Alert archive / Wisconsin / Special Marine Warnings in 2021

Special Marine Warning 21, NWS Green Bay, WI

July 6, 2021

NWS Green Bay, WI issued this special marine warning at Jul 6, 2021, 1:34 PM CDT. It was in force for 41 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 6, 2021, 1:34 PM CDT (18:34 UTC)
Expired: Jul 6, 2021, 2:15 PM CDT
In force: 41 min
Issued by: NWS Green Bay, WI
Area: Storm-based polygon
Hail: 0.75 in
Wind: 40.0 mph

The radar

The Green Bay radar (KGRB), 58 km from the middle of the area, began a volume at 18:36 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 6.6 hours before the alert went out and 56 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: 34 J/kg
Mixed-layer CIN: -188 J/kg
Mixed-layer LCL: 1667 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 49 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

830 
WHUS53 KGRB 061834
SMWGRB
LMZ542-543-565-567-061930-
/O.NEW.KGRB.MA.W.0021.210706T1834Z-210706T1930Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Special Marine Warning
National Weather Service Green Bay WI
134 PM CDT Tue Jul 6 2021

The National Weather Service in Green Bay has issued a

* Special Marine Warning for...

Nearshore and open waters of Lake Michigan from Sturgeon Bay to
Sheboygan...

* Until 230 PM CDT.

* At 132 PM CDT, a strong thunderstorm was located near Manitowoc, 
  moving northeast at 15 knots. A wind gust of 49 knots was reported 
  at the Manitowoc County Airport. 

  HAZARD...Wind gusts to 50 knots and small hail.

  SOURCE...Radar indicated.

  IMPACT...Small craft could be damaged in briefly higher winds and 
           suddenly higher waves.

* Locations impacted include...
  Rawley Point Light, Two Rivers and Manitowoc. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

LAT...LON 4410 8767 4409 8766 4413 8760 4417 8762
      4413 8759 4417 8761 4414 8758 4414 8756
      4415 8757 4417 8757 4415 8756 4418 8752
      4428 8754 4437 8736 4412 8717 4404 8763
TIME...MOT...LOC 1832Z 247DEG 16KT 4412 8761 

HAIL...<.75IN
WIND...40KTS

$$

Kallas

3 follow-up statements

248 
FZUS73 KGRB 061859
MWSGRB

Marine Weather Statement
National Weather Service Green Bay WI
159 PM CDT Tue Jul 6 2021

LMZ542-543-565-567-061930-
/O.CON.KGRB.MA.W.0021.000000T0000Z-210706T1930Z/
159 PM CDT Tue Jul 6 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 230 PM CDT...

For the following areas...

Nearshore and open waters of Lake Michigan from Sturgeon Bay to
Sheboygan...

At 157 PM CDT, a strong thunderstorm was located near Rawley Point 
Light, moving northeast at 20 knots. Another strong thunderstorm was 
located 5 miles southeast of Mishicot. 

HAZARD...Wind gusts to 40 knots and small hail.

SOURCE...Radar indicated.

IMPACT...Small craft could be damaged in briefly higher winds and 
         suddenly higher waves.

Locations impacted include...
Rawley Point Light and Two Rivers. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

LAT...LON 4418 8752 4428 8754 4437 8736 4412 8717
      4406 8749 4412 8756 4415 8756 4417 8757
      4416 8755
TIME...MOT...LOC 1857Z 245DEG 20KT 4416 8748 

HAIL...<.75IN
WIND...40KTS

$$

Kallas

232 
FZUS73 KGRB 061908
MWSGRB

Marine Weather Statement
National Weather Service Green Bay WI
208 PM CDT Tue Jul 6 2021

LMZ567-061916-
/O.CAN.KGRB.MA.W.0021.000000T0000Z-210706T1930Z/
208 PM CDT Tue Jul 6 2021

...THE SPECIAL MARINE WARNING IS CANCELLED...

The affected areas were...

Open waters of Lake Michigan from Two Rivers to Sheboygan...

The thunderstorm has weakened and no longer poses a significant 
threat to boaters.

A Severe Thunderstorm Watch is in effect until 1000 PM CDT for east 
central Wisconsin.

LAT...LON 4412 8756 4418 8752 4421 8751 4423 8751
      4428 8753 4437 8736 4418 8722 4416 8744
      4414 8745
TIME...MOT...LOC 1906Z 240DEG 25KT 4424 8751 

$$

LMZ542-543-565-061930-
/O.CON.KGRB.MA.W.0021.000000T0000Z-210706T1930Z/
208 PM CDT Tue Jul 6 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 230 PM CDT...

For the following areas...

Nearshore waters from Sturgeon Bay to Sheboygan...
Open waters of Lake Michigan from Sturgeon Bay to Two Rivers...

At 206 PM CDT, a strong thunderstorm was located over Rawley Point
Light, moving northeast at 25 knots.

HAZARD...Wind gusts to 40 knots and small hail.

SOURCE...Radar indicated.

IMPACT...Small craft could be damaged in briefly higher winds and 
         suddenly higher waves.

Locations impacted include...
Rawley Point Light.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to safe harbor until hazardous weather passes.

&&

A Severe Thunderstorm Watch is in effect until 1000 PM CDT for east 
central Wisconsin.

LAT...LON 4412 8756 4418 8752 4421 8751 4423 8751
      4428 8753 4437 8736 4418 8722 4416 8744
      4414 8745
TIME...MOT...LOC 1906Z 240DEG 25KT 4424 8751 

HAIL...<.75IN
WIND...40KTS

$$

Kallas

987 
FZUS73 KGRB 061915
MWSGRB

Marine Weather Statement
National Weather Service Green Bay WI
215 PM CDT Tue Jul 6 2021

LMZ542-543-565-061925-
/O.CAN.KGRB.MA.W.0021.000000T0000Z-210706T1930Z/
215 PM CDT Tue Jul 6 2021

...THE SPECIAL MARINE WARNING IS CANCELLED...

The affected areas were... 

Nearshore waters from Sturgeon Bay to Sheboygan...
Open waters of Lake Michigan from Sturgeon Bay to Two Rivers...

The thunderstorm has weakened and no longer poses a significant
threat to boaters.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
east central Wisconsin.

LAT...LON 4412 8756 4418 8752 4421 8751 4423 8751
      4428 8753 4437 8736 4418 8722 4416 8744
      4414 8745
TIME...MOT...LOC 1913Z 247DEG 16KT 4426 8746 

$$

Kallas

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 5, 7:11 PM CDT	Special Weather Statement	GRB	Marathon	49 min
Jul 5, 8:03 PM CDT	Special Weather Statement	GRB	Outagamie	27 min
Jul 5, 8:23 PM CDT	Special Weather Statement	GRB	Calumet, Outagamie, Winnebago	52 min
Jul 6, 4:13 AM CDT	Beach Hazards Statement	GRB	Kewaunee, Manitowoc	60 hr
Jul 6, 4:28 AM CDT	Small Craft Advisory	GRB		60 hr
Jul 6, 1:36 PM CDT	Special Weather Statement	GRB	Brown, Calumet, Kewaunee, Manitowoc, Outagamie, Shawano and 1 more	54 min
Jul 6, 2:29 PM CDT	Special Weather Statement	GRB	Brown, Calumet, Kewaunee, Manitowoc, Oconto, Outagamie and 2 more	46 min
Jul 6, 3:14 PM CDT	Special Weather Statement	GRB	Outagamie	46 min
Jul 6, 3:16 PM CDT	Special Weather Statement	GRB	Brown, Manitowoc	44 min
Jul 6, 3:18 PM CDT	Special Weather Statement	GRB	Kewaunee	42 min
Jul 6, 3:21 PM CDT	Special Weather Statement	GRB	Portage	39 min
Jul 6, 3:27 PM CDT	Special Weather Statement	GRB	Wood	78 min
Jul 6, 3:35 PM CDT	Special Weather Statement	GRB	Langlade	40 min
Jul 6, 3:38 PM CDT	Severe Thunderstorm Warning	GRB	Marathon, Wood	52 min
Jul 6, 3:45 PM CDT	Special Weather Statement	GRB	Calumet	45 min
Jul 6, 3:52 PM CDT	Special Weather Statement	GRB	Outagamie	53 min
Jul 6, 4:03 PM CDT	Special Weather Statement	GRB	Menominee	42 min
Jul 6, 4:28 PM CDT	Severe Thunderstorm Warning	GRB	Marathon, Portage, Wood	62 min
Jul 6, 4:29 PM CDT	Special Weather Statement	GRB	Calumet	46 min
Jul 6, 4:44 PM CDT	Special Weather Statement	GRB	Menominee	46 min
Jul 6, 4:55 PM CDT	Special Weather Statement	GRB	Oconto	50 min
Jul 6, 4:59 PM CDT	Special Weather Statement	GRB	Calumet	46 min
Jul 6, 5:11 PM CDT	Areal Flood Advisory	GRB	Marathon, Portage, Shawano, Waupaca, Wood	3 hr
Jul 6, 5:27 PM CDT	Severe Thunderstorm Warning	GRB	Marathon, Portage, Shawano, Waupaca, Waushara, Wood	48 min
Jul 6, 5:56 PM CDT	Special Weather Statement	GRB	Portage	49 min
Jul 6, 6:14 PM CDT	Special Weather Statement	GRB	Winnebago	46 min
Jul 6, 6:21 PM CDT	Areal Flood Advisory	GRB	Calumet, Outagamie, Winnebago	3 hr
Jul 6, 6:25 PM CDT	Special Weather Statement	GRB	Marathon	50 min

Nearby

Special Marine Warnings in Wisconsin, 2021 Every special marine 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.