Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 022250
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
350 PM MST MON MAR 2 2015

.SYNOPSIS...A PAIR OF WEATHER SYSTEMS WILL CROSS THE REGION
TONIGHT THROUGH TUESDAY. HIGH PRESSURE WILL BRING A DRYING AND
WARMING TREND FOR THE LATTER HALF OF THE WEEK.


&&

.SHORT TERM (THROUGH 12Z FRIDAY)...A BROAD UPPER LEVEL TROUGH
EVIDENT IN WATER VAPOR IMAGERY ENCOMPASSES MUCH OF THE INTERIOR
WEST THIS AFTERNOON. A SHORTWAVE TROUGH EJECTING NORTHEAST FROM
THE MAIN TROUGH POSITION IS CURRENTLY LIFTING ALONG THE UT/NV
BORDER...AND WILL CONTINUE NORTHEAST THIS EVENING. LIFT WITHIN THE
DEFORMATION AXIS ASSOCIATED WITH THIS EJECTING WAVE HAS SPREAD
ACROSS FAR NORTHWEST UT...AND IS FORECAST BY SHORT RANGE MODELS TO
SHIFT EAST-SOUTHEAST INTO THE WASATCH FRONT AND ADJACENT MOUNTAINS
THIS EVENING. SNOW LEVELS MAY REMAIN JUST ABOVE THE VALLEY FLOORS
DURING THE ONSET BUT SHOULD FALL BY MID TO LATE EVENING. MEANWHILE
FURTHER SOUTH DRIER AIR ALOFT IN THE WAKE OF THIS WAVE HAS SPREAD
INTO SOUTHERN UT TURNING PRECIPITATION MORE CONVECTIVE...AS THE
PRIMARY MOISTURE AXIS HAS SHIFTED EAST TOWARD THE FOUR CORNERS
REGION.

IN THE WAKE OF THIS EJECTING WAVE MAY SEE A TEMPORARY BREAK...OR
AT LEAST A DOWNWARD TREND...IN PRECIPITATION AREAWIDE INTO THE
OVERNIGHT HOURS. THIS BREAK WILL BE SHORT...AS A NORTHERN STREAM
SHORTWAVE CURRENTLY CARVING INTO THE NORTHERN ROCKIES WILL DIG
SOUTHWARD THROUGH NORTHERN UT TUESDAY. THE ASSOCIATED COLD FRONT
IS EXPECTED TO REACH FAR NORTHWEST UT AROUND 12Z...THEN SWEEP
SOUTHWARD THROUGH NORTHERN UT DURING THE MORNING HOURS
TUESDAY BRINGING A PERIOD OF SNOW TO MUCH OF THE AREA. SNOW LEVELS
WILL FALL TO THE VALLEY FLOORS /IF THEY HAVENT ALREADY/ WITH THIS
FRONT...AND ALTHOUGH THERE WILL LIKELY BE SOME ACCUMULATION ON
THE VALLEY FLOORS...EXPECT A FAIRLY SIGNIFICANT OROGRAHPIC
SIGNATURE TO THE SNOWFALL TOTALS TUESDAY AS A FAVORABLE NORTHWEST
FLOW DEVELOPS IMMEDIATELY BEHIND THIS BOUNDARY...AND PERSISTS
THROUGH MID MORNING. BY AFTERNOON THIS BOUNDARY WILL SHIFT INTO
SOUTHERN UT AND WEAKEN WITH TIME.

WENT AHEAD AND EXTENDED THE GOING WINTER WX ADVISORY INTO THE
WASATCH FRONT/BACK AND CACHE VALLEY...WITH SOME IMPACT EXPECTED ON
THE MORNING COMMUTE. ALSO UPGRADED THE CENTRAL/SOUTHERN WASATCH
AND WESTERN UINTAS WITH A PERIOD OF HEAVY SNOW EXPECTED TUESDAY
MORNING...ON TOP OF WHAT OCCURS THIS EVENING.

MID LEVEL RIDGING IS FORECAST TO SLOWLY BUILD INLAND FOR THE MID
TO LATTER PORTION OF THE WEEK. INITIALLY A COOL NORTHWEST FLOW
WILL PREVAIL INTO WEDNESDAY...HOWEVER AS HEIGHTS RISE SHOULD
QUICKLY SEE A WARMING TREND DEVELOP BY THURSDAY.

&&

.LONG TERM (AFTER 12Z FRIDAY)...THE WEST COAST RIDGE IS FORECAST TO
AMPLIFY AND SHIFT OVER CALIFORNIA THROUGH THE DAY FRIDAY...ALLOWING
FOR A CONTINUING WARMING TREND ACROSS UTAH AND SOUTHWEST WYOMING.

THE BIGGEST DISCREPANCY IN THE EXTENDED FORECAST IS FOR
SATURDAY...WHEN THE ECMWF HAS A WEAK SHORTWAVE MOVING THROUGH THE
AREA FROM THE NORTH. HOWEVER...THIS WAVE IS NOWHERE TO BE SEEN IN
THE GFS OR CANADIAN MODELS...SO HAVE NOT PUT MUCH REFLECTION OF THIS
WAVE IN THE FORECAST...WITH THE EXCEPTION OF SOME SLIGHTLY INCREASED
SKY COVER AND 10 PERCENT POPS IN NORTHERN UTAH. EVEN IF THE MORE
AGGRESSIVE ECMWF WERE TO VERIFY...THE MAIN IMPACT WOULD BE A COOLING
OF TEMPERATURES...AS PRECIP ASSOCIATED WITH THIS WAVE IS MINIMAL AND
PRIMARILY CONFINED TO THE NORTHEASTERN QUARTER OF THE CWA.

FOR SUNDAY THROUGH MONDAY...HIGH PRESSURE LOOKS TO DOMINATE THE
WEATHER ACROSS MUCH OF THE WESTERN CONUS YET AGAIN...THOUGH PERHAPS
NOT AS STRONG OR WARM AS SOME PARTS OF FEBRUARY. IN OTHER WORDS...NO
SIGNIFICANT PRECIPITATION IS EXPECTED FOR AT LEAST A WEEK AFTER THE
CURRENTLY ONGOING STORM EXITS THE REGION TOMORROW NIGHT.

&&

.AVIATION...SHOWERS SHOULD CONTINUE TO FILL IN NEAR THE SLC TERMINAL
BETWEEN 23Z AND 02Z...WITH ONGOING MVFR CONDITIONS LIKELY THROUGH AT
LEAST 02Z...AND A 60 PERCENT CHANCE OF IFR CONDITIONS IN SNOW
BETWEEN 02Z AND 05Z. SNOW ACCUMULATION ON UNTREATED SURFACES IS
EXPECTED TO BE TRACE TO ONE INCH THIS EVENING...WITH ANOTHER 1 TO 2
INCHES POSSIBLE BETWEEN 12Z AND 17Z TUESDAY.

THE SURFACE WIND FORECAST AT THE TERMINAL IS FAIRLY LOW CONFIDENCE.
THE MOST LIKELY SCENARIO IS THAT WINDS SWITCH TO THE SOUTH BETWEEN
23Z AND 00Z DUE TO SHOWERS SOUTH OF THE TERMINAL. HOWEVER...THERE IS
A 30 PERCENT CHANCE THAT PREDOMINANTLY NORTHWESTERLY WINDS COULD
CONTINUE BETWEEN 23Z AND 03Z.


&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER STORM WARNING UNTIL 9 PM MST THIS EVENING FOR UTZ020.

     WINTER STORM WARNING UNTIL 4 PM MST TUESDAY FOR UTZ008-009-518.

     WINTER WEATHER ADVISORY UNTIL 4 PM MST TUESDAY FOR UTZ007-010-
     517.

     WINTER WEATHER ADVISORY UNTIL NOON MST TUESDAY FOR UTZ001>004-
     006.

     WINTER WEATHER ADVISORY UNTIL 9 PM MST THIS EVENING FOR UTZ012-
     013-016.

WY...WINTER WEATHER ADVISORY UNTIL 4 PM MST TUESDAY FOR WYZ021.

&&

$$

SEAMAN/SCHOENING

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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