Area Forecast Discussion
Issued by NWS Glasgow, MT

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000
FXUS65 KGGW 042007
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
207 PM MDT TUE AUG 4 2015

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

SYNOPTIC SET UP... A HOT HIGH PRESSURE RIDGE RUN UP FROM THE FOUR
CORNERS THROUGH WYOMING AND EASTERN MONTANA. NORTHEAST MONTANA
CURRENTLY RESIDES DIRECTLY UNDER THE RIDGE AXIS AS IT TRAVELS FROM
WEST TO EAST. FARTHER WEST A LARGE CLOSED COLD CORE TROUGH EXISTS
OVER THE BRITISH COLUMBIA COAST.

THIS AFTERNOON THROUGH WEDNESDAY MORNING... RIDGE AXIS WILL SLOWLY
TRAVEL TO THE EAST OVERNIGHT ALLOWING THE SURFACE TROUGH OFF OF
THE FRONT RANGE TO ESTABLISH A FOCAL POINT FOR CURRENTLY DEVELOPING
THUNDERSTORMS. THE STORMS WILL FOLLOW THE SURFACE TROUGH OVERNIGHT
DIRECTLY BEHIND THE RIDGE AXIS INTO NORTH DAKOTA UNTIL THE SURFACE
TROUGH SNAPS BACK IN PLACE DURING THE MORNING HOURS. A FEW
ISOLATED CELLS WILL BE CAPABLE OF GUSTY WINDS AND SMALL HAIL...
BUT SO FAR THE THREAT IS MINIMAL AND FOCUS MOSTLY ON RAIN WITH A
SLIGHT POSSIBILITY FOR TRAINING.

WEDNESDAY... WITH THUNDERSTORMS HAVING WORKED OVER THE ATMOSPHERE
A SHORT STABLE PERIOD WITH DRY CONDITIONS IS EXPECTED WEDNESDAY.
MEANWHILE THE BRITISH COLUMBIA LOW WILL DROP SOUTH INTO THE
PACIFIC NORTHWEST.

WEDNESDAY NIGHT THROUGH THURSDAY... THE LOW TO THE WEST WILL MOVE
INLAND AND RIP ITSELF APART IN NEWLY DEVELOPED ZONAL FLOW. THE
PIECES OF VORTICITY AND SHORTWAVE ENERGY ARE CURRENTLY A MESS AND
EACH MODEL IS PLACING LIFT ZONES IN DIFFERENT LOCATIONS ACROSS
NORTHEAST MONTANA AND THE WHOLE OF MONTANA FOR THAT MATTER. WITH
PLACEMENT CONFIDENCE THIS LOW... HAVE DECIDED TO BROAD BRUSH THIS
SECOND WAVE IN POP FIELDS. GAH


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
PERIOD STARTS OFF WITH AN UPPER TROUGH OVER ALBERTA AND SASK THAT
DRIFTS EAST INTO THE WEEKEND. THEN REMNANTS FROM A LOW OFF THE
NORTHERN CALIFORNIA COAST MOVES NE INTO MONTANA LATE IN THE WEEKEND.

THURSDAY NIGHT THROUGH FRIDAY...SYSTEM WILL BE FAIRLY WRAPPED UP
JUST TO OUR NORTH WITH A GOOD CHANCE OF SHOWERS NORTH OF THE BORDER.
DRIER AIR WILL BE IN PLACE OVER MONTANA SO MUCH LOWER CHANCES FOR
SHOWERS ARE EXPECTED HERE. BREEZY CONDITIONS CAN BE EXPECTED FRIDAY
AFTERNOON BUT AT THIS POINT SHOULD BE SHY OF LAKE WIND ADVISORY.

CALIFORNIA SYSTEM THEN MOVES IN FOR THE NEXT CHANCE OF
SHOWERS/THUNDERSTORMS MAINLY SATURDAY NIGHT AND SUNDAY. IT LOOKS
LIKE THE BRUNT OF THIS AFFECTS THE SOUTHERN ZONES.

EARLY NEXT WEEK...UPPER TROUGH MOVES INTO THE PACIFIC NW BUT MODELS
ARE NOT IN AGREEMENT YET WITH BRINGING SHOWER ACTIVITY INTO THE CWA.
THEREFORE KEPT THINGS DRY FOR NOW AS UPPER RIDGE SEEMS TO BE THE
BIGGER PLAYER.

TEMPERATURES WILL BE ABOUT 5 TO 10 DEGREES COOLER THAN NORMAL BUT
WILL WARM TO NEAR NORMAL LATE IN THE PERIOD. TFJ


&&

.AVIATION...
FLIGHT CATEGORY: VFR... OUTSIDE OF THUNDERSTORMS.

SYNOPSIS: LOW PRESSURE TROUGH WILL MOVE EAST THROUGH THE AREA
BRINGING A BROKEN LINE OF THUNDERSTORMS. BRIEF PERIODS OF HEAVY
RAIN...GUSTY ERRATIC WINDS TO 35 KTS...AND SMALL HAIL WILL BE
POSSIBLE WITH THESE THUNDERSTORMS. TIMING OF THUNDER WILL BEGIN
IMPACTING KGGW AROUND 19Z AND THEN SPREAD TO THE OTHER TAF SITES
INTO THE AFTERNOON. REMAINING OVERNIGHT SHOWERS SHOULD EXIT THE
AREA BY 12Z.

CIGS: SCT150 INITIALLY WITH DECREASING CONDITIONS TO ROUGHLY
BKN080 AS MID-LEVEL CUMULUS BUILDUPS AND AREAS OF THUNDERSTORMS
MOVE IN THIS AFTERNOON.

WINDS: SOUTHEAST WINDS AT 10 TOP 15 KTS THIS MORNING AND EARLY
AFTERNOON... VEERING TO THE WEST AT 10 KTS AFTER THE SURFACE TROUGH
PASSES THIS AFTERNOON INTO THE EVENING.

EQUIPMENT: WITH KGDV AWOS DOWN EXPECTED -AMD NOT SKED- UNTIL THE
FAA RETURNS THIS EQUIPMENT BACK TO WORKING STATUS.

GAH


&&

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


&&

$$

WEATHER.GOV/GLASGOW




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