Alert archive / Montana / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 61, NWS Great Falls, MT
NWS Great Falls, MT issued this severe thunderstorm warning at Aug 17, 2021, 3:00 PM MDT for Beaverhead County, Madison County, Montana. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 17, 2021, 3:00 PM MDT (21:00 UTC)
- Expired
- Aug 17, 2021, 3:30 PM MDT
- In force
- 30 min
- Issued by
- NWS Great Falls, MT
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Beaverhead County, MT, Madison County, MT
The radar
The Missoula radar (KMSX), 198 km from the middle of the area, began a volume at 21:03 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Great_falls, MT (KTFX), launched 12:00Z, 9.0 hours before the alert went out and 240 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2898 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 15 m²/s²
- 0-3 km storm-relative helicity
- 155 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
370
WUUS55 KTFX 172100
SVRTFX
MTC001-057-172130-
/O.NEW.KTFX.SV.W.0061.210817T2100Z-210817T2130Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Great Falls MT
300 PM MDT Tue Aug 17 2021
The National Weather Service in Great Falls has issued a
* Severe Thunderstorm Warning for...
Northwestern Madison County in southwestern Montana...
Central Beaverhead County in southwestern Montana...
* Until 330 PM MDT.
* At 258 PM MDT, a severe thunderstorm was located near Twin Bridges,
or 12 miles northwest of Sheridan, moving northeast at 45 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated. Additionally, 60 mph wind gust reported
at Dillon Airport.
IMPACT...Expect damage to roofs, siding, and trees.
* Locations impacted include...
Sheridan, Twin Bridges, Silver Star, Harrison, Pony, Waterloo and
Glen.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4568 11258 4570 11253 4576 11250 4574 11247
4575 11217 4585 11209 4585 11199 4568 11168
4519 11234 4547 11280
TIME...MOT...LOC 2058Z 210DEG 42KT 4555 11241
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH
$$
mpj1 follow-up statement
021
WWUS55 KTFX 172125
SVSTFX
Severe Weather Statement
National Weather Service Great Falls MT
325 PM MDT Tue Aug 17 2021
MTC001-057-172134-
/O.EXP.KTFX.SV.W.0061.000000T0000Z-210817T2130Z/
Madison MT-Beaverhead MT-
325 PM MDT Tue Aug 17 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN MADISON AND
CENTRAL BEAVERHEAD COUNTIES WILL EXPIRE AT 330 PM MDT...
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire. However gusty winds and heavy rain are still
possible with multiple thunderstorms moving through the region.
LAT...LON 4568 11258 4570 11253 4576 11250 4574 11247
4575 11217 4585 11209 4585 11199 4568 11168
4519 11234 4547 11280
TIME...MOT...LOC 2124Z 210DEG 42KT 4571 11228
$$
mpjThe office that day
Everything else NWS Great Falls, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 2:53 PM MDT | Special Weather Statement | TFX | Broadwater, Jefferson | 52 min |
| Aug 17, 3:33 PM MDT | Special Weather Statement | TFX | Beaverhead, Broadwater, Cascade, Gallatin, Jefferson, Judith Basin and 3 more | 57 min |
| Aug 17, 4:38 PM MDT | Special Weather Statement | TFX | Cascade, Chouteau | 52 min |
| Aug 17, 4:51 PM MDT | Special Weather Statement | TFX | Gallatin | 54 min |
| Aug 17, 5:42 PM MDT | Special Weather Statement | TFX | Chouteau, Hill | 63 min |
Nearby
Severe Thunderstorm Warnings in Montana, 2021Every severe thunderstorm warning in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.