Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 031442
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
842 AM MDT MON AUG 3 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...

MORNING UPDATE... CHANGE FOR THIS MORNING WERE FOCUSED ON WIND
FIELDS TWEAKS TO TODAY... AND A BRIEF LOOK AT QPF FOR THE TUESDAY
TO WEDNESDAY PERIODS.

THERE WAS A SMALL CHANCE FOR LAKE WIND ADVISORY CRITERIA THIS
AFTERNOON/EVENING BUT UPON ENTERING THE LATEST MODEL DATA CHANCE
HAVE DROPPED SLIGHTLY. CURRENT SURFACE ANALYSIS SHOWS A VERY SHARP
GRADIENT PRESSURE GRADIENT ACROSS THE REGION WHICH COULD STILL LEAD
TO THESE WINDS... BUT THIS IS PREDICTED TO SLACKEN AS THE HIGH
MOVES TO THE EAST.

QPF FROM TUESDAY TO WEDNESDAY IS LOOKING TO FINALLY LOCK INTO
PLACE. WILL BE TAKING A CLOSER LOOK AT POPS TO SEE IF SOME SHARPER
BOUNDARY APPEAR THIS AFTERNOON AMONG THOSE PERIODS. GAH


PREVIOUS SHORT TERM DISCUSSION...
THE GOES WATER VAPOR IMAGERY REVEALS AN UPPER LEVEL RIDGE TO THE
WEST AND A STACKED LOW OVER HUDSON BAY. THIS WILL MAINTAIN THE
NORTHWEST FLOW ALOFT ACROSS NORTHEAST MONTANA...BRINGING CONTINUED
NEAR NORMAL WARM AND DRY CONDITIONS TO THE REGION TODAY. THE
MOVEMENT OF A CUTOFF LOW MOVING OUT OF THE GULF INTO NORTHERN
BRITISH COLUMBIA WILL NUDGE THE RIDGE AXIS MORE TO THE WEST TODAY
WHICH WILL AID IN BRINGING IN WARMER TEMPERATURES THAN SUNDAY. A
SURFACE LOW IN THE NORTHERN ROCKIES BEGINS TO DEVELOP AHEAD OF THE
APPROACHING TROUGH.

TONIGHT...A CUTOFF UPPER LOW THAT HAD BEEN LINGERING OVER THE GREAT
BASIN DRIFTS NORTHEAST INTO WYOMING AS A COLD FRONT FORMS OVER
CENTRAL MONTANA...ALONG WITH THE SURFACE LOW. TIMING FOR STORMS
MOVING INTO THE LOCAL AREA SUGGEST THE AREA REMAINING DRY THROUGH
THE NIGHT.

TUESDAY/TUESDAY NIGHT...WITH THE BC TROUGH EJECTING MOISTURE OVER
THE DIVIDE AND THE UNDERCUTTING UPPER LOW DIRECTLY SOUTH OF THE
RIDGE AXIS ACROSS NEMONT...AND WITH INCREASED INSTABILITY AND
LOCAL DISTURBANCES AND WEAK FRONTS...THUNDERSTORMS AND RAIN
SHOWERS SHOULD DEVELOP IN THE WESTERN COUNTIES BEFORE NOON AND
SPREAD ABOUT HALF WAY ACROSS THE CWA BY 00Z. THE STORMS WILL
BASICALLY BE IN A VERTICAL NORTH-SOUTH LINE AND SLOWLY DRIFT EAST.
BY EVENING STORMS WILL BEGIN TO SPREAD INTO THE EASTERN ZONES. SPC
HAS GENERALLY KEPT THE AREA WITHIN ITS GENERAL THUNDERSTORM AREA
ON ITS CONVECTIVE OUTLOOK. WITH THE BC TROUGH PICKING UP PACIFIC
MOISTURE...QPF AMOUNTS COULD BE LOCALLY HEAVY. MODELS DIFFER IN
AMOUNTS AND LOCATION...BUT MOST OF THE AREA HAS A CHANCE FOR SOME
WETTING RAINS. THE STRONGEST BREEZE OF THE SHORT TERM PERIOD
WILL BE A BRISK SOUTHEASTERLY WIND IN FRONT OF THE FRONTAL
BOUNDARY DUE TO THE NARROW SURFACE TROUGH STRETCHING NW TO SE
ACROSS EAST MONTANA.

WEDNESDAY...THE LINE OF STORMS SHOULD EXIT THE AREA BEFORE NOON.
THE BC UPPER TROUGH WILL HAVE DESCENDED INTO SOUTHERN BC AND THE
NORTHERN PAC-NW BY THE END OF THE DAY. WITH THE FRONTAL BOUNDARY
WELL TO THE EAST...TEMPERATURES WILL RUN BELOW NORMAL...UPPER 70S
AND MID 80S. A SECONDARY BOUNDARY WILL DEVELOP MORE SHOWER AND
THUNDER TO OUR WEST THAT MIGHT DRIFT INTO THE WESTERN ZONES BEFORE
EVENING.

SCT


.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
WEDNESDAY NIGHT AND THURSDAY... A COLD FRONT WILL MOVE THROUGH
EASTERN MONTANA WHICH WILL BE FOLLOWED BY AN UPPER TROUGH/LOW THURSDAY
AND THURSDAY NIGHT. THE FRONTAL PASSAGE WILL BRING ENOUGH MOISTURE
AND INSTABILITY FOR A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS.
MODELS CURRENTLY TRACK THE UPPER LOW ACROSS SOUTHERN SASKATCHEWAN
WHICH WILL PUT MOST OF NE MONTANA IN A DRY SLOT. THIS WILL LIMIT
PRECIP CHANCES LATE THURSDAY NIGHT AND FRIDAY. WILL MAINTAIN A
SLIGHT CHANCE FOR NOW.

AN UPPER RIDGE ON SATURDAY WILL ALLOW FOR DRY WEATHER MOST OF THE
DAY. FLOW ALOFT TURNS SOUTHWEST BY EVENING AND COULD BRING A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS SOUTH OF THE MISSOURI
RIVER IN THE AFTERNOON AND EVENING WITH CHANCES FOR THUNDERSTORMS
OVERSPREADING THE ENTIRE FORECAST AREA LATE SATURDAY NIGHT AND
SUNDAY AS A FRONTAL SYSTEM AND SHORTWAVE TROUGH MOVES THROUGH THE
AREA. CHANCES FOR SHOWERS AND THUNDERSTORMS LINGER INTO SUNDAY
NIGHT BEFORE THE TROUGH MOVES TO THE EAST ON MONDAY WITH MAINLY
DRY WEATHER. FORRESTER


&&

.AVIATION...
FLIGHT CATEGORY: VFR.

SYNOPSIS: UPPER RIDGING WILL MAKE FOR MOSTLY CLEAR SKIES AND
EXCELLENT FLYING WEATHER TODAY AND TONIGHT.

CIGS: SKC-SCT120.

VSBY: UNRESTRICTED.

WINDS: EAST TO SOUTHEAST 5-10KTS TODAY AND TONIGHT IN MOST AREAS.
KGGW WILL HAVE STRONGER EAST WINDS AROUND 15 KNOTS TONIGHT DUE TO
THE LOCAL EFFECTS OF THE MILK RIVER VALLEY.

EQUIPMENT: WITH KGDV AWOS DOWN WILL BE ADDING -AMD NOT SKED- TO TAF
UNTIL SITE TURNS ON AGAIN.

&&

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

&&

$$

WEATHER.GOV/GLASGOW





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