Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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039
FXUS65 KSLC 132303
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
403 PM MST SAT FEB 13 2016

.SYNOPSIS...A COUPLE OF WEAK WEATHER DISTURBANCES WILL CROSS
NORTHERN UTAH THIS WEEKEND. HIGH PRESSURE ALOFT WILL REBOUND
ACROSS THE REGION EARLY NEXT WEEK.



&&

.SHORT TERM (THOUGH 00Z WEDNESDAY)...A SHORTWAVE TROUGH IS MOVING
THROUGH THE INTERMOUNTAIN WEST THIS AFTERNOON...WITH THE WEAK LOW
LEVEL COLD FRONT BRUSHING NORTHERN UTAH AND SOUTHWEST WYOMING.
WHILE THIS WAVE HAS NOT ELIMINATED LOW LEVEL TEMPERATURE
INVERSIONS...IT HAS WEAKENED THEM...WITH ASSOCIATED STRATUS OVER
WESTERN UTAH DISSIPATING AT THE EDGES. THE PRIMARY REMAINING
FOG/STRATUS IS NEAR THE GREAT SALT LAKE AND UTAH LAKE...AS WELL AS
IN SOME OF THE LOWER BASINS OF THE NORTHWEST DESERT.

OTHER THAN THE LINGERING LOW LEVEL STRATUS...SKIES TONIGHT SHOULD
GENERALLY BE CLEAR THROUGH AT LEAST MIDNIGHT...SO EXPECT SOME
PATCHY FOG TO FORM AGAIN OVERNIGHT IN THE NORTHERN AND WESTERN
VALLEYS. CLOUDS AND A CHANCE OF PRECIPITATION WILL THEN INCREASE
FROM THE NORTH AS THE NEXT DISTURBANCE MOVES THROUGH THE
AREA...WITH THE JET STREAM MOVING OVERHEAD SUNDAY MORNING.

THE BEST CHANCE OF SNOW WILL BE IN THE FAR NORTHERN MOUNTAINS
SUNDAY MORNING THROUGH MONDAY MORNING IN THE MOIST NORTHWEST
FLOW...THOUGH THE NORTHERN VALLEYS COULD SEE SOME LIGHT
PRECIPITATION AS WELL. THIS PRECIP COULD START AS SNOW IN THE
STILL SOMEWHAT INVERTED VALLEYS...LIKELY CHANGING TO RAIN OR
RAIN/SNOW MIX OVER TIME...THOUGH WITH LOW CONFIDENCE IN TIMING
THIS P-TYPE SWITCH. THIS SERIES OF WEAK WAVES IN MOIST NORTHWEST
FLOW COULD ALSO HELP SLOWLY WEAKEN OR ELIMINATE INVERSION
CONDITIONS...THOUGH AREAS SUCH AS DELTA AND THE SEVIER VALLEY MAY
BE TOO FAR SOUTH AND COULD REMAIN INVERTED INTO MID- WEEK.

THE AIRMASS SLOWLY WARMS AND DRIES MONDAY NIGHT AND TUESDAY...AS
THE RIDGE AXIS SHIFTS FROM THE WEST COAST TO THE GREAT BASIN.
VALLEY WARMING IS NOT EXPECTED TO BE DRAMATIC ON TUESDAY...AS LOW
LEVEL CONDITIONS WILL PROBABLY BE SOMEWHAT STABLE...BUT THAT COULD
CHANGE AS A PACIFIC TROUGH BEGINS TO APPROACH WEDNESDAY.


.LONG TERM (AFTER 00Z WEDNESDAY)...RIDGE AXIS IS PROGGED TO SHIFT
EAST WEDNESDAY AHEAD OF THE NEXT APPROACHING STORM SYSTEM. EC/GFS
AGREE THE SYSTEM WILL MOVE THROUGH LATE THURSDAY/EARLY FRIDAY...A
RELATIVE QUICK HITTER. HOWEVER...THEY DISAGREE ON THE REST OF THE
DETAILS. EC IS SHOWING A BROADER SYSTEM THAT IMPACTS THE ENTIRE
FORECAST AREA WHILE THE GFS SHOWS A MORE COMPACT SYSTEM JUST
IMPACTING NORTHERN AND CENTRAL UTAH. EITHER SOLUTION SHOULD BE
STRONG ENOUGH TO AT LEAST SIGNIFICANTLY WEAKEN REMAINING
INVERSIONS. A FULL MIX OUT SEEMS LIKELY...PARTICULARLY WITH THE
STRONGER AND COLDER FRONT IN THE GFS SOLUTION. AS A
RESULT...SHOWING SIGNIFICANT WARMING BEGINNING WEDNESDAY AS FLOW
ALOFT INCREASES AHEAD OF THE SYSTEM.

BEHIND THE EXITING SYSTEM...RIDGING IS PROGGED TO START TO BUILD
BACK IN ON FRIDAY BUT BECOMES MORE ZONAL OVER THE
WEEKEND...PARTICULARLY IN THE ECMWF SOLUTION...WITH A WEAK TROUGH
PASSING TO THE NORTH OF THE AREA.

&&

.AVIATION...AT THE SLC TERMINAL...MVFR CONDITIONS IN HAZE ARE
EXPECTED TO DETERIORATE BACK TO IFR BETWEEN 02Z AND 04Z...WITH LIFR
CONDITIONS POSSIBLE AFTER ABOUT 06Z. LIGHT NORTHWESTERLY WINDS ARE
EXPECTED TO SHIFT TO THE SOUTHEAST BETWEEN 03Z AND 05Z.

&&

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

$$

SHORT TERM...SCHOENING
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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