Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 271603
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
903 AM MST THU NOV 27 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
UPDATE...FORECAST LARGELY UNFOLDING AS EXPECTED. FREEZING RAIN
CURRENTLY FALLING ALONG A LINE FROM ROUGHLY THOENY TO JORDAN...AND
PUSHING EAST. ONLY TWEAK WAS TO PUSH FREEZING RAIN MENTION TO THE
CANADIAN BORDER BASED ON THE LATEST ROAD REPORTS. ANTICIPATE
ANOTHER UPDATE AROUND NOON TO CLEAN UP THE HIGHLIGHT PACKAGE. GILCHRIST

PREVIOUS DISCUSSION...WARM FRONT LOCATED OVER CENTRAL MONTANA
EARLY THIS MORNING. BAND OF SNOW EXTENDS AHEAD OF THE FRONT FROM
CENTRAL ALBERTA THROUGH SW SASKATCHEWAN INTO NORTHEAST MONTANA.
THIS OVERRUNNING PRECIP WILL CONTINUE TODAY ACROSS THE FORECAST
AREA AS THE WARM FRONT MOVES INTO NORTHEAST MONTANA. WARMING ALOFT
WILL TURN THE SNOW TO FREEZING RAIN AHEAD OF THE WARM FRONT TODAY.
EXPECT THE TRANSITION FROM SNOW TO FREEZING RAIN TO OCCUR FROM SW
TO NE ACROSS THE AREA. AT THE SAME TIME... THE PRECIPITATION WILL
DIMINISH AS THE WARM FRONT MOVES THROUGH. AT THIS POINT... IT
LOOKS LIKE THE SWITCH FROM SNOW TO FREEZING RAIN WILL OCCUR AS FAR
EAST AS WHITEWATER... GLASGOW AND WIBAUX BY 18Z AND THROUGH THE
NORTHEAST CORNER OF THE STATE BY EVENING. MEANWHILE... IT LOOKS
LIKE THE WARM FRONT WILL BE NEAR MALTA AND JORDAN BY 18Z AND
WHITEWATER... GLASGOW AND WIBAUX BY EVENING. WHILE HEAVY SNOW IS
NO LONGER EXPECTED... ENOUGH SNOW AND/OR FREEZING RAIN IS EXPECTED
TODAY TO WARRANT MAINTAINING A WINTER WEATHER ADVISORY. WILL
DOWNGRADE WINTER STORM WARNING IN THE SOUTHWEST TO A WINTER
WEATHER ADVISORY MAINLY FOR THE POSSIBILITY OF FREEZING RAIN THIS
MORNING.

THE WARM FRONT BECOMES QUASI-STATIONARY OVER NORTHEAST MONTANA
TONIGHT AND FRIDAY MORNING WITH THE MOISTURE STAYING TO THE NORTH
FOR THE MOST PART. FRIDAY LOOKS TO BE A MILD DAY WITH LIMITED
CHANCES FOR MIXED PRECIPITATION.

SURFACE LOW MOVES ACROSS NORTHEAST MONTANA DURING THE DAY ON
FRIDAY AND WILL START TO BRING THE FRONT BACK SOUTH AS A COLD
FRONT IN THE AFTERNOON. THAT FRONT WILL MOVE TO THE SOUTH FRIDAY
NIGHT WITH STRONG COLD AIR ADVECTION. WHILE THE ATMOSPHERE WILL BE
MOIST... UPPER LEVEL DYNAMICS ARE LIMITED AS SHORTWAVE TROUGH
STAYS TO THE WEST. WILL MENTION A CHANCE OF RAIN AND SNOW FRIDAY
NIGHT.

WITH COLD AIR ADVECTION CONTINUING ON SATURDAY... WILL SEE LITTLE
RISE IN TEMPERATURES AS BITTER COLD AIR MOVES IN. WILL MAINTAIN A
CHANCE OF SNOW WITH BEST CHANCE IN THE SOUTHWEST WHERE UPSLOPE IS
EXPECTED. FORRESTER


.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...

SYNOPTIC SET UP...A STRONG BROAD ARCTIC AIR-MASS EXISTS OVER THE
MAJORITY OF CANADA...MONTANA...THE DAKOTAS...AND THE UPPER
MISSISSIPPI VALLEY. A LARGE WEAK TROUGH SETS BEHIND THIS AIR-MASS
OVER THE PACIFIC NORTHWEST AND OFF THE COAST OF BRITISH COLUMBIA.
FARTHER WEST BEHIND THE TROUGH. A MORE POWERFUL WARM RIDGE LIES
SOUTH OF THE ALEUTIANS.

SATURDAY NIGHT THROUGH SUNDAY...SUPER COLD AIR WILL PASS THROUGH
THE REGION THEN MODIFY WARMER AND EXIT TO THE EAST. 850 MB
TEMPERATURES WILL DROP INTO THE 20 BELOW CELSIUS RANGE DURING THIS
TIME AND THE REMNANTS OF SNOW SHOWERS SHOULD EXIT THE AREA BY
SUNDAY AFTERNOON.

SUNDAY NIGHT ONWARD...CONDITIONS LOOK TO BE DRY THROUGH MOST OF
THESE PERIODS. FLOW WILL TRANSITION TO NORTHWEST AND KEEP MONTANA
ON THE WARMER SIDE OF IT. THE WEAK TROUGH OFF THE COAST OF BRITISH
COLUMBIA WILL MOVE THROUGH THE AREA ON MONDAY NIGHT/TUESDAY BUT
MODELS ARE HAVING A HARD TIME PLACING ITS PASSAGE...DROPPING
CONFIDENCE IN ANY SORT OF IMPACT WEATHER MAKER. BY WEDNESDAY THE
RIDGE BEGINS TO TAKE HOLD AND RE-SYNCS THE MODELS FAIRLY WELL WITH
PROGRESSIVELY WARMER CONDITIONS.

GAH

&&

.AVIATION...
FLIGHT CATEGORY: VFR TO IFR.

SYNOPSIS: THE NW TO SE ORIENTATED FRONTAL BOUNDARY SITUATED TO OUR
SOUTHWEST IS SLOWLY MOVING NORTHEAST AS A WARM FRONT.
OVERRUNNING MOISTURE FROM THE NW WILL FLOW ALONG THIS BOUNDARY TO
BRING ABOUT CONTINUOUS PRECIPITATION. LIGHT SNOW IS STILL EXPECTED
TO SPREAD ACROSS ALL TERMINALS THIS MORNING WITH PERSISTENT IFR
POSSIBLE. BULK OF THE PRECIPITATION SHOULD BEGIN DIMINISHING AND
EXITING THE TERMINALS NEAR SUNSET.

FREEZING RAIN: THERE IS A SIGNIFICANT THREAT FOR TRANSITION FROM
SNOW TO FREEZING RAIN TODAY WHICH CAN ACCUMULATE ICE ON RUNWAYS
AND AIRCRAFT WINGS. AFTERWARD...FREEZING RAIN IS STILL A
POSSIBILITY THROUGH FRIDAY FOR ALL TERMINALS OTHER THAN KGDV...
BUT CHANCES FOR PRECIPITATION WILL BE TOO LOW FOR NOW TO DECLARE
FZRA IN THE TAFS DIRECTLY.

CEILINGS: BOUNCING BETWEEN VFR AND IFR. 1 TO 2 KFT WITH FUEL
LOADING WILL BE THE MOST COMMON. PERSISTENT CEILINGS BELOW 1KFT
ARE MOST LIKELY ONCE CONTIGUOUS SNOWFALL STARTS. CEILINGS WILL
BEGIN TO IMPROVE NEAR SUNSET AS THE BULK OF PRECIPITATION SLOWS
AND EXITS.

VSBY: VFR TO IFR. MOST COMMON RANGE WILL BE AROUND 4 TO 3SM WITH
CONTINUOUS SNOW. DROPS AS LOW AS 2SM WILL BE POSSIBLE WITH MORE
INTENSE SNOW BANDS.

AREA WINDS: SOUTHEAST AROUND 5 TO 15KTS...VEERING FURTHER TO THE
SOUTHWEST DURING THE LATE AFTERNOON.

BEYOND THE TAF CYCLE: THERE IS A SMALL CHANCE FOR WIDESPREAD FOG
AND LOW STRATUS TONIGHT.

GAH/SCT

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
GARFIELD...MCCONE...NORTHERN PHILLIPS...PRAIRIE.

WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR
PETROLEUM...SOUTHWEST PHILLIPS.

WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR
DANIELS...DAWSON...EASTERN ROOSEVELT...NORTHERN VALLEY...
RICHLAND...SHERIDAN...WESTERN ROOSEVELT...WIBAUX.

&&

$$

WEATHER.GOV/GLASGOW




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