Alert archive / Minnesota / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 389
The Storm Prediction Center issued this severe thunderstorm watch at Jul 23, 2021, 11:22 PM CDT for 22 counties in Minnesota. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 23, 2021, 11:22 PM CDT (04:22 UTC)
- Expired
- Jul 24, 2021, 3:36 AM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 22 counties
Anoka County, MN, Benton County, MN, Big Stone County, MN, Chippewa County, MN, Douglas County, MN, Grant County, MN, Isanti County, MN, Kanabec County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, Meeker County, MN, Mille Lacs County, MN, Morrison County, MN, Otter Tail County, MN, Pope County, MN, Sherburne County, MN, Stearns County, MN, Stevens County, MN, Swift County, MN, Todd County, MN, Traverse County, MN, Wilkin County, MN
The radar
The Minneapolis radar (KMPX), 206 km from the middle of the area, began a volume at 04:25 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
- 20%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 24, 12:41 AM CDT | Severe Thunderstorm Warning | FGF | Grant, Otter Tail, Wilkin | 49 min |
| Jul 24, 12:43 AM CDT | Severe Thunderstorm Warning | ABR | Big Stone, Traverse | 47 min |
| Jul 24, 12:58 AM CDT | Severe Thunderstorm Warning | FGF | Grant | 47 min |
| Jul 24, 1:05 AM CDT | Severe Thunderstorm Warning | FGF | Becker, Otter Tail | 40 min |
| Jul 24, 1:34 AM CDT | Severe Thunderstorm Warning | FGF | Grant, Otter Tail | 41 min |
| Jul 24, 1:37 AM CDT | Severe Thunderstorm Warning | MPX | Morrison, Stearns, Todd | 38 min |
| Jul 24, 1:51 AM CDT | Severe Thunderstorm Warning | FGF | Otter Tail, Wadena | 39 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
Minneapolis, MN (KMPX), launched 00:00Z, 4.4 hours before the alert went out and 204 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
- 2540 J/kg
- Mixed-layer CIN
- -32 J/kg
- Mixed-layer LCL
- 1098 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 124 m²/s²
- 0-3 km storm-relative helicity
- 143 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 6.4
The text
As transmitted.
220 WWUS20 KWNS 240421 SEL9 SPC WW 240421 MNZ000-241000- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 389 NWS Storm Prediction Center Norman OK 1120 PM CDT Fri Jul 23 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of West-central Minnesota * Effective this Friday night and Saturday morning from 1120 PM until 500 AM CDT. * Primary threats include... Isolated damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A complex of thunderstorms initially over northeastern SD and southeastern ND, which has a history of producing measured severe gusts, may persist at severe levels through a channel of relatively unstable and weakly capped boundary-layer air and into the watch. This activity will be preceded by a smaller convective cluster that also has produced severe gusts in Marshall County SD. Isolated large hail also may be noted. The severe thunderstorm watch area is approximately along and 50 statute miles north and south of a line from 40 miles north of Ortonville MN to 40 miles southeast of Alexandria MN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 387...WW 388... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 29030. ...Edwards
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 23, 7:44 PM CDT | Mesoscale Discussion | SPC | Aitkin, Carlton, Cass, Lake, Saint Louis | 2 hr |
| Jul 23, 9:07 PM CDT | Mesoscale Discussion | SPC | Lac qui Parle, Lincoln, Lyon, Murray, Pipestone, Redwood and 2 more | 2 hr |
| Jul 23, 10:33 PM CDT | Mesoscale Discussion | SPC | Big Stone, Clay, Grant, Otter Tail, Stevens, Traverse and 1 more | 117 min |
| Jul 24, 1:10 AM CDT | Mesoscale Discussion | SPC | Big Stone, Chippewa, Douglas, Grant, Kandiyohi, Meeker and 9 more | 95 min |
Nearby
Severe Thunderstorm Watches in Minnesota, 2021Every severe thunderstorm watch in 2021
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.