Winter Storm in Utah, March 9 to 13, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
400 AM MST THU MAR 9 2006

.SHORT TERM (TODAY THROUGH FRIDAY NIGHT)...
NEXT STORM SYSTEM OVER THE PAC NW QUICKLY APPROACHING EARLY THIS
MORNING. EXTENSIVE AREA OF CLOUDS WILL OVERSPREAD ERN UT/WRN CO THIS
MORNING. SFC OBS AND UPSTREAM RADARS INDICATE SOME AREAS OF LIGHT
SNOW WITH THIS...BUT MAIN PCPN WILL HOLD OFF UNTIL LATE TODAY AND
TONIGHT. SFC COLD FRONT REACHING NW UT THIS MORNING WILL MOVE TO A SW
UT-NE UT LINE BY LATE TODAY. W-SW OROGRAPHICS WILL HELP INCREASE
ACROSS THE NRN CO MTNS THIS AFTN. CLOSER PROXIMITY TO THE FRONT WILL
RESULT IN SNOW FOR THE ERN UINTAS DESPITE BEING SOMEWHAT SHADOWED BY
THE HIGHER WRN UINTAS. SOME MID-LEVEL INSTABILITY SHOWN BY
BUFKIT SHOULD FOSTER THE DEVELOPMENT OF SHOWERS ELSEWHERE THIS AFTN.

FRONT EXPECTED TO SLOW/STALL AS LEAD SHORTWAVE LIFTS INTO SWRN
CANADA BY EVE...AND WILL HAVE TO WAIT FOR A SECONDARY WAVE CURRENTLY
NEAR TO 138W/45N TO CATCH UP. ONCE IT DOES...BOTH NAM/GFS SHOW RAPID
DEVELOPMENT OF A SFC LOW OVER SRN UT TONIGHT. NAM TAKES THIS LOW
AND ASSOCIATED 700 MB LOW UP THE I-70 CORRIDOR FRI MORNING ALONG A
TIGHT 700 MB BAROCLINIC ZONE.  GFS TRACKS LOW FARTHER S...AND
WITH BOTH MODLES SHOWING THE SECONDARY SHORTWAVE AND 120+ KT UPPER
JET TRACKING NEAR OR JUST S OF THE 4-CORNERS ON FRI...GFS MAY BE MORE
CORRECT. COMBINATION OF STRONG LOW LEVEL CONVERGENCE WITH DYNAMICS
AND INSTABILITY...SOLID ADVISORY SNOW AMTS ANTICIPATED FOR MOST MTNS
WITH POTENTIAL FOR HVY SNOW CRITERIA BEING MET /12 INCHES/. DEPENDS
ON WHERE BAROCLINIC ZONE SETS UP AND HOW MUCH CONVECTIVE INPUT IS
REALIZED. POTENTIAL FOR 3+ INCHES OF SNOW IN MANY NW AND WCNTL
VALLEYS LATE TONIGHT AND FRI MORNING. WILL LET DAY SHIFT TAKE ONE
MORE LOOK AT TIMING AND LOCATION FOR ANY VALLEY ADVISORIES.

FOR THE SAN JUANS MTNS IN SW CO...700 MB SW WINDS AT 30 KTS WILL
PROVIDE STEADY OROGPRAPHIC LIFT TONIGHT INTO FRI AS MOISTURE
INCREASES. 00Z NAM40 HAS LIFTED INDEX NEAR OR BELOW ZERO WITH SOME
CAPE ON FRI FOR ADDED CONVECTIVE PUNCH.

WILL BE ISSUING A WINTER STORM WATCH FOR THE MTNS OF WRN CO AS WELL
AS THE EAST TAVAPUTS PLATEAU IN ERN UT FOR TONIGHT THROUGH FRI. A
BIT DIFFICULT ON DECIDING AN ENDING TIME WITH WRN TROUGH
RELOADING...BUT BELIEVE WILL SEE SOME BREAK FRI NIGHT BETWEEN
SHORTWAVES. IN NE UT...HAVE GONE WITH A SNOW ADVISORY FOR
THE ERN UINTAS THIS AFTN AND TONIGHT AS EXPECT SNOW TO LIGHTEN FRI
MORNING AS FRONT/BAROCLINIC ZONE SLIP SOUTHWARD.

.LONG TERM (SATURDAY THROUGH THURSDAY)...
THE SAN JUAN MOUNTAINS AND THE ADJACENT LOWER VALLEYS...INCLUDING
DURANGO AND PAGOSA SPRINGS...WILL LIKELY GET THE STORM THEY NEED ON
SATURDAY AND SATURDAY NIGHT.  ANOTHER STRONG WAVE AND SURFACE FRONT
WILL MOVE MOVE ACROSS ARIZONA...PLACING OUR SRN ZONES IN DEEP MOIST
SOUTHWESTERLY FLOW.  MOISTURE IS NOT PLENTIFUL BUT IT WILL BE
SUFFICIENT WITH THE TIGHT THERMAL GRADIENT ASSOCIATED WITH THE
ARIZONA FRONT AND STRONG QG FORCING WITH CYCLONIC CURVED JET ALOFT.
THE PACIFIC WEATHER SYSTEM MOVING INTO ARIZONA HAS GOOD STRUCTURE
AND HINTS AT A SURFACE WARM FRONT MOVING NORTHWARD INTO SOUTHWEST
COLORADO ON SATURDAY.  ISENTROPIC ANALYSIS SHOWS STRONG UPGLIDE IN
THE 00Z NAM AND GFS MODEL DATA.  THEN THE COLDER AIR ARRIVES TO KEEP
THE AIR MASS VERY UNSETTLED ON SATURDAY NIGHT...BUT FAVORABLE
SOUTHWEST FLOW PERSISTS AS A SURFACE LOW FORMS OVER ERN COLORADO.
GIVEN THE PROMISING PICTURE THE MODELS ARE SHOWING...WILL ENHANCE
THE GRIDDED DATA WITH EMPHASIS ON HEAVY SNOW.  FOR THE REMAINDER OF
THE FORECAST AREA ON SATURDAY AND SATURDAY NIGHT...VERY ACTIVE WITH
SIGNIFICANT SNOWFALL CONTINUING AS DEEP COLD TROUGH AXIS GRADUALLY
MOVES ACROSS THE CENTRAL ROCKIES DURING THE WEEKEND.

MONDAY AND TUESDAY WILL BE TRANSITION DAYS AS THE JET REPOSITIONS
AND SHIFTS NORTHWARD.  SHORT WAVE ENERGY WILL TRACK ACROSS THE
COLORADO AND WYOMING BORDER FOR A CHANCE OF SNOW ACROSS THE NRN
VALLEYS AND MOUNTAINS.  SNOW OVER THE SRN MOUNTAINS WILL DIMINISH
WITH ADDITIONAL HEAVY SNOW NO LONGER EXPECTED.

WEDNESDAY AND THURSDAY...MEDIUM RANGE MODELS SHOW WESTERLY FLOW OVER
THE CONUS BUT WITH A FLAT RIDGE AXIS OVER COLORADO.  THE THREAT OF
MOUNTAIN SNOW CONTINUES TO DECREASE WITH ACCUMULATIONS ON THE LIGHT
SIDE.  TEMPERATURES WILL RECOVER AND SHOULD BE NEAR SEASONAL VALUES
BY THURSDAY.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
.CO...WINTER STORM WATCH TONIGHT THROUGH FRIDAY AFTERNOON FOR THE
        WESTERN COLORADO MOUNTAINS...ZONES 3 4 9 10 12 13 17 18 19.
.UT...SNOW ADVISORY FOR THE ERN UINTA MTNS FROM NOON UNTIL 5 AM
        FRIDAY...ZONE 23.
      WINTER STORM WATCH FROM THE EAST TAVAPUTS PLATEAU TONIGHT
        THROUGH FRIDAY AFTERNOON...ZONE 25.

&&

JAD/PF

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
507 AM MST THU MAR 9 2006

COZ001>014-017>023-UTZ022>025-027>029-101245-
ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES-
CENTRAL COLORADO RIVER BASIN-
CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN-
CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR-
EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS-
ELKHEAD AND PARK MOUNTAINS-FLAT TOPS-
FOUR CORNERS/UPPER DOLORES RIVER-
GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS-
GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN-
NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER-
ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH-
SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU-
UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY-
UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS-
507 AM MST THU MAR 9 2006

...SNOW ADVISORY FOR THE EASTERN UINTA MOUNTAINS FROM NOON MST
TODAY UNTIL 5 AM MST FRIDAY...
...WINTER STORM WATCH FOR THE WESTERN COLORADO MOUNTAINS AND EAST
TAVAPUTS PLATEAU THIS EVENING THROUGH FRIDAY AFTERNOON...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN
COLORADO.

.DAY ONE...TODAY AND TONIGHT
SNOW WILL DEVELOP OVER THE MOUNTAINS TODAY...AND COULD BE POTENTIALLY
HEAVY TONIGHT. TRAVELERS SHOULD ANTICIPATE WINTER DRIVING CONDITIONS
TODAY ACROSS THE EASTERN UINTA MOUNTAINS IN NORTHEAST UTAH...AND
TONIGHT FOR THE MOUNTAINS OF WESTERN COLORADO. SNOW IS LIKELY AT MANY
VALLEY LOCATIONS TONIGHT AS WELL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

SNOW WILL CONTINUE ACROSS THE MOUNTAINS AND MANY VALLEYS ON FRIDAY...
AND CONTINUE TO CAUSE TRAVEL PROBLEMS OVER MOUNTAIN PASSES. TOTAL
SNOWFALL OF 12 INCHES IS POSSIBLE FOR MANY MOUNTAIN LOCATIONS BY
FRIDAY EVENING.

UNSETTLED CONDITIONS WILL PERSIST SATURDAY AND SATURDAY NIGHT...
ESPECIALLY FOR THE SAN JUAN MOUNTAINS AND LOWER ELEVATIONS FROM
CORTEZ TO PAGOSA SPRINGS WHERE ACCUMULATING SNOWFALL IS EXPECTED.
THE CHANCE OF SNOW THEN PERSISTS FOR EASTERN UTAH AND WESTERN
COLORADO SUNDAY THROUGH TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. HOWEVER...YOU
ARE ENCOURAGED TO PHONE IN OR EMAIL REPORTS TO THE GRAND JUNCTION
FORECAST OFFICE.

JAD