Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 212238
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
338 PM MST WED JAN 21 2015

.SYNOPSIS...HIGH PRESSURE ALOFT WILL EXPAND ACROSS THE WESTERN
STATES THROUGH THE LATTER HALF OF THE WEEK.

&&

.SHORT TERM (THRU 00Z SUN)...THE AXIS OF THE COLD WAVE DROPPING
OUT OF THE NORTH SITS OVER NERN UT AT THIS TIME AND WILL CONTINUE
TO MOVE SOUTH AND OUT OF THE AREA TONIGHT. THE COLDEST AIR WITH
THIS WAVE IS OVER THE CWA AND THIS LOW LEVEL COLD PUSH HAS
GENERATED PATCHY STRATOCUMULUS. THIS HAS MOSTLY FORMED ALONG THE
I-15 CORRIDOR FROM SRN SALT LAKE CO SWD TO NEAR CEDAR CITY. THE
MAJORITY OF IT OVER NERN UT IS EAST OF THE CWA BORDER AND IT
SHOULD PRETTY MUCH STAY THERE THE REST OF THE AFTN.

EXPECT THIS TO MOSTLY DISSIPATE FAIRLY QUICKLY AFTER SUNSET WITH
SKIES REMAINING CLEAR OVERNIGHT. THE THREAT OF FOG IS MINIMAL
TONIGHT AS THE LOW LEVELS HAVE DRIED CONSIDERABLY WITH THE ARRIVAL
OF THIS COLDER AIR AND DEWPOINT SPREADS ARE 10-15 DEG F OR MORE AT
THIS TIME EVEN IN THE MOST FOG PRONE VALLEYS INCLUDING THE UINTA
BASIN.

LOCAL BREEZY NORTH WINDS WILL PERSIST THRU THE EVENING ACROSS MUCH
OF CENTRAL AND SRN UT WITH LOCALLY STRONG GUSTS BELOW GAPS IN
WASHINGTON CO. EXPECT WINDS TO BE ONLY MARGINALLY INTO THE ADVISORY
RANGE AND DO NOT PLAN ON ISSUING ANY WIND HIGHLIGHTS.

THE LOW LEVEL COOLING AND MIXING HAS KEPT THE AIR QUALITY FROM
DETERIORATING TODAY. EXPECT STAGNANT CONDITIONS TO BEGIN TOMORROW
AND THE SLIGHT COOLING WITH THE WEAK SPLITTING WAVE THAT CROSSES
THE REGION FROM THE NORTH FRI/FRI NIGHT WILL HAVE LITTLE IMPACT ON
THE DEVELOPING INVERSIONS. SO THE AIR QUALITY TREND FOR URBAN
AREAS WILL BE DOWNWARDS AFTER TODAY.

RIDGE CONDITIONS THEN DOMINATE THE CWA HEADING INTO THE WEEKEND.

&&

.LONG TERM (AFTER 00Z SUNDAY)...HIGH PRESSURE IS EXPECTED TO BUILD
OVER THE FORECAST AREA THROUGH SUNDAY AS THE TROUGH CONTINUES ITS
DIVE SOUTHWARD. THIS WILL RESULT IN DRYING AND WARMING FOR THE
LATTER HALF OF THE WEEKEND.

BY MONDAY...GLOBAL MODELS INDICATE THAT THE STORM WILL MOVE BACK
NORTHWARD ALONG THE CALIFORNIA COAST...SHIFTING THE RIDGE EASTWARD.
GFS IS FASTER AND STRONGER WITH THE SYSTEM...BRINGING A DECENT
AMOUNT OF MOISTURE AND INSTABILITY OVER MUCH OF UTAH AND SOUTHWEST
WYOMING TUESDAY NIGHT/WEDNESDAY...ENOUGH FOR AT LEAST SOME LIGHT
PRECIP. THE WEAKER EC SOLUTION WOULD LIKELY JUST PUT SOME THICKER
CLOUDS OVER THE CWA...BUT FELT THE THREAT WAS ENOUGH TO MAINTAIN
SLIGHT CHANCE/CHANCE POPS AS THE SYSTEM PASSES. ALL GUIDANCE KEEPS
AT LEAST A BIT OF RESIDUAL MOISTURE OVER AT LEAST NORTHERN AND
CENTRAL UTAH THROUGH DAY 7.

&&

.AVIATION...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGH THE
EVENING WITH MOSTLY CLEAR SKIES. NORTHWEST WINDS ARE EXPECTED TO
SHIFT TO THE SOUTHEAST BETWEEN 03Z AND 05Z.

&&

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