Alert archive / Minnesota / Severe Thunderstorm Watches in 2020
Severe Thunderstorm Watch 447
The Storm Prediction Center issued this severe thunderstorm watch at Aug 21, 2020, 6:20 PM CDT for 34 counties in Minnesota. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 21, 2020, 6:20 PM CDT (23:20 UTC)
- Expired
- Aug 22, 2020, 2:00 AM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 34 counties
Blue Earth County, MN, Brown County, MN, Carver County, MN, Chippewa County, MN, Cottonwood County, MN, Dakota County, MN, Faribault County, MN, Freeborn County, MN, Hennepin County, MN, Jackson County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, Le Sueur County, MN, Lincoln County, MN, Lyon County, MN, Martin County, MN, McLeod County, MN, Meeker County, MN, Murray County, MN, Nicollet County, MN, Pope County, MN, Redwood County, MN, Renville County, MN, Rice County, MN, Scott County, MN, Sibley County, MN, Stearns County, MN, Steele County, MN, Stevens County, MN, Swift County, MN, Waseca County, MN, Watonwan County, MN, Wright County, MN, Yellow Medicine County, MN
The radar
The Minneapolis radar (KMPX), 124 km from the middle of the area, began a volume at 23:22 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
- 30%
- One or more gusts of 65 knots or more
- 10%
- 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
- 50%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 6:39 PM CDT | Severe Thunderstorm Warning | MPX | Pope, Stevens, Swift | 51 min |
| Aug 21, 7:20 PM CDT | Severe Thunderstorm Warning | MPX | Chippewa, Kandiyohi, Pope, Swift | 55 min |
| Aug 22, 1:22 AM CDT | Flash Flood Warning | MPX | Blue Earth, Brown, Nicollet | 4 hr |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Aberdeen, SD (KABR), launched 12:00Z, 11.3 hours before the alert went out and 258 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
- 1536 J/kg
- Mixed-layer CIN
- -277 J/kg
- Mixed-layer LCL
- 1392 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 16 m²/s²
- 0-3 km storm-relative helicity
- 36 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.4
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 5:02 PM CDT | Mesoscale Discussion | SPC | Big Stone, Chippewa, Kandiyohi, Lac qui Parle, Redwood, Stevens and 2 more | 58 min |
Nearby
Severe Thunderstorm Watches in Minnesota, 2020Every severe thunderstorm watch in 2020
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.