Winter Storm in Utah, April 2 to 4, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
330 AM MST FRI APR 2 2004

.SHORT TERM (TODAY THROUGH SATURDAY NIGHT)...A MOIST SOUTHEAST FLOW
WILL AFFECT EASTERN UTAH AND WESTERN COLORADO THROUGH SATURDAY NIGHT
AS A STORM SYSTEM GATHERS STRENGTH OVER THE DESERT SOUTHWEST. KGJX
RADAR INDICATES SCATTERED SHOWERS OCCURRING OVER SOUTHWEST COLORADO
AND EASTERN UTAH AS WEAK H5 PVA AND MOIST ISENTROPIC UPGLIDE PROVIDE
SOME LIFT. ASOS/AWOS SITES REPORTING MAINLY LOW-MID CLOUD DECK SO
SUSPECT PRECIP IS LIGHT AND FALLING IN THE HIGHER TERRAIN. FIRST
SIGNIFICANT STORM IN SEVERAL WEEKS POISED TO HIT SOUTHEAST UTAH AND
SOUTHWEST COLORADO THE NEXT 12-48 HOURS.

TODAY AND TONIGHT...INITIAL SOUTHERN WAVE FROM PACIFIC TROUGH NOW
BEING LIFTED BACK NORTH BY DEEPENING UPPER LOW NOW OVER SOUTHERN
CALIFORNIA. A VERY MOIST AIR MASS IS STREAMING NORTH/WEST AS SYSTEM
CONTINUES TO WRAP UP AROUND THE NORTHERN BAJA REGION. ENERGY FROM
SOUTHERN WAVE WILL ROTATE ACROSS AZ/NM THIS MORNING AND APPROACH THE
FOUR CORNERS THIS AFTERNOON. AS THIS OCCURS...POTENTIALLY SIGNIFICANT
PRECIP EVENT WILL DEVELOP THIS EVENING AND PERSIST THROUGH SATURDAY
MORNING ACROSS THE SOUTHERN VALLEYS/SOUTHERN SAN JUAN MTNS AND THE
ABAJO MTNS OF SE UTAH. NOT MUCH COLD AIR OVER THE AREA SO EXPECT SNOW
LEVELS TO LOWER TO BETWEEN 7500 AND 8500 FEET...WITH SIGNIFICANT SNOW
ACCUMS ABOVE 8500 FT TONIGHT THROUGH 18Z/SAT. TIGHTENING EAST-WEST
PRESSURE GRADIENT WILL STRENGTHEN SOUTHEAST FLOW ACROSS THE AREA
TODAY. EXPECT LOCALLY WINDY CONDITIONS TO DEVELOP AND PERSIST THROUGH
SATURDAY...ESPECIALLY ALONG/WEST OF THE DIVIDE AND AROUND THE FOUR
CORNERS. DEEP/STRONG SOUTHEAST FLOW WILL COMBINE WITH VERY MOIST
AND UNSTABLE AIR MASS TO CREATE THIS RAIN/SNOW POTENTIAL ACROSS THE
SOUTH. 06Z/META GENERATES 1.0-2.0 QPF BETWEEN 00Z-12Z/SAT ACROSS THE
FOUR CORNERS AREA. WILL ISSUE A WINTER STORM WATCH FOR THE SOUTHERN
SAN JUAN MTNS (ABOVE 8500FT) FOR TONIGHT THROUGH 18Z/SAT FOR >12 NEW
SNOWFALL. IN THE LOWER ELEVATIONS...PERSISTENT RAINFALL COULD CREATE
LOCAL FLOODING ESPECIALLY OVER BURN SCARS FROM PREVIOUS YEARS
WILDFIRES.

SATURDAY AND SATURDAY NIGHT...STORM WILL REMAIN NEARLY STATIONARY
OVER THE DESERT SOUTHWEST WITH SEVERAL WAVES ROTATING AROUND THE
CENTER OF CIRCULATION. THESE WAVES COMBINED WITH MOIST AIR MASS WILL
CONTINUE THE THREAT OF SHOWERS AND ISOLD THUNDERSTORMS...MAINLY
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. TEMPS WILL COOL
SEVERAL DEGREES DUE TO CLOUDS AND PRECIP. AS STORM DRIFTS EAST...A
STRONGER PIECE OF ENERGY WILL APPROACH THE FOUR CORNERS...CREATING
ANOTHER CHANCE OF SIGNIFICANT RAIN/SNOW ACROSS SE UTAH/SW COLO
SATURDAY NIGHT.  DJN.83

.LONG TERM (SUNDAY-FRIDAY)...
SUNDAY...DEEP SOUTHEASTERLY FLOW ALOFT WILL CONTINUE TO WRAP
ABUNDANT MOISTURE INTO THE REGION...AS CUTOFF LOW OVER ARIZONA
REMAINS NEARLY STATIONARY. THE SOUTHWEST SAN JUANS AND THE 4-CORNERS
REGION WILL REMAIN THE FAVORED AREA FOR SIGNIFICANT PRECIP AS MORE
ENERGY WRAPS AROUND THE LOW. HAVE CUT GUIDANCE TEMPS SEVERAL
CATEGORIES...ESPECIALLY OVER THE SOUTHERN ZONES TO ACCOUNT FOR DENSE
CLOUD COVER AND PRECIP. THE CHANCE OF PRECIP DECREASES QUICKLY NORTH
OF INTERSTATE 70 WITH ONLY SLIGHT CHANCE POPS IN STORE DUE TO THE
POSITIONING OF THE UPPER LOW AND UNFAVORABLE EASTERLY COMPONENT.

SUNDAY NIGHT/MONDAY...THE UPPER LOW BEGINS TO FILL AND LIFT SLOWLY
ENE THROUGH NEW MEXICO AND EXTREME SOUTHERN COLORADO. SYSTEM MOVES
SLOW ENOUGH THAT WE HAVE ADJUSTED MONDAY GRIDS TO ACCOUNT FOR MORE
WIDESPREAD PRECIPITATION...WITH SOUTHERN AREAS STILL FAVORED. NO
MAJOR CHANGE IN TEMPS EXPECTED AS CLOUD COVER...SHOWERS AND COOLING
ALOFT KEEP TEMPS BELOW SEASONAL NORMS.

TUESDAY...DRIER DAY EXPECTED...WITH SHOWERS CONFINED ALONG THE
DIVIDE AS THE LOW EXITS TO OUR EAST. TEMPS TO REBOUND TO NEAR
SEASONAL NORMS.

WEDNESDAY...SHRTWV RIDGING BUILDS IN AHEAD OF YET ANOTHER LOW CLOSING
OFF NEAR SRN CALIFORNIA.  LATEST EC/UKMET/GFS ARE IN AGREEMENT ATTM.
THIS LOW IS EXPECTED TO DROP WELL SOUTH...PROVIDING MINIMAL IMPACT ON
OUR FA.

THURSDAY/FRIDAY...NORTHWEST FLOW DEVELOPS AS RIDGE AXIS SHIFTS
EAST...WITH A SERIES OF WEAK WAVES EXPECTED TO PASS THROUGH THE
REGION.  FIRST SYSTEM DUE IN LATE THURSDAY...WITH ANOTHER
EXPECTED BY LATE FRIDAY. WILL TREND FOR MORE CLOUD COVER...BUT KEEP
ANY MENTION OF POPS OUT FOR NOW. NO MAJOR SWINGS IN TEMPS EXPECTED.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
.CO...WINTER STORM WATCH TONIGHT THROUGH 11 AM MST SATURDAY MORNING
      FOR ZONE 19 (SOUTHWEST SAN JUAN MOUNTAINS) ABOVE 8500 FEET.
.UT...NONE.

DJN/JDC

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
915 AM MST FRI APR 2 2004

COZ001>014-017-018-020-UTZ023>025-027>029-031200-
LOWER YAMPA RIVER BASIN-CENTRAL YAMPA RIVER BASIN-
ROAN AND TAVAPUTS PLATEAUS-ELKHEAD AND PARK MOUNTAINS-
UPPER YAMPA RIVER BASIN-GRAND VALLEY-DEBEQUE TO SILT CORRIDOR-
CENTRAL COLORADO RIVER BASIN-GRAND AND BATTLEMENT MESAS-
GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-
CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN-
WEST ELK AND SAWATCH MOUNTAINS-FLAT TOPS-UPPER GUNNISON RIVER VALLEY-
UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-NORTHWEST SAN JUAN MOUNTAINS-
PARADOX VALLEY/LOWER DOLORES RIVER-EASTERN UINTA MOUNTAINS-
EASTERN UINTA BASIN-TAVAPUTS PLATEAU-ARCHES/GRAND FLAT-
LA SAL AND ABAJO MOUNTAINS-CANYONLANDS/NATURAL BRIDGES-
915 AM MST FRI APR 2 2004

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

.DAY ONE...TODAY AND TONIGHT...

SCATTERED SHOWERS AND AFTERNOON THUNDERSTORMS WILL AFFECT AREAS
MAINLY SOUTH OF I-70. GUSTY WINDS TO 50 MPH ARE POSSIBLE AROUND
THUNDERSTORMS THROUGH THIS EVENING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY...

THE CHANCE FOR MOUNTAIN SNOW AND VALLEY RAIN WITH ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS WILL CONTINUE MONDAY AND TUESDAY...AS A
SLOW-MOVING STORM SYSTEM MOVES FROM THE DESERT SOUTHWEST ACROSS
COLORADO.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

COZ019-021>023-UTZ022-031200-
SOUTHWEST SAN JUAN MOUNTAINS-FOUR CORNERS/UPPER DOLORES RIVER-
ANIMAS RIVER BASIN-SAN JUAN RIVER BASIN-SOUTHEAST UTAH-
905 AM MST FRI APR 2 2004

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

.DAY ONE...TODAY AND TONIGHT...

GUSTY WINDS TO 50 MPH ARE POSSIBLE AROUND THUNDERSTORMS THIS
AFTERNOON AND EVENING. SNOW SHOWERS WILL OCCUR OVER THE SAN JUAN
MOUNTAINS OF SOUTHWEST COLORADO THIS EVENING...BECOMING MORE
WIDESPREAD AND LOCALLY HEAVY OVERNIGHT. SIGNIFICANT SNOW
ACCUMULATIONS OF UP TO ONE TO TWO FEET ARE POSSIBLE IN THE SAN JUAN
AND LA SAL MOUNTAINS BETWEEN TONIGHT AND SATURDAY. SNOW LEVELS WILL
INITIALLY BE AROUND 9500 FEET...BUT WILL LOWER TO AROUND 8000 FEET
OVERNIGHT. REFER TO THE DENWSWGJT FOR MORE DETAILS. HEAVY RAIN IS
POSSIBLE IN THE SOUTHERN COLORADO VALLEYS FROM CORTEZ TO PAGOSA
SPRINGS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY...

THE POTENTIAL FOR SIGNIFICANT SNOWFALL WILL PERSIST THROUGH SUNDAY
ACROSS THE SOUTHERN MOUNTAINS OF SOUTHEAST UTAH AND SOUTHWEST
COLORADO. LOCALLY HEAVY RAIN IS POSSIBLE IN THE VALLEYS. THE CHANCE
FOR MOUNTAIN SNOW AND VALLEY RAIN WITH ISOLATED AFTERNOON AND EVENING
THUNDERSTORMS WILL CONTINUE THROUGH TUESDAY...AS A SLOW-MOVING
STORM SYSTEM MOVES FROM THE DESERT SOUTHWEST ACROSS COLORADO. BELOW
8000 FEET...RAINFALL TOTALS OF 1 TO 3 INCHES ARE POSSIBLE BETWEEN
TODAY AND TUESDAY. FLASH FLOODING IS ALSO POSSIBLE DURING THIS
PERIOD...ESPECIALLY IN THE MISSIONARY RIDGE BURN AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. HOWEVER...
SPOTTERS ARE ENCOURAGED TO REPORT THEIR RAINFALL AMOUNTS TO THE
NATIONAL WEATHER SERVICE IN GRAND JUNCTION.

BA