Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 010233
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
833 PM MDT FRI OCT 31 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
UPDATE...
IR SATELLITE IMAGERY CURRENTLY SHOWS SOME HIGH CLOUDINESS ACROSS
WESTERN PORTIONS OF THE CWA AND GRADUALLY PUSHING EAST. CHANGES
THIS EVENING REFLECT THESE OBSERVATIONS AND NEAR TERM
EXPECTATIONS. ALSO INCLUDED MORE MESOSCALE DETAIL IN THE WIND
GRIDS. OTHERWISE A QUIET HALLOWEEN NIGHT IS IN STORE WITH
TEMPERATURES FALLING THROUGH THE 30S LATER TONIGHT WITH WINDS
BECOMING LIGHT. MALIAWCO

PREVIOUS SHORT TERM DISCUSSION...
AS AREA WINDS NEAR FORT PECK LAKE HAVE NOW DIMINISHED BELOW 15 MPH
WITH A RELAXING PRESSURE GRADIENT AND THE LOSS OF DAYTIME
HEATING...CHOSE TO CANCEL THE LAKE WIND ADVISORY JUST PREVIOUS TO
ITS EXPIRATION THIS EVENING. EXPECT WINDS TO CONTINUE TO DIMINISH
THROUGH TONIGHT. BMICKELSON

PREVIOUS SHORT TERM DISCUSSION...MAIN FORECAST CHALLENGE CENTERS
ON THE NEXT UP- COMING STORM SYSTEM FROM THE SOUTHWEST TOWARD THE
END OF THIS WEEKEND. RECENT MODEL RUN UPDATES INDICATE A SLOWER
AND MORE DELAYED ONSET OF PRECIPITATION BEGINNING SATURDAY NIGHT
THAN WHAT WAS EARLIER ANTICIPATED.

OVERALL EFFECT WILL BE TO SEE RAIN BEGINNING LATE SATURDAY NIGHT
FOR SOME ISOLATED WESTERN AND NORTHERN LOCATIONS OF OUR
CWA...BECOMING A BIT MORE WIDESPREAD ACROSS OUR NORTHWESTERN
ZONES BY SUNDAY EVENING...THEN CHANGING OVER TO SNOW OVERNIGHT
SUNDAY NIGHT THROUGH EARLY MONDAY MORNING.

NOTEWORTHY IS THAT THE RECENT MODEL RUNS HAVE BEGUN TO SHOW MORE
OF A DRY-SLOT FOR THIS STORM SYSTEM OVER MORE OF OUR SOUTHERN AND
EASTERN ZONES...ESPECIALLY BEFORE THE FINISHING BACKSIDE OF THE
STORM PUSHES THROUGH THE CWA MONDAY MORNING. TRIED TO SCALE BACK
THE POPS AND PRECIP AMOUNTS TO REFLECT THIS THINKING THERE.

LOCATIONS MOST FAVORABLE FOR ACCUMULATING SNOW WILL BE THE HIGHER
ELEVATIONS OF THE LITTLE ROCKIES AND NORTHERN VALLEY COUNTY...AND
THESE WILL BE ISOLATED AT BEST. MAYBE UP TO 2 INCHES AROUND THE
ZORTMAN MINE AND UP TO 1 INCH NEAR OPHEIM. EXPECTING LESS THAN A
HALF INCH ELSEWHERE. SNOW FORECASTING PARAMETER ANALYSIS INDICATES
THAT A RAIN AND SNOW MIX IS MOST LIKELY GIVEN WET BULB TEMPS NOT
QUITE COLD ENOUGH AND 1000-500 MB THICKNESSES NOT QUITE LOW
ENOUGH. ALTHOUGH...TOWARD THE END OF THE STORM SYSTEM...MONDAY
MORNING COULD SEE THESE PARAMETERS BRIEFLY FAVOR ACCUMULATING
SNOW. BMICKELSON


.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
BIGGEST CHANGES WERE MADE EARLY IN THE PERIOD AS 12Z MODELS SHOWED A
LITTLE BIT OF A DRIER TREND FOR SUNDAY NIGHT AND MONDAY. LOWERED
POPS ACCORDINGLY. REST OF FORECAST WAS LEFT ALONE. TFJ

PREVIOUS DISCUSSION...
A 00Z RUN OF THE MODEL GUIDANCE HAS COME IN WITH A MORE
NORTHWESTWARD PROGRESSION OF THE UPPER LEVEL LOW AS IT TRACKS
NORTHEAST ACROSS SOUTHERN SASKATCHEWAN ON SUNDAY NIGHT. OVERNIGHT
LOWS MAY SUPPORT A MIX WITH AND CHANGE TO SNOW AS THIS SYSTEM
ABRUPTLY MOVES NORTHEAST...HOWEVER...GIVEN THE FAST MOTION...DO
NOT SEE SUPPORT FOR MUCH ACCUMULATION. RIGHT NOW THE LITTLE ROCKY
MOUNTAINS AND PLACES ALONG THE INTERNATIONAL BORDER SUCH AS OPHEIM
STAND THE GREATEST CHANCE AT SEEING LIGHT SNOWFALL ACCUMULATIONS.
A MIX OF RAIN AND SNOW MAY CONTINUE INTO EARLY MONDAY AS THE
SYSTEM TRANSLATES FAR ENOUGH AWAY THAT IT LOSES INFLUENCE ON THE
CWA. HAVE TRENDED POPS AND QPF AMOUNTS DOWN SOME WITH THIS PACKAGE
GIVEN MODEL TRENDS SHIFTING NORTHWEST...HOWEVER...AM CAUTIOUS
GIVEN THAT THIS PORTION OF THE EVENT IS STILL A FEW DAYS AWAY AND
MODEL SOLUTIONS CAN CERTAINLY WOBBLE OVER THE NEXT FEW CYCLES.
CONFIDENCE WILL CERTAINLY INCREASE IF FUTURE RUN TO RUN
CONSISTENCY BECOMES ESTABLISHED.

AN UPPER LEVEL RIDGE WILL BECOME ESTABLISHED OVER THE WESTERN U.S.
DRIVING NORTHWEST FLOW ALOFT OVER MUCH OF MONTANA THROUGH MUCH OF
THE UPCOMING WEEK. WILL HAVE AN UPWARD TREND IN TEMPERATURES
DURING THE PERIOD AND MAINTAIN DRY CONDITIONS FOR NOW AS
PRECIPITATION CHANCES WILL BE MINIMAL OTHER THAN SUBTLE AND
MOISTURE-STARVED SHORTWAVES THAT MAY BE EMBEDDED IN THE UPPER
FLOW. MALIAWCO

&&

.AVIATION...
FLIGHT CATEGORY: VFR.

SYNOPSIS: A LOW OVER CENTRAL CALIFORNIA WILL CONTINUE TO TRACK
TOWARDS THE REGION THIS TERMINAL CYCLE. EXPECT HIGHS CLOUDS TO
SLOWLY LOWER HOWEVER REMAIN VFR THROUGH 00Z SATURDAY. PROTON


&&

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

&&

$$

WEATHER.GOV/GLASGOW





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