Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 251458
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
858 AM MDT SAT OCT 25 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH MONDAY...

MORNING UPDATE...
FEW CHANGE TO THE FORECAST THIS MORNING. MOST CHANGES WERE TWEAKS
TO WIND FIELDS AND SKY COVERAGE. A RIDGE ALOFT WILL MOVE THROUGH
THE AREA BRINGING CLEARING SKIES. RIDGE IS EVIDENT ON SATELLITE
WITH CLOUDS STRETCHING FROM NEVADA TO WESTERN MONTANA AND THEN
ARCHING BACK TO WESTERN NORTH DAKOTA. GAH


PREVIOUS SHORT TERM DISCUSSION...
AN UPPER LEVEL RIDGE WILL BRING WARM AND DRY WEATHER TO EASTERN
MONTANA TODAY. WILL SEE SOME MID AND HIGH CLOUDS AT TIMES SPILLING
OVER THE RIDGE ESPECIALLY IN THE NORTH. WITH HIGH PRESSURE SYSTEM
MOVING TO THE EAST AND LOW PRESSURE SYSTEM MOVING INTO THE PACIFIC
NORTHWEST TODAY...SOUTHEAST WINDS WILL DEVELOP BY AFTERNOON AS
SURFACE GRADIENT TIGHTENS. WIND SPEEDS MAY APPROACH LAKE WIND
ADVISORY CRITERIA THIS AFTERNOON AND EVENING. IT IS MARGINAL AT
THIS TIME WILL HOLD OFF ON ISSUING LAKE WIND ADVISORY FOR TODAY.

FLOW ALOFT TURNS TO THE SOUTHWEST TONIGHT AHEAD OF AN UPPER TROUGH
THAT MOVES INLAND FROM THE PACIFIC. WINDS WILL DIMINISH OVERNIGHT
AS A PREFRONTAL SURFACE TROUGH MOVES THROUGH THE FORECAST AREA.

THE FIRST OF 2 COLD FRONTS MOVES THROUGH EASTERN MONTANA SUNDAY
MORNING. WITH THE MAIN SURFACE LOW IN SASKATCHEWAN...WINDS WILL TURN
TO THE WEST AND BECOME GUSTY BY AFTERNOON. GOOD SURFACE MIXING
WILL COMPENSATE MOST OF THE COLD AIR ADVECTION SO THAT SUNDAY WILL
BE NEARLY OR EQUALLY WARM AS TODAY. A LAKE WIND ADVISORY IS LIKELY
FOR FORT PECK LAKE SUNDAY AFTERNOON. A SHORTWAVE WITHIN THE
SOUTHWEST FLOW ALOFT MAY COMBINE WITH MARGINALLY UNSTABLE AIRMASS
IN THE SOUTH FOR A SLIGHT CHANCE OF THUNDERSTORMS IN THE
AFTERNOON.

THE UPPER TROUGH MOVES INTO THE AREA SUNDAY NIGHT WITH THE SECOND
COLD FRONT. WINDS WILL TURN TO THE NORTHWEST LATE SUNDAY NIGHT AND
A BAND OF MOISTURE ASSOCIATED WITH THE UPPER TROUGH WILL MOVE IN
TO NORTHEAST MONTANA BY MONDAY MORNING. TEMPERATURES WILL BECOME
COLD ENOUGH NEAR THE CANADIAN BORDER LATE SUNDAY NIGHT AND ACROSS
MOST OF NORTHEAST MONTANA MONDAY MORNING FOR A MIX OF RAIN AND
SNOW. 850 MB TEMPERATURES FALL TO -2 TO -3C ON MONDAY WHICH IS
COLD ENOUGH FOR SNOW. HOWEVER... GOOD MIXING WILL KEEP SURFACE
TEMPERATURES FAR ENOUGH ABOVE FREEZING IN MOST AREAS AND MODELS
KEEP MOISTURE PROFILE WARMER THAN -10C FOR THE MOST PART WHICH
LIMITS THE AMOUNT OF ICE CRYSTALS NECESSARY FOR SNOW TO DEVELOP.
WILL KEEP PRECIP TYPE AS EITHER RAIN MIXED SNOW OR ALL RAIN IN
MOST AREAS. WILL MAKE AN EXCEPTION FOR A FEW HIGHER ELEVATION
AREAS LIKE OPHEIM AND ZORTMAN THAT ARE PRONE TO RECEIVING ALL SNOW
IN THIS SCENARIO. LOOK FOR A COLD AND BLUSTERY DAY ON MONDAY.  FORRESTER


.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...

BY MONDAY NIGHT...THE COLD LOW PRESSURE TROUGH WILL BE ON THE WAY
OUT OF OUR CWA...LEAVING A FEW TRAILING AREAS OF LIGHT
PRECIPITATION OVER OUR EASTERN AND NORTHEASTERN ZONES. 850 MB
TEMPERATURES AND 1000-500 MB THICKNESSES ARE BOTH SUPPORTIVE OF
SNOWFALL...BUT SURFACE WET-BULB TEMPERATURES ARE NOT QUITE COLD
ENOUGH AND MAY BE MORE INDICATIVE OF A RAIN-SNOW MIX. ALTHOUGH
DURING THE EVENING AND OVERNIGHT HOURS...CONDITIONS TO SUPPORT
SNOW COULD BE A BIT MORE LIKELY. AS THE GROUND HAS NOT HAD A
CHANCE TO FREE AND STILL REMAINS RELATIVELY WARM...DO NOT EXPECT
MUCH IN THE WAY OF ACCUMULATION. MAYBE A TRACE TO LESS THAN 0.25
INCH.

TUESDAY MORNING THROUGH TUESDAY AFTERNOON...A SHORT-WAVE RIDGE
WILL LIKELY ALLOW DAYTIME TEMPERATURES TO THAW AGAIN AND PRECIP TO
BE DRIVEN AWAY FROM THE AREA. ALTHOUGH IT SHOULD BE NOTED THAT
THIS SPECIFIC TIME PERIOD IS WHEN THE GFS ENSEMBLE SPREAD SHOWS THE
MOST UNCERTAINTY AND LEAST CONFIDENCE.

LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...AN EMBEDDED SHORT-
WAVE DISTURBANCE WILL RESULT MAINLY IN SOME CLOUDY SKIES. MODEL
NOT VERY BULLISH ON MOISTURE AT THIS TIME.

THURSDAY AND BEYOND...MODELS IN PRETTY GOOD AGREEMENT SHOWING A
HIGHLY AMPLIFIED UPPER LEVEL RIDGE KEEPING PRECIP AWAY FROM THE
REGION AS TEMPERATURES WARM UP AGAIN TO SLIGHTLY ABOVE NORMAL
LEVELS FOR THIS TIME OF YEAR. BMICKELSON

&&

.AVIATION...

FLIGHT CATEGORY: VFR.

SYNOPSIS: AN UPPER-LEVEL RIDGE OF HIGH PRESSURE WILL MOVE ACROSS
THE AREA. PERIODS OF PARTLY CLOUDY AND CLEAR SKIES ARE EXPECTED
THROUGH THE TAF PERIOD.

AREA WINDS: OUT OF THE WEST BETWEEN 10 TO 20 KTS THROUGH THE
EVENING... VEERING TO THE SOUTHWEST OVERNIGHT AND WEST LATE IN THE
MORNING.

GAH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW







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