FXUS65 KGGW 260957
AFDGGW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
257 AM MST SAT DEC 26 2009
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH MONDAY...
A MAJOR WINTER STORM CONTINUES OVER THE DAKOTAS AND POINTS EAST
THIS MORNING. THE WESTERN EDGE OF THE STORM AFFECTING AREAS AS FAR
WEST AS SIDNEY AND GLENDIVE AT 10Z. WILL MAINTAIN CURRENT WINTER
WEATHER HEADLINES FOR WINTER STORM WARNING FOR WIBAUX COUNTY AND
SNOW AND BLOWING SNOW ADVISORY FOR EASTERN ROOSEVELT...RICHLAND...
DAWSON AND PRAIRIE COUNTIES THROUGH THIS AFTERNOON. THE STORM WILL
GRADUALLY MOVE TO THE EAST TODAY ENDING THE SNOW. NORTHWEST WINDS
20 TO 30 MPH WITH HIGHER GUSTS WILL KEEP THE SNOW BLOWING WITH
VISIBILITY LESS THAN A HALF MILE INTO AT LEAST THIS AFTERNOON AS
THE SURFACE GRADIENT FROM SURFACE LOW OVER WISCONSIN EXTENDS INTO
EASTERN MONTANA. I-94 IS CURRENT CLOSED FROM GLENDIVE MT ALL THE
WAY TO THE MINNESOTA BORDER.
TO THE WEST...THERE IS ENOUGH NORTHWEST WIND TO MAINTAIN CURRENT
WIND CHILL ADVISORY FOR THIS MORNING. WITH WIND SPEEDS AROUND 10 MPH AT
MALTA...SACO AND WHITEWATER...WILL ADD MOST OF PHILLIPS COUNTY TO
WIND CHILL ADVISORY FOR THIS MORNING. TEMPERATURES SHOULD WARM
ENOUGH DURING THE DAY TO ALLOW THIS ADVISORY TO EXPIRE AT 18Z.
THE STORM SYSTEM MOVES EAST TONIGHT AND SURFACE HIGH TAKES OVER
DIMINISHING THE WINDS. THE SURFACE HIGH WILL PREVAIL OVER EASTERN
MONTANA THROUGH MONDAY WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. WHILE
APPROACHING UPPER LEVEL HIGH FROM ALBERTA WILL BRING WARMING
ALOFT...RADIATIONAL COOLING UNDER CLEAR SKIES AND LIGHT WINDS WILL
ALLOW FOR A FAIRLY COLD NIGHT WITH MOST VALLEY AREAS HAVING LOWS
BELOW ZERO. EXPECT A SIMILAR SCENARIO SUNDAY NIGHT WITH
TEMPERATURES SLIGHTLY WARMER. THE STRONG LOW LEVEL INVERSION
UNDERNEATH THE WARMING ALOFT WILL ALSO KEEP VALLEY AREAS MUCH
COLDER THAN RIDGE AREAS FOR HIGHS ON SUNDAY AND MONDAY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
WEAK UPPER RIDGING OVER THE REGION WILL BE INTERRUPTED BY A
CLIPPER/SHORT WAVE EJECTING OUT OF THE SOUTHERN CANADIAN ROCKIES
TUESDAY. THE MODELS DISAGREE WITH ITS TRACK BUT THE MAIN EFFECTS
APPEAR TO BE SENDING A WEAK COLD FRONT ACROSS THE ZONES AND
CHANGING SOUTHWESTERLY WINDS TO THE NORTHWEST. NOT ENOUGH
MOISTURE TO CAUSE ANY PRECIPITATION BUT TEMPERATURES WILL BE
KNOCKED DOWN A BIT AND DO NOT RECOVER MUCH FOR MOST OF THE
EXTENDED PERIOD.
THE UPPER TROUGH FURTHER DEVELOPS BEHIND THE SHORTWAVE WEDNESDAY.
A SHARPER COLD FRONT/BOUNDARY WILL DRAPE ACROSS THE CWA WITH MUCH
COLDER AIR TO THE NORTH. LITTLE QPF IS AVAILABLE BUT LIMITED
OVERRUNNING MOISTURE COULD GENERATE LIGHT SNOW ALONG THE COLD
BOUNDARY WEDNESDAY THROUGH THURSDAY. IF ANY SNOW DEVELOPS...IT
WILL LIKELY BE OVER OUR SW ZONES WHILE A STRONG SURFACE HIGH KEEPS
OUR NE DRY. BEEFED POPS UP A BIT WEDNESDAY NIGHT AND THURSDAY.
THURSDAY NIGHT MODELS DEVELOP ANOTHER UPPER RIDGE OVER THE
WEST WHICH WILL MAINTAIN A NORTHERLY FLOW ALOFT AND CONTINUED
COLD...BUT DRY...CONDITIONS. HOWEVER THE RIDGE IS FLATTENED BY THE
NEXT SHORTWAVE TREKKING EAST ACROSS THE PACNW...REACHING NE MT
FRIDAY NIGHT WITH A LITTLE MORE QPF IN TOW FOR THE POSSIBILITY OF
SNOW. SCT
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL AT KGGW AND KOLF THROUGH THE WEEKEND.
SOME BROKEN MID CLOUDS MAY INTERMITTENTLY MOVE THROUGH IN FLOW
AROUND A MONSTER UPPER LOW PRESSURE SYSTEM AFFECTING MUCH OF THE
MIDWEST AND PLAINS. KSDY AND KGDV WILL REMAIN JUST INSIDE THE EDGE
OF THE CLOUDS AND SNOW ROTATING AROUND THE AFOREMENTIONED
SYSTEM...RESULTING IN PREVAILING MVFR CONDITIONS WITH SOME
OCCASIONAL IFR CONDITIONS TODAY. A NORTHWEST WIND WILL PREVAIL AT
ALL SITES TODAY WITH SPEEDS AT KGGW AND KOLF GENERALLY AROUND 15
KT OR LESS. KSDY AND KGDV WILL BE UNDER A TIGHTER PRESSURE
GRADIENT WITH RESULTANT SPEEDS OF GENERALLY 15 TO 25 KT WITH
OCCASIONAL GUSTS 30 KT GENERATING BLOWING SNOW WHICH WILL REDUCE
VISIBILITIES TO AROUND 1 OR 2 MILES. THE STORM SYSTEM WILL PULL
FARTHER EAST THIS EVENING BRINGING VFR TO ALL SITES. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM MST THIS MORNING FOR CENTRAL AND
SOUTHERN VALLEY-DANIELS-SHERIDAN-WESTERN ROOSEVELT-GARFIELD-
MCCONE-NORTHERN VALLEY CENTRAL AND SOUTHEAST PHILLIPS-NORTHERN
PHILLIPS.
WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR
RICHLAND-DAWSON-PRAIRIE-EASTERN ROOSEVELT.
WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR WIBAUX.
&&
$$
WEATHER.GOV/GLASGOW
