Alert archive / Montana / Special Weather Statements in 2021
Special Weather Statement, NWS Great Falls, MT
NWS Great Falls, MT issued this special weather statement at Aug 8, 2021, 8:39 PM MDT for Jefferson County, Montana. It was in force for 51 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 8, 2021, 8:39 PM MDT (02:39 UTC)
- Expired
- Aug 8, 2021, 9:30 PM MDT
- In force
- 51 min
- Issued by
- NWS Great Falls, MT
- Hail
- 0.75 in
- Wind
- 40
County Jefferson County, MT
The radar
The Great Falls radar (KTFX), 191 km from the middle of the area, began a volume at 02:43 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 00:00Z, 2.7 hours before the alert went out and 213 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
- 633 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 42 m²/s²
- 0-3 km storm-relative helicity
- -108 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
323
WWUS85 KTFX 090239
SPSTFX
Special Weather Statement
National Weather Service Great Falls MT
839 PM MDT Sun Aug 8 2021
MTZ015-052-090330-
Madison MT-Jefferson MT-
839 PM MDT Sun Aug 8 2021
...Strong thunderstorms will impact portions of northern Madison and
southern Jefferson Counties through 930 PM MDT...
At 838 PM MDT, Doppler radar was tracking a strong thunderstorm near
Whitehall, or 22 miles southeast of Butte, moving east at 40 mph.
HAZARD...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...
Whitehall, Twin Bridges, Silver Star, Harrison, Pony, Cardwell, Lewis
And Clark Caverns State Park and Waterloo.
This includes the following highways...
Interstate 90 between mile markers 235 and 271.
Highway 287 between mile markers 68 and 81, and between mile markers
83 and 88.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.
&&
LAT...LON 4574 11248 4575 11219 4585 11243 4593 11242
4605 11172 4604 11166 4584 11166 4580 11171
4579 11180 4577 11173 4574 11172 4574 11166
4563 11150 4549 11249
TIME...MOT...LOC 0238Z 253DEG 35KT 4580 11213
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH
$$
HARTThe office that day
Everything else NWS Great Falls, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 6:45 PM MDT | Special Weather Statement | TFX | Gallatin | 45 min |
| Aug 8, 6:51 PM MDT | Special Weather Statement | TFX | Glacier | 24 min |
| Aug 8, 7:27 PM MDT | Special Weather Statement | TFX | Beaverhead | 48 min |
| Aug 8, 7:51 PM MDT | Special Weather Statement | TFX | Beaverhead | 39 min |
| Aug 8, 8:09 PM MDT | Special Weather Statement | TFX | Silver Bow | 36 min |
| Aug 8, 9:17 PM MDT | Special Weather Statement | TFX | Gallatin | 28 min |
| Aug 9, 3:47 AM MDT | Areal Flood Advisory | TFX | Glacier, Pondera, Toole | 3 hr |
Nearby
Special Weather Statements in Montana, 2021Every special weather statement 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.