Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 13, NWS Twin Cities, MN

May 15, 2021Polk County, Wisconsin

NWS Twin Cities, MN issued this severe thunderstorm warning at May 15, 2021, 4:07 PM CDT for Polk County, Wisconsin. It was in force for 23 min. 2 reports 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: May 15, 2021, 4:07 PM CDT (21:07 UTC)
Expired: May 15, 2021, 4:30 PM CDT
In force: 23 min
Issued by: NWS Twin Cities, MN
Area: Storm-based polygon
Hail: 1.5 in
Wind: 60.0 mph

County Polk County, WI

The radar

The Minneapolis radar (KMPX), 102 km from the middle of the area, began a volume at 21:11 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

Time	Report	Where	Remark
May 15, 4:19 PM CDT	HAIL 1	4 Nw Amery, WI
May 15, 4:29 PM CDT	HAIL 1	3 W Amery, WI	LOT OF SMALL HAIL, SOME QUARTER SIZE.

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

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 9.1 hours before the alert went out and 105 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 894 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 120 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

316 
WUUS53 KMPX 152107
SVRMPX
WIC095-152130-
/O.NEW.KMPX.SV.W.0013.210515T2107Z-210515T2130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Twin Cities/Chanhassen MN
407 PM CDT Sat May 15 2021

The National Weather Service in the Twin Cities has issued a

* Severe Thunderstorm Warning for...
  South central Polk County in northwestern Wisconsin...

* Until 430 PM CDT.

* At 406 PM CDT, a severe thunderstorm was located 6 miles south of
  Balsam Lake, or 35 miles north of River Falls, moving south at 10
  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.

* Locations impacted include...
  Amery.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near a lake, get away from the water and move indoors or 
inside a vehicle. Remember, lightning can strike out to 15 miles 
from the parent thunderstorm. If you can hear thunder, you are close 
enough to be struck by lightning. Move to safe shelter now!  Do not 
be caught on the water in a thunderstorm.

&&

LAT...LON 4540 9256 4543 9246 4529 9231 4527 9250
TIME...MOT...LOC 2106Z 341DEG 9KT 4536 9247 

HAIL...1.50IN
WIND...60MPH
 
$$

ETA

1 follow-up statement

668 
WWUS53 KMPX 152120
SVSMPX

Severe Weather Statement
National Weather Service Twin Cities/Chanhassen MN
420 PM CDT Sat May 15 2021

WIC095-152130-
/O.CON.KMPX.SV.W.0013.000000T0000Z-210515T2130Z/
Polk WI-
420 PM CDT Sat May 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM CDT
FOR SOUTH CENTRAL POLK COUNTY...

At 419 PM CDT, a severe thunderstorm was located near Amery, or 33
miles north of River Falls, moving south at 10 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.

Locations impacted include...
Amery, Wanderoos and Deronda. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near a lake, get away from the water and move indoors or 
inside a vehicle. remember, lightning can strike out to 15 miles 
from the parent thunderstorm. If you can hear thunder, you are close 
enough to be struck by lightning. Move to safe shelter now!  Do not 
be caught on the water in a thunderstorm.

&&

LAT...LON 4536 9252 4537 9240 4529 9231 4527 9250
TIME...MOT...LOC 2119Z 341DEG 9KT 4533 9245 

HAIL...1.50IN
WIND...60MPH
 
$$

ETA

The office that day

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

Issued	Product	Office	Counties	Lasted
May 15, 3:48 PM CDT	Special Weather Statement	MPX	Polk	27 min
May 15, 4:29 PM CDT	Severe Thunderstorm Warning	MPX	Polk	22 min
May 15, 4:50 PM CDT	Special Weather Statement	MPX	Saint Croix	40 min
May 15, 5:07 PM CDT	Severe Thunderstorm Warning	MPX	Saint Croix	23 min
May 15, 5:27 PM CDT	Severe Thunderstorm Warning	MPX	Saint Croix	33 min
May 15, 5:44 PM CDT	Severe Thunderstorm Warning	MPX	Pierce	46 min
May 15, 6:28 PM CDT	Severe Thunderstorm Warning	MPX	Pepin, Pierce	62 min

Nearby

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.