High Wind in Utah, April 15, 2002

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
343 AM MDT MON APR 15 2002

CORRECTED REFERENCE TO NORTHWEST CO IN FIRST PARAGRAPH

LOTS TO CONSIDER AND MUCH TO DO EARLY THIS MORNING...SO WILL ATTEMPT
TO KEEP THIS DISCUSSION BRIEF. AS IN PREVIOUS DISCUSSION...
SIGNIFICANT CHANGES COMING TODAY AND THROUGHOUT THE REMAINDER OF
THE NEAR TERM.

STRONG FRONT ALIGNED SOUTHWEST TO NORTHEAST ACROSS NORTHWEST UTAH TO
KSLC EARLY AT 08Z THIS MORNING. FRONT WILL MAKE SLOW PROGRESS
EASTWARD DURING THE DAY AS UPPER TROF DEEPENS OVER THE SOUTHWEST.
STRENGTHENING SURFACE GRADIENT AND 7H WINDS TO NEAR 50 KNOTS THIS
AFTERNOON POINTS TO WIND EVENT FOR NORTHEAST UTAH AND NORTHWEST
CO. COMBINE VIRGA OR LIGHT SHOWERS DURING THE AFTERNOON AND WIND
GUSTS TO OVER 75 MPH IN THE MOUNTAINS OR NEAR 60 MPH IN THE VALLEYS
SEEMS PROBABLE. THEREFORE...WILL HOIST HIGH WIND WARNING FOR THOSE
AREAS. ADJOINING ZONES TO THE EAST HAVE LESS CHANCE OF SEEING WINDS
OF THIS STRENGTH...BUT STILL VERY WINDY AND WILL USE WIND ADVISORY
FOR THOSE ZONES (DETAILS AT THE BOTTOM). MEANWHILE...WAA AHEAD OF
THE FRONT POINTS TO ANOTHER WARM...DRY DAY. MOS GUIDANCE APPEARS TO
BE A GOOD FIRST GUESS. THIS...OF COURSE...BRINGS FIRE DANGER TO
HIGH LEVEL AND WILL ENCOURAGE ISSUANCE OF BROAD RED FLAG WARNING FOR
TODAY.

AS THE TROF BEGINS TO SHIFT EASTWARD OVERNIGHT FRONT GETS MOVING
EASTWARD. STRONG CAA AND VIGOROUS LIFT ALONG THE FRONTAL BOUNDARY
POINTS TO CATEGORICAL POPS MOST LOCATIONS TONIGHT. THIS BRINGS
ISSUE OF SNOW ACCUMULATIONS FOR THE MOUNTAINS TO LIGHT. STEEP LAPSE
RATES...VIGOROUS LIFT ALONG THE FRONT AIDED BY JET SHOULD YIELD
CONVECTIVE SNOWS WITH RATES OF 2 TO 3 INCHES PER HOUR BRIEFLY FOR
THE NORTHERN MOUNTAINS. MITIGATING FACTOR IS 7H TEMPERATURES WHICH
WILL NOT DIP TO BELOW ZERO FOR THE NORTH-CENTRAL MOUNTAINS OF CO
UNTIL LATE TONIGHT. EXCEPTION IS UTZ023 WHICH WILL SEE GOOD SHOT OF
DYNAMICS AND COLD AIR THIS EVENING...WANING LATER TONIGHT.
CONSEQUENTLY...WILL ISSUE SNOW AND BLOWING SNOW ADVISORY FOR UTZ023
WILL ADD ACCUMULATIONS TO REMAINDER OF THE NORTHERN MOUNTAINS FOR
LATER TONIGHT. POSSIBILITY OF ADVISORY LEVEL SNOWS FOR OTHER
MOUNTAIN ZONES LESS CLEAR AND WILL HAVE DAY SHIFT TAKE ANOTHER LOOK
AT FORECAST FOR TONIGHT.

SYSTEM PUSHES THROUGH THE REMAINDER OF CO ON TUESDAY WITH DECREASING
SHOWERS IN THE AFTERNOON. 7H TEMPERATURES SIGNIFICANTLY COOLER AND
WILL GENERALLY FOLLOW MOS GUIDANCE OR BELOW MOST LOCATIONS. WEAK
WAA AND SHORTWAVE AHEAD OF NEXT SYSTEM WILL BRING SOME CLOUDS TO THE
NORTH...BUT NO PRECIPITATION TUESDAY NIGHT. GRADIENT WINDS SHOULD
HELP OFFSET COOLING OVERNIGHT...SO FROST IN GROWING AREAS NOT
ANTICIPATED. NL

WEDNESDAY-SUNDAY:  MEDIUM RANGE MODELS STILL SPLIT ON HANDLING OF
TROUGH OVER WESTERN U.S. THIS WEEK.  ON THE PROGRESSIVE SIDE ARE THE
MRF AND UK...MOVING THE TROUGH EAST OF THE AREA BY WEEKS END.  THE
EC...CANADIAN AND NOGAPS CONTINUE TO CUTOFF A LOW OVER CA/NV
KEEPING THE LOW TO OUR WEST THROUGH THE END OF THE WEEK. THEREFORE
CONFIDENCE CONTINUES TO BE LOW...ESPECIALLY IN THE LATER PERIODS.
WILL CONTINUE TO BROADBRUSH WITH CHANCE/SLIGHT CHANCE FOR MOST OF THE
PERIOD KEEPING THE LATER DAYS DRY. WILL TREND WED A LITTLE DRIER DUE
TO THE SLIGHTLY SLOWER SOLUTION ON THE PROGRESSIVE SIDE AND WILL ADD
CHANCE TO FRI FOR THE SAME REASON.  WILL NOT CHANGE TEMPERATURE
FORECAST MUCH AT THIS TIME...HOWEVER IF THE CUTOFF SOLUTION
VERIFIES...FORECAST WILL PROBABLY BE TOO COOL DUE TO WARM SOUTHERLY
FLOW OVER THE CENTRAL ROCKIES.  HEFFERNAN

EMERGENCY MANAGERS IN NORTHEAST UTAH AND NORTHWEST COLORADO SHOULD
MAINTAIN A HIGH LEVEL OF WEATHER AWARENESS THIS AFTERNOON DUE TO
HIGH WINDS...DRY FUELS AND SCATTERED DRY LIGHTNING THIS AFTERNOON.
THESE CONDITIONS WILL BRING A SERIOUS WILDFIRE THREAT TO MUCH OF
NORTHEAST UTAH AND NORTHWEST COLORADO. OTHER EMERGENCY MANAGERS IN
WESTERN COLORADO AND EASTERN UTAH SHOULD MAINTAIN A HEIGHTENED LEVEL
OF WEATHER AWARENESS THIS AFTERNOON FOR STRONG WINDS AND DRY FUELS...
THOUGH LIGHTNING IS UNLIKELY.

.GJT...HIGH WIND WARNING THIS AFTERNOON FOR UTZ023.
       HIGH WIND WARNING THIS AFTERNOON AND EVENING FOR COZ001-003
         AND UTZ024-025.
       WIND ADVISORY THIS AFTERNOON AND EVENING FOR COZ002-004-
         005-006-007-008-009-011-013-017-020 AND UTZ027-028-029.
       SNOW AND BLOWING SNOW ADVISORY FOR UTZ023 TONIGHT.