Alert archive / Minnesota / Severe Thunderstorm Watches in 2026

Severe Thunderstorm Watch 607

August 20, 202629 counties in Minnesota

The Storm Prediction Center issued this severe thunderstorm watch at Aug 20, 2026, 6:07 PM CDT for 29 counties in Minnesota. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Aug 20, 2026, 6:07 PM CDT (23:07 UTC)
Expired
Aug 21, 2026, 12:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 29 counties

Aitkin County, MN, Benton County, MN, Blue Earth County, MN, Brown County, MN, Carlton County, MN, Carver County, MN, Cass County, MN, Crow Wing County, MN, Isanti County, MN, Itasca County, MN, Kanabec County, MN, Kandiyohi County, MN, Le Sueur County, MN, McLeod County, MN, Meeker County, MN, Mille Lacs County, MN, Morrison County, MN, Nicollet County, MN, Pine County, MN, Redwood County, MN, Renville County, MN, Saint Louis County, MN, Scott County, MN, Sherburne County, MN, Sibley County, MN, Stearns County, MN, Todd County, MN, Watonwan County, MN, Wright County, MN

The radar

The Duluth radar (KDLH), 106 km from the middle of the area, began a volume at 23:10 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
10%
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
30%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Aug 20, 6:16 PM CDTSevere Thunderstorm WarningMPXRedwood, Renville, Yellow Medicine44 min
Aug 20, 6:45 PM CDTSevere Thunderstorm WarningDLHAitkin, Cass, Crow Wing60 min
Aug 20, 6:48 PM CDTSevere Thunderstorm WarningDLHItasca, Saint Louis36 min
Aug 20, 6:58 PM CDTSevere Thunderstorm WarningMPXRedwood, Yellow Medicine47 min
Aug 20, 7:41 PM CDTSevere Thunderstorm WarningDLHAitkin, Carlton, Crow Wing, Pine64 min
Aug 20, 7:43 PM CDTSevere Thunderstorm WarningMPXBrown, Redwood39 min
Aug 20, 7:55 PM CDTSevere Thunderstorm WarningMPXPope, Stearns50 min
Aug 20, 7:56 PM CDTSevere Thunderstorm WarningMPXMeeker, Stearns49 min
Aug 20, 8:21 PM CDTSevere Thunderstorm WarningMPXBrown, Redwood54 min
Aug 20, 8:34 PM CDTSevere Thunderstorm WarningDLHCrow Wing56 min
Aug 20, 8:39 PM CDTTornado WarningMPXMeeker36 min
Aug 20, 9:12 PM CDTSevere Thunderstorm WarningMPXMorrison48 min
Aug 20, 9:15 PM CDTSevere Thunderstorm WarningMPXMcLeod, Meeker, Wright17 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, 11.1 hours before the alert went out and 166 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 2026-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 19 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 2026-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 square meters per square second.19395878Sfc1 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
19 J/kg
Mixed-layer CIN
-264 J/kg
Mixed-layer LCL
1140 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
139 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

562 
WWUS20 KWNS 202305
SEL7  
SPC WW 202305
MNZ000-210500-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 607
NWS Storm Prediction Center Norman OK
610 PM CDT Thu Aug 20 2026

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Minnesota

* Effective this Thursday night from 610 PM until Midnight CDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 2
    inches in diameter possible
  Scattered damaging wind gusts to 70 mph possible
  A tornado or two possible

SUMMARY...Severe thunderstorms including some supercells should
continue to develop through early/mid-evening, with large hail and
damaging winds as the primary severe concerns, although a tornado
cannot be entirely ruled out.

The severe thunderstorm watch area is approximately along and 50
statute miles east and west of a line from 35 miles north of Hibbing
MN to 40 miles south southeast of Redwood Falls MN. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU7).

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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 604...WW 605...WW 606...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
29025.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 20, 5:31 PM CDTMesoscale DiscussionSPCAitkin, Anoka, Benton, Blue Earth, Brown, Carver and 37 more119 min

Nearby

Severe Thunderstorm Watches in Minnesota, 2026Every severe thunderstorm watch 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.