Heavy Snow in Utah, January 11 to 12, 2001

UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UTAH
230 PM MST THU JAN 11 2001

SYNOPSIS...A LARGE PACIFIC STORM SYSTEM WILL MOVE SLOWLY ACROSS UTAH
TONIGHT AND FRIDAY.  A SECOND WEAKER SYSTEM WILL MOVE ACROSS THE
NORTH LATE SATURDAY.

DISCUSSION...MOSTLY CLOSED LOW GRADUALLY OPENS INTO A BROAD TROF AS
IT MOVES SLOWLY EASTWARD TONIGHT/FRI.  TROF AXIS DOESNT MOVE ACROSS
OUR AREA UNTIL FRI NIGHT.  THE MOST WIDESPREAD WEATHER WITH THE
SYSTEM WILL BE TONIGHT AS THE BROAD BAND OF WEATHER THAT IS JUST
MOVING INTO WESTERN UT FROM EASTERN NV MOVES ACROSS UT.  HEAVY SNOW
ALMOST GUARANTEED FOR SOUTH EXPOSURES IN THE SOUTHERN MOUNTAINS WITH
ADVISORY AMOUNTS LIKELY IN MOST OTHER SOUTHERN AREAS AND ALONG THE
EAST SLOPES AS THE EASTERLY SURFACE COMPONENT CONTINUES MOST OF THE
NIGHT.

THINGS GET A LITTLE MORE FUZZY FOR FRI.  12Z ETA MOVED A
CONSOLIDATED 700MB TROF EAST ACROSS THE STATE EARLY FRI.  THAT
PRODUCED UPSLOPE SNOW ALONG THE WASATCH FRONT FRI AND STARTED TO
INHIBIT ANY SNOW IN MOST OTHER AREAS.  THE 18Z ETA FORMS A CLOSED
700MB CENTER W OF 4HV EARLY FRI WITH ANOTHER IN THE NORTHERN
ROCKIES.  THAT PUTS AND EASTERLY FLOW OVER MOST OF NORTHERN UT AND
WOULD BE WEAKLY DOWNSLOPE ALONG THE WASATCH FRONT AND UPSLOPE ON THE
EAST SIDE.  ALTHOUGH THE AVN DIDNT SHOW THE CLOSED CIRCULATIONS ITS
PRECIPITATION FIELDS WERE MORE LIKE THE 18Z ETA.  WILL GO WITH THE
LATER AND HOPEFULLY BETTER SOLUTION SO THE MAIN AREAS OF SNOW FRI
WILL BE IN THE EAST AND SOUTH.  WILL KEEP MOST OF THE ADVISORIES AND
WARNINGS ABOUT AS IS IN THE NEW PACKAGE BUT WILL EXTEND THE
ADVISORIES IN THE SOUTHWEST THROUGH TONIGHT AND IN THE SOUTHEAST
THROUGH FRI MORNING.

AFTER THAT IT LOOKS LIKE A BIT OF A BREAK FRI NIGHT AND EARLY SAT
THEN BY LATE SAT A WEAK SHORTWAVE BEGINS TO PUSH INTO NORTHWEST UT
IN A NORTHWESTERLY FLOW.  EXPECT SOME LIGHT SNOW AGAIN MAINLY IN
OROGRAPHICALLY FAVORED AREAS OF NORTHWEST UT FROM LATE SAT THROUGH
SUN.

FOR THE REST OF THE EXTENDED PERIOD THE TROFFINESS OVER THE WEST
DEVELOPS INTO A CLOSED LOW THAT DRIFTS SOUTHWARD MON/TUE.  THE
EASTERLY FLOW KEEPS THINGS FAIRLY QUIET IN THE NORTH THOSE DAYS
WHILE THE PROXIMITY OF THE LOW KEEPS THE SOUTH UNSETTLED.  IN THE
WED/THU PERIOD THE LOW HAS MOVED FAR ENOUGH SOUTH TO LET THINGS
IMPROVE IN THE SOUTH WHILE A NORTHWEST FLOW SETTLES OVER THE NORTH
AGAIN WITH BRUSH BY SHORTWAVES.

AND ITS ALL MUCH NICER THAN THE STAGNATION WE HAD TO DEAL WITH FOR
THE LAST COUPLE OF WEEKS.

SLC 8645 CDC +611  SANDERS

.SLC...WINTER STORM WARNING THRU TONIGHT SW MTNS AND HENRY
       MTNS...UTZ017-18.
    ...SNOW ADVISORY WASATCH MOUNTAINS SOUTH OF I-80...WESTERN
       UINTAS AND WESTERN TAVAPUTS THROUGH TONIGHT...UTZ008>010.
    ...SNOW ADVISORY THROUGH TONIGHT WESTERN UINTA BASIN...CASTLE
       COUNTRY AND SAN RAFAEL SWELL...SOUTHWLEST AND WEST CENTRAL
       VALLEYS...SANPETE AND SEVIER VALLEYS...UTZ011>016.
    ...SNOW ADVISORY ABOVE 5000 FEET THROUGH NOON FRIDAY SOUTH-CENTRAL
       UTAH AND GLEN CANYON REC AREA...UTZ020-21.