High Wind in Utah, October 23, 2001

UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SALT LAKE CITY UT
330 AM MDT TUE OCT 23 2001

.SYNOPSIS...A COLD FRONT WILL MOVE INTO NORTHERN UTAH THIS MORNING
AND ACROSS THE STATE DURING THE DAY.  IT WILL BRING MUCH COOLER AIR
WITH LIMITED MOISTURE. COOL NORTHWEST FLOW WILL CONTINUE OVER THE
INTERMOUNTAIN REGION WEDNESDAY.

.DISCUSSION...INITIAL VORT MAX WORKING OUT OF GULF OF ALASKA LOW AT
LEADING EDGE OF JET PUSHING INTO WESTERN MONTANA THIS MORNING.  UPPER
LEVEL WARM FRONT HAS PASSED STATE OVERNIGHT WITH SOME MID LEVEL
CLOUDINESS AND ISOLATED SHOWERS IN THE NORTH.  THE COLD FRONT WILL
PUSH INTO NORTHWEST UTAH LATER THIS MORNING AND THROUGH THE WASATCH
FRONT BY NOON.  GOOD AMOUNT OF COLD AIR BEHIND FRONT AS EVIDENT BY
OPEN-CELLULAR CUMULUS OFF PACIFIC COAST THIS MORNING.  JET ORIENTED
FROM PACIFIC NORTHWEST INTO WESTERN WYOMING WITH SECOND WAVE ALONG
THE JET MOVING INTO PACIFIC NORTHWEST.  JET BECOMES MORE NORTHWEST TO
SOUTHEAST ORIENTED THIS AFTERNOON FROM SEA-EVW AS SYSTEM BEGINS TO
DROP ALONG THE CONTINENTAL DIVIDE IN WYOMING.

FIRST WAVE AND SURFACE LOW INTO NORTHERN PLAINS BY THIS EVENING.
COLD FRONT SHOULD BE THROUGH THE STATE BY THIS TIME AS WELL.  STRONG
SURFACE HIGH PRESSURE BEHIND FRONT WITH STRONG GRADIENT.  COMBINED
WITH STRONG FLOW AT 700MB...SURFACE WINDS WILL BECOME QUITE BREEZY
ACROSS MUCH OF THE STATE...ESPECIALLY WITH THE FRONT.  DO NOT BELIEVE
WE WILL REACH ADVISORY LEVELS. AS THE FRONT REACHES EXTREME SOUTHWEST
UTAH TONIGHT...PRESSURE GRADIENT AND LOW LEVEL TEMP ADVECTION COULD
CREATE NEAR ADVISORY LEVEL WINDS IN THE GAPS IN WASHINGTON COUNTY AS
WELL.

EVEN THOUGH THE LOW LEVEL FLOW IS FAVORABLE FOR OROGRAPHIC
ENHANCEMENT OF PRECIP...INSTABILITY CAPPED AT ROUGHLY 600MB THIS
AFTERNOON.  THIS WILL NOT LOWER MUCH THROUGH THE NIGHT WITH LOW LEVEL
INSTABILITY REMAINING.  IN EFFECT...LAKE EFFECT SHOWERS COULD DEVELOP
OVERNIGHT TONIGHT.  MM5 SUGGESTS THIS AS WELL WITH GOOD LOW LEVEL
CONVERGENCE OVER THE LAKE. MM5 ALSO POINTS TO NOT MUCH PRECIPITATION
IN THE VALLEYS OUTSIDE OF FRONTAL PASSAGE. SINCE THE DEPTH OF THE
INSTABILITY AND LATE ARRIVAL OF COLDER AIR...NORTHERN MOUNTAINS WILL
NOT SEE MUCH (BELOW ADVISORY LEVELS) IN THE WAY OF SNOWFALL
ACCUMULATIONS.  DO NOT EXPECT ANY PRECIP WITH THE FRONT TO REACH PAST
THE CENTRAL MOUNTAINS TODAY WITH THE UPPER LEVEL SUPPORT FROM THE JET
LOST FARTHER SOUTH.

AS THE STORM CONTINUES TO DIG INTO THE PLAINS TUESDAY NIGHT AND
WEDNESDAY...THE FLOW TURNS MORE NORTHERLY AND DRIVES EVEN COLDER AIR
THROUGH THE FORECAST AREA.  JET LIFTS NORTH AS RIDGE BEGINS TO BUILD
THROUGH THE DAY.  AIR MASS REALLY STABLE BY THIS TIME...BUT A FEW
MOUNTAIN SHOWERS ISNT OUT OF THE QUESTION.  A DRY AND COLD NORTHWEST
FLOW WILL REMAIN THROUGH THURSDAY AS THE RIDGE CONTINUES TO BUILD
OVER THE WEST.  THE RIDGE AXIS APPROACHES THE AREA FRIDAY WITH A
FAIR AMOUNT OF WARMING AT THE MID LEVELS.   BY THE WEEKEND...RIDGE
OVER THE ROCKIES WITH A TROUGH IN THE EASTERN PACIFIC.  A SHORT WAVE
TROUGH MAY EXIT THIS LOW SUNDAY OR MONDAY BRINGING SOME CLOUDINESS
AND A SLIGHT CHANCE FOR PRECIP MONDAY.  FOR NOW...WILL LEAVE PARTLY
CLOUDY IN THE FORECAST AS TIMING AND STRENGTH IN DOUBT.

SLC 420 CDC 000  NELSON

.SLC...NONE.