Alert archive / Wisconsin / Special Marine Warnings in 2021

Special Marine Warning 21, NWS Milwaukee, WI

August 6, 2021

NWS Milwaukee, WI issued this special marine warning at Aug 6, 2021, 4:23 PM CDT. It was in force for 52 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: Aug 6, 2021, 4:23 PM CDT (21:23 UTC)
Expired: Aug 6, 2021, 5:15 PM CDT
In force: 52 min
Issued by: NWS Milwaukee, WI
Area: Storm-based polygon
Hail: 0.75 in
Wind: 34.0 mph

The radar

The Green Bay radar (KGRB), 81 km from the middle of the area, began a volume at 21:25 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, 9.4 hours before the alert went out and 79 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: 132 J/kg
Mixed-layer CIN: -114 J/kg
Mixed-layer LCL: 962 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 98 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

894 
WHUS53 KMKX 062123
SMWMKX
LMZ643-669-062215-
/O.NEW.KMKX.MA.W.0021.210806T2123Z-210806T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SPECIAL MARINE WARNING
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
423 PM CDT FRI AUG 6 2021

THE NATIONAL WEATHER SERVICE IN MILWAUKEE/SULLIVAN HAS ISSUED A

* SPECIAL MARINE WARNING FOR...
  LAKE MICHIGAN NEARSHORE AND OPEN WATERS TO MID LAKE FROM SHEBOYGAN
  WI TO PORT WASHINGTON WI...

* UNTIL 515 PM CDT.

* AT 423 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR 
  CLEVELAND...OR NEAR SHEBOYGAN...MOVING NORTHEAST AT 20 KNOTS.

  HAZARD...WIND GUSTS 34 KNOTS OR GREATER AND LARGE HAIL.

  SOURCE...RADAR.

  IMPACT...SMALL CRAFT COULD BE DAMAGED IN BRIEFLY HIGHER WINDS AND 
           SUDDENLY HIGHER WAVES. LARGE HAIL COULD RESULT IN 
           STRUCTURAL DAMAGE.

* THE SEVERE THUNDERSTORM WILL REMAIN OVER MAINLY OPEN WATERS.

LAT...LON 4390 8756 4378 8754 4376 8770 4379 8771
      4379 8772 4380 8772 4382 8773 4386 8773
      4387 8774 4389 8773 4390 8773
TIME...MOT...LOC 2123Z 232DEG 18KT 4383 8778 

HAIL...>.75IN
WIND...>34KTS

$$

HANSEN

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 6, 3:06 PM CDT	Special Weather Statement	MKX	Calumet	24 min
Aug 6, 3:44 PM CDT	Special Weather Statement	MKX	Sheboygan	31 min
Aug 6, 3:48 PM CDT	Special Marine Warning	MKX		42 min
Aug 6, 4:04 PM CDT	Severe Thunderstorm Warning	MKX	Fond du Lac, Sheboygan	41 min
Aug 6, 4:09 PM CDT	Severe Thunderstorm Warning	MKX	Dodge, Fond du Lac	39 min
Aug 6, 4:21 PM CDT	Severe Thunderstorm Warning	MKX	Sheboygan	24 min
Aug 6, 4:38 PM CDT	Severe Thunderstorm Warning	MKX	Sheboygan	52 min
Aug 6, 4:41 PM CDT	Special Marine Warning	MKX		64 min
Aug 6, 4:58 PM CDT	Severe Thunderstorm Warning	MKX	Dodge, Jefferson	32 min
Aug 6, 5:06 PM CDT	Severe Thunderstorm Warning	MKX	Ozaukee, Sheboygan	24 min
Aug 6, 5:08 PM CDT	Special Marine Warning	MKX		52 min
Aug 6, 5:23 PM CDT	Special Marine Warning	MKX		111 min
Aug 6, 5:26 PM CDT	Special Weather Statement	MKX	Dodge, Ozaukee, Washington, Waukesha	94 min
Aug 6, 6:22 PM CDT	Severe Thunderstorm Warning	MKX	Jefferson	38 min
Aug 6, 6:53 PM CDT	Special Weather Statement	MKX	Jefferson, Milwaukee, Waukesha	82 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.