Alert archive / Montana / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 87, NWS Great Falls, MT
NWS Great Falls, MT issued this severe thunderstorm warning at Aug 21, 2009, 6:37 PM MDT for Lewis and Clark County, Montana. It was in force for 38 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 21, 2009, 6:37 PM MDT (00:37 UTC)
- Expired
- Aug 21, 2009, 7:15 PM MDT
- In force
- 38 min
- Issued by
- NWS Great Falls, MT
- Area
- Storm-based polygon
County Lewis and Clark County, MT
The radar
The Great Falls radar (KTFX), 85 km from the middle of the area, began a volume at 00:37 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, 0.6 hours before the alert went out and 140 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
- 520 J/kg
- Mixed-layer CIN
- -202 J/kg
- Mixed-layer LCL
- 2750 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 164 m²/s²
- 0-3 km storm-relative helicity
- 243 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
In the hours before
Special weather statement, Aug 21, 6:19 PM MDT, 18 minutes before
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</html>The office that day
Everything else NWS Great Falls, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 6:19 PM MDT | Special Weather Statement | TFX | Lewis and Clark | 56 min |
| Aug 21, 7:14 PM MDT | Special Weather Statement | TFX | Lewis and Clark | 46 min |
| Aug 21, 7:51 PM MDT | Special Weather Statement | TFX | Meagher | 39 min |
| Aug 21, 8:32 PM MDT | Special Weather Statement | TFX | Lewis and Clark | 58 min |
| Aug 21, 9:54 PM MDT | Special Weather Statement | TFX | Fergus | 66 min |
Nearby
Severe Thunderstorm Warnings in Montana, 2009Every severe thunderstorm warning in 2009
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.