Area Forecast Discussion
Issued by NWS Salt Lake City, UT

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000
FXUS65 KSLC 282250
AFDSLC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
350 PM MST SAT FEB 28 2015

.SYNOPSIS...AN UPPER LEVEL TROF WILL LINGER OVER THE GREAT BASIN
THROUGH MONDAY THEN SHIFT EAST LATE TUESDAY. SEVERAL DISTURBANCES
WILL MOVE THROUGH THIS TROUGH HAVING THE GREATEST IMPACT ACROSS MAINLY
CENTRAL AND SOUTHERN UTAH.


&&

.DISCUSSION...
SHORT TERM (THROUGH 12Z TUESDAY)...SATELLITE IMAGERY SHOWING
SEVERAL DISTURBANCES MOVING EAST NORTHEAST FROM CENTRAL CALIFORNIA
ACROSS SOUTHERN NEVADA INTO SOUTHWEST UTAH THIS AFTERNOON. AS THE
MAIN TROUGH DEEPENS OFF THE CALIFORNIA COAST THE FLOW ALOFT WILL
BECOME MORE SOUTHERLY ALLOWING THESE DISTURBANCES TO MOVE FARTHER
NORTHWARD ACROSS CENTRAL UTAH AND INTO PORTIONS OF NORTHERN UTAH
AND SOUTHWEST WYOMING TONIGHT. THE MAIN PUNCH WILL BE ACROSS THE
CENTRAL MOUNTAINS...WASATCH PLATEAU...AND INTO CASTLE COUNTRY
WHERE SIGNIFICANT SNOW IS POSSIBLE. HAVE ADDED ZONE 10 TO THE
WINTER WEATHER ADVISORY FOR TONIGHT. THE GFS SHOWS ANOTHER
BULLSEYE OF PRECIPITATION OVER WESTERN UTAH FROM ABOUT SLC TO ELY
NEVADA BUT HARD TO FIND UPPER LEVEL SUPPORT FOR THIS AREA.

SOME CANYON WINDS ARE EXPECTED TONIGHT ACROSS THE NORTHERN AND
CENTRAL WASATCH FRONT DUE TO LOWERING PRESSURES ACROSS SOUTHERN
UTAH COMBINING WITH THE MODERATELY STRONG HIGH PRESSURE SYSTEM
OVER WYOMING. THIS EVENT THOUGH SHOULD ONLY PRODUCE WINDS IN THE
30-40 MPH RANGE WITH OCCASIONAL GUSTS ABOVE 40 IN THE FAVORED
CANYONS.

THE MODELS ARE SHOWING SOMEWHAT OF A HIATUS IN THE WEATHER SUNDAY
MORNING THROUGH EARLY AFTERNOON BEFORE THE SOUTHWESTERLY FLOW
RELOADS WITH A SUB TROPICAL TAP WHICH BRINGS AMPLE MOISTURE BACK
INTO THE SOUTHERN HALF OF THE CWA. THE SNOW LEVELS WILL RISE
ACROSS MOST AREAS OF SOUTHERN UTAH TO NEAR 5500-6500 FEET WHICH
MEANS RAIN FOR SOUTH CENTRAL BUT COULD SEE ALL SNOW OR A MIXTURE
OVER THE SOUTHWEST VALLEYS EXCLUDING ST GEORGE WHERE RAIN WILL
OCCUR. HAVE NOT ISSUED ANY HIGHLIGHTS FOR THIS NEXT STORM SYSTEM
SINCE DID NOT WANT TO HAVE CONFUSION BETWEEN WHAT IS EXPECTED
TONIGHT AND WHAT IS EXPECTED SUNDAY NIGHT THROUGH TUESDAY.
HOWEVER...SOUTHERN MOUNTAINS LOOK TO RECEIVE SIGNIFICANT SNOW
AMOUNTS.

THE SUB TROPICAL MOISTURE DOES NOT EVER REACH NORTHERN UTAH BUT
THERE WILL BE RESIDUAL MOISTURE THAT THE NORTHERN BRANCH OF THE
TROUGH WILL BE ABLE TO ACT ON FOR MONDAY INTO TUESDAY. SCATTERED
SHOWERS ARE EXPECTED SUNDAY NIGHT THROUGH TUESDAY NIGHT.

.LONG TERM (AFTER 12Z TUESDAY)...GFS AND ECMWF IN GENERAL AGREEMENT
WITH DROPPING ONE LAST SIGNIFICANT UPPER LEVEL DISTURBANCE SOUTHEAST
IN NORTHWEST FLOW ACROSS THE FORECAST AREA ON TUESDAY.  THIS
SAID...ECMWF IS A BIT STRONGER AND SLOWER WITH DISTURBANCE...ALSO
INDICATING A BIT MORE MOISTURE TO WORK WITH.  MID LEVEL LAPSE RATES
LOOK DECENT IN THE MORNING...BUT LESS IMPRESSIVE IN THE AFTERNOON AS
COLD POOL ALOFT SLIDES EAST.  ALL CONSIDERED...LIKELY POPS IN
TERRAIN AREAS LOOK GOOD...WITH CHANCE WORDING SUFFICING ELSEWHERE.
POTENTIAL CERTAINLY EXISTS FOR ADDITIONAL ACCUMULATIONS IN THE
MOUNTAINS...ESPECIALLY FAVORED NORTHWEST FLOW REGIONS.  SOME SNOW
SHOWERS MAY LINGER INTO EVENING...BUT WITH DRYING ALOFT AND LOSS OF
ANY INSTABILITY...SHOULD NOT SEE MUCH TUESDAY NIGHT.  A FEW
CONVECTIVE SNOW SHOWERS MAY LINGER INTO THE DAY ON
WEDNESDAY...THOUGH AGAIN...VERY LIGHT IN NATURE.

MODELS IN GOOD AGREEMENT WITH SLOWLY BUILDING RIDGE ACROSS GREAT
BASIN AS THE WEEK PROGRESSES...WITH RIDGE CENTERED OVER FORECAST
AREA BY SATURDAY.  BY LATE IN THE WEEK...SHOULD SEE TEMPERATURES
RETURNING TO ABOVE NORMAL READINGS.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KSLC INTO THE
EVENING HOURS...THOUGH CEILINGS BELOW 7000 FEET CAN NOW BE EXPECTED
FOR MUCH OF PERIOD.  THERE IS A 30 PERCENT CHANCE FOR AN MVFR
VISIBILITY DUE TO SNOW DURING THE EVENING.  STILL EXPECT A PERIOD OF
MVFR CONDITIONS WITH LIGHT SNOW BETWEEN 09Z AND 14Z.  THERE IS A 10
PERCENT CHANCE FOR IFR CONDITIONS DURING THIS PERIOD AS WELL.
SOUTHEAST WIND SHOULD PREVAIL THROUGH THE BULK OF THE TAF PERIOD.


&&


.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WINTER WEATHER ADVISORY UNTIL 9 AM MST SUNDAY FOR UTZ010-012-013-
     517-518.


WY...NONE.
&&

$$

PUBLIC...
SHORT TERM...STRUTHWOLF
LONG TERM...BARJENBRUCH
AVIATION...BARJENBRUCH

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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