Area Forecast Discussion
Issued by NWS Glasgow, MT

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000
FXUS65 KGGW 030203 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
803 PM MDT SUN AUG 2 2015

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

AN UPPER LEVEL RIDGE TO THE WEST AND A CLOSED UPPER LOW OVER
HUDSON BAY ARE GENERATING A NORTHWEST FLOW ALOFT FOR NORTHEAST
MONTANA THIS EVENING. THIS IS A DRY PATTERN WITH MOSTLY CLEAR
SKIES. THERE ARE SOME SCATTERED HIGH CLOUDS RIDING OVER THE RIDGE
THAT MIGHT SPREAD ACROSS PARTS OF THE AREA. NO UPDATE NEEDED. SCT

PREVIOUS DISCUSSION...
SYNOPTIC SET UP... SHORT TERM BEGINS WITH A HOT HIGH PRESSURE
RIDGE OVER THE WESTERN HALF OF THE CONUS WHICH IS CRESTING OVER
SOUTHERN BRITISH COLUMBIA. A CLOSED LOW SETS OVER THE CANADIAN
SHIELD. NORTHEAST MONTANA SETS BETWEEN THESE TWO FEATURES UNDER
NORTHWEST FLOW ALOFT. TO THE WEST ANOTHER CLOSED LOW RESIDES OVER
THE NORTHERN COAST OF BRITISH COLUMBIA.

THIS AFTERNOON THROUGH MONDAY... THE BC CLOSED LOW WILL DROP SOUTH
AND FORCE THE RIDGE CREST AND AXIS OVER SOUTHERN ALBERTA WHICH
WILL BRING IN WARMER AIR ACROSS NORTHEAST MONTANA. THIS WILL ALSO
GENERATE A LEE SURFACE TROUGH OFF OF THE FRONT RANGE. EXPECT
CONDITIONS TO BE DRY AND TEMPERATURES TO WARM.

MONDAY NIGHT THROUGH TUESDAY... RIDGE AXIS WILL MOVE OVER CENTRAL
MONTANA MONDAY NIGHT AND INTO EASTERN MONTANA TUESDAY AFTERNOON.
THIS WILL ACT TO DESTABILIZE THE AREA SLOWLY AND PROBABLY
COINCIDE DURING PEAK HEATING WHICH MAY BRING A COUPLING AFFECT
FOR STRONGER THUNDERSTORMS ALONG THE SURFACE TROUGH WHEN THE WEST
SIDE OF THE RIDGE AXIS MOVES THROUGH. CHANCES ARE SLOWLY INCHING
UP. ALL MODELS SHOW THIS LIFT IN THE FORM OF A THIN NORTH/SOUTH
ORIENTED LINE OF THUNDERSTORMS... BUT PLACEMENT OF THE STORMS IS
WAFFLING BETWEEN CENTRAL MONTANA OVER THE MOUNTAIN CLUSTERS AND
EASTERN MONTANA OVER THE HIGH PLAINS. CONFIDENCE IS ABOVE AVERAGE
IN STORMS... BUT PLACEMENT IS BELOW AVERAGE. GAH

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
THE GOING EXTENDED FORECAST IS IN GOOD SHAPE. ONLY TWEAKS WERE TO
CONTINUE TO TREND UP POPS FOR TUESDAY NIGHT...AND TO TREND UP POPS FOR
NEXT WEEKEND AS SOME CONSISTENCY EXISTS FOR THE PASSAGE OF A
STRONGER UPPER TROUGH. GILCHRIST.

PREVIOUS LONG TERM DISCUSSION...THE EXTENDED PERIOD BEGINS
TUESDAY EVENING AS A CLOSED LOW OVER BRITISH COLUMBIA AND
ASSOCIATED UPPER TROUGH FEED IN PACIFIC MOISTURE INTO THE PACIFIC
NORTHWEST AND ULTIMATELY NORTHERN HIGH PLAINS. AS DIFFLUENT
SOUTHWEST FLOW ALOFT SETS UP...SHOWERS AND THUNDERSTORMS ARE
EXPECTED AND GIVEN AMPLE MOISTURE...LOCALLY HEAVY RAINFALL IS A
POTENTIAL AS WELL.

THAT SYSTEM WILL ONLY GRADUALLY PUSH EAST INTO THURSDAY AS THE
NEXT SHORTWAVE APPROACHES EMBEDDED IN THE UPPER FLOW ACROSS THE
REGION. THUS EXPECT UNSETTLED CONDITIONS TO CONTINUE INTO MIDWEEK
BUT THURSDAY COULD BE A DAY TO WATCH FOR MORE WIDESPREAD COVERAGE
OF SHOWERS AND THUNDERSTORMS. MUCH DEPENDS ON SPECIFIC
TIMING/PLACEMENT OF SHORTWAVES AND SOME DIFFERENCES DO EXIST AMONG
THE 00Z MODEL GUIDANCE DESPITE OVERALL BROAD AGREEMENT BETWEEN THE
00Z GFS AND ECMWF.

WITH ENSEMBLE 500MB HEIGHTS SHOWING INCREASING SPREAD TOWARD THE
END OF NEXT WEEK...WILL HAVE POPS TRENDED TOWARD CLIMATOLOGY WITH
TEMPERATURES SEASONABLE FOR THE TIME OF YEAR. MALIAWCO


&&

.AVIATION...
FLIGHT CATEGORY: VFR.

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

CIGS: SKC-SCT120.

VSBY: UNRESTRICTED.

WINDS: NORTH 5-10KTS...BECOMING EAST-SOUTHEAST TONIGHT INTO
MONDAY.

GILCHRIST/PROTON

&&

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

&&

$$

WEATHER.GOV/GLASGOW






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