Alert archive / Wisconsin / Flash Flood Warnings in 2021

Flash Flood Warning 9, NWS Green Bay, WI

August 28, 2021Calumet County, Manitowoc County, Wisconsin

NWS Green Bay, WI issued this flash flood warning at Aug 28, 2021, 11:08 PM CDT for Calumet County, Manitowoc County, Wisconsin. It was in force for 89 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 28, 2021, 11:08 PM CDT (04:08 UTC)
Expired
Aug 29, 2021, 12:37 AM CDT
In force
89 min
Issued by
NWS Green Bay, WI
Area
Storm-based polygon
Flood severity
None

Counties Calumet County, WI, Manitowoc County, WI

The radar

The Green Bay radar (KGRB), 61 km from the middle of the area, began a volume at 04:08 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 00:00Z, 4.1 hours before the alert went out and 58 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, Green Bay/Straub, WI at 00:00Z on 2021-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 969 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, Green Bay/Straub, WI at 00:00Z on 2021-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 square meters per square second.193958Sfc1 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
969 J/kg
Mixed-layer CIN
-84 J/kg
Mixed-layer LCL
1292 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
110 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.0

Open this sounding in Storm Lab

The text

As transmitted.

846 
WGUS53 KGRB 290408
FFWGRB
WIC015-071-290700-
/O.NEW.KGRB.FF.W.0009.210829T0408Z-210829T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Green Bay WI
1108 PM CDT Sat Aug 28 2021

The National Weather Service in Green Bay has issued a

* Flash Flood Warning for...
  Southeastern Calumet County in east central Wisconsin...
  Southwestern Manitowoc County in east central Wisconsin...

* Until 200 AM CDT.

* At 1108 PM CDT, local law enforcement reported thunderstorms 
  producing heavy rain across the warned area. Between 2 and 3 
  inches of rain have fallen. Additional rainfall amounts of 1 to 2 
  inches are possible in the warned area. Flash flooding is already 
  occurring.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Law enforcement reported.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Manitowoc, Cleveland, St. Nazianz, Camp Rokilio Scout Camp, St 
  Anna, Central Lake Winnebago, Kiel, New Holstein, Newton, Spring 
  Valley, Brothertown, Clover, St Nazianz, School Hill, Louis 
  Corners, Steinthal, Millhome, Osman, Meggers and Newtonberg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4399 8831 4403 8804 4409 8763 4397 8764
      4390 8767 4389 8808 4389 8814 4389 8816
      4394 8816 4394 8832

FLASH FLOOD...OBSERVED

$$

Kurimski
1 follow-up statement
342 
WGUS73 KGRB 290537
FFSGRB

Flash Flood Statement
National Weather Service Green Bay WI
1237 AM CDT Sun Aug 29 2021

WIC015-071-290547-
/O.CAN.KGRB.FF.W.0009.000000T0000Z-210829T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Calumet WI-Manitowoc WI-
1237 AM CDT Sun Aug 29 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN CALUMET AND 
SOUTHWESTERN MANITOWOC COUNTIES...

Local law enforcement indicated that flood waters have receded and 
the heaviest rain has ended. Flooding is no longer expected to pose 
a significant threat. Please continue to heed remaining road 
closures.

LAT...LON 4399 8831 4403 8804 4409 8763 4397 8764
      4390 8767 4389 8808 4389 8814 4389 8816
      4394 8816 4394 8832

$$

Kurimski

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 28, 8:48 PM CDTSpecial Weather StatementGRBFlorence42 min
Aug 28, 9:02 PM CDTSpecial Weather StatementGRBManitowoc43 min
Aug 28, 10:06 PM CDTAreal Flood AdvisoryGRBCalumet, Manitowoc62 min
Aug 28, 10:24 PM CDTRiver Flood WarningGRBWood21 days
Aug 28, 10:38 PM CDTAreal Flood AdvisoryGRBPortage, Waupaca, Wood3 hr
Aug 28, 11:22 PM CDTFlash Flood WarningGRBPortage, Waupaca3 hr
Aug 29, 12:08 AM CDTAreal Flood AdvisoryGRBOutagamie3 hr
Aug 29, 1:15 AM CDTSpecial Marine WarningGRB34 min

Nearby

Flash Flood Warnings in Wisconsin, 2021Every flash flood 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.