Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 180156
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
756 PM MDT WED SEP 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
UPDATE...ADJUST TEMPERATURES FOR HIGH LOWS ALONG THE CMR AND LOWER
TEMPERATURES IN THE NORTHEASTERN CWA VALLEYS AS PER PREVIOUS
NIGHT/S TRENDS SUGGEST. OTHERWISE NO OTHER CHANGES MADE.   PROTON

PREVIOUS DISCUSSION...UPPER RIDGING WILL CONTINUE WARM AND MAINLY DRY
CONDITIONS OVERNIGHT TONIGHT...WITH LIGHT SOUTHERLY WINDS AT THE
SURFACE. A WEAK DISTURBANCE PUSHING FROM SOUTHWEST MONTANA COULD
BRING AN ISOLATED THUNDERSTORM TO PETROLEUM COUNTY THIS EVENING.

THURSDAY AFTERNOON ANOTHER WEAK SHORTWAVE WILL BEGIN TO BREAK DOWN THE
UPPER RIDGE...CREATING GOOD POTENTIAL FOR SHOWERS AND THUNDERSTORMS.
PREVIOUS MODEL RUNS WERE SHOWING AMPLE POTENTIAL INSTABILITY
ACROSS THE LOWER YELLOWSTONE VALLEY...AS WELL AS WIBAUX COUNTY.
THE LATEST RUNS ARE NOW FURTHER EAST WITH THE BETTER
INSTABILITY...DIMINISHING THE POTENTIAL FOR SEVERE WX ACROSS
EASTERN MONTANA.

THURSDAY NIGHT UNSETTLED CONDITIONS WILL CONTINUE ACROSS THE REGION
AS THE UPPER RIDGE IS BROKEN DOWN.

FRIDAY ANOTHER DISTURBANCE IN THE WESTERLY FLOW ALOFT AND ITS
ASSOCIATED MAINLY DRY COLD FRONT WILL PUSH THROUGH...BRINGING
GUSTY NORTHWEST WINDS AS WELL AS SLIGHT CHANCE FOR SHOWERS AND
THUNDERSTORMS ACROSS THE SOUTH AND EAST. GILCHRIST


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

AFTERNOON UPDATE...
WITH EXCELLENT MODEL AGREEMENT GOING ON THROUGH MONDAY NIGHT SAW NO
REASON TO CHANGE THE FORECAST THROUGH THEN AT THIS TIME. HAVE
RAISED POPS FROM ZERO TO MENTION OR NON-MENTION LEVELS TUESDAY
ONWARD AND CHAOS QUICKLY FILLS IN BEHIND THE EXITING RIDGE. GAH

PREVIOUS SHORT TERM DISCUSSION...
GIVEN THE EXCELLENT MODEL AGREEMENT IN THE EXTENDED PERIOD
THROUGH EARLY MONDAY MORNING...EXPECTING A HIGH LEVEL OF FORECAST
CONFIDENCE THROUGH THAT SAME TIME PERIOD. ONLY MATTER OF
SIGNIFICANCE WILL BE A PARTING AND GLANCING PASS OF RAIN SHOWERS
OVER OUR NORTHEASTERN ZONES AS A FAST-MOVING NORTHERN-STREAM
CANADIAN SHORT-WAVE DISTURBANCE SLIDES ACROSS THE NORTHERN HIGH
PLAINS. OTHERWISE...THIS HIGH CONFIDENCE PORTION OF THE FORECAST
WILL BE HIGHLIGHTED BY COMFORTABLY WARM TEMPERATURES AND NO
PRECIPITATION UNDER ANOTHER PROMINENT RIDGE OF HIGH PRESSURE.

BEGINNING LATER ON MONDAY...THE SOUTHERN STREAM PUSHES A WEAK LOW
PRESSURE SYSTEM ORIGINALLY FROM CALIFORNIA THROUGH THE CENTRAL
ROCKIES. NORTHEAST MONTANA WILL BE MORE UNDER THE INFLUENCE OF THE
NORTHERN STREAM HIGH PRESSURE RIDGE OR RATHER A BENIGN FLOW PATTERN.

BY TUESDAY NIGHT...A VERY CHAOTIC PATTERN OF HIGHLY DISAGREEABLE
WEATHER MODELS IMPLIES A VERY LOW LEVEL OF FORECAST CONFIDENCE BY
THE MIDDLE OF NEXT WEEK. THE MYSTERY BEING WHAT KIND OF WEATHER
SYSTEM WILL MOVE INTO THE AREA TOWARD THE END OF NEXT WEEK
FOLLOWING THE BENIGN PATTERN EARLY NEXT WEEK. BMICKELSON


&&

.AVIATION...

FLIGHT CATEGORY: VFR

SYNOPSIS: MID TO HIGH LEVEL CLOUDS WILL MOVE UP AND AROUND THE
CREST OF A RIDGE COVERING THE WESTERN THIRD OF THE US. THE RIDGE WILL
BUILD OVER THE NEXT 15 HOURS OVER NORTHEAST MONTANA AND CREATE DRY
CONDITIONS FOR ALL TAF SITES THROUGH THE TAF CYCLE. RIDGE BREAK-
DOWN IS ANTICIPATED THURSDAY AFTERNOON AND MAY BRING AN ISOLATED
THUNDERSTORM OR TWO INTO THE LATE TAF CYCLE.

FOG: NAM MODEL IS HINTING AT ISOLATED VALLEY FOG ALONG THE
MISSOURI RIVER VALLEY WHICH COULD IMPACT KOLF BETWEEN 09-15Z
THURSDAY MORNING. AS DEWPOINT DEPRESSIONS SEEM HIGH AND MID-LEVEL
CLOUDS ARE IN PLACE...CONFIDENCE IN THIS IS LESS THAN AVERAGE AND
HAS NOT BEEN ADDED TO THE TAF AT THIS TIME.

AREA WINDS: FROM THE SOUTHEAST BETWEEN 5 TO 15 KTS THROUGH THE
CYCLE.

GAH/BLM




&&

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

&&

$$

WEATHER.GOV/GLASGOW





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