Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 031040
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
440 AM MDT THU SEP 3 2015

.SYNOPSIS...AN UPPER LEVEL TROUGH WILL SETTLE INTO THE PACIFIC
NORTHWEST LATER TODAY...THEN TURN EAST ACROSS THE GREAT BASIN AND
NORTHERN ROCKIES THIS WEEKEND. THE ASSOCIATED COLD FRONT WILL
REACH NORTHWEST UTAH FRIDAY NIGHT...THEN PRESS EAST ACROSS THE
STATE SATURDAY. THIS FRONT WILL BRING FALL LIKE TEMPERATURES TO
THE REGION FOR THE WEEKEND.

&&

.SHORT TERM (UNTIL 06Z MONDAY)...THE UPPER TROUGH SAGGING SOUTH
OUT OF WESTERN CANADA WILL SETTLE INTO THE PACIFIC NORTHWEST LATER
TODAY. THIS TROUGH WILL LINGER ACROSS THE PACIFIC NORTHWEST INTO
EARLY SATURDAY...THEN TURN EAST AND TRACK ACROSS THE NORTHERN
ROCKIES/NORTHERN GREAT BASIN DURING THE LATTER HALF OF THE
WEEKEND.

A WARM AND INCREASING STRONG SOUTHWEST FLOW ALOFT WILL EXIST AHEAD
OF THE ADVANCING UPPER TROUGH ACROSS THE GREAT BASIN THE NEXT
COUPLE OF DAYS. WINDS WILL BECOME AN ISSUE FOR MUCH OF WESTERN AND
NORTHERN UTAH STARTING LATE THIS AFTERNOON. THE WELL-DEFINED
SURFACE TROUGH POSITIONED ACROSS EASTERN NEVADA COMBINED WITH
SUPPORTING SOUTHWEST FLOW ALOFT WILL CREATE WINDY CONDITIONS
ACROSS MAINLY WEST-CENTRAL THROUGH NORTHWEST UTAH. WIND SPEEDS
WILL LIKELY BUMP UP AGAINST WIND ADVISORY CRITERIA...WITH A FEW OF
THE FAVORED AREAS OF NORTHWEST UTAH MEETING CRITERIA. AT THIS
POINT HAVE OPTED TO HOLD OFF ON AN ADVISORY AS IMPACTS WILL BE
CONFINED TO A FEW FAVORED AREAS.

STRONG WINDS LOOK TO BE FAR MORE WIDESPREAD FRIDAY AS THE NEAR 700
MB WINDS INCREASE TO AROUND 35 TO 45 KNOTS AND THE SURFACE COLD
FRONT ASSOCIATED WITH THE PACIFIC NORTHWEST TROUGH MOVES TOWARDS
NORTHEAST NEVADA. SUSPECT THAT WIND SPEEDS WILL REMAIN JUST BELOW
HIGH WIND CRITERIA AS THE FRONT IS NOT EXPECTED TO REACH FAR
NORTHWEST UTAH UNTIL FRIDAY EVENING. THE HIGH WIND THREAT WILL
SHIFT INTO SOUTHERN UTAH SATURDAY. NEAR 700 MB WINDS APPROACHING
50 KNOTS AND THE SURFACE FRONT ADVANCING INTO CENTRAL UTAH WILL
GENERATE STRONG WINDS WITH THE POTENTIAL TO MEET HIGH WIND
CRITERIA. THE ONE THING THAT COULD HOLD WINDS BACK A BIT WOULD BE
CLOUD COVER WHICH WOULD INHIBIT DAY TIME MIXING.

GOES IMAGERY CONTINUES TO PLACE THE MOISTURE PLUME ACROSS SOUTH-
CENTRAL THROUGH EASTERN UTAH. MOISTURE HAS ALSO SHOWN A MODEST
INCREASE ACROSS WESTERN UTAH OVERNIGHT...THOUGH SURFACE DEW POINTS
REMAIN FAIRLY LOW. SUSPECT THAT ISOLATED CONVECTION WILL AGAIN
POP UP IN THE DEEP LAYER MOISTURE ACROSS SOUTHERN/EASTERN UTAH.
NORTHERN AND WESTERN UTAH WILL LIKELY SEE MINIMAL CONVECTION UNTIL
LATE THIS AFTERNOON/THIS EVENING WHEN THE WEAK VORTICITY MAX
CURRENTLY ALONG THE SOUTHERN CALIFORNIA COAST LIFTS NORTHEAST
THROUGH NORTHEAST NEVADA/EXTREME NORTHWEST UTAH.

STRONG DEEP LAYER SOUTHERLY FLOW ALOFT WILL LIKELY INHIBIT THE
DEVELOPMENT OF DEEP CONVECTION...EVEN WHERE SUBSTANTIAL MOISTURE
EXISTS ACROSS EASTERN UTAH THROUGH FRIDAY NIGHT. PRECIP ASSOCIATED
WITH THE ADVANCING UPPER TROUGH WILL LIKELY HOLD OFF UNTIL
SATURDAY WHEN THE FRONT MOVES EAST ACROSS THE REGION AND THE
TRAILING UPPER TROUGH AND COLDER AIR ALOFT SURGES EAST ACROSS THE
NORTHERN THIRD OF THE STATE. DYNAMIC SUBSIDENCE TRAILING THE UPPER
TROUGH WILL BRING A FAIRLY QUICK END TO ANY PRECIP OVERNIGHT
SATURDAY. MUCH COLDER AIR AIR WILL FOLLOW THE FRONT...WITH
READINGS FEELING FALL-LIKE FOR THE LATTER HALF OF THE LABOR DAY
WEEKEND.

.LONG TERM (AFTER 06Z MONDAY)...AS THE WEEKEND TROUGH RACES AWAY
FROM THE REGION....YET ANOTHER SHORTWAVE IS FORECAST TO MOVE
SOUTHWARD ALONG THE CANADIAN COAST. MODEL TO MODEL VARIATION IS
FAIRLY DIVERSE IN THE EVOLUTION OF THIS SHORTWAVE AS IT MOVES INTO
THE PACIFIC NORTHWEST/NORTHERN INTERMOUNTAIN REGION. THE 00Z GFS
CARVES OUT A FAIRLY SIGNIFICANT TROUGH THAT SLOWLY MOVES ACROSS THE
PACIFIC NORTHWEST INTO IDAHO MONDAY INTO TUESDAY. THE 00Z EC...ON
THE OTHER HAND...HAS A WEAKER...MORE CONTINENTAL TROUGH THAT RACES
EAST ALONG THE US/CANADIAN BORDER.

THE DISCREPANCIES BETWEEN THE MODELS HAVE AN IMPACT ON THE
SIGNIFICANCE OF ANY EARLY WEEK COLD FRONT. FOR NOW...LEANED TOWARD
THE EC SOLUTION AND KEPT A SLOW WARMING TREND IN THE FORECAST NEXT
WEEK. ASIDE FROM THE POSSIBILITY OF WEAK CONVECTION ACROSS MAINLY
THE SOUTHERN MOUNTAINS TUESDAY AND WEDNESDAY AFTERNOON...AT THIS
TIME THE THREAT OF PRECIPITATION IS QUITE LOW FOR THE MAJORITY OF
THE LONG TERM FORECAST PERIOD.

&&

.FIRE WEATHER...A STRONG UPPER LEVEL TROUGH ALONG THE WEST COAST
WILL CONTINUE TO INCREASE WINDS ACROSS THE DISTRICT THROUGH
SATURDAY. HUMIDITIES ARE EXPECTED TO FALL BELOW CRITICAL THRESHOLDS
MOST AFTERNOONS ACROSS THE WESTERN HALF OF THE DISTRICT...WITH POOR
OVERNIGHT RECOVERIES. GIVEN THE ONLY ZONE WITH CRITICAL FUELS IN
UTAH CONTINUES TO BE FAR SOUTHWEST UTAH...NO HEADLINES HAVE BEEN
ISSUED...ALTHOUGH WINDS MAY BE HIGH ENOUGH TO WARRANT A FIRE WEATHER
WATCH FOR THIS ZONE FRIDAY AND SATURDAY.

A MUCH COOLER AIRMASS WILL BUILD INTO THE DISTRICT SUNDAY.

&&

.AVIATION...GUSTY SOUTH WINDS WILL CONTINUE AT THE SLC TERMINAL
THROUGH THE DAY.

&&

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

&&

$$

CONGER/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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