Alert archive / Wisconsin / Severe Thunderstorm Warnings in 2025

Severe Thunderstorm Warning 21, NWS Green Bay, WI

May 15, 2025Portage County, Waupaca County, Wisconsin

NWS Green Bay, WI issued this severe thunderstorm warning at May 15, 2025, 6:37 PM CDT for Portage County, Waupaca County, Wisconsin. It was in force for 38 min. 4 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, 2025, 6:37 PM CDT (23:37 UTC)
Expired: May 15, 2025, 7:15 PM CDT
In force: 38 min
Issued by: NWS Green Bay, WI
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Portage County, WI, Waupaca County, WI

The radar

The Green Bay radar (KGRB), 98 km from the middle of the area, began a volume at 23:41 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, 6:50 PM CDT	HAIL 1.5	2 Wsw Amherst Junction, WI
May 15, 6:50 PM CDT	HAIL 1.5	2 Wsw Amherst Junction, WI
May 15, 7:05 PM CDT	HAIL 0.5	Rosholt, WI	Report from mPING: Half-inch (0.50 in.).
May 15, 7:05 PM CDT	HAIL 0.5	Rosholt, WI	Report from mPING: Half-inch (0.50 in.).

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

The watch it was issued in

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

Issued	Product	Office	Lasted
May 15, 3:05 PM CDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 11.6 hours before the alert went out and 99 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: 1019 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -10 m²/s²
0-3 km storm-relative helicity: 22 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

908 
WUUS53 KGRB 152337
SVRGRB
WIC097-135-160015-
/O.NEW.KGRB.SV.W.0021.250515T2337Z-250516T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service GREEN BAY WI
Issued by National Weather Service Milwaukee/Sullivan WI
637 PM CDT Thu May 15 2025

The National Weather Service in GREEN BAY has issued a

* Severe Thunderstorm Warning for...
  Eastern Portage County in central Wisconsin...
  Northwestern Waupaca County in northeastern Wisconsin...

* Until 715 PM CDT.

* At 637 PM CDT, a severe thunderstorm was located 8 miles west of
  Hartman Creek State Park, or 15 miles southeast of Stevens Point,
  moving northeast at 50 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...
  Amherst, Iola, Rosholt, Amherst Junction, Scandinavia, Peru,
  Blaine, Nelsonville, Schmidt Corner, Northland, Keene, Fancher,
  Norske, Arnott, Bancroft, Custer, and Standing Rock Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Tornado Watch remains in effect until 1000 PM CDT for central and
northeastern Wisconsin.

&&

LAT...LON 4430 8955 4468 8934 4468 8899 4426 8931
TIME...MOT...LOC 2337Z 206DEG 44KT 4434 8939 

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

$$

GEHRING

1 follow-up statement

761 
WWUS53 KGRB 152350 RRA
SVSGRB

Severe Weather Statement
National Weather Service GREEN BAY WI
Issued by National Weather Service Milwaukee/Sullivan WI
650 PM CDT Thu May 15 2025

WIC097-135-160015-
/O.CON.KGRB.SV.W.0021.000000T0000Z-250516T0015Z/
Portage WI-Waupaca WI-
650 PM CDT Thu May 15 2025

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM CDT
FOR EASTERN PORTAGE AND NORTHWESTERN WAUPACA COUNTIES...

At 650 PM CDT, a severe thunderstorm was located over Amherst, or 13
miles east of Stevens Point, moving northeast at 50 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...
Amherst, Iola, Rosholt, Amherst Junction, Scandinavia, Peru, Blaine,
Nelsonville, Schmidt Corner, Northland, Fancher, Norske, and Standing
Rock Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1000 PM CDT for central and
northeastern Wisconsin.

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

&&

LAT...LON 4444 8943 4468 8934 4468 8899 4426 8931
TIME...MOT...LOC 2350Z 206DEG 44KT 4449 8929 

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

$$

GEHRING

The office that day

Everything else NWS Green Bay, WI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 14, 8:14 PM CDT	Dense Fog Advisory	GRB	Brown, Door, Kewaunee, Manitowoc, Marinette, Oconto	15 hr
May 15, 4:06 AM CDT	Small Craft Advisory	GRB		19 hr
May 15, 4:20 PM CDT	Severe Thunderstorm Warning	GRB	Portage, Wood	55 min
May 15, 4:50 PM CDT	Severe Thunderstorm Warning	GRB	Marathon	55 min
May 15, 5:11 PM CDT	Tornado Warning	GRB	Portage, Wood	49 min
May 15, 5:12 PM CDT	Tornado Warning	GRB	Marathon, Wood	48 min
May 15, 5:24 PM CDT	Severe Thunderstorm Warning	GRB	Portage, Waushara	66 min
May 15, 5:24 PM CDT	Tornado Warning	GRB	Marathon	51 min
May 15, 5:46 PM CDT	Tornado Warning	GRB	Marathon, Portage	44 min
May 15, 5:46 PM CDT	Tornado Warning	GRB	Portage, Waupaca, Waushara	44 min
May 15, 5:51 PM CDT	Severe Thunderstorm Warning	GRB	Langlade, Lincoln, Marathon, Oneida, Portage, Wood	39 min
May 15, 6:05 PM CDT	Tornado Warning	GRB	Marathon	55 min
May 15, 6:16 PM CDT	Tornado Warning	GRB	Portage	34 min
May 15, 6:17 PM CDT	Tornado Warning	GRB	Lincoln	17 min
May 15, 6:20 PM CDT	Severe Thunderstorm Warning Considerable damage threat	GRB	Langlade, Lincoln, Marathon, Oneida	55 min
May 15, 6:39 PM CDT	Special Marine Warning	GRB		2 hr
May 15, 6:53 PM CDT	Special Marine Warning	GRB		112 min

Nearby

Severe Thunderstorm Warnings in Wisconsin, 2025 Every severe thunderstorm warning in 2025

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.