Alert archive / Wisconsin / Tornado Warnings in 2026

Tornado Warning 81, NWS Milwaukee, WI

August 18, 2026Columbia County, Sauk County, Wisconsin

NWS Milwaukee, WI issued this tornado warning at Aug 18, 2026, 4:48 PM CDT for Columbia County, Sauk County, Wisconsin. It was in force for 42 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 18, 2026, 4:48 PM CDT (21:48 UTC)
Expired
Aug 18, 2026, 5:30 PM CDT
In force
42 min
Issued by
NWS Milwaukee, WI
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Columbia County, WI, Sauk County, WI

The radar

The La Crosse radar (KARX), 112 km from the middle of the area, began a volume at 21:49 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 was reported inside it

TimeReportWhereRemark
Aug 18, 4:48 PM CDTTSTM WND DMG1 Ene Reedsburg, WIDelayed report of broken limbs and down trees in Reedsburg. Time estimated from radar.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 18, 2:48 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 9.8 hours before the alert went out and 332 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.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2026-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1301 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2026-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 72 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1301 J/kg
Mixed-layer CIN
-78 J/kg
Mixed-layer LCL
956 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
88 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.9

Open this sounding in Storm Lab

The text

As transmitted.

978 
WFUS53 KMKX 182148
TORMKX
WIC021-111-182230-
/O.NEW.KMKX.TO.W.0081.260818T2148Z-260818T2230Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Milwaukee/Sullivan WI
448 PM CDT Tue Aug 18 2026

The National Weather Service in Milwaukee/Sullivan has issued a

* Tornado Warning for...
  Western Columbia County in south central Wisconsin...
  Northeastern Sauk County in south central Wisconsin...

* Until 530 PM CDT.

* At 447 PM CDT, a severe thunderstorm capable of producing a tornado
  was located near Reedsburg, moving east at 45 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Baraboo, Wisconsin Dells, Lake Delton, and West Baraboo around 455 
  PM CDT.
  Lake Wisconsin around 505 PM CDT.
  Portage around 510 PM CDT.

Other locations impacted by this tornadic thunderstorm include Rock
Springs, Okee, North Freedom, Devils Lake St Park, and Merrimac.

Other landmarks included are the following Locations Mirror Lake
State Park, Gibraltar Rock Natural Area County Park, Pine Island
State Wildlife Area, and Kilbourn Dam.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4364 9005 4364 8946 4329 8960 4353 9009
TIME...MOT...LOC 2147Z 290DEG 40KT 4357 8994 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

SHEPPARD
1 follow-up statement
436 
WWUS53 KMKX 182205
SVSMKX

Severe Weather Statement
National Weather Service Milwaukee/Sullivan WI
505 PM CDT Tue Aug 18 2026

WIC021-111-182230-
/O.CON.KMKX.TO.W.0081.000000T0000Z-260818T2230Z/
Columbia WI-Sauk WI-
505 PM CDT Tue Aug 18 2026

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM CDT FOR WESTERN
COLUMBIA AND NORTHEASTERN SAUK COUNTIES...

At 504 PM CDT, a severe thunderstorm capable of producing a tornado
was located over Lake Delton, or near Wisconsin Dells, moving east at
40 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

This dangerous storm will be near...
  Baraboo around 510 PM CDT.
  Portage around 515 PM CDT.

Other locations impacted by this tornadic thunderstorm include Devils
Lake St Park, Okee, and Merrimac.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4364 8982 4364 8946 4329 8960 4341 8985
TIME...MOT...LOC 2204Z 286DEG 34KT 4356 8976 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

SHEPPARD

The office that day

Everything else NWS Milwaukee, WI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 18, 2:44 PM CDTSpecial Weather StatementMKXDodge61 min
Aug 18, 3:57 PM CDTSevere Thunderstorm WarningMKXColumbia, Sauk78 min
Aug 18, 3:59 PM CDTSevere Thunderstorm WarningMKXGreen Lake, Marquette76 min
Aug 18, 4:11 PM CDTSpecial Marine WarningMKX2 hr
Aug 18, 4:12 PM CDTTornado WarningMKXGreen Lake, Marquette48 min
Aug 18, 4:52 PM CDTSevere Thunderstorm WarningMKXFond du Lac, Sheboygan38 min
Aug 18, 4:56 PM CDTSevere Thunderstorm WarningMKXDodge, Fond du Lac49 min
Aug 18, 5:07 PM CDTAreal Flood AdvisoryMKXGreen Lake, Marquette3 hr
Aug 18, 5:08 PM CDTSevere Thunderstorm WarningMKXColumbia, Dane, Sauk52 min
Aug 18, 5:16 PM CDTSevere Thunderstorm WarningMKXFond du Lac33 min
Aug 18, 5:27 PM CDTSevere Thunderstorm WarningMKXDodge, Fond du Lac, Sheboygan, Washington63 min
Aug 18, 5:42 PM CDTSevere Thunderstorm WarningMKXColumbia, Dane, Dodge, Jefferson63 min
Aug 18, 5:45 PM CDTTornado WarningMKXColumbia, Dane, Dodge18 min
Aug 18, 5:54 PM CDTSevere Thunderstorm WarningMKXDodge, Washington36 min
Aug 18, 6:23 PM CDTSevere Thunderstorm WarningMKXDane, Dodge, Jefferson, Milwaukee, Ozaukee, Washington and 1 more67 min
Aug 18, 6:28 PM CDTSpecial Marine WarningMKX2 hr
Aug 18, 6:33 PM CDTTornado WarningMKXWashington, Waukesha42 min
Aug 18, 6:42 PM CDTTornado WarningMKXWaukesha33 min
Aug 18, 6:51 PM CDTTornado WarningMKXMilwaukee23 min
Aug 18, 6:54 PM CDTSevere Thunderstorm WarningMKXMilwaukee, Racine, Waukesha51 min

Nearby

Tornado Warnings in Wisconsin, 2026Every tornado warning in 2026Tornadoes in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.