An upper level wave moving over the Northern Rockies generated sufficient lift, moisture, and wind shear to initiate a supercell thunderstorm.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MSO wrote it up.
An upper level wave moving over the Northern Rockies generated sufficient lift, moisture, and wind shear to initiate a supercell thunderstorm.
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 Aug 25, 12:38 PM MST, 3 hours 57 minutes earlier.
Area Forecast Discussion National Weather Service Missoula MT 138 PM MDT Thu Aug 25 2022 ...Flash Flood Watch in Effect through Friday Morning for Western Montana... .DISCUSSION...A low pressure center currently spinning over eastern Washington and the northern Idaho Panhandle will continue to pump moisture over the Northern Rockies from the southwest today. This will aid in the development of scattered showers and thunderstorm across the region once again. Much like the past couple days, these storms will be capable of producing brief heavy rainfall as they pass overhead. Locations such as recent burn scars or flood prone regions should keep an eye out for flash flooding and/or excessive runoff from the heavy rain. Frequent lightning, as well as gusty outflow winds up to 40 mph will be common with these thunderstorms. While we are not expecting a big severe weather outbreak, there could be an isolated storm or two that could become severe, especially for areas in western Montana along and east of the Highway 93 corridor. As the low slowly moves to the east across northwest Montana this evening, we expect showers and thunderstorms to continue to some degree overnight for northwest and west-central Montana. Afternoon showers and thunderstorms will continue once again Friday, but will not be as widespread as to what will occur today and what has been experienced the past couple days. Forecast ensembles are much more in agreement with a cutoff mid- level low pressure system moving across west-central Montana during the day on Saturday. This has increased our confidence in the chances for another round of showers and thunderstorms during the afternoon and evening time period, particularly for west- central and southwest Montana. This low pressure will also tighten the surface pressure gradient, creating breezy west-southwest winds. Wind gusts up to around 30-40 mph will be common for locations along and south of I-90 in western Montana, as well as for Lemhi County. The timing for the stronger winds are expected to be between 3PM and 9PM Saturday. Long range forecast models are trending toward another ridge of high pressure re-establishing itself over the Northern Rockies next week. This will allow for warmer temperatures and drier conditions to return. As of right now, it is not likely to create the extremely hot temperatures we've experienced this month thus far. && .AVIATION...Showers and thunderstorms are already developing across western Montana this afternoon, and are expected to become more widespread as the afternoon progresses. KMSO, KGPI, KBTM and KSMN will be under the threat for thunderstorm activity through the evening hours. All aviation terminals will likely see activity in the vicinity between 25/2000Z-26/0100Z. KGPI and KMSO could see showers and thunderstorms returning overnight tonight and early Friday morning around 26/0900Z-26/1400Z. The main threats with the thunderstorms this evening and overnight, will be brief heavy rainfall and frequent lightning. There will be a small chance that the strongest storms could bring small hail and gusty erractic winds up to 35kts. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...ID...None. &&
Special Weather Statement
National Weather Service Missoula MT
232 PM MDT Thu Aug 25 2022
MTZ003-004-252100-
Flathead/Mission Valleys MT-Lower Clark Fork Region MT-
232 PM MDT Thu Aug 25 2022
...A strong thunderstorm will impact portions of east central
Mineral, southern Lake, west central Missoula and southeastern
Sanders Counties through 300 PM MDT...
At 232 PM MDT, Doppler radar was tracking a strong thunderstorm near
Alberton, or 19 miles east of Superior, moving east at 20 mph.
HAZARD...Winds in excess of 30 mph and nickel size hail and heavy
rain.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Stark.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4705 11460 4717 11462 4725 11419 4704 11414
TIME...MOT...LOC 2032Z 261DEG 19KT 4710 11450
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...30 MPHSpecial Weather Statement National Weather Service Missoula MT 331 PM MDT Thu Aug 25 2022 MTZ003>005-043-252200- Flathead/Mission Valleys MT-Missoula/Bitterroot Valleys MT- Lower Clark Fork Region MT-Potomac/Seeley Lake Region MT- 331 PM MDT Thu Aug 25 2022 ...A strong thunderstorm will impact portions of south central Lake and central Missoula Counties through 400 PM MDT... At 331 PM MDT, Doppler radar was tracking a strong thunderstorm near Frenchtown, or 15 miles northwest of Missoula, moving east at 15 mph. HAZARD...Half-inch size hail and heavy rain. SOURCE...Radar indicated. IMPACT...Minor damage to outdoor objects is possible. Locations impacted include... Missoula, Wye, Evaro, Frenchtown, Arlee, Ninemile and Huson. This includes the following highways... Interstate 90 between mile markers 80 and 101. Highway 93 N between mile markers 0 and 13, and between mile markers 15 and 16. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with this storm and may lead to localized flooding. Do not drive your vehicle through flooded roadways. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 4686 11433 4703 11442 4717 11407 4692 11393 TIME...MOT...LOC 2131Z 249DEG 12KT 4697 11432 MAX HAIL SIZE...0.50 IN MAX WIND GUST...<30 MPH
Special Weather Statement
National Weather Service Missoula MT
407 PM MDT Thu Aug 25 2022
MTZ003-004-043-252230-
Flathead/Mission Valleys MT-Lower Clark Fork Region MT-
Potomac/Seeley Lake Region MT-
407 PM MDT Thu Aug 25 2022
...Strong thunderstorms will impact portions of southwestern Lake and
southeastern Sanders Counties through 430 PM MDT...
At 407 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 16 miles west of Kerr to 7 miles southwest of
Dixon. Movement was east at 25 mph.
HAZARD...Heavy rain, winds in excess of 30 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Ravalli, Old Agency, Dixon, Moiese, Round Butte and Charlo.
This includes the following highways...
Highway 93 N between mile markers 26 and 29.
Highway 200 W between mile markers 97 and 115.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4770 11422 4727 11412 4726 11452 4765 11458
TIME...MOT...LOC 2207Z 273DEG 20KT 4760 11453 4723 11446
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...30 MPHSpecial Weather Statement
National Weather Service Missoula MT
427 PM MDT Thu Aug 25 2022
MTZ003-004-043-252300-
Flathead/Mission Valleys MT-Lower Clark Fork Region MT-
Potomac/Seeley Lake Region MT-
427 PM MDT Thu Aug 25 2022
...Strong thunderstorms will impact portions of southwestern Lake and
eastern Sanders Counties through 500 PM MDT...
At 425 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 8 miles west of Kerr to near Dixon. Movement
was east at 15 mph.
HAZARD...Very heavy rain, low visibility, ponding of water on
roadways, winds in excess of 40 mph and penny size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Ravalli, Ronan, St. Ignatius, Old Agency, Dixon, Allentown, Moiese,
Kicking Horse, Charlo and Fort Connah.
This includes the following highways...
Highway 93 N between mile markers 27 and 47.
Highway 200 W between mile markers 105 and 112.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4757 11397 4726 11392 4730 11439 4748 11441
TIME...MOT...LOC 2225Z 273DEG 13KT 4769 11437 4725 11435
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPHSpecial Weather Statement
National Weather Service Missoula MT
445 PM MDT Thu Aug 25 2022
MTZ007-252330-
Butte/Blackfoot Region MT-
445 PM MDT Thu Aug 25 2022
...A strong thunderstorm will impact portions of southwestern Deer
Lodge County through 530 PM MDT...
At 444 PM MDT, Doppler radar was tracking a strong thunderstorm 14
miles north of Wisdom, or 34 miles southwest of Anaconda, moving
northeast at 15 mph.
HAZARD...Winds in excess of 30 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Fishtrap.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
&&
LAT...LON 4585 11323 4579 11342 4580 11343 4583 11343
4584 11344 4586 11344 4587 11346 4590 11347
4602 11329 4587 11322
TIME...MOT...LOC 2244Z 242DEG 12KT 4581 11351
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...30 MPHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
448 PM MDT THU AUG 25 2022
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0446 PM HAIL 1 N MOIESE 47.39N 114.26W
08/25/2022 E1.50 INCH LAKE MT TRAINED SPOTTER
PING PONG SIZE HAIL, HEAVY RAIN AND STRONG
WINDS.
&&
RNThe Missoula radar (KMSX), 41 km away, was scanning. The volume nearest the first event began at 23:35 UTC.
1 hail. Local standard time, as filed.
Ping pong size hail, very heavy rain, and gusty winds were reported at the National Bison Range. A hay crop was destroyed near St. Ignatius. Hail damaged an RV roof.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2022Every state in 2022This day in weather historyWarnings in Montana, August 2022
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: 1051587.