Alert archive / Minnesota / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 68, NWS Twin Cities, MN

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

NWS Twin Cities, MN issued this severe thunderstorm warning at Jul 28, 2021, 10:21 PM CDT for Washington County, Minnesota; Saint Croix County, Wisconsin. It was in force for 24 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, 10:21 PM CDT (03:21 UTC)
Expired: Jul 28, 2021, 10:45 PM CDT
In force: 24 min
Issued by: NWS Twin Cities, MN
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Washington County, MN, Saint Croix County, WI

The radar

The Minneapolis radar (KMPX), 73 km from the middle of the area, began a volume at 03:19 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.

Issued	Product	Office	Lasted
Jul 28, 7:17 PM CDT	Severe Thunderstorm Watch PDS	SPC	7 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 3.4 hours before the alert went out and 76 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 4815 J/kg
Mixed-layer CIN: -38 J/kg
Mixed-layer LCL: 1185 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 374 m²/s²
0-3 km storm-relative helicity: 461 m²/s²
Significant tornado parameter: 8.9
Supercell composite: 48.1

Open this sounding in Storm Lab

The text

As transmitted.

516 
WUUS53 KMPX 290321
SVRMPX
MNC163-WIC109-290345-
/O.NEW.KMPX.SV.W.0068.210729T0321Z-210729T0345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Twin Cities/Chanhassen MN
1021 PM CDT Wed Jul 28 2021

The National Weather Service in the Twin Cities has issued a

* Severe Thunderstorm Warning for...
  East central Washington County in east central Minnesota...
  Southwestern St. Croix County in west central Wisconsin...

* Until 1045 PM CDT.

* At 1021 PM CDT, a severe thunderstorm was located near Roberts, or
  near River Falls, moving southeast 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 remain over mainly rural areas of
  east central Washington and southwestern St. Croix Counties,
  including the following locations... Afton State Park, Lake St
  Croix Beach, Lakeland, Lakeland Shores, Willow River State Park, St
  Marys Point, Burkhardt and Oak Park Heights.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in the Twin Cities.

&&

LAT...LON 4488 9238 4486 9269 4486 9276 4485 9277
      4485 9279 4502 9284 4504 9252
TIME...MOT...LOC 0321Z 318DEG 35KT 4493 9258 

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

CTG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 8:55 PM CDT	Severe Thunderstorm Warning	MPX	Chisago	50 min
Jul 28, 9:37 PM CDT	Severe Thunderstorm Warning	MPX	Washington	38 min
Jul 28, 10:57 PM CDT	Severe Thunderstorm Warning	MPX	Goodhue	48 min
Jul 28, 7:19 PM CDT	Special Weather Statement	MPX	Rusk	26 min
Jul 28, 7:37 PM CDT	Severe Thunderstorm Warning	MPX	Rusk	23 min
Jul 28, 7:43 PM CDT	Severe Thunderstorm Warning	MPX	Barron, Polk, Rusk	32 min
Jul 28, 8:01 PM CDT	Severe Thunderstorm Warning	MPX	Barron, Chippewa, Rusk	44 min
Jul 28, 8:09 PM CDT	Tornado Warning	MPX	Polk	35 min
Jul 28, 8:46 PM CDT	Severe Thunderstorm Warning	MPX	Barron, Chippewa, Rusk	59 min
Jul 28, 9:08 PM CDT	Tornado Warning	MPX	Chippewa	37 min
Jul 28, 9:25 PM CDT	Severe Thunderstorm Warning	MPX	Dunn, Saint Croix	65 min
Jul 28, 9:30 PM CDT	Severe Thunderstorm Warning	MPX	Chippewa, Eau Claire	60 min
Jul 28, 9:36 PM CDT	Tornado Warning	MPX	Saint Croix	24 min
Jul 28, 9:55 PM CDT	Tornado Warning	MPX	Saint Croix	35 min
Jul 28, 10:09 PM CDT	Severe Thunderstorm Warning	MPX	Dunn, Pepin, Pierce, Saint Croix	51 min
Jul 28, 10:18 PM CDT	Severe Thunderstorm Warning	MPX	Dunn, Eau Claire, Pepin	42 min
Jul 28, 10:36 PM CDT	Severe Thunderstorm Warning	MPX	Pepin	39 min

Nearby

Severe Thunderstorm Warnings in Minnesota, 2021 Severe Thunderstorm Warnings in Wisconsin, 2021 Every 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.