Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 14, NWS Twin Cities, MN

May 15, 2021Polk County, Wisconsin

NWS Twin Cities, MN issued this severe thunderstorm warning at May 15, 2021, 4:29 PM CDT for Polk County, Wisconsin. It was in force for 22 min. 1 report 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, 4:29 PM CDT (21:29 UTC)
Expired
May 15, 2021, 4:51 PM CDT
In force
22 min
Issued by
NWS Twin Cities, MN
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Polk County, WI

The radar

The Minneapolis radar (KMPX), 103 km from the middle of the area, began a volume at 21:30 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

TimeReportWhereRemark
May 15, 4:29 PM CDTHAIL 13 W Amery, WILOT 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, 9.5 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-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2021-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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 2021-05-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 57 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
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.

912 
WUUS53 KMPX 152129
SVRMPX
WIC095-152215-
/O.NEW.KMPX.SV.W.0014.210515T2129Z-210515T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Twin Cities/Chanhassen MN
429 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 515 PM CDT.

* At 429 PM CDT, a severe thunderstorm was located near Amery, or 31
  miles north of River Falls, moving southeast at 10 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...
  Amery around 435 PM CDT.

Other locations in the path of this severe thunderstorm include Clear
Lake.

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 4531 9249 4533 9236 4521 9221 4521 9246
TIME...MOT...LOC 2129Z 332DEG 10KT 4530 9245 

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

ETA
2 follow-up statements
163 
WWUS53 KMPX 152144
SVSMPX

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

WIC095-152215-
/O.CON.KMPX.SV.W.0014.000000T0000Z-210515T2215Z/
Polk WI-
444 PM CDT Sat May 15 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM CDT
FOR SOUTH CENTRAL POLK COUNTY...

At 443 PM CDT, a severe thunderstorm was located near Amery, or 29
miles north of River Falls, moving southeast at 10 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

Locations impacted include...
  Clear Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If on or near a lake or river, 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 4529 9244 4529 9231 4521 9221 4521 9242
TIME...MOT...LOC 2143Z 332DEG 10KT 4526 9242 

HAIL...1.00IN
WIND...<50MPH
 
$$

ETA
650 
WWUS53 KMPX 152151
SVSMPX

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

WIC095-152201-
/O.CAN.KMPX.SV.W.0014.000000T0000Z-210515T2215Z/
Polk WI-
451 PM CDT Sat May 15 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL POLK COUNTY IS
CANCELLED...
                
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 has been cancelled.  However small hail is
still possible with this thunderstorm.

LAT...LON 4529 9244 4529 9231 4521 9221 4521 9242
TIME...MOT...LOC 2150Z 332DEG 10KT 4524 9240 

$$

ETA

The office that day

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

IssuedProductOfficeCountiesLasted
May 15, 3:48 PM CDTSpecial Weather StatementMPXPolk27 min
May 15, 4:07 PM CDTSevere Thunderstorm WarningMPXPolk23 min
May 15, 4:50 PM CDTSpecial Weather StatementMPXSaint Croix40 min
May 15, 5:07 PM CDTSevere Thunderstorm WarningMPXSaint Croix23 min
May 15, 5:27 PM CDTSevere Thunderstorm WarningMPXSaint Croix33 min
May 15, 5:44 PM CDTSevere Thunderstorm WarningMPXPierce46 min
May 15, 6:28 PM CDTSevere Thunderstorm WarningMPXPepin, Pierce62 min

Nearby

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