Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 050908
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
308 AM MDT WED AUG 5 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
WATER VAPOR SHOWING A COMPLEX PATTERN IN PLACE OVER THE WESTERN
STATES WITH DISTURBANCES OVER TOPPING AN UPPER RIDGE. THE FIRST
DISTURBANCE IS EXITING THE NE ZONES THIS MORNING WITH THE NEXT ONE
MOVING IN FROM THE SOUTHWEST. THIS DISTURBANCE LOOKS TO MOVE INTO NE
MT MAINLY TONIGHT WITH THE BEST CHANCES FOR PRECIP TO LIKELY OCCUR
IN THE EASTERN ZONES. THE PERIOD ENDS WITH A WELL WRAPPED SYSTEM
THAT DRIFTS EAST OVER THE PRAIRIE PROVINCES OF CANADA.

TODAY...EXPECT AFTERNOON CUMULUS BUILD-UPS TO OCCUR MAINLY OVER
THE WESTERN ZONES WITH SHOWER/THUNDERSTORM ACTIVITY MOVING INTO
CENTRAL MONTANA.

SHOWER AND THUNDERSTORM ACTIVITY INCREASE TONIGHT MAINLY OVER THE SE
ZONES AS UPPER DISTURBANCES AND CLOSER PROXIMITY TO A SURFACE LOW
ALLOW FOR BETTER QG FORCING. UPPER DIFFLUENCE THEN PUSHES
PRECIPITATION INTO THE NE ZONES THURSDAY MORNING. UPPER CLOSED LOW
DRIVES DRIER AIR INTO THE CWA WHILE 700 MB LOW TO OUR NORTH KEEP
PRECIPITATION SHIELD TO OUR NORTH.

THURSDAY NIGHT AND FRIDAY...CANADIAN LOW SHOULD BE FAR ENOUGH TO OUR
NORTH FOR PRECIPITATION CONCERNS. OTHERWISE...IT WILL BE SLIGHTLY
COOLER THAN NORMAL AND MORE COMFORTABLE WITH A NW BREEZE. TFJ

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

THE PERIOD STARTS OFF FRIDAY EVENING WITH ZONAL FLOW ALOFT DUE TO
A SHORT-WAVE DISTURBANCE TREKKING EAST ACROSS THE PRAIRIE
PROVINCES. THERE WILL BE A CLOSED LOW OFF THE WEST COAST OF QUEEN
CHARLOTTE ISLAND AND A WEAKER SHORT-WAVE TROUGH MOVING INTO
CENTRAL CALIFORNIA. THIS TROUGH WILL GET CAUGHT UP IN THE
SOUTHWEST UPPER FLOW ESTABLISHED BY THE LARGER LOW TO THE NORTH.
THIS EMBEDDED DISTURBANCE WILL CARRY PACIFIC MOISTURE OVER THE
DIVIDE TO BRING SHOWERS AND THUNDER TO SOUTHERN MONTANA SATURDAY.
RIDGING WILL ALSO TRAVEL ACROSS THE PRAIRIE PROVINCES NORTH OF
MONTANA WHICH WILL KEEP MOST OF THE MOISTURE TO OUR SOUTH. BUT A
FEW SHOWERS COULD MAKE IT INTO THE CWA SATURDAY NIGHT AND SUNDAY
MORNING.

MONDAY THROUGH TUESDAY...A LONG-WAVE RIDGE SETS UP OVER THE MIDDLE
OF CONUS THAT WILL NUDGE HOT DESERT NORTH INTO THE REGION. DURING
THIS PERIOD WEAK DISTURBANCES IN THE UPPER FLOW COULD GENERATE A
FEW SHOWERS OR THUNDERSTORMS...BUT NOTHING SIGNIFICANT. THIS COULD
BE THE WARMEST TWO DAYS OF THE EXTENDED PERIOD.

WEDNESDAY AND BEYOND...FARTHER TO THE WEST THE UPPER TROUGH MOVES
INTO THE PACIFIC NW FORMING A STRONG COLD FRONT WEST OF THE
ROCKIES. THERE ARE MAJOR DIFFERENCES BETWEEN GFS AND EC WITH THE
TIMING OF THE TROUGH MOVING EAST. AS USUAL THE GFS IS QUICKER WITH
A WEAKENED FRONT ON WEDNESDAY. EC MAKES A GLANCING BLOW ON
THURSDAY. SCT

&&

.AVIATION...

WITH RECENT RAIN AND LIGHT WIND...MORNING FOG AND MIST IS
POSSIBLE.

A CLOSED LOW UPPER TROUGH MOVES INTO SOUTHERN BRITISH COLUMBIA AND
THE PACIFIC NORTHWEST TODAY. THIS WILL TURN UPPER FLOW TO THE
SOUTHWEST LOCALLY. THE BASE OF THE TROUGH WILL EJECT MOISTURE
ACROSS THE DIVIDE WHICH WILL REACH THE LOCAL AREA THIS EVENING IN
THE FORM OF THUNDERSTORMS AND RAIN SHOWERS.

VFR TODAY WITH POSSIBLE TEMPORARY MVFR CEILINGS AND VISIBILITIES
TONIGHT NEAR STORMS.

WINDS WILL GENERALLY BE LIGHT AND VARIABLE...EXCEPT SOUTHEAST 10KT
NEAR KGGW.

&&

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

&&

$$

WEATHER.GOV/GLASGOW




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