Alert archive / Montana / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 685
The Storm Prediction Center issued this severe thunderstorm watch at Jul 25, 2011, 5:47 PM MDT for 14 counties in Montana; 9 counties in North Dakota. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 25, 2011, 5:47 PM MDT (23:47 UTC)
- Expired
- Jul 26, 2011, 1:00 AM MDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 65 kt
All 23 counties
Blaine County, MT, Chouteau County, MT, Dawson County, MT, Fergus County, MT, Garfield County, MT, Judith Basin County, MT, McCone County, MT, Petroleum County, MT, Phillips County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Valley County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, Hettinger County, ND, McKenzie County, ND, Slope County, ND, Stark County, ND
The radar
The Glasgow radar (KGGW), 68 km from the middle of the area, began a volume at 23:49 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 10%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 25, 7:37 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Phillips, Valley | 68 min |
| Jul 25, 8:00 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 60 min |
| Jul 25, 8:51 PM MDT | Tornado Warning | GGW | Garfield | 24 min |
| Jul 25, 9:11 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone | 64 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Great_falls, MT (KTFX), launched 12:00Z, 11.8 hours before the alert went out and 247 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
- 3543 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- -28 m²/s²
- 0-3 km storm-relative helicity
- 24 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 25, 11:23 AM MDT | Mesoscale Discussion | SPC | Carter, Powder River | 97 min |
| Jul 25, 1:30 PM MDT | Severe Thunderstorm Watch | SPC | Big Horn, Carter, Custer, Fallon, Powder River, Rosebud and 1 more | 8 hr |
| Jul 25, 2:23 PM MDT | Mesoscale Discussion | SPC | Broadwater, Cascade, Chouteau, Fergus, Gallatin, Golden Valley and 10 more | 97 min |
| Jul 25, 4:39 PM MDT | Mesoscale Discussion | SPC | Carter | 96 min |
| Jul 25, 5:15 PM MDT | Mesoscale Discussion | SPC | Dawson, Garfield, McCone, Phillips, Prairie, Richland and 3 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Montana, 2011Severe Thunderstorm Watches in North Dakota, 2011Every severe thunderstorm watch in 2011
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.