Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 57, NWS Twin Cities, MN

July 28, 2021Chisago County, Washington County, Minnesota; Polk County, Saint Croix County, Wisconsin

NWS Twin Cities, MN issued this severe thunderstorm warning at Jul 28, 2021, 11:59 AM CDT for Chisago County, Washington County, Minnesota; Polk County, Saint Croix County, Wisconsin. It was in force for 31 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
Jul 28, 2021, 11:59 AM CDT (16:59 UTC)
Expired
Jul 28, 2021, 12:30 PM CDT
In force
31 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Chisago County, MN, Washington County, MN, Polk County, WI, Saint Croix County, WI

The radar

The Minneapolis radar (KMPX), 78 km from the middle of the area, began a volume at 17:01 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 nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 5.0 hours before the alert went out and 80 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 2021-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1458 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 2021-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 1 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
1458 J/kg
Mixed-layer CIN
-205 J/kg
Mixed-layer LCL
1435 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
1 m²/s²
0-3 km storm-relative helicity
154 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

As transmitted.

290 
WUUS53 KMPX 281659
SVRMPX
MNC025-163-WIC095-109-281730-
/O.NEW.KMPX.SV.W.0057.210728T1659Z-210728T1730Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Twin Cities/Chanhassen MN
1159 AM CDT Wed Jul 28 2021

The National Weather Service in the Twin Cities has issued a

* Severe Thunderstorm Warning for...
  Southeastern Chisago County in east central Minnesota...
  Northeastern Washington County in east central Minnesota...
  Northwestern St. Croix County in west central Wisconsin...
  South central Polk County in northwestern Wisconsin...

* Until 1230 PM CDT.

* At 1159 AM CDT, a severe thunderstorm was located over Scandia 
  moving east at 40 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.

* This severe thunderstorm will be near...
  Osceola around 1205 PM CDT.

Other locations in the path of this severe thunderstorm include New
Richmond and Star Prairie.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4533 9301 4542 9295 4529 9238 4506 9259
TIME...MOT...LOC 1659Z 289DEG 33KT 4528 9278 

HAIL...1.00IN
WIND...60MPH
 
$$

Dye
3 follow-up statements
637 
WWUS53 KMPX 281709
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1209 PM CDT Wed Jul 28 2021

MNC025-163-WIC095-109-281730-
/O.CON.KMPX.SV.W.0057.000000T0000Z-210728T1730Z/
Chisago MN-Washington MN-St. Croix WI-Polk WI-
1209 PM CDT Wed Jul 28 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 PM CDT
FOR SOUTHEASTERN CHISAGO...NORTHEASTERN WASHINGTON...NORTHWESTERN ST.
CROIX AND SOUTH CENTRAL POLK COUNTIES...

At 1209 PM CDT, a severe thunderstorm was located near Osceola, or 26
miles north of River Falls, moving east at 40 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...
  New Richmond and Star Prairie.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4525 9289 4537 9277 4529 9238 4506 9259
TIME...MOT...LOC 1709Z 289DEG 33KT 4525 9265 

HAIL...1.00IN
WIND...60MPH
 
$$

Dye
615 
WWUS53 KMPX 281720
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1220 PM CDT Wed Jul 28 2021

MNC025-163-WIC095-281730-
/O.CAN.KMPX.SV.W.0057.000000T0000Z-210728T1730Z/
Chisago MN-Washington MN-Polk WI-
1220 PM CDT Wed Jul 28 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CHISAGO...
NORTHEASTERN WASHINGTON AND SOUTH CENTRAL POLK COUNTIES IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4520 9246 4506 9259 4517 9275 4519 9276
      4521 9269 4521 9252
TIME...MOT...LOC 1720Z 289DEG 33KT 4522 9251 

$$

WIC109-281730-
/O.CON.KMPX.SV.W.0057.000000T0000Z-210728T1730Z/
St. Croix WI-
1220 PM CDT Wed Jul 28 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 PM CDT
FOR NORTHWESTERN ST. CROIX COUNTY...

At 1220 PM CDT, a severe thunderstorm was located over Star Prairie,
or 25 miles north of River Falls, moving east at 40 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...
New Richmond, Somerset, Star Prairie, Huntington, New Richmond
Airport and Boardman.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4520 9246 4506 9259 4517 9275 4519 9276
      4521 9269 4521 9252
TIME...MOT...LOC 1720Z 289DEG 33KT 4522 9251 

HAIL...1.00IN
WIND...60MPH
 
$$

Dye
726 
WWUS53 KMPX 281728
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
1228 PM CDT Wed Jul 28 2021

WIC109-281738-
/O.EXP.KMPX.SV.W.0057.000000T0000Z-210728T1730Z/
St. Croix WI-
1228 PM CDT Wed Jul 28 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN ST. CROIX COUNTY
WILL EXPIRE AT 1230 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However small hail
and gusty winds are still possible with this thunderstorm.

LAT...LON 4520 9246 4506 9259 4517 9275 4519 9276
      4521 9269 4521 9252
TIME...MOT...LOC 1728Z 289DEG 33KT 4520 9243 

$$

Dye

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 28, 4:13 AM CDTSpecial Weather StatementMPXPope, Stevens32 min
Jul 28, 4:19 AM CDTSpecial Weather StatementMPXTodd26 min
Jul 28, 4:45 AM CDTSpecial Weather StatementMPXStearns30 min
Jul 28, 4:46 AM CDTSpecial Weather StatementMPXChippewa, Pope, Stevens, Swift44 min
Jul 28, 4:53 AM CDTSevere Thunderstorm WarningMPXPope, Stevens28 min
Jul 28, 4:54 AM CDTSevere Thunderstorm WarningMPXStearns, Todd36 min
Jul 28, 5:29 AM CDTSevere Thunderstorm WarningMPXKandiyohi, Meeker, Stearns46 min
Jul 28, 6:17 AM CDTSpecial Weather StatementMPXMeeker28 min
Jul 28, 6:45 AM CDTSpecial Weather StatementMPXCarver, Wright30 min
Jul 28, 7:19 AM CDTSpecial Weather StatementMPXCarver, Le Sueur, Nicollet41 min
Jul 28, 11:43 AM CDTSpecial Weather StatementMPXChisago32 min
Jul 28, 12:28 PM CDTSpecial Weather StatementMPXSaint Croix32 min
Jul 28, 12:54 PM CDTSpecial Weather StatementMPXPierce36 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.