With lower pressure toward the northeast and higher pressure toward the southwest, persistent surface winds from the west and northwest spread across the region. Atmospheric conditions were favorable to allow some higher gusts from aloft to reach the surface, especially through Sioux Pass in Richland County on the 1st.
Every event with a place to put it; 8 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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 GGW wrote it up.
With lower pressure toward the northeast and higher pressure toward the southwest, persistent surface winds from the west and northwest spread across the region. Atmospheric conditions were favorable to allow some higher gusts from aloft to reach the surface, especially through Sioux Pass in Richland County on the 1st. These similar conditions were even more favorable for stronger and more widespread high winds on the 2nd, when fire weather conditions were ripe.
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 Glasgow, MT wrote its last area forecast discussion before the first event at Sep 1, 10:03 AM MST, 2 hours 17 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 1103 AM MDT Tue Sep 1 2020 Updated aviation section. .DISCUSSION... Morning update... Main change was to bump winds up and (cosmetically) bump relative humidities down today based on latest guidance. Tomorrow still looks like the windier day between today and tomorrow. Otherwise, the existing red flag warning and lake wind advisory look good. The update to them was to freshen up the wording a little. 97 Previous discussion... The persistent weather pattern over the continent, with low pressure centered over Hudson Bay, and high pressure centered over the Great Basin, will continue to direct upper level winds from the northwest along a very tight pressure gradient directly over our region. Some version of this pattern will stick around for several days. For at least today and tomorrow, low relative humidity and these gusty winds will create fire weather concerns. ***See the fire weather discussion below*** Dry conditions and warm temperatures will persist in this weather pattern for northeast Montana until the next cold front, set to arrive Wednesday evening. At this time, the associated precipitation with the cold front seems light or minimal at best. It will likely bring little relief in the form of rain, if any at all. By Thursday morning, the cold front is through the area and the chances for rain are done. After that, the next chances for precipitation will be with another cold front late in the weekend. The hottest day of the forecast will be Wednesday (tomorrow). The coldest night of the forecast will be next Monday night with possible frost. && .AVIATION... FLIGHT CONDITION: VFR WINDS: NW 20-30 kts with gusts to 40 kts or higher this afternoon. Winds become light and variable by 3-4z this evening. Winds pick up again by 15z on Wednesday out of the SW to W 15-20 kts and become NW 20-30 kts with gusts to 40 kts or higher by Wednesday afternoon. SYNOPSIS: Enhanced NW flow aloft will persist across the region over the next several days. A cold front on Wednesday evening will bring a few rain showers to the region. 97 && .FIRE WEATHER... The regional weather pattern will direct enhanced winds from the west and northwest across the area over the next few days. Strong daytime and afternoon heating will easily bring low relative humidity and gusty winds up to 40 mph for many locations. Any chances for relief in the form of precipitation will remain north of the international border until Wednesday evening. Wednesday night, rainfall amounts will be light, if any at all. We are expecting Red Flag conditions today and Wednesday across the entire forecast area. Of the two days, Wednesday seems to be the day of greatest concern since temperatures will be warmer, humidity will be lower, and winds will be a bit stronger for some locations, compared with today. For today, the strongest west and slightly northwest winds will be in the north and east (Fire Weather Zones 120, 122, and 134) with relative humidity values bottoming out around 20%. Winds will temporarily subside tonight through early Wednesday morning. Expect winds to increase again again more from the northwest mid- day through Wednesday afternoon before tapering later Wednesday night. The lowest RH values Wednesday afternoon are expected in our southwest (Zone 137). Thursday should see a break from fire weather conditions, with relative humidity dropping not quite as low and winds barely in the 10 to 15 mph range. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until midnight MDT Wednesday night for MTZ120-122-134>137. Lake Wind Advisory until midnight MDT Wednesday night For Fort Peck Lake for Central and Southeast Phillips...Central and Southern Valley...Garfield...McCone...Petroleum. && weather.gov/glasgow
The national radar mosaic for the moment the first event began.
7 high wind, 1 wildfire. Local standard time, as filed.
At the Sioux Pass MT-16 DOT site (MTSOO), a 59 mph wind gust was recorded.
At the Malta South US-191 DOT site (MTMAL), sustained winds of at least 40 mph were recorded at least every hour for 6 hours through the mid day and afternoon. The peak wind gusts of 61 mph were recorded from 11:30 MST to 11:38 MST.
The Huff fire began on September 2nd on private land and was quickly spread toward the southeast by sustained winds of 45 mph and wind gusts up to 61 mph, narrowly missing the town of Jordan and crossing over Highway 200. The fire was not completely contained until the morning of September 10th.
From Saint Marie to Glasgow to Fort Peck Lake over the course of about three hours, sustained wind speeds of 40 mph or greater were common with occasional wind gusts of 58 mph or greater. The peak wind gust of 66 mph was recorded at 14:44 MST at the King Coulee RAWS site (KIGM8).
For about 2 hours at the Fort Peck Dam handar site (GGWFP), sustained winds of at least 40 mph and peak wind gusts of 61 mph were recorded.
At the Jordan airport ASOS site (KJDN), a 61 mph wind gust was recorded.
At the Lindsay Divide MT-200 DOT site (MTLND), 59 mph wind gusts were recorded for these two minutes.
Severe wind gusts lasted for a little more than one hour during the late afternoon, at the Beaver Hill I-94 DOT site (MTBVR). The peak wind gust of 71 mph was recorded at 15:55 MST.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2020Every state in 2020This day in weather historyWarnings in Montana, September 2020
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: 915184, 915206, 917805, 917789, 915410, 915202, 915198, 915424.