Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 180252 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
752 PM MST WED DEC 17 2014

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

SENT AN UPDATE TONIGHT TO REDUCE POPS AND CLEAR PRECIP OUT TO
FLURRIES...FOLLOWING FORECAST SOUNDING AND LATEST MODEL PRECIP
OUTPUT. ALSO CANCELLED THE DENSE FOG ADVISORY AS AREA OBSERVATIONS
AND SPOTTER REPORT INDICATE THAT THE VISIBILITIES HAVE IMPROVED AND
CLOUD DECK HAS LIFTED ENOUGH TO NO LONGER POSE A THREAT TO THOSE
HIGHER ELEVATION AREAS. A FEW ISOLATED AREAS OF PATCHY MIST OR FOG
MAY BRIEFLY BE POSSIBLE STILL TONIGHT...BUT CONFIDENCE IS LOW.
BMICKELSON

PREVIOUS SHORT TERM DISCUSSION...PATCHY DENSE FREEZING FOG
CONTINUES ACROSS THE OPHEIM AREA THIS AFTERNOON AND WILL HAVE THE
DENSE FOG ADVISORY EXTENDED UNTIL 9 PM. THE NEXT SHIFT CAN MONITOR
TRENDS TO BEST DETERMINE IF OR WHEN FOG MAY LIFT. OTHERWISE EXPECT
LOW STRATUS TO CONTINUE TO PLAGUE THE CWA. WILL CONTINUE WITH
SLIGHT CHANCE POPS OVERNIGHT ACROSS PORTIONS OF THE
REGION...FOLLOWING 12Z NAM GUIDANCE IN PARTICULAR. EXPECT MAINLY
LIGHT SNOW OR PERHAPS A MIX WITH FREEZING RAIN BUT AMOUNTS SHOULD
BE QUITE MINIMAL.

A WEAK UPPER SHORTWAVE WILL PASS ACROSS THE REGION ON THURSDAY AND
THURSDAY NIGHT WITH A SHORTWAVE RIDGE BUILDING IN ON FRIDAY. THIS
WILL BRING ABOUT A WIND SHIFT TO THE WEST...HELPING TO REMOVE
POTENTIAL FOR LOW STRATUS AND FOG GRADUALLY WITH TIME. THUS...THE
TREND TOWARD THE END OF THE WEEK WILL BE FOR DRIER CONDITIONS AND
MODERATING TEMPERATURES. MUCH OF NORTHEAST MONTANA WILL SEE HIGHS
BY FRIDAY MARCH ABOVE FREEZING WITH THE EXCEPTION OF DEEPER VALLEY
LOCATIONS AND PLACES ALONG THE CANADIAN BORDER. MALIAWCO


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE BEST POTENTIAL FOR PRECIPITATION NOW LOOKS TO COME SUNDAY.
POPS WERE RAISED AND THE PRECIPITATION LOOKS TO OCCUR WITH
TEMPERATURES AT OR ABOVE FREEZING BUT THERE WILL BE CONCERNS FOR
FREEZING RAIN AND SOME SNOW. WILL HIGHLIGHT THIS IN AN HAZARDOUS
WEATHER OUTLOOK BUT IT LOOKS TO BE A MARGINAL EVENT AT THIS TIME.

REST OF FORECAST LOOKED GOOD. THERE IS SOME POTENTIAL FOR STRONG NW
WINDS AFTER SUNDAY/S DISTURBANCE PASSES...ABOUT TUESDAY...BUT 850 MB
WINDS ONLY GET TO ABOUT 40 KTS. THEREFORE NOT EXPECTING WIDESPREAD
STRONG WINDS. POSSIBLY ISSUES IN THE NORMALLY WINDY SPOTS (I.E. SE
PHILLIPS COUNTY). TFJ

PREVIOUS DISCUSSION...

THE GENERAL SYNOPTIC FLOW REGIME FOR THE EXTENDED FORECAST PERIOD
WILL BE FROM THE WEST AND NORTHWEST WITH A FEW EMBEDDED SMALL-
SCALE DISTURBANCES EARLY IN THE PERIOD...FOLLOWED BY A LARGER-
SCALE STORM SYSTEM OVER THE REGION TOWARD CHRISTMAS EVE.

FIRST...EARLY SUNDAY MORNING...A SMALL DISTURBANCE EMERGES OVER
THE CANADIAN ROCKIES AND GAINS ENOUGH FORCING AND MOISTURE TO
SQUEEZE OUT SOME LIGHT PRECIPITATION. BASICALLY WENT WITH A MODEL
BLEND HERE...SLIGHTLY FAVORING THE EC FOR ITS RUN TO RUN
CONSISTENCY. NOT EXPECTING MUCH...MAYBE A HALF INCH OF SNOW NORTH
OF THE MISSOURI RIVER AND SOME LIGHT RAIN SOUTH OF THE MISSOURI
RIVER.

MONDAY NIGHT THROUGH WEDNESDAY NIGHT...A STRONGER AND MORE-
ESTABLISHED NORTHWESTERLY FLOW ALOFT SEEMS TO TAKE ROOT OVER THE
REGION AND SETS UP SOME HIGHER ELEVATION AREAS OF CENTRAL MONTANA
WITH OVER-RUNNING AND ACCUMULATING PRECIPITATION. THIS WILL LIKELY
REMAIN CONFINED TO THE NE AND SW CORNERS OF OUR CWA. MODELS
INDICATE THAT THIS PRECIPITATION TREND WILL LATER THE BECOME
ENHANCED BY A COLD AIR MASS...LARGER TROUGH...AND STRONGER STORM
SYSTEM POSSIBLY BY CHRISTMAS TIME. TRIED TO REFLECT THIS THINKING
WITH THE FORECAST GRIDS. BMICKELSON

&&

.AVIATION...

SYNOPSIS: WEAK FLOW ALOFT WILL CONTINUE OVER THE REGION THROUGH
THE TERMINAL FORECAST PERIOD.

FLIGHT CATEGORY: MVFR...ISOLATED IFR.

CIGS AND VSBY: CIGS WILL RANGE FROM 010-020 WITH A SOLID STRATUS
DECK HOLDING IN OVER THE AREA.

WIND: SOUTHEAST UNDER 15 KNOTS EXPECTED.

PROTON


&&

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

&&

$$

WEATHER.GOV/GLASGOW





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