Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 108, NWS Twin Cities, MN

August 28, 2021Polk County, Wisconsin; Chisago County, Isanti County, Minnesota

NWS Twin Cities, MN issued this severe thunderstorm warning at Aug 28, 2021, 1:29 PM CDT for Polk County, Wisconsin; Chisago County, Isanti County, Minnesota. It was in force for 46 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 28, 2021, 1:29 PM CDT (18:29 UTC)
Expired
Aug 28, 2021, 2:15 PM CDT
In force
46 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon
Hail
1.5 in
Wind
60.0 mph

Counties Chisago County, MN, Isanti County, MN, Polk County, WI

The radar

The Minneapolis radar (KMPX), 96 km from the middle of the area, began a volume at 18:32 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.

The watch it was issued in

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

IssuedProductOfficeLasted
Aug 28, 10:34 AM CDTTornado WatchSPC4 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 6.5 hours before the alert went out and 97 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 2021-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1550 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 2021-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 139 square meters per square second.193958Sfc1 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
1550 J/kg
Mixed-layer CIN
-130 J/kg
Mixed-layer LCL
676 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
139 m²/s²
0-3 km storm-relative helicity
193 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.3

Open this sounding in Storm Lab

The text

As transmitted.

422 
WUUS53 KMPX 281829
SVRMPX
MNC025-059-WIC095-281915-
/O.NEW.KMPX.SV.W.0108.210828T1829Z-210828T1915Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Twin Cities/Chanhassen MN
129 PM CDT Sat Aug 28 2021

The National Weather Service in the Twin Cities has issued a

* Severe Thunderstorm Warning for...
  Central Chisago County in east central Minnesota...
  Southeastern Isanti County in east central Minnesota...
  Northwestern Polk County in northwestern Wisconsin...

* Until 215 PM CDT.

* At 129 PM CDT, a severe thunderstorm was located near North Branch,
  or 8 miles east of Cambridge, moving east at 35 mph.

  HAZARD...Ping pong ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees.

* This severe thunderstorm will remain over mainly rural areas of
  central Chisago, southeastern Isanti and northwestern Polk
  Counties, including the following locations... Spring Lake, Wolf
  Creek, Branch, Cushing, Wild River State Park, Weber, Trade River
  and Harris.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 400 PM CDT for east central
Minnesota...and northwestern Wisconsin.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4543 9260 4544 9313 4562 9315 4565 9287
      4565 9261
TIME...MOT...LOC 1829Z 266DEG 30KT 4553 9305 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.50 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$
2 follow-up statements
150 
WWUS53 KMPX 281853
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
153 PM CDT Sat Aug 28 2021

MNC059-281902-
/O.CAN.KMPX.SV.W.0108.000000T0000Z-210828T1915Z/
Isanti MN-
153 PM CDT Sat Aug 28 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN ISANTI COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 400 PM CDT for east central
Minnesota...and northwestern Wisconsin.

LAT...LON 4547 9260 4547 9292 4564 9298 4565 9287
      4565 9261
TIME...MOT...LOC 1852Z 266DEG 30KT 4554 9277 

$$

MNC025-WIC095-281915-
/O.CON.KMPX.SV.W.0108.000000T0000Z-210828T1915Z/
Chisago MN-Polk WI-
153 PM CDT Sat Aug 28 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 215 PM CDT
FOR CENTRAL CHISAGO AND NORTHWESTERN POLK COUNTIES...

At 152 PM CDT, a severe thunderstorm was located 10 miles northwest
of Taylors Falls, or 22 miles southeast of Pine City, moving east at
35 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Trade River, Wolf Creek, Cushing and Wild River State Park. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 400 PM CDT for east central
Minnesota...and northwestern Wisconsin.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4547 9260 4547 9292 4564 9298 4565 9287
      4565 9261
TIME...MOT...LOC 1852Z 266DEG 30KT 4554 9277 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$
727 
WWUS53 KMPX 281906
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
206 PM CDT Sat Aug 28 2021

MNC025-WIC095-281916-
/O.EXP.KMPX.SV.W.0108.000000T0000Z-210828T1915Z/
Chisago MN-Polk WI-
206 PM CDT Sat Aug 28 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CHISAGO AND
NORTHWESTERN POLK COUNTIES WILL EXPIRE AT 215 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

A Tornado Watch remains in effect until 400 PM CDT for east central
Minnesota...and northwestern Wisconsin.

LAT...LON 4547 9260 4547 9292 4564 9298 4565 9287
      4565 9261
TIME...MOT...LOC 1906Z 266DEG 30KT 4555 9260 

$$

The office that day

Everything else NWS Twin Cities, MN issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 27, 8:21 PM CDTFlash Flood WarningMPXFreeborn4 hr
Aug 27, 11:48 PM CDTSpecial Weather StatementMPXFreeborn87 min
Aug 28, 8:14 AM CDTSpecial Weather StatementMPXStevens61 min
Aug 28, 9:27 AM CDTSevere Thunderstorm Warning Considerable damage threatMPXLac qui Parle33 min
Aug 28, 9:49 AM CDTSevere Thunderstorm WarningMPXDouglas, Pope, Stevens56 min
Aug 28, 9:54 AM CDTSevere Thunderstorm WarningMPXSwift51 min
Aug 28, 10:31 AM CDTSevere Thunderstorm Warning Destructive damage threatMPXSwift44 min
Aug 28, 10:41 AM CDTSevere Thunderstorm WarningMPXDouglas, Pope, Stearns, Todd49 min
Aug 28, 10:53 AM CDTSevere Thunderstorm WarningMPXKandiyohi52 min
Aug 28, 11:20 AM CDTSevere Thunderstorm Warning Considerable damage threatMPXStearns40 min
Aug 28, 11:24 AM CDTTornado WarningMPXStearns36 min
Aug 28, 11:32 AM CDTSevere Thunderstorm Warning Considerable damage threatMPXMorrison, Todd43 min
Aug 28, 11:45 AM CDTSevere Thunderstorm Warning Considerable damage threatMPXBenton, Mille Lacs, Morrison, Sherburne45 min
Aug 28, 12:04 PM CDTTornado WarningMPXBenton, Mille Lacs41 min
Aug 28, 12:27 PM CDTSevere Thunderstorm Warning Considerable damage threatMPXIsanti, Kanabec, Mille Lacs48 min
Aug 28, 12:43 PM CDTSpecial Weather StatementMPXAnoka47 min
Aug 28, 1:07 PM CDTSpecial Weather StatementMPXChisago23 min
Aug 28, 6:06 PM CDTSevere Thunderstorm Warning Considerable damage threatMPXBrown, Redwood, Watonwan54 min
Aug 28, 6:19 PM CDTTornado WarningMPXBrown, Redwood26 min
Aug 28, 6:26 PM CDTSevere Thunderstorm Warning Considerable damage threatMPXBlue Earth, Faribault, Martin, Watonwan64 min
Aug 28, 6:43 PM CDTSevere Thunderstorm WarningMPXBlue Earth, Brown, Nicollet, Redwood, Renville, Sibley and 1 more62 min
Aug 28, 6:51 PM CDTTornado WarningMPXBrown, Nicollet24 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2021Severe Thunderstorm Warnings in Wisconsin, 2021Every severe thunderstorm warning 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.