Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 152156
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
356 PM MDT WED OCT 15 2014

.SYNOPSIS...A COLD FRONT ACROSS NORTHWEST UTAH LATE THIS AFTERNOON
WILL SWEEP SOUTH INTO CENTRAL UTAH THIS EVENING...THEN STALL
ACROSS SOUTHERN UTAH THURSDAY. HIGH PRESSURE ALOFT WILL RETURN
FOR LATE THURSDAY AND FRIDAY. A SPLITTING STORM SYSTEM WILL BRING
SOME MOISTURE INTO SOUTHERN UTAH THIS WEEKEND.

&&

.SHORT TERM (THROUGH 12Z SUNDAY)...THE UPPER LEVEL TROUGH LIFTING
EAST-NORTHEAST INTO THE NORTHERN ROCKIES LATE THIS AFTERNOON WILL
GRAZE FAR NORTHERN UTAH THIS EVENING. THE ASSOCIATED SURFACE COLD
CURRENTLY OVER EXTREME NORTHWEST UTAH WILL SWEEP THROUGH THE NORTH
THIS EVENING THEN PASS THROUGH CENTRAL UTAH LATE TONIGHT. THE
REMNANT OF THIS FRONT WILL STALL ACROSS SOUTHERN UTAH ON FRIDAY.

STRONG SOUTHERLY WINDS AND WARM TEMPERATURES EXIST AHEAD OF THE
ADVANCING FRONT THIS AFTERNOON. THE FAVORABLE SURFACE PRESSURE
GRADIENT WILL LOSE SOME OF THE STRONG SUPPORTING NEAR 700 MB WIND
THIS EVENING...RESULTING IN A GRADUALLY DECREASE IN WIND SPEEDS
EARLY THIS EVENING. WILL ALLOW THE CURRENT WIND ADVISORY TO EXPIRE
AS SCHEDULED AT 0000 UTC...THOUGH A FEW AREAS COULD SEE ADVISORY
CRITERIA WINDS PERSIST FOR AN HOUR OR TWO ACROSS SOUTHERN UTAH.

GUSTY WEST-NORTHWEST WINDS WILL ALSO FOLLOW THE COLD FRONT ACROSS
NORTHERN UTAH EARLY THIS EVENING. FAIRLY STRONG COLD ADVECTION
TRAILING THE FRONT ACROSS THE FAR NORTH WILL DECREASE FAIRLY
QUICKLY DURING THE EVENING...WITH STRONG NORTHWEST WINDS ALSO
DECREASING LATER IN THE EVENING.

WEAK CONVECTION IN THE COLD AIR TRIALING THE FRONT AT BEST
GENERATING VIRGA OR VERY LIGHT SHOWERS ACROSS NORTHERN NEVADA AND
SOUTHERN IDAHO. SOME OF THIS ACTIVITY COULD SPILL INTO THE FAR
NORTHERN PORTION OF UTAH...THOUGH WITH WEAK DYNAMIC LIFT...LIMITED
MOISTURE AND WANING COLD ADVECTION WOULD NOT THINK THAT ANY
FURTHER DEVELOPMENT WILL OCCUR PAST MID-EVENING.

BUILD HEIGHT LATE THURSDAY/FRIDAY AHEAD OF THE NEXT EASTERN
PACIFIC TROUGH WILL BRING ABOVE NORMAL TEMPS BACK TO THE FORECAST
AREA BY FRIDAY. ONE THING TO WATCH WILL BE THE UPPER LOW CURRENTLY
NEAR 22/124. THIS FEATURE IS PROGGED TO DRIFT NORTHEAST INTO THE
DESERT SOUTHWEST BY FRIDAY NIGHT...THEN TRACK JUST SOUTH OF THE
FOUR CORNERS SATURDAY. THIS SYSTEM DOES NOT LOOK TO BE A BIG
RAIN-MAKER...THOUGH SUFFICIENT MOISTURE WORKING WITH THE AVAILABLE DYNAMIC
LIFT COULD GENERATE SOME SHOWERS ACTIVITY ACROSS THE SOUTH THIS
WEEKEND. FOR NOW WILL KEEP THE POPS LOW WITH LIMITED AREAL
COVERAGE INTO SATURDAY EVENING.

THE PREVIOUSLY MENTIONED EASTERN PACIFIC UPPER TROUGH LOOKS TO BE
FAIRLY ENERGETIC AS IT REACHES THE WEST COAST FRIDAY NIGHT.
HOWEVER...THIS FEATURE WILL SPLIT HARD AS IT MOVES INLAND WITH THE
NORTHERN SPLIT MOVING WELL TO THE NORTH OF UTAH AND THE SOUTHERN
SPLIT FORMING A CLOSED LOW OVER SOUTHWEST ARIZONA/NORTHWEST MEXICO
LATE IN THE WEEKEND. THE SOUTHERN FEATURE WILL LIKELY REMAIN TOO
FAR REMOVED TO HAVE ANY SIGNIFICANT IMPACT ON EVEN SOUTHERN UTAH.
COULD SEE ENOUGH MOISTURE WORK NORTH AHEAD OF THIS FEATURE TO
SPAWN ISOLATED CONVECTION OVER THE SOUTHERN MOUNTAINS SATURDAY
AFTERNOON/EARLY EVENING.

&&

.LONG TERM (AFTER 12Z SUNDAY)...ON SUNDAY...PACIFIC LOW IS PROGGED
TO TRACK NEAR THE ARIZONA/MEXICO BORDER...BUT SHOULD BRING JUST A
BIT OF MOISTURE INTO SOUTHERN UTAH. THIS WOULD BE ENOUGH FOR A FEW
SHOWERS OVER THE HIGHER TERRAIN AND HAVE MAINTAINED THE SLIGHT
CHANCE POPS FOR THIS TIMEFRAME.

ON MONDAY...SOUTHWEST FLOW IS PROGGED TO INCREASE AHEAD OF THE NEXT
APPROACHING PACIFIC STORM SYSTEM. 12Z GFS LOOKS SIMILAR TO THE 00Z
ECMWF...BRINGING THIS SYSTEM ACROSS PRIMARILY NORTHERN UTAH TUESDAY
AND WEDNESDAY. THIS SYSTEM ALSO LOOKS TO BE A BIT LACKING IN
MOISTURE BUT SHOULD BRING ANOTHER COLD FRONT INTO AT LEAST NORTHERN
AND CENTRAL UTAH. BEHIND THAT SYSTEM...STRONG HIGH PRESSURE IS
PROGGED TO REBUILD AFTER DAY 7.

&&

.AVIATION...THE SLC TERMINAL WILL SEE VFR CONDITIONS THROUGH THE
EVENING. GUSTY SOUTHERLY WINDS WILL CONTINUE UNTIL THE PASSAGE OF A
COLD FRONT BETWEEN 23Z AND 00Z. THERE IS A 30 PERCENT CHANCE THE
FRONTAL PASSAGE WILL OCCUR AN HOUR OR TWO LATER THAN EXPECTED. WINDS
WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT AND WEAKEN DURING THE
EARLY EVENING.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WIND ADVISORY UNTIL 6 PM MDT THIS EVENING FOR UTZ002>005-015-016.

WY...NONE.
&&

$$

SHORT TERM...CONGER
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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