Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 250413
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1013 PM MDT FRI JUL 24 2015

.SYNOPSIS...SOUTHWESTERLY FLOW ALOFT WILL PREVAIL ACROSS THE REGION
THROUGH THE WEEKEND. MOISTURE WILL REMAIN CONFINED TO FAR NORTHWEST
UTAH THROUGH TONIGHT...OTHERWISE A DRY AIRMASS WILL SETTLE ACROSS
THE AREA.

&&

.DISCUSSION...WATER VAPOR LOOP SHOWS A WEAK WAVE LIFTING ACROSS
CENTRAL NEVADA...AHEAD OF A DEEP CLOSED LOW OVER BRITISH COLUMBIA.
AMDAR 400- 250MB WIND OBSERVATIONS SHOW A 75-110KT SOUTHWESTERLY
JET FROM CENTRAL CALIFORNIA INTO THE NORTHERN ROCKIES.
GOES/GPS/RAP/00Z SLC RAOB INDICATE THE PRECIPITABLE WATER VALUE
RANGES BETWEEN 0.25"- 0.40" MOUNTAINS AND MOST SOUTHWEST/CENTRAL
VALLEYS...TO 0.60"-1.00" ACROSS NORTHWEST UTAH AND THE SOUTHEAST
VALLEYS.

UPDATED FORECAST TO REMOVE POPS FOR ALL BUT THE FAR NORTHWEST CORNER
OF UTAH THROUGH MIDNIGHT. STRONG DRYING ON SOUTHWEST FLOW HAS KEPT
INSTABILITY FROM DEVELOPING FURTHER TO THE SOUTHEAST. THIS GRADIENT
WILL REMAIN ESTABLISHED OVERNIGHT.

ALSO LOWERED SKY TO CLEAR MOST LOCATIONS BASED ON SATELLITE TRENDS.
TWEAKED TEMPERATURES AND WIND BUT EDITS WERE MINOR. REST UNCHANGED.

CONVECTION HAS SENT AN OUTFLOW ACROSS THE WEST DESERT...NEARING THE
WASATCH FRONT AND TOOELE FROM THE NORTHWEST. GUSTS OF 35-60 MPH HAVE
BEEN COMMON. THEY SHOULD LAST ABOUT AN HOUR WITH PASSAGE OF THE
OUTFLOW BOUNDARY...THOUGH THE BOUNDARY IS LIKELY TO BEGIN TO LOSE
ITS FORWARD PROGRESSION DURING THE NEXT HOUR.

PREVIOUS DISCUSSION...

DRY SOUTHWESTERLY FLOW ON THE NORTHWEST SIDE OF AN UPPER-LEVEL RIDGE
CONTINUES TO RESULT IN CLEAR SKIES FOR THE MAJORITY OF THE CWA. THE
EXCEPTIONS ARE OVER THE FAR SOUTHEAST WHERE RETURN FLOW AROUND THE
RIDGE HAS GENERATED SOME CLOUD COVER...AND THE FAR NORTHWEST WHERE
ISOLATED SHOWERS AND STORMS ARE STILL EXPECTED THIS AFTERNOON AND
EVENING AS A WEAK SHORTWAVE MOVES THROUGH.

SATURDAY AND SUNDAY...A VERY PLEASANT WEEKEND IS ANTICIPATED AS DRY
SOUTHWESTERLY FLOW CONTINUES. TEMPERATURES WILL WARM UNDER CLEAR
SKIES AHEAD OF AN UPPER-LEVEL TROUGH ADVANCING EASTWARD FROM THE
PACIFIC...WITH SUNDAY LIKELY THE WARMEST DAY DURING THE FORECAST
PERIOD.

MONDAY...A FAIRLY IMPRESSIVE UPPER-LEVEL TROUGH FOR JULY WILL PASS
JUST NORTHWEST OF THE CWA...FROM IDAHO INTO MONTANA. A WEAK SURFACE
TROUGH WILL ACCOMPANY THIS FEATURE WITH SOME GUSTY WINDS POSSIBLE
BEFORE AND AFTER ITS PASSAGE ON MONDAY. PRECIPITATION IS NOT
EXPECTED WITH THIS SYSTEM...AS ANY MOISTURE ASSOCIATED WITH THE
SYSTEM WILL BE CONCENTRATED FURTHER NORTH.

TUESDAY THROUGH FRIDAY...COLD AIR ADVECTION BEHIND THE UPPER-LEVEL
TROUGH ON MONDAY AND TUESDAY WILL LEAD TO VERY PLEASANT CONDITIONS
OVER THE NORTHERN CWA WITH HIGH TEMPERATURES UP TO 15 DEGREES BELOW
NORMAL ON TUESDAY. AN UPPER-LEVEL RIDGE WILL BEGIN BUILDING OVER THE
WESTERN U.S. FOLLOWING THIS SYSTEM...AND TEMPERATURES WILL INCREASE
THROUGHOUT THE WEEK. BY THURSDAY AND FRIDAY...THE EC SUGGESTS THAT
SOME MOISTURE WILL WORK ITS WAY INTO THE SOUTHERN CWA...BUT THE GFS
DISAGREES AND CONFIDENCE IN THIS FORECAST IS LOW.

&&

.AVIATION...OUTFLOW WINDS FROM EARLIER THUNDERSTORMS ARE CROSSING
THE OGDEN AREA AT THIS TIME AND ARE EXPECTED TO ARRIVE AT THE SLC
TERMINAL AROUND 445-500Z. THIS WILL BRING A WIND SHIFT BACK TO THE
NORTHWEST...WITH GUSTY WINDS POSSIBLE FOR A TIME.

WINDS ARE EXPECTED TO SHIFT BACK TO THE SOUTHEAST BETWEEN 06-08Z.

&&

.FIRE WEATHER...A DRYING AND WARMING TREND WILL CONTINUE ACROSS UTAH
THROUGH THE UPCOMING WEEKEND. TWO AREAS OF MOISTURE CURRENTLY OVER
EXTREME NORTHWEST UTAH AND NEAR THE FOUR CORNERS REGION WILL FUEL A
FEW SHOWERS AND THUNDERSTORMS THIS EVENING.

A STRONG AND UNSEASONABLY COLD UPPER LEVEL TROUGH WILL SETTLE INTO
THE PACIFIC NORTHWEST SUNDAY...THEN SWING EAST ACROSS THE NORTHERN
ROCKIES EARLY NEXT WEEK. THE ASSOCIATED COLD FRONT WILL SETTLE INTO
NORTHWEST UTAH LATE SUNDAY NIGHT/EARLY MORNING...THEN SWEEP SOUTH
ACROSS BUT EXTREME SOUTHERN UTAH THROUGH MONDAY NIGHT. DRY AIR AHEAD
OF THE FRONT WILL LIMIT PRECIPITATION. WINDS WILL BE THE MAIN ISSUE
BOTH AHEAD OF AND BEHIND THE FRONT SUNDAY AFTERNOON THROUGH MORNING
AFTERNOON. LOW HUMIDITIES AND STRONG SOUTHERLY WINDS OVER WEST-
CENTRAL AND SOUTHWEST UTAH SHOULD CREATE CRITICAL FIRE WEATHER
CONDITIONS IN THE ZONES WHICH CURRENTLY HAVE DRY FUELS. COOL
TEMPERATURES AND MODESTLY HIGHER HUMIDITIES BEHIND THE FRONT WILL
PERSIST THROUGH TUESDAY NIGHT. A WARMING TREND WILL DEVELOP AGAIN
MIDWEEK AS HIGH PRESSURE ALOFT SETTLES OVER THE GREAT BASIN.

&&

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

$$

SHORT TERM...ROGOWSKI/RUTZ
FIRE WEATHER...CONGER
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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