Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 300301
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
901 PM MDT WED JUL 29 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
THE MAIN CHANGE WAS TO EXPAND AREA OF ISOLATED SHOWERS FROM
INHERITED GRIDS PER RECENT RADAR OBSERVATIONS. BEST BET FOR THIS
WILL BE ALONG THE CANADIAN BORDER. THE REST OF FORECAST IS IN FINE
SHAPE. MALIAWCO

PREVIOUS DISCUSSION...

THE UPPER LOW STORM SYSTEM HAS MOVED INTO ONTARIO THIS AFTERNOON.
THIS LOW WILL WORK ITS WAY INTO HUDSON BAY BY FRIDAY. OUT WEST
THERE IS AN UPPER RIDGE THAT IS DEVELOPING. THIS RIDGE WILL
AMPLIFY TO THE NORTHWEST THROUGH FRIDAY. THIS PATTERN WILL
ESTABLISH A NORTHWEST FLOW ALOFT OVER NORTHEAST MONTANA. WITH NOT
MUCH CHANGE IN THE FLOW PATTERN...THE LOCAL AREA WILL BE ON THE
BOUNDARY BETWEEN THE COOLER AIR OF THE TROUGH AND THE WARMER AIR
OF THE RIDGE. THIS BOUNDARY WILL NOT WANDER MUCH FROM THE AREA.
THEREFORE TEMPERATURES THAT BEGAN SLIGHTLY BELOW NORMAL TODAY WILL
BECOME NORMAL ON THURSDAY AND RISE SLIGHTLY ABOVE NORMAL ON FRIDAY
AS THE WESTERN RIDGE GAINS STRENGTH. WITH NO DISTURBANCES OR
FRONTAL BOUNDARY MOVING THROUGH THE AREA...CONDITIONS WILL REMAIN
DRY.

TONIGHT/THURSDAY MORNING...CUMULUS HAS DEVELOPED DURING THE
AFTERNOON WHICH SHOULD DISSIPATE BY SUNSET. WITH THE NW FLOW
PATTERN AND DRY CONDITIONS...AND THE SURFACE PRESSURE GRADIENT
RELAXING...SKIES WILL MOSTLY REMAIN CLEAR TONIGHT AND WIND WILL
DIMINISH. WITH THE RECENT HEAVY RAIN AND WET GROUND...CONDITIONS
COULD BE GOOD FOR PATCHY FOG LATE TONIGHT. HOWEVER SIMILAR
CONDITIONS THIS MORNING DID NOT DEVELOP FOG. SO WILL KEEP MENTION
FROM WX GRIDS FOR NOW.

THURSDAY THROUGH FRIDAY...WITH MOSTLY CLEAR SKIES...EXPECT GRADUAL
WARMING INTO FRIDAY. WINDS ON THURSDAY WILL STILL BE NORTHWESTERLY
AND INCREASE TO AROUND 10-15 KTS WITH EFFICIENT MIXING. HOWEVER ON
FRIDAY A SURFACE TROUGH DEVELOPS IN THE LEE OF THE NORTHERN
ROCKIES WHICH WILL SHIFT SURFACE WIND AROUND TO THE SOUTH.

SCT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE GOING FORECAST WAS IN OVERALL FINE SHAPE. THE ONLY TWEAKS MADE WERE
A GENTLE NUDGE TOWARD THE LATEST EXTENDED MODEL CONSENSUS. GILCHRIST

PREVIOUS LONG TERM DISCUSSION...DRY WEATHER AND HOT TEMPERATURES
WILL BE THE THEME TO START OFF THE EXTENDED PERIOD FRIDAY NIGHT
AND SATURDAY WITH SURFACE HIGH PRESSURE OVER THE AREA AND A
WESTERN RIDGE DRIVING NORTHWEST FLOW ALOFT ACROSS THE REGION.

SOME FLATTENING OF THE RIDGE WILL OCCUR SUNDAY INTO MONDAY...AND
SUBTLE SHORTWAVES ON THE PERIPHERY OF THE RIDGE MAY ALLOW FOR
ENHANCED FORCING FOR ASCENT...ALLOWING FOR AN ISOLATED THREAT OF A
SHOWER OR THUNDERSTORM. OTHERWISE CONTINUED WARM CONDITIONS CAN BE
EXPECTED THROUGH EARLY NEXT WEEK...MAYBE A SHADE COOLER THANKS TO
LOWER 500MB HEIGHTS DUE TO THE FLATTENING RIDGE.

A STRONGER AND DEEPER SHORTWAVE LOOKS TO ENTER INTO CENTRAL
BRITISH COLUMBIA PER LATEST ECMWF/GFS WHICH MAY HELP TO RE-AMPLIFY
THE UPPER RIDGE ACROSS THE NORTHERN HIGH PLAINS LEADING TO DRIER
CONDITIONS ON TUESDAY AND PERHAPS A GRADUAL UPTICK IN TEMPERATURES
TOWARD MIDWEEK. AS THAT WAVE/CLOSED LOW APPROACHES IT MAY PUSH THE
RIDGE FAR ENOUGH SOUTH TO DELIVER DIFFLUENT SOUTHWEST FLOW ALOFT
ACROSS THE REGION ALONG WITH INCREASING CHANCES FOR SHOWERS AND
THUNDERSTORMS. GIVEN INCREASING SPREAD IN 500MB HEIGHTS BY DAY 7
AND 8 HOWEVER...DECIDED TO HAVE SLIGHT CHANCE POPS TO COVER
POTENTIAL BUT NOT YET WILLING TO GET TO BULLISH UNTIL MODEL
CONSENSUS INCREASES. MALIAWCO


&&

.AVIATION...
FLIGHT CATEGORY: VFR.

SYNOPSIS: UPPER RIDGING WILL MAKE FOR EXCELLENT FLYING WEATHER
OVER THE NEXT 24 HOURS.

CIGS: PERIODS OF SCT-FEW MID TO HIGH LEVEL CLOUDS.

VIS: UNRESTRICTED.

WIND: LIGHT AND VARIABLE OVERNIGHT THEN NORTHWEST 5 TO 15 KNOTS
DURING THE DAY ON THURSDAY.

PROTON

&&

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

&&

$$

WEATHER.GOV/GLASGOW





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