Heavy Snow in Utah, December 6 to 9, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1045 AM MST MON DEC 6 2004

.SYNOPSIS...SERIES OF FAST MOVING PACIFIC STORMS WILL MOVE ACROSS
THE AREA BEGINNING LATE TONIGHT THROUGH WEDNESDAY NIGHT WITH THE
BRUNT OF THE STORMINESS AFFECTING NORTHERN PORTIONS.

&&

.DISCUSSION...FOG OVER NORTHWEST UT GENERALLY THINNING AND HAVE
ALLOWED THE ADVISORY TO EXPIRE. MOST OF THE CLOUDS AND SNOW
ASSOCIATED WITH THE OLD CLOSED LOW MOVING INTO NM HAVE ALSO MOVED
EAST OF THE AREA.  WEAK SHORTWAVE NEAR THE NV BORDER WILL MOVE
ACROSS THE AREA THROUGH THE AFTERNOON WITH PARTIAL CLEARING BEHIND
IT.

THEN THE VERY MOIST WESTERLY FLOW PUSHES INTO THE AREA LATE TONIGHT
AND CONTINUES AT TIMES THROUGH THURSDAY. THE INITIAL PORTION OF THIS
WILL BE ASSOCIATED WITH STRONG WARM ADVECTION THEN A SERIES OF WEAK
FAST MOVING IMPULSES RIPPLE PAST.

THIS LOOKS LIKE AN IDEAL SITUATION FOR OUR FAR NORTHERN AREAS TO GET
HEAVY SNOW. ISENTROPIC LEVEL FORECASTS SHOW STRONG UPGLIDE OVER THE
TRAPPED COLD AIR STARTING AFTER MIDNIGHT AND CONTINUING THROUGH
TUESDAY. THIS WILL RESULT IN THE HEAVY SNOW BEING WIDESPREAD WITH
THE TERRAIN FEATURES MOSTLY MASKED BY THE COLD AIR.  BUT STILL
OROGRAPHIC ENHANCEMENT...ESPECIALLY IN THE SECOND HALF OF THE WATCH
PERIOD AS THE ISENTROPIC LIFT SUBSIDES.

THE TRAPPED COLD AIR WILL BE SLOW TO SCOUR OUT OF THE NORTHERN
VALLEYS. THE 12Z ETA SUGGESTS IT MAY NOT BE COMPLETELY ELIMINATED IN
THE FAR NORTH. FORECAST SOUNDINGS IN NORTHERN BOX ELDER COUNTY AND
CACHE COUNTY NEVER GET ABOVE FREEZING ALTHOUGH IT DOES GET COLD
ENOUGH AFTER THE WEAK SHORTWAVE LATE TUESDAY NIGHT THAT THOSE AREAS
WILL BE CLOSE TO MIXING.  BUT RAPID WARMING ALOFT PUSHES BACK OVER
THE AREA WEDNESDAY. SO THE WINDOW FOR POSSIBLE MIXING IS QUITE SHORT
AND COMES AT A TIME THAT IS LESS FAVORABLE FOR LOW LEVEL WINDS.

HAVE ISSUED A WINTER STORM WATCH TO ADDRESS THE ABOVE EXPECTATION.
OTHER AREAS WILL ALSO GET SIGNIFICANT SNOW...ESPECIALLY IN THE
NORTHERN MOUNTAINS...BUT PROBABLY AT RATES THAT CAN BE HANDLED WITH
ADVISORIES.

EARLIER FORECASTS REASONABLE OVER THE SOUTHERN TWO-THIRDS OF THE
AREA SO NO DRAMATIC CHANGES EXPECTED THERE.
&&

.SLC WATCHES/WARNINGS/ADVISORIES...

UT...WINTER STORM WATCH EXTREME NORTH LATE TONIGHT THROUGH TUESDAY
NIGHT.
WY...WINTER STORM WATCH LATE TONIGHT THROUGH TUESDAY NIGHT.
ID...WINTER STORM WATCH LATE TONIGHT THROUGH TUESDAY NIGHT.

&&

SANDERS

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1105 AM MST MON DEC 6 2004

IDZ024-025-UTZ001-002-005>010-WYZ021-071300-
CACHE VALLEY/IDAHO PORTION-CACHE VALLEY/UTAH PORTION-
GREAT SALT LAKE DESERT AND MOUNTAINS-NORTHERN WASATCH FRONT-
SOUTHWEST WYOMING-WASATCH MOUNTAIN VALLEYS-WASATCH MOUNTAINS I-
80 NORTH-WASATCH MOUNTAINS SOUTH OF I-80-
WASATCH MOUNTAINS/IDAHO PORTION-WASATCH PLATEAU/BOOK CLIFFS-
WESTERN UINTA MOUNTAINS-
1105 AM MST MON DEC 6 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE VALLEYS...MOUNTAIN VALLEYS
AND DESERTS OF EXTREME NORTHERN UTAH...EXTREME SOUTHEAST IDAHO AND
SOUTHWEST WYOMING.

.DAY ONE...THE REST OF TODAY

NO HAZARDOUS WEATHER EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH MONDAY

A SERIES OF FAST MOVING STORMS WILL BRING ABUNDANT MOISTURE ACROSS
MOST AREAS TUESDAY THROUGH WEDNESDAY NIGHT. HEAVY SNOW IS LIKELY
STARTING LATE TONIGHT AND CONTINUING THROUGH TUESDAY NIGHT IN THE
MOUNTAINS NORTH OF ABOUT I-80 AND WHERE COLD AIR REMAINS TRAPPED IN
THE CACHE VALLEY AND EXTREME NORTHERN OF THE WASATCH FRONT AND WEST
DESERTS. SEE SLCWSWSLC FOR DETAILS.

SIGNIFICANT SNOWFALL IS ALSO POSSIBLE IN THE REMAINDER OF THE
NORTHERN UTAH MOUNTAINS. SEE SLCSPSSLC FOR DETAILS. A SECOND SURGE
OF MOISTURE MAY PRODUCE A SECOND PERIOD OF SNOW WEDNESDAY NIGHT AND
THURSDAY.

.SPOTTER INFORMATION STATEMENT...

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

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
1215 PM MST MON DEC 6 2004

UTZ002>006-008>010-012-062300-
CASTLE COUNTRY-GREAT SALT LAKE DESERT AND MOUNTAINS-
NORTHERN WASATCH FRONT-SALT LAKE AND TOOELE VALLEYS-
SOUTHERN WASATCH FRONT-WASATCH MOUNTAIN VALLEYS-
WASATCH MOUNTAINS SOUTH OF I-80-WASATCH PLATEAU/BOOK CLIFFS-
WESTERN UINTA MOUNTAINS-
1215 PM MST MON DEC 6 2004

...EXTENDED PERIOD OF SNOW FOR SOUTHWEST WYOMING AND MOUNTAINS OF
NORTHERN UTAH AND SOUTHERN IDAHO AS WELL AS VALLEYS MAINLY NEAR THE
IDAHO AND UTAH BORDER...

A MOIST PACIFIC SYSTEM WILL MOVE INTO THE SOUTHERN IDAHO AND
NORTHERN UTAH AREA LATE TONIGHT AND CONTINUE THROUGH WEDNESDAY
NIGHT. THE STORM SYSTEM WILL START OUT COLD BUT TEMPERATURES WILL
GRADUALLY WARM THROUGH THE PERIOD...ESPECIALLY WEDNESDAY INTO
THURSDAY AS A WARM FRONT MOVES NORTH OF THE AREA. SIGNIFICANT SNOW IS
LIKELY THROUGH TUESDAY NIGHT IN SOUTHWEST WYOMING AND BOTH THE
VALLEYS AND MOUNTAINS THAT STRADDLE THE IDAHO AND UTAH BORDER AND
ACROSS MOST OF THE NORTHERN MOUNTAINS AND NEARBY VALLEYS OF UTAH.

THE MOUNTAINS AND NEARBY VALLEYS OF NORTHERN UTAH...
SOUTHERN IDAHO...AND SOUTHWEST WYOMING WILL LIKELY RECEIVE THE
HEAVIEST SNOWFALL FROM THIS STORM.  A WINTER STORM WATCH
HAS BEEN ISSUED FOR THESE AREAS STARTING LATE TONIGHT
THROUGH TUESDAY NIGHT....WHERE ACCUMULATIONS COULD RANGE UP TO 10
INCHES IN THE VALLEYS AND TWO FEET IN WASATCH MOUNTAINS NORTH OF I-
80.  SEE SLCWSWSLC FOR MORE DETAILS.

OTHER AREAS NEAR THE WATCH AREA WILL SEE LESSER SNOWFALL
AMOUNTS THROUGH WEDNESDAY NIGHT...WITH SNOWFALL TOTALS BY LATE
WEDNESDAY ON THE ORDER OF 12-18 INCHES FOR THE MOUNTAINS
ABOVE 7000 FEET SOUTH OF I-80...AND 5-10 INCHES POSSIBLE IN THE
NEARBY MOUNTAIN VALLEYS AND WASATCH FRONT BENCHES FROM DAVIS COUNTY
NORTHWARD. THIS STORM MIGHT ALSO IMPACT THE PRICE AREA...WHERE
SNOWFALL AMOUNTS COULD RANGE BETWEEN 3-6 INCHES. MODERATE TO STRONG
SOUTHWEST WINDS WILL ACCOMPANY THIS STORM ACROSS THE MOUNTAINS
CAUSING CONSIDERABLE BLOWING AND DRIFTING.

THIS STORM WILL CREATE HAZARDOUS WINTER DRIVING CONDITIONS
LATE TONIGHT THROUGH WEDNESDAY. IF YOU HAVE TRAVEL OR OUTDOOR
ACTIVITIES PLANNED STAY WELL INFORMED OF THIS
DEVELOPING WINTER STORM. TUNE INTO NOAA WEATHER RADIO...LOCAL
BROADCAST STATIONS...OR VISIT WEATHER.GOV ON THE INTERNET FOR UPDATES
ON THE WEATHER CONDITIONS AND FORECASTS.