Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 250347
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
947 PM MDT SUN AUG 24 2014

.SYNOPSIS...THE NEXT STORM SYSTEM WILL MOVE ACROSS THE REGION MONDAY
AND TUESDAY...POSSIBLY LINGERING INTO WEDNESDAY.

&&

.DISCUSSION...SOUTHWEST FLOW IS DEVELOPING OVER THE EASTERN GREAT
BASIN THIS EVENING AS THE UPSTREAM TROUGH STARTS TO DROP DOWN FROM
THE PACIFIC NORTHWEST. THIS HAS CAUSED THE COLD FRONT THAT WAS
STALLED OVER SOUTHERN/CENTRAL UTAH EARLIER TODAY TO START LIFTING
NORTH. MOST OF THE STORMS FIRST DEVELOPED NEAR THIS BOUNDARY EARLIER
TODAY ACROSS THE CENTRAL MOUNTAINS AND INTO EAST-CENTRAL UTAH. FOCUS
HAS NOW SHIFTED FARTHER NORTH TO THE WEST DESERTS THROUGH UTAH
COUNTY AND INTO THE UINTAS. MESOSCALE ANALYSIS STILL SHOWS SOME
INSTABILITY NEAR THIS AXIS...IN ADDITION TO THE LOW-LEVEL LIFT DUE
TO THE BOUNDARY...WHICH SHOULD SUSTAIN STORMS THROUGH LATE TONIGHT.
HRRR/RAP INDICATING STORMS GRADUALLY WANING FROM WEST TO EAST LATE
THIS EVENING...THEN LINGERING OVER THE UINTA MOUNTAINS THROUGH
AROUND 09-10Z. A FEW STORMS ARE THEN EXPECTED TO DEVELOP ACROSS FAR
NORTHERN UTAH LATE TONIGHT INTO TOMORROW MORNING IN DIFLUENCE REGION
AHEAD OF THE APPROACHING TROUGH.

UPDATED FORECAST A FEW HOURS AGO TO INCREASE POPS. NO FURTHER
UPDATES THIS EVENING.

PREVIOUS DISCUSSION FOLLOWS...

HEADING INTO MONDAY MORNING...THE NORTHERN HALF OF THE CWA WILL
BEGIN TO FEEL THE INFLUENCE OF THE PRIMARY TROUGH DIVING OUT OF THE
PACIFIC NORTHWEST AND INTO NEVADA. THE BEST SHOWERS FROM THIS WAVE
LOOK TO BE PRIMARILY CONFINED TO FAR NORTHERN UTAH THROUGH MONDAY
AFTERNOON...AS THE TROUGH BEGINS TO CLOSE OFF OVER NEVADA...BUT
MODELS ALSO INDICATE SOME MOISTURE MOVING INTO SOUTHERN UTAH AS
EARLY AS MONDAY AFTERNOON.

MODELS HAVE STRUGGLED WITH THE DETAILS OF THIS TROUGH...BUT THE
PRIMARY DISCREPANCY AT THE MOMENT IS WITH THE TIMING OF THE LOW
MOVING THROUGH THE FORECAST AREA...WITH THE ECMWF CURRENTLY ABOUT
6-12 HOURS SLOWER THAN THE GFS. THAT SAID...BOTH MODELS INDICATE
THE TROUGH IMPACTING MUCH OF THE AREA THROUGH THE DAY
TUESDAY...AND TAPPING SIGNIFICANTLY INCREASED MOISTURE FROM THE
SOUTH. HAVE INCREASED POPS CONSIDERABLY FOR
TUESDAY...PARTICULARLY IN SOUTHERN AND EASTERN UTAH.

WITH THE TIMING DIFFERENCES...THE GFS HAS THE TROUGH MOVING INTO
COLORADO ON WEDNESDAY MORNING...WHILE THE EC HAS IT LINGERING OVER
UTAH UNTIL WEDNESDAY EVENING. THE CURRENT FORECAST IS A BIT OF A
COMPROMISE BETWEEN THESE TWO SOLUTIONS. EITHER WAY...BOTH INDICATE
STRONG RIDGING BUILDING OVER THE AREA THURSDAY AND FRIDAY...WITH
SIGNIFICANTLY WARMER TEMPERATURES FOR THE END OF THE WORK WEEK.
SATURDAY IS POTENTIALLY THE WARMEST DAY OF THE WEEK...AS WARM
ADVECTION SOUTHWESTERLY FLOW INCREASES AHEAD OF THE NEXT TROUGH IN
THE PROGRESSIVE PATTERN. THIS NEXT TROUGH CURRENTLY LOOKS TO
IMPACT THE AREA SATURDAY NIGHT AND SUNDAY...THOUGH CURRENT
SOLUTIONS INDICATE THAT THIS MIGHT ONLY BE A GLANCING BLOW FOR
MOST OF THE CWA.

&&

.AVIATION...NORTHERLY WINDS WILL CONTINUE AT THE SLC TERMINAL
THROUGH 04-05Z. WINDS WILL THEN TURN BACK TO THE SOUTHEAST. VFR
CONDITIONS WILL PREVAIL...ALTHOUGH THERE IS A 10 PERCENT CHANCE OF
THUNDERSTORMS IMPACTING THE TERMINAL THROUGH 08Z.

&&

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

$$

CHENG

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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