Alert archive / Minnesota / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 516
The Storm Prediction Center issued this severe thunderstorm watch at Oct 10, 2021, 1:42 PM CDT for 5 counties in Minnesota. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 10, 2021, 1:42 PM CDT (18:42 UTC)
- Expired
- Oct 10, 2021, 8:25 PM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 55 kt
Counties Cook County, MN, Itasca County, MN, Koochiching County, MN, Lake County, MN, Saint Louis County, MN
The radar
The Duluth radar (KDLH), 115 km from the middle of the area, began a volume at 18:42 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
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 20%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 10, 2:26 PM CDT | Tornado Warning | DLH | Itasca, Koochiching, Saint Louis | 34 min |
| Oct 10, 2:31 PM CDT | Severe Thunderstorm Warning | DLH | Saint Louis | 29 min |
| Oct 10, 2:42 PM CDT | Tornado Warning | DLH | Saint Louis | 18 min |
| Oct 10, 3:02 PM CDT | Severe Thunderstorm Warning | DLH | Saint Louis | 28 min |
| Oct 10, 3:14 PM CDT | Severe Thunderstorm Warning | DLH | Lake, Saint Louis | 31 min |
| Oct 10, 3:41 PM CDT | Severe Thunderstorm Warning | DLH | Lake, Saint Louis | 49 min |
| Oct 10, 4:19 PM CDT | Severe Thunderstorm Warning | DLH | Saint Louis | 26 min |
| Oct 10, 5:28 PM CDT | Severe Thunderstorm Warning | DLH | Cook | 47 min |
| Oct 10, 5:36 PM CDT | Tornado Warning | DLH | Cook | 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
International Fa, MN (KINL), launched 12:00Z, 6.7 hours before the alert went out and 95 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1493 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 22 m²/s²
- 0-3 km storm-relative helicity
- -10 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
284
WWUS20 KWNS 101838
SEL6
SPC WW 101838
MNZ000-LSZ000-110200-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 516
NWS Storm Prediction Center Norman OK
140 PM CDT Sun Oct 10 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Northeast Minnesota
Lake Superior
* Effective this Sunday afternoon and evening from 140 PM until
900 PM CDT.
* Primary threats include...
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
Isolated damaging wind gusts to 65 mph possible
A tornado or two possible
SUMMARY...Scattered thunderstorms will continue to intensify this
afternoon over northeast Minnesota, before the storms move northward
into Canada. The strongest cells will be capable of large hail and
gusty winds. An isolated tornado or two is also possible.
The severe thunderstorm watch area is approximately along and 45
statute miles north and south of a line from 80 miles west northwest
of Hibbing MN to 20 miles south southeast of Grand Marais MN. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU6).
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.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 55 knots. A
few cumulonimbi with maximum tops to 450. Mean storm motion vector
20030.
...HartSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 9, 8:27 PM CDT | Mesoscale Discussion | SPC | Becker, Douglas, Grant, Otter Tail, Pope, Stevens and 4 more | 93 min |
| Oct 9, 11:20 PM CDT | Mesoscale Discussion | SPC | Benton, Cass, Chippewa, Crow Wing, Kandiyohi, Lac qui Parle and 7 more | 115 min |
| Oct 10, 12:57 PM CDT | Mesoscale Discussion | SPC | Itasca, Koochiching, Lake, Lake of the Woods, Saint Louis | 2 hr |
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.