Alert archive / Iowa / Tornado Watches in 2021
Tornado Watch 16
The Storm Prediction Center issued this tornado watch at Mar 10, 2021, 2:46 PM CST for 34 counties in Iowa; 14 counties in Minnesota; Buffalo County, Pepin County, Pierce County, Wisconsin. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 10, 2021, 2:46 PM CST (20:46 UTC)
- Expired
- Mar 10, 2021, 8:00 PM CST
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 51 counties
Allamakee County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Buchanan County, IA, Butler County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Dallas County, IA, Fayette County, IA, Floyd County, IA, Franklin County, IA, Grundy County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Howard County, IA, Humboldt County, IA, Iowa County, IA, Jasper County, IA, Kossuth County, IA, Marshall County, IA, Mitchell County, IA, Palo Alto County, IA, Polk County, IA, Poweshiek County, IA, Story County, IA, Tama County, IA, Webster County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Wright County, IA, Dakota County, MN, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Winona County, MN, Buffalo County, WI, Pepin County, WI, Pierce County, WI
The radar
The La Crosse radar (KARX), 133 km from the middle of the area, began a volume at 20:46 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
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 70%
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 |
|---|---|---|---|---|
| Mar 10, 4:13 PM CST | Tornado Warning | MPX | Dakota, Rice, Scott | 14 min |
| Mar 10, 4:23 PM CST | Tornado Warning | MPX | Le Sueur, Rice, Waseca | 26 min |
| Mar 10, 4:36 PM CST | Tornado Warning | MPX | Dakota, Rice, Scott | 24 min |
| Mar 10, 4:47 PM CST | Tornado Warning | MPX | Dakota, Rice | 28 min |
| Mar 10, 5:15 PM CST | Tornado Warning | MPX | Dakota, Rice | 30 min |
| Mar 10, 5:27 PM CST | Severe Thunderstorm Warning | MPX | Dakota, Ramsey, Washington | 29 min |
| Mar 10, 5:34 PM CST | Severe Thunderstorm Warning | DMX | Grundy, Marshall | 24 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 12:00Z, 8.8 hours before the alert went out and 208 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
- 946 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 76 m²/s²
- 0-3 km storm-relative helicity
- 219 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
106 WWUS20 KWNS 102043 SEL6 SPC WW 102043 IAZ000-MNZ000-WIZ000-110200- URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 16 NWS Storm Prediction Center Norman OK 240 PM CST Wed Mar 10 2021 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of central and northeastern Iowa southeastern Minnesota a small portion of west central Wisconsin * Effective this Wednesday afternoon and evening from 240 PM until 800 PM CST. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Scattered severe thunderstorms are expected to develop by late this afternoon. This may include a few supercells with the potential to produce tornadoes, before a broken squall line evolves and advances eastward with damaging wind gusts likely becoming the primary severe hazard this evening. The tornado watch area is approximately along and 70 statute miles east and west of a line from 25 miles north northeast of Rochester MN to 5 miles southeast of Des Moines IA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and 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. && AVIATION...Tornadoes and 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 400. Mean storm motion vector 23040. ...Kerr
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 10, 1:32 PM CST | Mesoscale Discussion | SPC | Adair, Audubon, Benton, Black Hawk, Boone, Bremer and 38 more | 118 min |
| Mar 10, 5:43 PM CST | Mesoscale Discussion | SPC | Allamakee, Benton, Black Hawk, Bremer, Buchanan, Butler and 21 more | 2 hr |
Nearby
Tornado Watches in Iowa, 2021Tornado Watches in Minnesota, 2021Tornado Watches in Wisconsin, 2021Every tornado 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.