Alert archive / Montana / Tornado Watches in 2010
Tornado Watch 228
The Storm Prediction Center issued this tornado watch at May 27, 2010, 4:39 PM MDT for 14 counties in Montana; 8 counties in North Dakota. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- May 27, 2010, 4:39 PM MDT (22:39 UTC)
- Expired
- May 28, 2010, 1:00 AM MDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 22 counties
Big Horn County, MT, Carter County, MT, Custer County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Powder River County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Rosebud County, MT, Treasure County, MT, Wibaux County, MT, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, McKenzie County, ND, Slope County, ND, Stark County, ND, Williams County, ND
The radar
The Glasgow radar (KGGW), 157 km from the middle of the area, began a volume at 22:36 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
- 50%
- One or more EF2 to EF5 tornadoes
- 30%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 50%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
16 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 27, 8:34 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Prairie | 26 min |
| May 27, 8:58 PM MDT | Severe Thunderstorm Warning | GGW | McCone, Prairie | 47 min |
| May 27, 9:01 PM MDT | Tornado Warning | GGW | McCone, Prairie | 59 min |
| May 27, 9:25 PM MDT | Tornado Warning | GGW | Dawson, McCone, Prairie | 50 min |
| May 27, 9:29 PM MDT | Severe Thunderstorm Warning | GGW | McCone | 61 min |
| May 27, 9:57 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 23 min |
| May 27, 10:11 PM MDT | Severe Thunderstorm Warning | BYZ | Big Horn, Rosebud, Treasure, Yellowstone | 58 min |
| May 27, 10:14 PM MDT | Tornado Warning | GGW | Dawson, Richland | 31 min |
| May 27, 10:27 PM MDT | Severe Thunderstorm Warning | GGW | Garfield | 63 min |
| May 27, 10:43 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt, Valley | 62 min |
| May 27, 10:47 PM MDT | Tornado Warning | GGW | Garfield | 28 min |
| May 27, 10:55 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone | 64 min |
| May 27, 10:57 PM MDT | Severe Thunderstorm Warning | BYZ | Rosebud, Treasure | 63 min |
| May 27, 11:17 PM MDT | Severe Thunderstorm Warning | GGW | Daniels, Roosevelt, Valley | 58 min |
| May 27, 11:42 PM MDT | Severe Thunderstorm Warning | GGW | Garfield, McCone, Roosevelt | 63 min |
| May 28, 12:40 AM MDT | Severe Thunderstorm Warning | GGW | McCone, Roosevelt, Valley | 65 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, 10.7 hours before the alert went out and 356 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
- 13 J/kg
- Mixed-layer CIN
- -58 J/kg
- Mixed-layer LCL
- 788 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- -23 m²/s²
- 0-3 km storm-relative helicity
- 41 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 |
|---|---|---|---|---|
| May 26, 8:30 PM MDT | Mesoscale Discussion | SPC | Big Horn, Carter, Custer, Powder River, Rosebud, Treasure | 60 min |
| May 27, 2:35 PM MDT | Mesoscale Discussion | SPC | Cascade, Chouteau, Hill, Judith Basin, Liberty | 115 min |
| May 27, 2:54 PM MDT | Mesoscale Discussion | SPC | Big Horn, Custer, Dawson, Fallon, Garfield, McCone and 9 more | 96 min |
Nearby
Tornado Watches in Montana, 2010Tornado Watches in North Dakota, 2010Every tornado watch in 2010
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.