Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 171100
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
500 AM MDT FRI APR 17 2015

.SYNOPSIS...A COLD UPPER LOW NEAR THE FOUR CORNERS AREA WILL
CONTINUE TO DRIFT SLOWLY EAST THROUGH TONIGHT. A COOL NORTHWEST
FLOW WILL FOLLOW FOR THE WEEKEND.

&&

.DISCUSSION...THE COLD CORE UPPER LOW IS ON THE MOVE EARLY THIS
MORNING BEGINNING TO SHIFT EAST ACROSS SRN CO. THE COLD AIR WITH
THIS FEATURE HAS MODIFIED SOMEWHAT BUT REMAINS COLD ENOUGH FOR
SNOW TO REACH THE VALLEY FLOORS IN ERN UT JUST EAST OF OUR CWA.

THIS WRAPAROUND PRECIP SHOULD PERSIST ACROSS ERN UT THRU THE
MORNING AND WOULD EXPECT ANY SNOW REACHING THE VALLEYS SHOULD MELT
AS IT FALLS AND NOT HAVE ANY IMPACT ON TRAVEL. LOCAL SLUSHY
ACCUMULATION IS POSSIBLE ABOVE ABOUT 6500-7000 FT THRU ABOUT MID
MORNING BUT EVEN THIS SHOULD NOT HAVE MUCH IMPACT OTHER THAN OVER
THE HIGHEST PASSES SUCH AS INDIAN CANYON BETWEEN PRICE AND
DUCHESNE.

PRECIP SHOULD TURN MORE SHOWERY THIS AFTN AND COULD SPREAD A
LITTLE FARTHER WEST BUT THE CONTINUED WARMING AIRMASS AS THE LOW
DRIFTS EAST SHOULD RAISE SNOW LEVELS AND PRECLUDE ANY ROAD
IMPACTS.

TEMPS WILL CONTINUE TO MODIFY TODAY WARMING BACK TO NEAR SEASONAL
NORMALS ACROSS THE WRN CWA BUT REMAINING COOLER OVER THE EAST
UNDER THE CLOUDS AND PRECIP.

IT APPEARS THE PRECIP THREAT FROM THE CO LOW MOVES EAST OF OUR
CWA BY SAT MORNING BUT A WEAK DISTURBANCE IN THE TRAILING NNWLY
FLOW COULD SET OFF A FEW SHOWERS OVER THE NERN CWA SAT AFTN AND
OVERNIGHT. ANOTHER WEAK FEATURE COULD BRING SOME WEAK CONVECTION
SUN AFTN TO THE HIGHER TERRAIN ACROSS MORE OF THE CWA WITH YET
ANOTHER FOR MON.

TEMPS MODIFY A LITTLE MORE SAT THEN LEVEL OFF SUN AND MON AS THE
WEAK WAVES IN THE FLOW KEEP THE AIRMASS FROM WARMING ANY FURTHER.

&&

.LONG TERM (AFTER 00Z TUESDAY)...MODELS ARE IN BASIC AGREEMENT THAT
A RIDGE WILL BE OVER THE EASTERN GREAT BASIN TUESDAY WITH SOME KIND
OF WEAK TROUGHINESS OVER ARIZONA AND CALIFORNIA...WITH THE EC A
LITTLE FARTHER EAST WITH A POSSIBLE WEAK CIRCULATION. EITHER WAY
THIS PLACES UTAH UNDER A DIFFLUENT FLOW ALOFT. NOT CONFIDENT THAT
ANYTHING WILL OCCUR TUESDAY BUT LEFT THE TOKEN POPS INTACT. BY
WEDNESDAY THIS LOBE OF TROUGHINESS MOVES NORTHWARD ACROSS THE CWA
CREATING SLIGHTLY BETTER LIFT FOR A CHANCE OF SHOWERS MAINLY OVER
THE CENTRAL AND NORTHERN MOUNTAINS.

AFTER THIS POINT THE GFS AND EC DIVERGE IN THE DETAILS BUT OVERALL
HAVE TROUGHINESS OVER THE GREAT BASIN WITH EITHER A TROUGH OR
MULTIPLE CLOSED LOWS. NOT POSITIVE WHICH SOLUTION IS MORE LIKELY TO
OCCUR SO WENT WITH THE IDEA THAT TROUGHINESS WILL BE ACROSS THE
REGION AND THEREFORE AT LEAST A SLIGHT CHANCE OR CHANCE OF SHOWERS
ACROSS THE CWA. THE GFS IS A LITTLE MORE PROGRESSIVE WITH A NEGATIVE
OPEN TROUGH DIGGING INTO CALIFORNIA AND THE SOUTHWEST BY THURSDAY
...PLACING UTAH UNDER A GREATER DIFFLUENT FLOW. MEANWHILE THE EC HAS
A CLOSED LOW WEST OF SAN DIEGO WITH SOME DIFFLUENCE OVER MAINLY
SOUTHWEST UTAH. KNOWING THAT IT IS HIGHLY UNLIKELY THAT EITHER ONE
OF THE SOLUTIONS WILL BE RIGHT ON...HAVE GONE WITH A BROAD BRUSH
APPROACH WITH MOSTLY CLOUDY SKIES AND SLIGHTLY HIGHER THAN CLIMO
POPS THURSDAY THROUGH FRIDAY. HAVE COOLED THE DAILY MAX DUE TO CLOUD
COVER AND COOLER H7 TEMPERATURES MOVING INTO THE REGION.

&&

.AVIATION...NORTHERLY WINDS ARE EXPECTED TO GENERALLY PREVAIL AT THE
SLC TERMINAL THROUGH THE TAF PERIOD BUT THERE IS A 40 PERCENT CHANCE
THAT WINDS WILL PERIODICALLY SHIFT TO OTHER DIRECTIONS AT LIGHT
SPEEDS THROUGH 15Z. NO OTHER METEOROLOGICAL CONCERNS.

&&

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

$$

SHORT TERM...WILENSKY
LONG TERM/AVIATION...STRUTHWOLF

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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