Alert archive / Wisconsin / Tornado Watches in 2018
Tornado Watch 385
The Storm Prediction Center issued this tornado watch at Sep 20, 2018, 6:23 PM CDT for 6 counties in Iowa; 7 counties in Minnesota; 20 counties in Wisconsin. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 20, 2018, 6:23 PM CDT (23:23 UTC)
- Expired
- Sep 20, 2018, 11:29 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 65 kt
All 33 counties
Allamakee County, IA, Chickasaw County, IA, Floyd County, IA, Howard County, IA, Mitchell County, IA, Winneshiek County, IA, Dodge County, MN, Fillmore County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Wabasha County, MN, Winona County, MN, Adams County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Lincoln County, WI, Marathon County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Portage County, WI, Saint Croix County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Wood County, WI
The radar
The La Crosse radar (KARX), 60 km from the middle of the area, began a volume at 23:25 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
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 70%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
14 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 20, 6:38 PM CDT | Severe Thunderstorm Warning | ARX | Dodge, Mower, Olmsted | 52 min |
| Sep 20, 6:46 PM CDT | Tornado Warning | ARX | Dodge | 29 min |
| Sep 20, 7:04 PM CDT | Severe Thunderstorm Warning | ARX | Olmsted, Wabasha, Winona | 56 min |
| Sep 20, 7:13 PM CDT | Tornado Warning | ARX | Wabasha | 32 min |
| Sep 20, 7:13 PM CDT | Tornado Warning | MPX | Dunn, Pepin, Pierce | 36 min |
| Sep 20, 7:37 PM CDT | Severe Thunderstorm Warning | MPX | Chippewa, Dunn, Eau Claire, Pepin, Saint Croix | 38 min |
| Sep 20, 7:53 PM CDT | Severe Thunderstorm Warning | ARX | Buffalo, Trempealeau | 37 min |
| Sep 20, 8:08 PM CDT | Severe Thunderstorm Warning | MPX | Chippewa, Eau Claire | 37 min |
| Sep 20, 8:13 PM CDT | Severe Thunderstorm Warning | ARX | Howard, Mitchell | 47 min |
| Sep 20, 8:33 PM CDT | Severe Thunderstorm Warning | ARX | Howard | 42 min |
| Sep 20, 8:53 PM CDT | Severe Thunderstorm Warning | ARX | Clark | 40 min |
| Sep 20, 8:57 PM CDT | Severe Thunderstorm Warning | GRB | Marathon, Portage, Wood | 48 min |
| Sep 20, 9:42 PM CDT | Severe Thunderstorm Warning | GRB | Langlade, Lincoln, Marathon | 48 min |
| Sep 20, 10:09 PM CDT | Severe Thunderstorm Warning | GRB | Marathon, Portage, Wood | 51 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, 11.4 hours before the alert went out and 174 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
- 18 J/kg
- Mixed-layer CIN
- -80 J/kg
- Mixed-layer LCL
- 461 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 195 m²/s²
- 0-3 km storm-relative helicity
- 20 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted.
875
WWUS20 KWNS 202322
SEL5
SPC WW 202322
IAZ000-MNZ000-WIZ000-210500-
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 385
NWS Storm Prediction Center Norman OK
625 PM CDT Thu Sep 20 2018
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Northeast Iowa
Southeast Minnesota
Western and central Wisconsin
* Effective this Thursday night from 625 PM until Midnight CDT.
* Primary threats include...
A couple tornadoes possible
Scattered damaging winds likely with isolated significant gusts
to 75 mph possible
SUMMARY...Fast-moving squall line with embedded bowing segments will
be capable of producing isolated to scattered severe wind gusts and
a brief tornado.
The tornado watch area is approximately along and 65 statute miles
north and south of a line from 20 miles west southwest of Rochester
MN to 15 miles south southeast of Mosinee WI. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU5).
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.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 383...WW 384...
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 25050.
...GramsSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 20, 2:15 PM CDT | Mesoscale Discussion | SPC | Buena Vista, Cerro Gordo, Cherokee, Clay, Dickinson, Emmet and 12 more | 3 hr |
| Sep 20, 2:31 PM CDT | Mesoscale Discussion | SPC | Adair, Adams, Audubon, Boone, Buena Vista, Calhoun and 23 more | 119 min |
| Sep 20, 3:11 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Adams, Audubon, Boone, Buena Vista, Calhoun and 38 more | 8 hr |
| Sep 20, 5:29 PM CDT | Mesoscale Discussion | SPC | Allamakee | 2 hr |
| Sep 20, 5:48 PM CDT | Mesoscale Discussion | SPC | Audubon, Boone, Bremer, Buena Vista, Butler, Calhoun and 37 more | 57 min |
| Sep 20, 3:33 PM CDT | Tornado Watch | SPC | Blue Earth, Brown, Carver, Cottonwood, Dakota, Faribault and 22 more | 4 hr |
Nearby
Tornado Watches in Wisconsin, 2018Tornado Watches in Minnesota, 2018Tornado Watches in Iowa, 2018Every tornado watch in 2018
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.