Area Forecast Discussion
Issued by NWS Glasgow, MT

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000
FXUS65 KGGW 242210
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
310 PM MST MON NOV 24 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...

THE SHORT TERM PERIOD WILL BE RATHER ACTIVE AS AN ALBERTA CLIPPER
ZIPS SOUTHEAST ACROSS NORTHEAST MONTANA LATE TONIGHT AND TUESDAY
MORNING. THERE WILL BE A SHORT BREAK IN THE ACTION LATE TUESDAY.
THEN BEGINNING WEDNESDAY MORNING A FRONTAL BOUNDARY WITH
OVERRUNNING MOISTURE WILL PRODUCE SEVERAL INCHES OF SNOW THAT WILL
CARRY INTO THE EXTENDED PERIOD.

TONIGHT AND TUESDAY...A SHORT-WAVE DISTURBANCE CAN BE SEEN
CROSSING THE CANADIAN ROCKIES AT AROUND 06Z TONIGHT AS A SURFACE
TROUGH DEVELOPS IN THEIR LEE. THIS FAST MOVING DISTURBANCE WILL
SLIDE ACROSS NEMONT SOMETIME AFTER MIDNIGHT THROUGH TUESDAY...WITH
QPF AMOUNTS THAT COULD RESULT IN ONE TO TWO INCHES OF WIDESPREAD
LIGHT SNOW. BY AFTERNOON THE CLOSED SURFACE LOW MOVES INTO THE
DAKOTAS TO RAMP UP NORTHWEST WIND TO AROUND 15KT TO 25KT. ALTHOUGH
MOST OF THE SNOW WILL FALL BEFORE THE WIND RAMPS UP...THE SNOW
WILL BE LOOSE ENOUGH TO BE PICKED UP WITH THE WIND...LIKELY
LEADING TO WIDESPREAD AREAS OF BLOWING SNOW. THE WIND WILL ALSO
BRING ABOUT SOME WARMING SO HIGHS WILL RUN CLOSER TO NORMAL. DUE
TO THE COMBINATION OF AROUND TWO INCHES OF SNOW AND WIND CAUSING
BLOWING AND DRIFTING SNOW...DECIDED TO GO WITH A WINTER WX ADVSRY
FOR SNOW AND BLSN FROM 5AM TO 5PM TUESDAY...PLUS AN NPW FROM 11 AM
TO 5PM FOR FORT PECK LAKE.

TUESDAY NIGHT...LOW STRATUS AND LIGHT SNOW SHOWERS WILL NOT ADD
MUCH TO THE SNOW ACCUMULATION. BUT A SHORT-WAVE TROUGH ROTATING
AROUND THE HUDSON BAY ARCTIC LOW WILL BACKDOOR A COLD FRONT TO
CAUSE OVERNIGHT TEMPERATURES TO FALL TO AROUND NORMAL.

WEDNESDAY...THE PRE-THANKSGIVING TRAVEL WILL BE FURTHER IMPACTED
BY THE NEXT STORM. THERE WILL BE A RATHER DISTINCT BOUNDARY
BETWEEN THE ARCTIC AIR-MASS TO THE EAST AND THE WARMER AIR IN THE
WEST. OVERRUNNING THIS BOUNDARY WILL BE A SIGNIFICANT AMOUNT OF
MOISTURE THAT WILL GREATLY IMPACT WESTERN AND CENTRAL MONTANA
TUESDAY AND TUESDAY NIGHT. BY WEDNESDAY MORNING THIS BOUNDARY WILL
HAVE MOVED NORTHEAST INTO THE WESTERN AREAS OF OUR CWA. SOME EARLY
MORNING LIGHT SNOW WILL HAVE ALREADY HAVE AFFECTED PETROLEUM
COUNTY AND SW PHILLIPS COUNTY. THIS OVERRUNNING EVENT MOVES
FURTHER INTO THE CWA DURING THE DAY. SINCE THE SNOW WILL STAY
CLOSE TO THE BOUNDARY AND THE BOUNDARY ONLY SLOWLY MOVES
NORTHEAST...SNOW AMOUNTS WILL BE GREATEST IN THE SOUTHWEST ZONES
AND TAPER OFF FURTHER TO THE NORTHEAST...AFFECTING AROUND HALF THE
CWA. DANIELS...SHERIDAN... ROOSEVELT AND RICHLAND COUNTIES MIGHT
NOT SEE MUCH PRECIPITATION. FOR NOW WENT WITH A WINTER WX WATCH
BEGINNING 5AM WEDNESDAY MORNING THAT CARRIES INTO THE THE EXTENDED
PERIOD FOR ALL COUNTIES IN THE SW HALF OF THE CWA. IF TRENDS
CONTINUE THE HEAVIEST SNOW WILL OCCUR IN SW PHILLIPS...PETROLEUM
AND WESTERN GARFIELD COUNTIES...UP TO 6 OR 7 INCHES.

SCT


.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE BULK OF THE CHANGES FOR THIS AFTERNOONS UPDATE REVOLVED AROUND
THE UPCOMING MIDWEEK STORM. CONDITIONS CONTINUE TO LOOK FAVORABLE
FOR FREEZING RAIN LATE WEDNESDAY NIGHT INTO THURSDAY. ALTHOUGH
AMOUNTS LOOK ON THE LIGHT SIDE...FELT IT PRUDENT WITH UPCOMING
THANKSGIVING HOLIDAY TRAVEL TO HIGHLIGHT THE THREAT WITH A WINTER
STORM WATCH FOR FREEZING RAIN. OTHER CHANGES WERE MAINLY TO TREND
UP POPS GIVEN MODERATE CONFIDENCE. THE REMAINDER OF THE FORECAST
WAS LARGELY UNCHANGED. GILCHRIST

PREVIOUS DISCUSSION...NORTHWEST FLOW WITH OVERRUNNING
PRECIPITATION FOR MIDWEEK EXPECTED TO TRANSITIONS TO A BRIEF
WARMING CHINOOK BEFORE ANOTHER ARCTIC AIRMASS CLIPS THE REGION FOR
THE WEEKEND. MODELS IN REASONABLE AGREEMENT WITH PACIFIC RIDGE
FLATTENING OUT AND MOVING EAST AS A SHORTWAVE TROF DROPS SOUTH
ALONG THE CANADIAN ROCKIES. AS THE UPPER FLOW TURNS TO THE WEST
AND SPREADS WARM AIR ACROSS THE DIVIDE...THE FRONTAL BOUNDARY WILL
LIFT EASTWARD WEDNESDAY NIGHT AND THURSDAY. WITH THE WARM AIR
MOVING EAST...EXPECT A TRANSITION FROM SNOW TO RAIN OR FREEZING
RAIN BEFORE THE PRECIPITATION ENDS.

WARM FRONT EXPECTED TO BE ORIENTED EAST-WEST NEAR THE CANADIAN
BORDER THURSDAY NIGHT AND FRIDAY WITH WARM AND DRIER AIR IN PLACE.
ALSO ON FRIDAY THE CANADIAN ROCKIES SHORTWAVE BEGINS TO MAKE ITS
TURN TO THE EAST...SENDING A CLIPPER TOWARD THE NORTHERN PLAINS.
COLD FRONT DROPS INTO EASTERN MONTANA FRIDAY NIGHT PULLING MUCH
COLDER AIR BACK INTO THE STATE FOR SATURDAY AND SUNDAY. EBERT

&&

.AVIATION...
SYNOPSIS: DISTURBANCES IN A NORTHWEST FLOW ALOFT WILL KEEP
ISOLATED SNOW SHOWERS IN THE FORECAST THROUGH THIS EVENING. LATE
TONIGHT INTO TUESDAY A STRONGER UPPER TROUGH WILL PUSH THROUGH
CREATING GOOD POTENTIAL FOR SNOW SHOWERS...AND PERIODS OF POOR
FLYING WEATHER INTO TUESDAY.

CIGS: BKN MID AND HIGH CLOUDS TODAY AND TONIGHT. BKN-OVC LOW
CLOUDS WITH SNOW EARLY TUESDAY MORNING...IMPROVING BY MIDDAY
TUESDAY.

VISIBILITY: UNRESTRICTED OUTSIDE OF SNOW SHOWERS THROUGH THIS
EVENING. RESTRICTIONS TO IFR LEVELS POSSIBLE WITH SNOW ON
TUESDAY.

WINDS: NORTHWEST 5-10KTS TODAY...BECOMING SOUTHWEST LATE
TONIGHT...BEFORE GOING WESTERLY AND INCREASING TO 13 TO 18KTS ON
TUESDAY.

GILCHRIST


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST TUESDAY FOR
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
DANIELS...DAWSON...EASTERN ROOSEVELT...GARFIELD...MCCONE...
NORTHERN PHILLIPS...NORTHERN VALLEY...PETROLEUM...PRAIRIE...
RICHLAND...SHERIDAN...SOUTHWEST PHILLIPS...WESTERN ROOSEVELT...
WIBAUX.

WINTER STORM WATCH FROM LATE TUESDAY NIGHT THROUGH THURSDAY
AFTERNOON FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND
SOUTHERN VALLEY...GARFIELD...MCCONE...NORTHERN PHILLIPS...
PETROLEUM...PRAIRIE...SOUTHWEST PHILLIPS.

LAKE WIND ADVISORY FROM 11 AM TO 5 PM MST TUESDAY FOR FORT PECK
LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.

WINTER STORM WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
AFTERNOON FOR DANIELS...DAWSON...EASTERN ROOSEVELT...NORTHERN
VALLEY...RICHLAND...SHERIDAN...WESTERN ROOSEVELT...WIBAUX.

&&

$$

WEATHER.GOV/GLASGOW




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