Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 292310
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
410 PM MST THU JAN 29 2015

.SYNOPSIS...A DEVELOPING UPPER LOW OVER THE SOUTHERN GREAT BASIN
WILL SPREAD MOISTURE INTO UTAH TONIGHT THROUGH SATURDAY. THE
DEEPEST MOISTURE WILL REMAIN PRIMARILY OVER CENTRAL AND SOUTHERN
UTAH.

&&

.SHORT TERM (THRU 00Z MON)...A LOOSELY ORGANIZED UPPER TROF
REMAINS OFF THE WEST COAST SWD DOWN TO AN UPPER LOW WEST OF
CENTRAL BAJA AND ON SWD INTO THE TROPICAL ERN PAC. THE MOISTURE
TAP FOR THIS TROF IS STILL CONNECTED TO THE ITCZ JUST NORTH OF THE
EQUATOR SO ABUNDANT MOISTURE IS STILL FEEDING INTO THIS SYSTEM.

MOISTURE CONTINUES TO INCREASE ACROSS THE CWA THIS AFTN AND LIGHT
RAIN HAS BEEN NOTED AT MILFORD. LIFT IS FORECAST TO INCREASE
TONIGHT AS THE UPPER TROF EDGES INLAND AND EXPECT LIGHT PRECIP TO
SPREAD ACROSS MUCH OF THE CWA OVERNIGHT BECOMING LOCALLY HEAVY
ACROSS THE SOUTH.

THE LIFT ACROSS SRN/CENTRAL UT INCREASES FRI AS THE WEST COAST
TROF CONSOLIDATES AROUND A DEVELOPING UPPER LOW OVER THE LOWER CO
RIVER VALLEY AND CONTINUES INTO SAT MORNING UNTIL THE UPPER LOW
RETREATS SWD AND RIDGING BUILDING IN FROM THE NORTH SHUTS DOWN THE
PRECIP.

AS THIS IS A WARM STORM SNOW LEVELS WILL STAY NEAR ABOUT 6500 FT
AND SHOULD NOT HAVE MUCH OF AN IMPACT ON MAJOR VALLEY ROUTES. I
DO EXPECT HEAVY SNOW ABOVE THAT LEVEL IMPACTING PASSES THROUGH THE
CENTRAL AND SRN MTNS AND HAVE ISSUED A WINTER WEATHER ADVISORY FOR
THESE AREAS ABV 6500 FEET THRU 4PM SAT. EXPECT THE HEAVIEST TOTALS
TO STAY ABOVE ABOUT 8500 FT...ABOVE MOST MAJOR ROUTES.

VALLEY TEMPS WILL REMAIN RELATIVELY MILD ACROSS THE CWA TOMORROW
AND SAT ESPECIALLY ACROSS THE NORTH. CLEARING SKIES SAT NIGHT
COULD ALLOW MINS TO DIP INTO THE 20S SO SUN MAY NOT BE MUCH WARMER
THAN SAT IN THE NRN VALLEYS DUE TO INCREASING STABILITY UNDER THE
SHORT WAVE RIDGE.

&&

.LONG TERM (AFTER 00Z MONDAY)...THE NORTHERN PORTION OF THE CWA WILL
REMAIN UNDER A SOMEWHAT MOIST WEST NORTHWESTERLY FLOW MONDAY THROUGH
WEDNESDAY AS SEVERAL WEAK DISTURBANCES RIPPLE THROUGH. AS WOULD BE
EXPECTED WITH THESE WEAK RIPPLES THE TIMING DIFFERENCES BETWEEN THE
GFS AND EC CAN BE AND IS QUITE SIGNIFICANT. THEREFORE HAVE BASICALLY
KEPT MINIMAL POPS FROM MONDAY THROUGH WEDNESDAY ACROSS THE NORTH
FROM THE UINTAS AND WASATCH MOUNTAINS NORTHWARD AS IT IS HARD TO
SORT OUT TIMING ISSUES. NO MATTER WHICH MODEL SOLUTION IS FOLLOWED
THEY BOTH INDICATE THAT THESE SYSTEMS ARE WEAK. ALTHOUGH CLOUDS WILL
SPILL OVER THE REST OF THE CWA MONDAY THROUGH WEDNESDAY PRECIP IS
NOT EXPECTED OUTSIDE OF THE NORTHERN AREAS.

THE RIDGE ALONG THE WEST COAST STRENGTHENS TUESDAY AND THEN MIGRATES
INLAND INTO THE GREAT BASIN WEDNESDAY INTO THURSDAY. THIS WILL SHUT
OFF THE SOMEWHAT MOIST NORTHWEST FLOW INTO NORTHERN UTAH AND WARMING
AND DRYING CONDITIONS WILL ENSUE. ALTHOUGH 700MB TEMPS WARM ABOVE 0C
THURSDAY...THE NORTHERN VALLEYS MAY NOT RESPONSE VERY WELL DUE TO AN
INVERSION BEING IN PLACE. MOUNTAINS WILL WARM THE MOST.

THE BOTTOM LINE WITH THIS EXTENDED FORECAST IS THAT A MEAN RIDGE
REMAINS OVER THE WEST AND SHOWS NO SIGN OF CHANGING ANY TIME SOON.
THE MOSTLY DRY AND WARM CONDITIONS EXPERIENCED IN JANUARY IS
EXPECTED TO CONTINUE INTO THE FIRST WEEK OF FEBRUARY. NO MAJOR
STORMS ARE CURRENTLY IN SIGHT THROUGH DAY 10.

&&

.AVIATION...CIGS AT THE SLC TERMINAL ARE EXPECTED TO REMAIN ABOVE
10K FT AGL THROUGH 03Z BUT THEN LOWER AS A WEAK DISTURBANCE MOVES
ACROSS NORTHERN UTAH. THERE IS A 40 PERCENT CHANCE THAT CIGS WILL
REMAIN ABOVE 7K FT AGL THROUGH 05-06Z. WINDS WILL BE LIGHT NORTHERLY
THIS EVENING WITH A SHIFT TO THE SOUTH ABOUT 03Z BUT THERE IS A GOOD
CHANCE THAT THE WINDS WILL SHIFT CLOSER 05-06Z.

$$

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER WEATHER ADVISORY UNTIL 4 PM MST SATURDAY FOR UTZ010-013-
     517-518.

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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