Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 020846
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
246 AM MDT THU OCT 2 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
UPPER TROUGH AND COLD FRONT IS CURRENTLY MOVING SOUTH ACROSS
ALBERTA AND SASKATCHEWAN. THE COLD FRONT WILL MOVE SOUTH ACROSS
THE FORECAST AREA THIS MORNING. THE FRONT WILL BRING A CHANCE OF RAIN
SHOWERS AND GUSTY NORTHWEST WINDS. AT THIS POINT... IT LOOKS LIKE
TEMPERATURES WILL STAY WARM ENOUGH FOR MOSTLY RAIN. WILL MAINTAIN
LAKE WIND ADVISORY OVER FORT PECK LAKE TODAY AS TIGHT SURFACE
GRADIENT WILL RESULT IN NW WINDS 20 TO 35 MPH. THE CHANCES FOR
SHOWERS MOVE TO THE EAST THIS AFTERNOON AS HIGH PRESSURE BUILDS
INTO THE AREA.

THE SURFACE HIGH PRESSURE WILL MOVE IN TONIGHT WITH MOSTLY CLEAR
SKIES AND DIMINISHING WINDS. GOOD RADIATIONAL COOLING WILL ALLOW
TEMPERATURES IN MOST AREAS TO PLUMMET INTO THE MID TO UPPER 20S.

ON FRIDAY...A WARM FRONT WILL MOVE EAST INTO CENTRAL MONTANA AS
UPPER RIDGE MOVES INLAND FROM THE PACIFIC. SURFACE HIGH WILL
REMAIN OVER EASTERN MONTANA ALLOWING FOR MOSTLY SUNNY SKIES.

THE WARM FRONT WILL MOVE EAST ACROSS EASTERN MONTANA ON SATURDAY
AS THE UPPER RIDGE BUILDS INTO THE STATE. TEMPERATURES WILL
REBOUND CLOSER TO NORMAL. WILL SEE SOME CLOUDS WITH THE FRONT BUT
NOT ENOUGH MOISTURE EXPECTED FOR ANY PRECIPITATION. FORRESTER

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

SYNOPTIC SET UP... A LARGE TROUGH RUNS FROM NUNAVUT THROUGH
MANITOBA AND INTO THE GREAT LAKES. A LARGE RIDGE IS CENTERED OVER
CALIFORNIA AND ITS INFLUENCE SPREADS OUT OVER THE WESTERN HALF OF
THE CONUS. NORTHEAST MONTANA SETS BETWEEN THESE TWO FEATURES IN
NORTHWEST FLOW ALOFT. UP STREAM THE FLOW PEAKS IN A RIDGE OVER
NORTHERN ALBERTA AND BRITISH COLUMBIA AND THEN BENDS BACK OVER THE
GULF OF ALASKA.

SATURDAY NIGHT THROUGH SUNDAY... CONDITIONS SHOULD WARM SLIGHTLY.
A WEAK MESOSCALE SHORTWAVE IS APPEARING IN THE NORTHWEST FLOW IN
MULTIPLE MODELS BUT PLACEMENT OF THESE SHOWERS IS DIFFICULT TO
DETERMINE. BEST CHANCE CURRENTLY STANDS IN THE FAR NORTHEASTERN
CORNER OF THE CWA AS A NARROW NORTHWEST TO SOUTHEAST ORIENTED BAND
OF SHOWERS. BUT... PLACEMENT OF THIS BAND EAST OR WEST COULD SLIDE
OVER THE ENTIRE CWA OR BACK INTO THE DAKOTAS BY THE TIME THESE
FORECAST PERIODS ARRIVE.

SUNDAY NIGHT THROUGH TUESDAY... MODEL CONFIDENCE HAS INCREASED
SLIGHTLY TO AVERAGE AS VARIOUS MODELS ARE LINING UP ON THICKNESS
HEIGHTS AND RMOP CLIMATE NUMBERS RISE. CURRENTLY FLOW LOOKS LIKE
IT WILL BE DRY AND NORTHWEST THROUGH THESE PERIODS AND PEAKING IN A
WEAK RIDGE MONDAY NIGHT.

TUESDAY NIGHT NIGHT ONWARD... MODEL CONFIDENCE BREAKS DOWN AND
GOES BELOW AVERAGE AS MODEL SPREAD DOES NOT QUALIFY ABOVE
CLIMATOLOGY IN RMOP AND THICKNESS LINES BREAK APART. CHANGE DURING
FUTURE RUNS IN THE LARGE SCALE IS EXPECTED. BEST GUESS AT THIS
TIME IS FOR A WEAK FRONT TO PASS THROUGH THE AREA AS THE WEAK
RIDGE EXIT TO THE SOUTHEAST AND THEN TO SEE FLOW RETURN TO ZONAL
PATTERN. POPS AND TEMPS WERE MODERATED AND TWEAKED TOWARD
CLIMATOLOGY DURING THESE PERIODS. GAH


&&

.AVIATION...
FLIGHT CATEGORY: MAINLY VFR. ISOLATED HIGH MVFR POSSIBLE.

SYNOPSIS: A COLD FRONT WILL MOVE THROUGH NORTHEAST MONTANA DURING THE
MORNING HOURS BRINGING ISOLATED RAIN SHOWERS AND A DRAMATIC WIND
INCREASE.

LOW LEVEL WIND SHEAR: WITH THE RAPID INCREASE IN WINDS DIRECTLY
BEHIND THE FRONTAL PASSAGE... SOME STRONG SHEAR MAY BE POSSIBLE NEAR
THE FRONTAL INTERFACE FROM THE SURFACE UP TO 2000 FT. MODELS HINT
AT THIS ACROSS THE AREA... BUT DO NOT PLACE IT DIRECTLY OVER THE
TERMINALS. THEREFORE CONFIDENCE WAS TOO LOW TO PUT IN THE TAFS.

CEILINGS: WILL LOWER OVER THE NEXT 6 TO 12 HOURS OF THE TAF CYCLE
WITH PERIODS OF BRIEF HIGH MVFR POSSIBLE FROM 14 TO 20Z. FUEL
LOADING IS NOT ANTICIPATED.

SHOWERS: RAIN SHOWERS ARE ANTICIPATED POST FRONTAL PASSAGE... BUT
COVERAGE IS CURRENTLY TOO SPARCE TO PLACE DIRECTLY IN THE TAFS. SO
WILL BE USING VCSH UNTIL RADAR ECHOS ARE PICKED UP FOR BETTER
PLACEMENT AND TIMING. EXPECT AMENDMENTS FOR THIS.

AREA WINDS: LIGHT AND OUT OF THE WEST TONIGHT AHEAD OF THE
FRONT... VEERING TO WEST AND RAMPING UP TO 10 TO 20 KTS DURING THE
MORNING HOURS POST PASSAGE. THEN INCREASING TO SUSTAINED 20 TO 30
KTS... GUSTING TO 40 KTS DURING THE AFTERNOON HOURS. A SLOW RAMP
DOWN OVERNIGHT IS ANTICIPATED BEGINNING AFTER SUNDOWN.

GAH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR CENTRAL AND
SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...GARFIELD...
MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW




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