Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 302027
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
227 PM MDT SUN AUG 30 2015

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

AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE DIVIDE TONIGHT THAT
WILL SEND ANOTHER...STRONGER...COLD FRONT THROUGH NORTHEAST
MONTANA. TIMING PUTS THE FRONT HALFWAY THROUGH THE CWA AT 06Z AND
ALL THE WAY THROUGH BY 12Z. SOME PACIFIC MOISTURE HAS BEEN
ENTRAINED IN THE SOUTHWEST FLOW...SO THIS COULD BRING WETTING
RAINS TONIGHT...ALONG WITH THUNDER. MODELS ARE SHOWING STRONG
SHEAR PROFILES...THAT ALONG WITH SOME AFTERNOON HEATING HAS
PROMPTED SPC TO PLACE OUR WESTERN COUNTIES IN A MARGINAL
RISK...FOR STRONG WIND AND POSSIBLE HAIL THIS EVENING. SMOKE IS
THE OTHER ISSUE RIGHT NOW. THE TROUGH MOVING THROUGH...ALONG WITH
ASSOCIATED LIFT IS TENDING TO CLEAR THE SMOKE...FOR NOW. THEREFORE
CANCELLED THE DENSE SMOKE ADVISORY.

MONDAY...THE UPPER TROUGH MOVES OFF TO THE EAST AND ALL
WINDS...SURFACE TO ALOFT...WILL BECOME WESTERLY. SURFACE WIND
BEGINS TO RELAX AS THE SURFACE LOW MOVES FARTHER EAST. THE COOLER
AIR BEHIND THE COLD FRONT WILL DRIVE TEMPERATURE BACK TO NORMAL.

TUESDAY...FLOW ALOFT BACKS AROUND TO THE SOUTHWEST AND THE THERMAL
BOUNDARY FIRMS UP WITH NORTHEAST MONTANA BEGINS TO SEE HOT AIR
DRIFTING BACK INTO THE AREA. THIS WILL DRIVE TEMPERATURES BACK
ABOVE NORMAL.

MAIN FORECAST PROBLEM FOR THE NEXT FEW DAYS WILL BE THE SMOKE.
SHOWERS AND SOUTHWEST FLOW TODAY CLEARED SOME OF THE SMOKE OUT OF
THE AIR...BUT WITH WESTERLY FLOW AND SUBSIDENCE ON MONDAY EXPECT
THE SMOKE WILL RETURN. THIS AFTERNOON VISIBILITY HAS IMPROVED
EVERYWHERE. IF SMOKE BECOMES DENSE AGAIN THE DENSE SMOKE ADVISORY
WILL BE REISSUED. SCT


.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
MODELS CONTINUE THEIR AGREEMENT ON A SYSTEM LATE THIS WEEK WITH A
GOOD CHANCE OF SHOWERS AND COOLER TEMPERATURES. IN COORDINATION
WITH NEIGHBORING OFFICE TO OUR WEST...CONTINUED TREND OF RAISING
POPS AND LOWERING TEMPERATURES SLIGHTLY. REST OF CHANGES WERE
MINOR. TFJ

PREVIOUS DISCUSSION...
SYNOPTIC SET UP... LONG RANGE BEGINS WITH HOT HIGH PRESSURE OVER
THE DESERTS SOUTHWEST AND FOUR CORNERS AND A WARM RIDGE RUNNING
OUT OF COLORADO AND THEN MOVING NORTH UP THE HIGH PLAINS INTO
EASTERN MONTANA. A CLOSED LOW SETS OVER THE SOUTHERN COAST OF
BRITISH COLUMBIA AND IS GENERATING UNSTABLE SOUTHWEST FLOW ACROSS
NORTHERN CALIFORNIA THROUGH WESTERN MONTANA AND SOUTHERN
SASKATCHEWAN.

TUESDAY NIGHT THROUGH WEDNESDAY NIGHT... RIDGE WILL HAVE THE MOST
INFLUENCE DURING THIS TIME. EXPECT WARM TEMPERATURES WAITING FOR
AN UPPER LEVEL FRONT TO MOVE IN AND BEGIN MIXING DOWNWARD
WEDNESDAY EVENING.

THURSDAY THROUGH FRIDAY... UNSTABLE SOUTHWEST FLOW WILL MOVE OVER
THE AREA. CHANCES FOR A SHOWERS AND THUNDERSTORMS WILL INCREASE
DURING THIS TIME... BUT... MODELS HAVE NOT ESTABLISHED A SINGLE
JET OR WAVE FEATURES TO LATCH ONTO AND EACH MODEL IS A LITTLE
DIFFERENT IN WHERE THE ISOLATED SHOWERS WILL FORM OR MOVE.

FRIDAY NIGHT TO SATURDAY NIGHT... SYNOPTIC TROUGH BASE TO THE WEST
MOVES INTO WESTERN MONTANA. THIS WILL INCREASE CHANCES FOR RAIN
SHOWERS AND FURTHER DROP TEMPERATURES ACROSS THE REGION.

SUNDAY ONWARD... MODELS BEGIN HAVING TROUBLE WITH SYNOPTIC
FEATURES HERE... BUT THE GENERAL OUTCOME IS FOR THE BASE OF THE
TROUGH TO BE OVER NORTHEAST MONTANA OR HAVE JUST MOVED SOUTHEAST.
EXPECT TEMPERATURES TO BE AT THEIR LOWEST DURING THIS TIME AND
CHANCES FOR SHOWERS AND THUNDERSTORMS TO BACK OFF SLIGHTLY.  GAH



&&

.AVIATION...
FLIGHT CATEGORY: VFR

ANOTHER ROUND OF SHOWERS AND ISOLATED THUNDERSTORMS ARE TO MOVE IN
FROM THE SW THIS EVENING MAINLY AFFECTING THE KGGW AREA.
VISIBILITIES MAY DROP BELOW VFR IN HEAVIER SHOWERS.

NORTHWEST WINDS WILL INCREASE TONIGHT WITH ANOTHER COLD FRONTAL
PASSAGE. GUSTS TO 25 KTS ARE POSSIBLE. TFJ


&&

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

&&

$$

WEATHER.GOV/GLASGOW


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