Alert archive / Montana / Severe Thunderstorm Watches in 2007
Severe Thunderstorm Watch 537
The Storm Prediction Center issued this severe thunderstorm watch at Jul 18, 2007, 6:18 PM PDT for Bonner County, Boundary County, Shoshone County, Idaho; 6 counties in Montana. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 18, 2007, 6:18 PM PDT (01:18 UTC)
- Expired
- Jul 19, 2007, 12:00 AM PDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 70 kt
Counties Bonner County, ID, Boundary County, ID, Shoshone County, ID, Flathead County, MT, Lake County, MT, Lincoln County, MT, Mineral County, MT, Missoula County, MT, Sanders County, MT
The radar
The Missoula radar (KMSX), 150 km from the middle of the area, began a volume at 01:19 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
- 5%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- 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
- 10%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 18, 6:28 PM PDT | Severe Thunderstorm Warning | MSO | Sanders | 9 min |
| Jul 18, 6:32 PM PDT | Tornado Warning | MSO | Lake, Sanders | 28 min |
| Jul 18, 6:59 PM PDT | Tornado Warning | MSO | Lake | 46 min |
| Jul 18, 7:24 PM PDT | Severe Thunderstorm Warning | MSO | Flathead | 51 min |
| Jul 18, 7:29 PM PDT | Severe Thunderstorm Warning | MSO | Lincoln | 46 min |
| Jul 18, 7:38 PM PDT | Tornado Warning | MSO | Flathead, Lake | 52 min |
| Jul 18, 8:08 PM PDT | Severe Thunderstorm Warning | MSO | Flathead | 67 min |
| Jul 18, 8:10 PM PDT | Severe Thunderstorm Warning | MSO | Lincoln | 50 min |
| Jul 18, 8:23 PM PDT | Flash Flood Warning | MSO | Flathead, Lincoln | 3 hr |
| Jul 18, 8:37 PM PDT | Severe Thunderstorm Warning | MSO | Sanders | 38 min |
| Jul 18, 9:07 PM PDT | Severe Thunderstorm Warning | MSO | Flathead | 38 min |
| Jul 18, 10:18 PM PDT | Severe Thunderstorm Warning | MSO | Lincoln | 42 min |
| Jul 18, 11:16 PM PDT | Severe Thunderstorm Warning | MSO | Lincoln | 29 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
Spokane, WA (KOTX), launched 00:00Z, 1.3 hours before the alert went out and 93 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
- 114 J/kg
- Mixed-layer CIN
- -269 J/kg
- Mixed-layer LCL
- 1909 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 51 m²/s²
- 0-3 km storm-relative helicity
- 130 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 18, 9:11 PM PDT | Mesoscale Discussion | SPC | Flathead, Lake, Lincoln, Mineral, Missoula, Sanders | 94 min |
| Jul 19, 12:46 PM PDT | Mesoscale Discussion | SPC | Big Horn, Blaine, Carbon, Cascade, Chouteau, Fergus and 19 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Montana, 2007Severe Thunderstorm Watches in Idaho, 2007Every severe thunderstorm watch in 2007
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.