IT DIVES
SOUTH...WITH ONLY THE NORTHERN PORTION IMPACTING THE CWA. IT DOES
STILL LOOK TO BRING A GOOD COLD FRONT WITH 700 MB TEMPS AS LOW AS -
14C TO -16C. PREVIOUS RUNS SHOWED VERY GOOD FGEN ALONG THE FRONT
PRODUCING A WELL DEFINED BAND OF PRECIP. LATEST GUIDANCE SHOWS THE
PRECIP BEING MUCH MORE DISORGANIZED SO HAVE LOWERED POPS JUST A BIT.

EC IS STILL A BIT SLOWER THAN THE GFS IN MOVING THE SYSTEM OUT...BUT
BOTH HAVE HIGH PRESSURE MOVING BACK OVER UTAH AND SOUTHWEST WYOMING
BY WEDNESDAY AFTERNOON. THIS WILL USHER IN A DRYING AND WARMING
TREND FOR THE MIDDLE TO LATTER PART OF THE UPCOMING WEEK...WITH
TEMPERATURES EXPECTED TO MOVE BACK ABOVE NORMAL BY NEXT WEEKEND.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE SLC
TERMINAL DURING THE DAYTIME HOURS. HOWEVER...SHOWERS IN THE VICINITY
OF THE TERMINAL ARE EXPECTED BRING CIGS TO OR BELOW 6000 FT AGL
BETWEEN 17Z AND 19Z AND REMAIN IN PLACE DURING THE AFTERNOON. THERE
IS A 30 PERCENT CHANCE OF MVFR CONDITIONS DEVELOPING FOR PERIODS IN
RAIN AND SNOW. GENERALLY LIGHT WINDS ARE EXPECTED TO BECOME
PREVAILING NORTHWESTERLY BETWEEN 15Z AND 17Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER WEATHER ADVISORY UNTIL 9 AM MST SUNDAY FOR UTZ012-013-020-
     517-518.

WY...NONE.
&&

$$

SHORT TERM...WILENSKY
LONG TERM/AVIATION...TRAPHAGAN

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)



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