A disturbance brought enough instability to the region to generate a few thunderstorms, which produced strong to severe wind gusts and some hail.
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The episode as NWS GGW wrote it up.
A disturbance brought enough instability to the region to generate a few thunderstorms, which produced strong to severe wind gusts and some hail.
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 Aug 11, 1:38 PM MST, 3 hours 2 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 238 PM MDT Fri Aug 11 2017 .SHORT TERM...for northeast Montana...tonight through Sat... Isolated to widely scattered showers continue to cross portions of the CWA this afternoon in response to an advancing upper level trough. SPC has maintained a marginal risk for the SE zones and radar echoes indicate convection initiation upstream of the forecast area in adjacent southern Canada as well as the higher terrain of central Montana. While coverage would be isolated given only marginal convective parameters, did mention gusty winds and small hail in the grids for any of the stronger storms. Any activity is expected to clear late tonight with drier weather conditions on Saturday in advance of an approaching upper level ridge. Maliawco .LONG TERM...Sat night through Fri... The extended period picks up the forecast Saturday evening with the short-wave trough departing east, and a narrow amplified upper-level ridge axis moving across the Divide. The main item of interest will be the departing showers and thunderstorms. There may be enough convective energy to produce a few strong evening storms in the vicinity of the Yellowstone River Valley. Sunday, the ridge moves across the area for dry weather conditions. Thickness heights will ramp up from around 565dm now to 573dm Sunday afternoon. Temperatures will then trend up closer to normal: highs in the upper 70s in the northeast zones to the mid 80s in the southwest zones. One item to keep monitoring will be the southeast winds that are expected to reach 10-15kt. If they go higher, an NPW may be necessary. Sunday night through Monday night, a trough extension from the Alaska upper low will reach through western Canada into the Northern Rockies to send a cold front through the Northern high Plains. With a Pacific moisture fetch, rain showers and thunderstorms could begin Sunday evening and sweep across the area Monday. With increasingly unstable conditions before the front passes through, storms may intensify Monday afternoon and evening before exiting into the Dakotas. Model timing, plus or minus around 6 hours, remains a bit uncertain as to the exact timing of the front. But both the EC and the GFS suggest areas of wetting rains. Tuesday and beyond, after the front blows through, the area looks dry-slotted with near normal temperatures. A broad trough through the middle of the week will also put a lit on temperatures. Then late in the week a broad but shallow upper ridge will spread across the area, allowing highs to possibly reach normal. Forecast generally remains on track, with the main edits tweaking through the wet period. Templer Previous discussion - The trough moves to the east Saturday Night and an upper level ridge will be over Montana and Saskatchewan on Sunday with dry weather. The ridge moves to the east Sunday Night and flow aloft turns to the southwest as an upper trough moves inland from the Pacific. Models bring a shortwave in the SW flow aloft across the forecast area Monday afternoon and night with a chance of showers and thunderstorms. A few showers could linger in the east on Tuesday as the wave moves into the Dakotas. Otherwise, a more zonal flow aloft will allow for mainly dry weather. Surface high in zonal flow aloft will keep dry weather over the area on Wednesday and Thursday with temperatures near normal for mid August. A shortwave trough in the zonal flow aloft Thursday Night and Friday lacks moisture at this point. Will maintain dry forecast. Forrester && .AVIATION... VFR conditions will continue into tonight, though isolated to scattered showers and thunderstorms are expected at times. The primary impacts would come from gust and shifting winds associated with this activity. East winds of around 10 kts will also continue into tonight. Maliawco && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && weather.gov/glasgow
Special Weather Statement National Weather Service Glasgow MT 501 PM MDT FRI AUG 11 2017 MTZ024-025-112345- Richland MT-Dawson MT- 501 PM MDT FRI AUG 11 2017 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL RICHLAND AND NORTH CENTRAL DAWSON COUNTIES UNTIL 545 PM MDT... At 500 PM MDT, Doppler radar was tracking a strong thunderstorm 8 miles northwest of Lambert, or 28 miles west of Sidney, moving east at 20 mph. Dime size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Lambert and Enid. 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 4770 10491 4787 10482 4780 10436 4754 10450 TIME...MOT...LOC 2300Z 290DEG 17KT 4776 10476 TFJ
The Glasgow radar (KGGW), 164 km away, was scanning. The volume nearest the first event began at 23:37 UTC.
1 thunderstorm wind. Local standard time, as filed.
A trained spotter experienced winds associated with a severe thunderstorm estimated at 55 to 60 mph. The spotter observed that the town of Lambert 5 miles to the north appeared to be covered white with hail.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2017Every state in 2017This day in weather historyWarnings in Montana, August 2017
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: 716339.