A passing dry cold front coupled with a strong jet stream aloft allowed for very strong westerly winds, especially over the higher terrain of Glacier National Park. Winds at Logan Pass in Glacier National Park peaked at 56 mph with gusts up to 96 mph for a period of about five hours.
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The episode as NWS MSO wrote it up.
A passing dry cold front coupled with a strong jet stream aloft allowed for very strong westerly winds, especially over the higher terrain of Glacier National Park. Winds at Logan Pass in Glacier National Park peaked at 56 mph with gusts up to 96 mph for a period of about five hours.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Missoula, MT wrote its last area forecast discussion before the first event at Sep 26, 1:46 PM MST, 4 hours 14 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
246 PM MDT SAT SEP 26 2009
.DISCUSSION...BREEZY CONDITIONS WILL CONTINUE ACROSS WESTERN
MONTANA THROUGH THIS EVENING AS A STRONG JET AND DRY COLD FRONT
PUSH THROUGH. THE PRESSURE GRADIENT WILL WEAKEN AFTER THE FRONT
PASSES ALLOWING VALLEY WINDS TO DECREASE...BUT HIGH ELEVATION WINDS
WILL REMAIN BREEZY THROUGH THE NIGHT.
SUNDAY AND SUNDAY NIGHT AN UPPER LEVEL RIDGE WILL BUILD BACK OVER
THE REGION IN RESPONSE TO ANOTHER PACIFIC WEATHER SYSTEM
APPROACHING THE WEST COAST. A COOLER AIRMASS WILL LOWER
TEMPERATURES ABOUT 10 DEGREES FROM TODAY...BUT READINGS WILL REMAIN
ABOVE SEASONAL NORMALS.
MONDAY AND MONDAY NIGHT THE RIDGE WILL SHIFT EAST ALLOWING A MORE
PROGRESSIVE SOUTHWEST FLOW TO MOVE INTO THE REGION. THIS WILL
ALLOW FOR BETTER MIXING MONDAY AND ANOTHER BUMP UP IN
TEMPERATURES. A NORTH SOUTH ORIENTED JET ON THE FRONT END OF THE
NEXT PACIFIC SYSTEM SHOULD SLOW ITS EASTWARD PROGRESSION. THE MODELS HAVE
PICKED UP ON THIS AND SLOWED THE PRECIPITATION ASSOCIATED WITH THE
NEXT WEATHER SYSTEM. HAVE THEREFORE DELAYED THE ONSET OF
PRECIPITATION UNTIL AFTER MONDAY NIGHT.
TUESDAY THROUGH THURSDAY...LOW PRESSURE CURRENTLY SITUATED OVER
ALASKA IS STARTING TO PROGRESS SOUTH. THIS TROUGH WILL DIG INTO
THE PACIFIC NORTHWEST TUESDAY AND START TO PROGRESS INTO THE
NORTHERN ROCKIES BY TUESDAY EVENING. MODELS ARE IN BETTER
AGREEMENT THAN YESTERDAY WITH THE CONSENSUS BEING AN OPEN AND
PROGRESSIVE WAVE. COOLER TEMPERATURES AND LOWERING SNOW LEVELS CAN
BE EXPECTED BY LATE TUESDAY AS A COLD FRONT STARTS TO ADVANCE
THROUGH THE REGION. AHEAD OF THIS FRONT THE CHANCE OF
PRECIPITATION STARTS TO INCREASE AS A SOUTHERLY FLOW BRINGS
MOISTURE INTO THE REGION. THE BEST CHANCE OF PRECIPITATION WILL BE
OVER WESTERN MONTANA AND CENTRAL IDAHO WHERE THIS FRONT SLOWS DOWN
AND THE UPPER LEVEL FORCING PASSES OVER IT. THIS IS LIKELY TO
HAPPEN TUESDAY NIGHT INTO WEDNESDAY MORNING. THIS SYSTEM MOVES
EAST OF THE REGION BY EARLY THURSDAY WITH ANOTHER SYSTEM ON ITS
HEALS FOR THE WEEKEND.
&&
.AVIATION...A DRY COLD FRONT IS MAKING ITS WAY THROUGH WESTERN
MONTANA THIS AFTERNOON ASSOCIATED WITH A STRONG UPPER LEVEL JET.
THESE FEATURES WILL KEEP INCREASED WEST WINDS IMPACTING ALL NORTH
CENTRAL IDAHO AND WESTERN MONTANA AIRFIELDS THROUGH EARLY EVENING.
AFTER SUNSET...THE VALLEY WINDS WILL DECREASE...BUT RIDGETOP WINDS
WILL REMAIN STRONG WHICH MAY RESULT IN SOME LOW LEVEL WIND
SHEAR THROUGH THE NIGHT. RIDGING WILL BUILD BACK IN FOR SUNDAY
PUSHING THE JET OFF TO THE EAST. THIS WILL RESULT IN DECREASING
RIDGETOP WINDS BY AFTERNOON.
&&
.FIRE WEATHER...THE PASSING DRY COLD FRONT COMBINED WITH STRONGER
WINDS FROM AN ASSOCIATED JET WILL KEEP INCREASED WINDS ACROSS
NORTH CENTRAL IDAHO AND WESTERN MONTANA FIRE DISTRICTS THROUGH
THIS EVENING. THE RED FLAG WARNING WILL REMAIN IN EFFECT THROUGH
MIDNIGHT MDT.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...RED FLAG WARNING UNTIL MIDNIGHT MDT TONIGHT FOR BITTERROOT-
DEERLODGE/WEST BEAVERHEAD-EAST BEAVERHEAD-EAST LOLO-
FLATHEAD/GLACIER PARK-KOOTENAI-SALISH AND KOOTENAI
RESERVATION-WEST LOLO.
HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR WEST GLACIER
REGION.
ID...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING FOR CLEARWATER/NEZ
PERCE.
&&
SHORT TERM/AVIATION...MEAD
LONG TERM....LOEFFELBEINThe national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
The Logan Pass observation site reported sustained winds between 40 and 56 mph with gusts between 86 to 96 mph for a period of about five hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2009Every state in 2009This day in weather historyWarnings in Montana, September 2009
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 193369.