Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 160434
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
934 PM MST SAT NOV 15 2014

.SYNOPSIS...A VERY COLD UPPER LEVEL TROUGH WILL CONTINUE TO TRACK
ACROSS THE AREA TONIGHT. HIGH PRESSURE ALOFT WILL DEVELOP OVER
THE REGION EARLY IN THE UPCOMING WEEK.

&&

.DISCUSSION...LATE EVENING WATER VAPOR AND H5 ANALYSIS PLACES THE
WESTERN LOBE OF THE COLD SPLITTING TROUGH ACROSS EASTERN
NEVADA...TRACKING SOUTHEAST WITH AXIS OVER NORTH-CENTRAL UTAH.
THE SURFACE COLD FRONT NOW RESIDES SOUTH OF THE BORDER PER MSAS
MSLP AND SURFACE OBS WITH A STRONG NORTHERLY GRADIENT IN PLACE
ACROSS THE AREA.

STRONG FRONTOGENIC DEVELOPMENT OCCURRED ALONG AND NEAR THE H7
BAROCLINICITY ACROSS MUCH OF CENTRAL/SOUTHERN UTAH OVER THE LAST
SEVERAL HOURS. THIS AS THE AFOREMENTIONED SHORT WAVE AND
ASSOCIATED PVA AIDED UPPER LEVEL SUPPORT. A RATHER NARROW BUT
EFFICIENT WEST- EAST ORIENTED SNOW BAND DEVELOPED AROUND SCIPIO
AND HAS SINCE PUSHED SOUTH INTO THE CEDAR CITY AREA. ALTHOUGH
THIS BAND WILL BE SHORT LIVED AREAS WHERE IT IMPACTS...HIGH PI
RATES WILL CONTINUE TO SUPPORT SOME ROAD ACCUMULATIONS FOR A
BRIEF WINDOW ELEVATIONS ELEVATIONS ABOVE ABOUT 5000FT. A WINTER
WEATHER ADVISORY REMAINS IN EFFECT FOR THE VALLEYS THROUGH
MIDNIGHT AND 3 AM FOR THE SOUTHERN/CENTRAL MOUNTAINS...AS
CONTINUED AND RAPID PROGRESSION OF THE UPPER TROUGH WILL SWEEP THE
MORE SIGNIFICANT PRECIP EAST THEREAFTER.

A STRONG GAP WIND EVENT IS BEGINNING TO RAMP UP IN WASHINGTON
COUNTY AS A BUILDING NE-SW MSLP GRADIENT AND COLD STRONG LOW LEVEL
COLD ADVECTION IS OCCURRING. GUSTS TO 49 MPH ALREADY NOTED AT
WHITE REEF AND TRENDING UP. H7 WINDS WILL CONTINUE TO VEER OVER
THE NEXT SEVERAL HOURS AIDING INCREASED SPEEDS WITH PEAK WIND
SPEED POTENTIAL LATER TONIGHT INTO EARLY TOMORROW MORNING. HAVE
MAINTAINED THE HIGH WIND WARNING AS SUCH...BUT EXPIRED THE
ADVISORY IN CASTLE COUNTY AS GUSTS SHOULD REMAIN SUB CRITICAL
LEVELS THERE.

DRIER AIR BOTH AT THE SURFACE AND ALOFT WILL CONTINUE FILTER IN
IN WAKE OF TROUGH PASSAGE LATER TONIGHT AND THROUGH TOMORROW. MAX
TEMPS AREAWIDE LOOK TO RUN ABOUT 20 DEGREES BELOW CLIMO UNDER
LARGELY CLOUD FREE SKIES. LIKLEY THE COLDEST DAY OF THE FALL THUS
FAR.

WILL LIKELY SEE NEAR TO SUB FREEZING TEMPS EVEN IN DIXIE TOMORROW
NIGHT. FUTURE SHIFTS WILL LOOK AT THIS POTENTIAL MORE CLOSELY AS
FREEZE HIGHLIGHTS MAY BE WARRANTED THERE. OUTSIDE OF THE COLD
TEMPS...RIDGING WILL DOMINATE INTO MIDWEEK ALLOWING DRY AND STABLE
CONDITIONS.

&&

.LONG TERM (AFTER 00Z WEDNESDAY)...THE RIDGE OVER THE GREAT BASIN ON
TUESDAY WILL SHIFT DIRECTLY OVER THE CWA TUESDAY NIGHT AS A PACIFIC
SHORTWAVE PUSHES INLAND. THAT SHORTWAVE IS EXPECTED TO SLIDE THROUGH
THE AREA IN SOME FORM OR FASHION ON WEDNESDAY...THOUGH THIS WAVE
LOOKS TO SPLIT A BIT AS IT MOVES THROUGH THE REGION. THE BEST COLD
ADVECTION AND CHANCE OF PRECIP SEEMS TO BE OVER THE FAR NORTHERN
PORTIONS OF THE CWA...AND HAVE INCREASED POPS A BIT THROUGH THIS
PERIOD.

BEYOND WEDNESDAY...GLOBAL MODELS HAVE SIMILAR IDEAS BUT WITH
DIFFERENT TIMING/DETAILS. A RIDGE BEGINS TO RE-BUILD OVER THE WEST
COAST ON WEDNESDAY NIGHT...PUTTING THE CWA IN A COOL NORTHWEST
FLOW...BUT THE AMPLITUDE AND EXACT PLACEMENT OF THIS RIDGE WILL
DETERMINE HOW MUCH MOISTURE LINGERS OVER THE AREA. FOR NOW...HAVE
KEPT SLIGHT CHANCE POPS ACROSS THE NORTHERN HALF OF THE CWA THROUGH
THURSDAY TO ACCOUNT FOR THE WETTER GFS SOLUTION. HAVE ALSO KEPT A
SLOW WARMING TREND IN THE VALLEYS FOR THE MIDDLE OF THE WEEK...AS
SLIGHTLY INCREASED MIXING AND CLOUD COVER COULD HELP WEAKEN SOME
INVERSIONS.

THE RIDGE LOOKS TO SHIFT OVER THE CWA ON THURSDAY NIGHT...WITH THE
NEXT SHORTWAVE MOVING INTO THE GREAT BASIN SOMETIME FRIDAY OR FRIDAY
NIGHT. IT REMAINS UNCERTAIN HOW MUCH OF THIS SHORTWAVE WILL SLIDE
SOUTH OF THE AREA...SO HAVE MAINTAINED JUST SLIGHTLY ABOVE CLIMO
POPS FOR FRIDAY AND SATURDAY...WITH SOME MINOR COOLING ON
SATURDAY.

&&

.AVIATION...NORTHERLY WINDS ARE EXPECTED TO REMAIN ENHANCED AT THE
SLC TERMINAL THROUGH ABOUT MIDNIGHT BEFORE DECREASING BUT REMAINING
NORTH. THERE IS A 30 PERCENT CHANCE THAT WINDS COULD BECOME LIGHT
AND VARIABLE BETWEEN 13 AND 16Z SUNDAY. OTHERWISE NORTHERLY WINDS
THROUGH SUNDAY. CLEAR SKIES WILL PREVAIL THROUGH THE TAF PERIOD.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER WEATHER ADVISORY UNTIL 3 AM MST SUNDAY FOR UTZ517-518.

     WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR
     UTZ014>016.

     HIGH WIND WARNING UNTIL NOON MST SUNDAY FOR UTZ019.

WY...NONE.
&&

$$

SHORT TERM/AVIATION...MERRILL/STRUTHWOLF
LONG TERM...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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