Alert archive / Montana / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 688
The Storm Prediction Center issued this severe thunderstorm watch at Jul 26, 2011, 2:43 PM MDT for 11 counties in Montana; Divide County, Williams County, North Dakota. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 26, 2011, 2:43 PM MDT (20:43 UTC)
- Expired
- Jul 26, 2011, 7:59 PM MDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Daniels County, MT, Dawson County, MT, Garfield County, MT, McCone County, MT, Petroleum County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT, Wibaux County, MT, Divide County, ND, Williams County, ND
The radar
The Glasgow radar (KGGW), 86 km from the middle of the area, began a volume at 20:42 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
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 26, 3:11 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum | 36 min |
| Jul 26, 3:24 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt, Sheridan | 66 min |
| Jul 26, 3:54 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Petroleum, Phillips | 66 min |
| Jul 26, 4:25 PM MDT | Severe Thunderstorm Warning | GGW | Roosevelt, Sheridan | 55 min |
| Jul 26, 4:39 PM MDT | Severe Thunderstorm Warning | BIS | Divide, Williams | 51 min |
| Jul 26, 4:56 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, Valley | 64 min |
| Jul 26, 5:53 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone | 37 min |
| Jul 26, 6:04 PM MDT | Severe Thunderstorm Warning | BIS | Williams | 28 min |
| Jul 26, 6:12 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Valley | 48 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
Glasgow Intl Airport, MT (KGGW), launched 12:00Z, 8.7 hours before the alert went out and 84 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
- 0 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- -88 m²/s²
- 0-3 km storm-relative helicity
- -31 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.3
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 25, 9:07 PM MDT | Mesoscale Discussion | SPC | Dawson, McCone, Prairie | 83 min |
| Jul 26, 9:45 AM MDT | Mesoscale Discussion | SPC | Roosevelt, Sheridan | 60 min |
| Jul 26, 1:07 PM MDT | Mesoscale Discussion | SPC | Daniels, Dawson, Fallon, Garfield, McCone, Petroleum and 7 more | 53 min |
| Jul 26, 2:59 PM MDT | Mesoscale Discussion | SPC | Dickey, Emmons, LaMoure, Logan, McIntosh, Sargent and 1 more | 2 hr |
| Jul 26, 4:21 PM MDT | Tornado Watch | SPC | Dickey, Emmons, LaMoure, Logan, McIntosh, Sioux | 5 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.