Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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716
FXUS65 KSLC 311741
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1041 AM MST SUN JAN 31 2016

.SYNOPSIS...A WINTER STORM WILL AFFECT MOST OF UTAH SOUTH OF I-80
AND SOUTHWEST WYOMING THROUGH MONDAY NIGHT. THE MOST SIGNIFICANT
SNOW ACCUMULATIONS AND GUSTY WINDS WILL BE ACROSS CENTRAL AND
SOUTHERN UTAH. COLD NORTHERLY FLOW WILL FOLLOW ACROSS THE REGION
FOR THE MIDDLE PORTION OF NEXT WEEK.

&&

.DISCUSSION...ENERGETIC STORM SYSTEM CONTINUES TO DEVELOP OVER
CENTRAL CALIFORNIA WITH MOISTURE SPREADING NORTHEAST ACROSS NEVADA
AND INTO SOUTHWEST UTAH AT THIS TIME. THE LATEST RUNS OF THE
GLOBAL AND LOCAL MODELS ARE ALL INDICATING A FARTHER NORTH EDGE TO
THE PRECIPITATION SHIELD FOR LATE TODAY THROUGH TONIGHT AND INTO
EARLY MONDAY. SATELLITE AND RADAR REVEALING THIS AS WELL SO HAVE
BOOSTED POPS ACROSS THE WEST CENTRAL UTAH AS WELL AS INTO
SOUTHERN UTAH COUNTY TODAY AND THEN ACROSS THE CENTRAL AND
SOUTHERN WASATCH VALLEYS AND MOUNTAINS AND THE SOUTHERN HALF OF
THE WASATCH BACK TONIGHT. RIGHT ENTRANCE REGION OF JET ACROSS
WYOMING ALONG WITH EXIT REGION OF JET ROUNDING BASE OF TROUGH OVER
CALIFORNIA AND ARIZONA PLACES UTAH UNDER A BROAD AREA OF
DIVERGENCE. ADD TO THIS 500 MB WARM ADVECTION AND ON THE MORE
LOCAL SCALE THE 700MB TROUGH AXIS/WARM ADVECTION EXTENDING AS FAR
NORTH AS UTAH COUNTY CAN SEE WHY THE MODELS ARE GENERATING
PRECIPITATION INTO THE WASATCH FRONT TONIGHT. WILL CONSIDER
ADDING A WINTER WEATHER ADVISORY FOR AT LEAST THE SOUTHERN
WASATCH MOUNTAINS AND WASATCH FRONT TONIGHT INTO MONDAY IN THE
AFTERNOON PACKAGE. MAY HAVE TO INCLUDE AREAS FARTHER NORTH AS WELL
BUT WILL WAIT AND SEE HOW THINGS COME TOGETHER EARLY THIS
AFTERNOON.

HAVE ADJUSTED TEMPS DOWNWARD ACROSS SOUTHERN AND WEST CENTRAL UTAH
TODAY AS COLD AIR IS IN PLACE ALREADY AND WITH SURFACE GRADIENT
REMAINING NORTHERLY ALONG WITH WIDESPREAD PRECIPITATION EXPECT
TEMPERATURES TO STRAIGHT LINE THROUGH THE DAY.

TEMPERATURES ACROSS SOUTHERN UTAH A BIT TRICKY AS WELL AS SNOW
LEVELS BUT THE BOTTOM LINE IS THAT ANYWHERE THE SNOW LEVEL IS NOT
A CONCERN HEAVY SNOW ACCUMULATIONS ARE EXPECTED. AT THE LAKE
POWELL ELEVATION PRECIP MAY REMAIN AS RAIN THROUGH THIS STORM BUT
JUST A FEW HUNDRED HIGHER EXPECT A MIXTURE OR POSSIBLY ALL SNOW
SO WILL CONTINUE WITH THE STORM WARNING.

WILL ADDRESS THE SOUTHWEST WYOMING WINTER STORM WATCH IN THE
AFTERNOON PACKAGE. MODELS ARE SHOWING A GOOD NORTHEAST MOIST FLOW
ACROSS THERE LATER TONIGHT AND MONDAY AND THIS WOULD BE UPSLOPE
FLOW INTO THE UINTAS. THE GFS IS THE MOST AGGRESSIVE WITH ABOUT
0.50 OF AN INCH OF PRECIP WHILE THE OTHER MODELS ARE CLOSER TO
0.15-0.20 OF AN INCH. WILL TACKLE WHAT TO ISSUE ON THE AFTERNOON
PACKAGE.

PATCHY DENSE FOG REMAINS ALONG THE WASATCH FRONT AND PORTIONS OF
THE GSL DESERT BUT ANTICIPATE THIS TO IMPROVE BY MIDDAY.


&&

.AVIATION...PERIODS OF IFR OR LIFR CONDITIONS IN PATCHY FOG ARE
POSSIBLE AT THE SLC TERMINAL THROUGH 18-19Z...BUT THE SHALLOW GROUND
FOG SHOULD DISSIPATE AFTER THAT. AS SHOWERS SHIFT NORTHWARD THROUGH
THE DAY...THERE IS A 30 PERCENT CHANCE THAT CEILINGS BELOW 7000FT
WILL DEVELOP BETWEEN 21Z AND 00Z...BUT AFTER 00Z IS MORE LIKELY FOR
THESE LOWER CIGS. THERE IS A 60 PERCENT CHANCE OF IFR SNOW AT THE
TERMINAL STARTING BETWEEN 23Z AND 06Z...BUT SNOW ACCUMULATION IS
GENERALLY EXPECTED TO BE LESS THAN AN INCH.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER STORM WARNING UNTIL 11 PM MST MONDAY FOR UTZ012>015-020-
     021.

     WINTER STORM WARNING UNTIL 11 PM MST MONDAY FOR UTZ016-517-518.

     WINTER WEATHER ADVISORY UNTIL 11 PM MST MONDAY FOR UTZ010-019.

WY...WINTER STORM WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT
     FOR WYZ021.

&&

$$

PUBLIC...STRUTHWOLF
AVIATION...SCHOENING

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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