Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 161530
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
930 AM MDT THU OCT 16 2014

.SYNOPSIS...HIGH PRESSURE WILL BUILD OVER THE AREA THROUGH
TOMORROW. A WEAK STORM SYSTEM WILL BRING SOME MOISTURE INTO
SOUTHERN UTAH THIS WEEKEND.

&&

.DISCUSSION...WATER VAPOR LOOP SHOWS A DISTURBANCE OVER THE
PACIFIC NORTHWEST PROPAGATING TOWARD THE EAST. AMDAR 400-250MB
WIND OBSERVATIONS REVEAL A WESTERLY 75-125KT JET OVER THE NORTHERN
ROCKIES. GOES/GPS/RAP/12Z RAOB INDICATE THE PRECIPITABLE WATER
VALUE RANGES BETWEEN 0.25" MOUNTAINS....TO 0.50" NORTHERN AND
CENTRAL VALLEYS.

WITH YESTERDAYS STORM ALREADY IN NORTH DAKOTA...SURFACE FRONT HAS
STALLED ACROSS CENTRAL UTAH TODAY. THE WAVE ENTERING IDAHO HAS
LITTLE SURFACE REFLECTION SO WINDS SHOULD BE A LOT MORE MUTED TODAY.
BIGGEST CONSEQUENCE OF THE SHORTWAVE IS PERIODS OF ABUNDANT MID AND
UPPER LEVEL CLOUDINESS ACROSS THE NORTH AND PARTS OF CENTRAL UTAH.
UPDATED SKY GRID WITH CURRENT SATELLITE IMAGERY AND AFTERNOON
FORECAST WITH UPDATED GUIDANCE. LITTLE CHANGES TO THE COOLER
AFTERNOON HIGHS. REST UNCHANGED.

PRECIOUS DISCUSSION...
MID AND HIGH LEVEL CLOUDS ARE STREAMING OVER MUCH OF UTAH AND
SOUTHWEST WYOMING EARLY THIS MORNING...AS A MILD ZONAL FLOW HAS
SET UP OVER THE GREAT BASIN FOLLOWING YESTERDAYS COLD FRONTAL
PASSAGE. THE SHORTWAVE TROUGH ASSOCIATED WITH THAT FRONT HAS
ALREADY MOVED WELL OFF TO THE NORTHEAST...AND THE LOW LEVEL
BOUNDARY HAS STALLED ACROSS CENTRAL UTAH. WEAK WARM ADVECTION WILL
BEGIN OVER THE AREA TODAY AND TONIGHT...AS A RIDGE BUILDS OVER THE
REGION. EVEN AFTER SOME BOUNDARY LAYER COLD AIR MOVED IN
YESTERDAY...HIGHS TODAY ARE STILL EXPECTED TO BE NEAR
CLIMATOLOGICAL NORMALS.

FRIDAY WILL BE WARMER AND STILL MOSTLY DRY...AS THE RIDGE SHIFTS
OVER THE ROCKIES. THE ONE LOCATION THAT COULD SEE SOME PRECIP LATE
FRIDAY IS FAR SOUTHERN UTAH...AS MOISTURE ASSOCIATED WITH A PACIFIC
LOW BEGINS MOVING UP FROM THE SOUTH. THAT MOISTURE IS EXPECTED TO
SPREAD INTO CENTRAL UTAH THROUGH THE DAY SATURDAY...AND HAVE
SLIGHTLY INCREASED POPS THROUGH THE WEEKEND...WITH THE FOCUS OF
SLIGHT CHANCE POPS ON THE HIGHER TERRAIN AND THE SOUTHEASTERN
PORTIONS OF THE CWA.

THAT LOW AND ASSOCIATED MOISTURE SHOULD BE SHUNTED OFF TO THE EAST
THROUGH THE DAY SUNDAY...AS THE REMNANTS OF ANOTHER PACIFIC TROUGH
SLIDE THROUGH SOUTHERN CALIFORNIA AND NEW MEXICO. THIS LEAVES THE
CWA WARM AND DRY AGAIN UNDER THE MEAN RIDGE LATE SUNDAY AND
MONDAY...WITH INCREASING SOUTHERLY FLOW MONDAY AND MONDAY NIGHT
AHEAD OF THE NEXT PACIFIC TROUGH.

MODELS ARE STILL WORKING OUT THE DETAILS OF HOW STRONG THIS TROUGH
WILL BE WHEN IT CROSSES THE CWA TUESDAY AND WEDNESDAY...BUT HAVE
CURRENTLY COME INTO DECENT AGREEMENT ABOUT A COOL AND WET FRONTAL
PASSAGE...WITH THE POSSIBILITY OF PRECIP ACROSS MOST OF THE FORECAST
AREA...AND 700MB TEMPS DROPPING TO -3 CELSIUS OVER NORTHERN UTAH.
HAVE INCREASED POPS THROUGH THIS TIME FRAME...AND LOWERED
TEMPERATURES FOR WEDNESDAY AND WEDNESDAY NIGHT. MODELS ARE IN GOOD
AGREEMENT THAT THE TROUGH LEAVES THE AREA WEDNESDAY NIGHT...WITH THE
HIGH AMPLITUDE MEAN RIDGE RETURNING FOR THURSDAY THROUGH
SATURDAY...SO MORE WARMER AND DRIER WEATHER IS STILL ON TAP AFTER
THE BRIEF APPEARANCE OF TYPICAL OCTOBER WEATHER.

&&

.AVIATION...MAIN ISSUE FOR THE SLC TERMINAL WILL BE THE WIND SHIFT
THIS AFTERNOON. EXPECT WINDS TO BECOME LIGHT AND VARIABLE BETWEEN
1630-1730Z...THEN BECOME PREDOMINANTLY NORTHERLY.

&&

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

$$

PUBLIC...ROGOWSKI/SCHOENING
AVIATION...KRUSE

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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