Heavy Snow Warning 9, NWS Salt Lake City, UT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
835 PM MST TUE MAR 14 2006

AMENDED HEADLINES

.SYNOPSIS...A COLD FRONT WILL SWEEP ACROSS UTAH LATER TONIGHT
THROUGH EARLY WEDNESDAY. ANOTHER COLD AND WET STORM IS EXPECTED THIS
WEEKEND AND WILL AFFECT THE ENTIRE REGION.

&&

.DISCUSSION...PREFRONTAL WINDS CONTINUE TO BLOW IN THE WESTERN
DESERTS AND TOOELE VALLEY. WINDS HAVE GUSTED INTO THE 40S THESE
AREAS AND IN THE 50S MPH ACROSS THE WASATCH RANGE. SURFACE COLD
FRONT IS THROUGH WENDOVER THIS PAST HOUR AND JUST EAST OF I-80
DUGWAY SENSOR...AND EXTENDS NORTHEAST TO JUST WEST OF LOGAN. AIR
MASS BEGINNING TO MOISTURE FROM TOP-DOWN OVER NORTHERN UTAH WITH
RADAR COVERAGE INCREASING ACROSS NORTHWEST UTAH AS UPPER DIVERGENCE
AND LEADING VORT MAX RIDE THROUGH THIS REGION. WELL DEFINED 700 MB
BAROCLINIC ZONE IS OBSERVED OVER NORTHEAST NEVADA AND PRODUCING
SNOWFALL. SURFACE COLD FRONT WILL MOVE INTO THE WASATCH FRONT
BETWEEN 05 AND 08Z...CROSSING SLC NEAR MIDNIGHT. JUST BEHIND THIS
THE BAROCLINIC ZONE WILL FOLLOW AND BRING A SWATH OF HEAVY SNOWFALL.
UPPER TROUGH AXIS AND PVA MAX IS OVER THE GREAT SALT LAKE AT ABOUT 5
AM AND REACHES THE WASATCH RANGE BY 8 AM. THIS PERIOD OF DEEP LIFT
WORKS ON THE 0.35 PRECIPITABLE WATER IN PLACE COMBINED WITH DEEP
LAYER INSTABILITY. THE HEAVIEST SNOW WILL BE ASSOCIATED WITH THIS
AREA OF LIFT FROM MIDNIGHT TO 8 AM WHILE 700 MB TEMPERATURES CRASH
TO -8C AT 2 AM WITH -10C AT 5 AM AND -12C BY 8 AM FOR WASATCH FRONT.
SALT LAKE COUNTY HEAVY SNOW LIKELY 3 AM TO 6 AM TIME FRAME.

BAROCLINIC ZONE WILL HOLD TOGETHER TO PRODUCE A BAND OF HEAVY SNOW
ALONG THE I-15 CORRIDOR FROM FILLMORE INTO THE SANPETE VALLEY. COLD
POCKET AT 500 MB OF -31C RIDES ACROSS THE GSL AT 8 AM WEDNESDAY BUT
IT EXITS QUICKLY TO THE EAST WITH RAPID DRYING AND STABILIZATION IN
THE AFTERNOON. NORTHWEST FLOW IN THE MORNING BACKS TO SOUTHWEST BY
AFTERNOON. MOST PRECIPITATION WILL END QUICKLY WITH ONLY LINGERING
LIGHT SNOW SHOWERS IN THE CENTRAL AND NORTHERN MOUNTAINS BY MIDDAY.

CURRENT HIGHLIGHTS LOOK GOOD BUT WILL UPDATE TO INCREASE CHANCES AND
ADD ACCUMULATIONS FOR I-15 CORRIDOR TO FILLMORE AND BEAVER AREA AND
FOR THE SANPETE VALLEY. DOWNSLOPE FLOW AND DEPARTING DYNAMICS WILL
NOT ALLOW MUCH TO SPILL EAST OF THE WASATCH PLATEAU IN THE EASTERN
VALLEYS. DURATION IS A LIMITING FACTOR BUT THE NORTHERN WASATCH
FRONT AND RANGE ZONES 2 AND 7 WILL BE CONSIDERED FOR AN UPGRADE
WHERE LOCAL WARNING CRITERIA COULD BE MET. NORTHERN WASATCH VALLEYS
SHOULD DUE WELL...ESPECIALLY NORTH OF I-80. THIS AREA WILL HAVE A
LITTLE MORE PREFRONTAL SNOW WHEN IT IS COLD ENOUGH TO SNOW AND WILL
HAVE A DIRECT HIT FROM THE DYNAMICS AND COLD POOL. WIND EXTEND WIND
ADVISORY A FEW HOURS FOR PREFRONTAL IN TOOELE VALLEY AND DUGWAY AND
FOR POST FRONTAL ACROSS THE NORTHWEST DESERTS.

WARM AIR ADVECTION TAKES OVER WEDNESDAY NIGHT. AIR MASS MOISTENS ON
THURSDAY. PRECIPITATION WILL INCREASE THURSDAY NIGHT INTO FRIDAY AS
AIR MASS MOISTENS AND DESTABILIZES WITH LIFT IN SOUTHWEST FLOW.
INITIAL WAVE COULD BRING A 700 MB CIRCULATION INTO NORTHWEST UTAH BY
FRIDAY NIGHT...BEFORE MOST OF THE ENERGY PULLS SOUTH INTO SOUTHERN
UTAH. UPPER TROUGH DIGS ACROSS LAKE TAHOE FRIDAY AND SATURDAY AND
THIS GRADUALLY SHIFTS EAST INTO THE GREAT BASIN FOR AN UNSETTLED AND
COOL PATTERN INTO THE WEEKEND. SNOW LEVELS WOULD BE VERY LOW BUT
PROBABLY NOT AS LOW AS THE RECENT EVENTS...UNLESS THE CENTER OF THE
LOW TRACKS A BIT FURTHER NORTH. THE CLOSED LOW SCENERIO WOULD STILL
SEND VORT LOBES NORTHWARD INTO THE UINTA MOUNTAINS AND SOUTHERN
WASATCH ON SUNDAY FOR WAVES OF SNOWFALL...FAVORED ON SOUTH FACING
SLOPES. 12Z GFS...UKMET AND ECMWF ALL DIG THE MAIN UPPER LOW ACROSS
LAS VEGAS AND CLOSE IT OFF THIS WEEKEND. THIS WOULD BRING THE
HEAVIEST PRECIPITATION AND SNOWFALL ACROSS SOUTHERN UTAH...WARNING
TYPE FOR AT LEAST THE MOUNTAINS. VARIOUS SOLUTIONS NEXT WEEK WITH AN
UPPER RIDGE OR LINGERING UPSTREAM ENERGY CARVING ACROSS NORTHERN
UTAH OR HANGING NEAR THE 4-CORNERS...POSSIBLE PATTERN CHANGE.

&&

.AVIATION...COLD FRONT MOVING THROUGH NW UTAH AT 03Z. FRONT SHOULD
MOVE THROUGH KSLC AROUND 06Z BRINGING A SHIFT TO NORTHWEST WINDS.
AREAS OF SNOW WILL DEVELOP ALONG THE NORTHERN WASATCH FRONT AHEAD OF
THE COLD FRONT WITH SNOW SPREADING INTO THE CENTRAL AND SOUTHERN
WASATCH FRONT ALONG AND BEHIND THE BOUNDARY. ANTICIPATE WIDESPREAD
MVFR CEILINGS AND IFR VISIBILITIES BETWEEN 06Z AND 12Z. ALSO
ANTICIPATE LOCALIZED IFR CEILINGS DURING THIS TIME. CEILINGS AND
VISIBILITIES SHOULD IMPROVE AFTER 15Z.

&&

.SLC WATCHES/WARNINGS/ADVISORIES...
UT...WIND ADVISORY UNTIL 1 AM TUESDAY FOR UTZ003-UTZ005.
     HEAVY SNOW WARNING UTZ002 1 AM THROUGH 9 AM WEDNESDAY
     WINTER STORM WARNING UTZ006-007 THROUGH 9 AM WEDNESDAY
     SNOW ADVISORY FROM MIDNIGHT TO NOON WEDNESDAY
     FOR UTZ001-UTZ003-UTZ004.
     SNOW AND BLOWING SNOW ADVISORY UNTIL NOON WEDNESDAY FOR
     UTZ008-UTZ009.

WY...NONE.
&&

PUBLIC...TARDY
AVIATION...GRAHAM

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1159 AM MST TUE MAR 14 2006

UTZ001>011-015-WYZ021-151400-
CACHE VALLEY/UTAH PORTION-GREAT SALT LAKE DESERT AND MOUNTAINS-
NORTHERN WASATCH FRONT-SALT LAKE AND TOOELE VALLEYS-SOUTHERN WASATCH
FRONT-SOUTHWEST WYOMING-WASATCH MOUNTAIN VALLEYS-WASATCH MOUNTAINS I-
80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80-WASATCH PLATEAU/BOOK CLIFFS-
WEST CENTRAL UTAH-WESTERN UINTA BASIN-WESTERN UINTA MOUNTAINS-
1159 AM MST TUE MAR 14 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE NORTHERN UTAH AND EXTREME
SOUTHWEST WYOMING.

.DAY ONE... TODAY AND TONIGHT

A PACIFIC STORM SYSTEM WILL MOVE INTO NEVADA LATE TODAY. SHOWERS
WELL AHEAD OF THE STORM WILL SPREAD INTO THE HIGH COUNTRY OF
NORTHERN UTAH LATE THIS AFTERNOON.  HEAVY SNOW WILL DEVELOP OVER THE
MOUNTAINS AND FAR NORTHERN VALLEYS OVERNIGHT. A SNOW ADVISORY HAS
BEEN ISSUED FOR THE WASATCH RANGE FOR LATE THIS AFTERNOON AND
TONIGHT. STRONG AND GUSTY SOUTH WINDS WILL ALSO OCCUR ACROSS
NORTHWEST UTAH TODAY AND THIS EVENING. SEE THE LATEST WEATHER
ADVISORY FOR DETAILS.

.DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY

THE TUESDAY STORM WILL EXIT NORTHERN UTAH EARLY ON WEDNESDAY. THE
SNOW ADVISORY WILL EXTEND THROUGH LATE WEDNESDAY MORNING. ANOTHER
PACIFIC STORM WILL ARRIVE OVER THE GREAT BASIN THIS WEEKEND. THIS
STORM WILL BE ON THE COLD SIDE...WITH WIDESPREAD SNOWFALL EXPECTED.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

UTZ012>014-016>021-151400-
CASTLE COUNTRY-CENTRAL AND SOUTHWEST MOUNTAINS-GLEN CANYON RECREATION
AREA/LAKE POWELL-HENRY MOUNTAINS-SAN RAFAEL SWELL-SANPETE/SEVIER
VALLEYS-SOUTH CENTRAL UTAH-SOUTHWEST UTAH-UTAHS DIXIE AND ZION
NATIONAL PARK-
645 AM MST TUE MAR 14 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHERN UTAH.

.DAY ONE... TODAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY

A COLD PACIFIC STORM SYSTEM WILL SETTLE OVER THE SOUTHERN GREAT BASIN
THIS WEEKEND. SIGNIFICANT SNOWFALLS ARE POSSIBLE ACROSS THE SOUTHERN
MOUNTAINS AND ADJACENT HIGHER VALLEYS OVER THE WEEKEND.