Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 291721
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1021 AM MST THU JAN 29 2015

.SYNOPSIS...A DEVELOPING UPPER LOW OVER THE SOUTHERN GREAT BASIN
WILL SPREAD MOISTURE INTO UTAH LATE TODAY THROUGH SATURDAY. THE
DEEPEST MOISTURE WILL REMAIN PRIMARILY OVER CENTRAL AND SOUTHERN
UTAH.

&&

.DISCUSSION...A LOOSELY ORGANIZED UPPER TROF EXTENDS FROM A WEAK
LOW CENTER OFF THE PACNW STATES SWD DOWN THE COAST TO AN UPPER
LOW WEST OF CENTRAL BAJA AND ON SWD INTO THE TROPICAL ERN PAC. THE
MOISTURE TAP FOR THIS TROF ORIGINATES IN THE ITCZ JUST NORTH OF
THE EQUATOR SO ABUNDANT MOISTURE IS AVAILABLE FOR THIS SYSTEM TO
WORK WITH.

THIS MOISTURE HAS ALREADY SPREAD INTO THE CWA AT MID AND UPPER
LEVELS WITH THE AIRMASS BECOMING SATURATED TONIGHT. THE LATEST GFS
PICKS UP ON A WEAK SHORT WAVE TROF E OF THE CENTER OFF THE PACNW
AND LIFTS IT NWD ACROSS NRN UT TONIGHT. THIS IS FORECAST TO
GENERATE ENOUGH LIFT FOR LIGHT PRECIP ACROSS THE NORTH FROM ABOUT
MIDNIGHT THRU TIL NOON FRI.

THE LIFT ACROSS THE SOUTH BECOMES STRONGER BY 12Z FRI AS THE WEST
COAST TROF CONSOLIDATES AROUND A DEVELOPING UPPER LOW OVER THE
LOWER CO RIVER VALLEY AND CONTINUES INTO SAT MORNING UNTIL THE
UPPER LOW RETREATS SWD AND RIDGING BUILDING IN FROM THE NORTH
SHUTS DOWN THE PRECIP.

AS THIS IS A WARM STORM SNOW LEVELS WILL STAY NEAR ABOUT 7000 FT
AND SHOULD BE TOO HIGH TO HAVE MUCH OF AN IMPACT ON MAJOR VALLEY
ROUTES. I DO EXPECT HEAVY SNOW ABOVE THAT LEVEL IMPACTING PASSES
THROUGH THE CENTRAL AND SRN MTNS AND WILL LIKELY BE ISSUING WINTER
WEATHER HIGHLIGHTS FOR THESE AREAS THIS AFTERNOON.

THIS NEW 12Z GFS HAS BACKED OFF ON THE MON/TUE TROF AND DEPICTS IT
AS A WEAK GRAZING WAVE WITH A LITTLE MOISTURE OVER THE CWA N OF
ABOUT SLC.

FOR NOW THE FOG AROUND THE NRN CWA IS BURNING OFF AND SHOULD
DISSIPATE BY NOON AS FORECAST. NO UPDATES PLANNED AT THIS TIME.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT THE SLC TERMINAL
THROUGHOUT THE DAY WITH INCREASING CLOUDS. PATCHY FOG ON THE
NORTH SIDE OF THE TERMINAL IS EXPECTED TO DISSIPATE BY 18Z. LIGHT
WINDS ARE EXPECTED TO BECOME PREVAILING NORTHWESTERLY BY 19Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...NONE.
WY...NONE.
&&

$$

PUBLIC...WILENSKY
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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