Alert archive / Wisconsin / Flash Flood Warnings in 2018

Flash Flood Warning 8, NWS Milwaukee, WI

August 27, 2018Ozaukee County, Wisconsin

NWS Milwaukee, WI issued this flash flood warning at Aug 27, 2018, 1:59 AM CDT for Ozaukee County, Wisconsin. It was in force for 3 hr. 5 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
Aug 27, 2018, 1:59 AM CDT (06:59 UTC)
Expired
Aug 27, 2018, 5:00 AM CDT
In force
3 hr
Issued by
NWS Milwaukee, WI
Area
Storm-based polygon
Flood severity
None

County Ozaukee County, WI

The radar

The Milwaukee radar (KMKX), 63 km from the middle of the area, began a volume at 07:03 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
Aug 27, 2:25 AM CDTHEAVY RAIN 3.763 W Cedarburg, WI
Aug 27, 2:30 AM CDTFLASH FLOODGrafton, WISTREET FLOODING IN GRAFTON, SAUKVILLE AND PORT WASHINGTON.
Aug 27, 3:00 AM CDTHEAVY RAIN 41 Se Thiensville, WI
Aug 27, 3:00 AM CDTHEAVY RAIN 8.5Port Washington, WI
Aug 27, 4:00 AM CDTHEAVY RAIN 9.181 S Port Washington, WI

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

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 00:00Z, 7.0 hours before the alert went out and 130 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 2018-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 103 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 2018-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 144 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
103 J/kg
Mixed-layer CIN
-176 J/kg
Mixed-layer LCL
894 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
144 m²/s²
0-3 km storm-relative helicity
110 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

200 
WGUS53 KMKX 270659
FFWMKX
WIC089-271000-
/O.NEW.KMKX.FF.W.0008.180827T0659Z-180827T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Milwaukee/Sullivan WI
159 AM CDT MON AUG 27 2018

The National Weather Service in Milwaukee/Sullivan has issued a

* Flash Flood Warning for...
  Southern Ozaukee County in southeastern Wisconsin...

* Until 500 AM CDT.

* At 158 AM CDT, Doppler radar indicated heavy rain across the warned
  area. Up to three inches of rain have already fallen. Flash
  flooding is already occurring in Mequon.

* Some locations that will experience flooding include...
  Mequon, Brown Deer, Grafton, Cedarburg, Port Washington, Saukville,
  Bayside and Thiensville.

Additional rainfall amounts of one inch are possible in the warned 
area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

&&

LAT...LON 4336 8786 4326 8789 4324 8789 4319 8788
      4319 8806 4337 8806 4337 8804 4340 8804
      4342 8782

$$

GEHRING
1 follow-up statement
835 
WGUS73 KMKX 270811
FFSMKX

Flash Flood Statement
National Weather Service Milwaukee/Sullivan WI
311 AM CDT MON AUG 27 2018

WIC089-271000-
/O.CON.KMKX.FF.W.0008.000000T0000Z-180827T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Ozaukee WI-
311 AM CDT MON AUG 27 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 500 AM CDT FOR
SOUTHERN OZAUKEE COUNTY...

At 308 AM CDT, Doppler radar indicated heavy rain coming to an end 
across the warned area. Three to six inches of rain have already 
fallen. Flash flooding of streets is already occurring in Grafton, 
Saukville, Port Washington and surrounding areas.

Some locations that will experience flooding include...
Mequon, Brown Deer, Grafton, Cedarburg, Port Washington, Saukville,
Bayside and Thiensville.

The heavy rainfall is coming to an end, lighter rainfall may return 
later this morning. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4336 8786 4326 8789 4324 8789 4319 8788
      4319 8806 4337 8806 4337 8804 4340 8804
      4342 8782

$$

GEHRING

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 26, 8:04 PM CDTTornado WarningMKXColumbia20 min
Aug 26, 8:08 PM CDTSpecial Weather StatementMKXGreen37 min
Aug 26, 8:42 PM CDTSevere Thunderstorm WarningMKXDane, Jefferson, Rock48 min
Aug 26, 8:50 PM CDTSpecial Weather StatementMKXDodge55 min
Aug 26, 9:02 PM CDTSevere Thunderstorm WarningMKXDodge31 min
Aug 26, 9:10 PM CDTSevere Thunderstorm WarningMKXJefferson35 min
Aug 26, 9:29 PM CDTSevere Thunderstorm WarningMKXJefferson, Waukesha31 min
Aug 26, 9:38 PM CDTSevere Thunderstorm WarningMKXDodge, Washington37 min
Aug 26, 9:53 PM CDTSevere Thunderstorm WarningMKXWalworth36 min
Aug 26, 10:18 PM CDTSevere Thunderstorm WarningMKXMilwaukee, Ozaukee, Waukesha16 min
Aug 26, 10:22 PM CDTSpecial Marine WarningMKX38 min
Aug 26, 11:04 PM CDTFlash Flood WarningMKXMilwaukee, Ozaukee3 hr
Aug 26, 11:06 PM CDTSevere Thunderstorm WarningMKXMilwaukee, Waukesha39 min
Aug 26, 11:10 PM CDTSpecial Marine WarningMKX65 min
Aug 26, 11:42 PM CDTSevere Thunderstorm WarningMKXRock, Walworth19 min
Aug 26, 11:48 PM CDTSpecial Marine WarningMKX57 min
Aug 27, 12:56 AM CDTSpecial Marine WarningMKX64 min
Aug 27, 2:14 AM CDTAreal Flood AdvisoryMKXDodge, Washington3 hr
Aug 27, 2:20 AM CDTAreal Flood AdvisoryMKXOzaukee, Sheboygan3 hr
Aug 27, 3:27 AM CDTSmall Craft AdvisoryMKX40 hr
Aug 27, 5:03 AM CDTAreal Flood WarningMKXOzaukee, Washington15 hr
Aug 27, 6:27 AM CDTMarine Dense Fog AdvisoryMKX5 hr
Aug 27, 9:12 AM CDTRiver Flood WarningMKXOzaukee72 hr
Aug 27, 9:12 AM CDTRiver Flood WarningMKXOzaukee4 days
Aug 27, 11:45 AM CDTFlash Flood WatchMKXColumbia, Dane, Dodge, Fond du Lac, Green, Green Lake and 10 more35 hr
Aug 27, 3:13 PM CDTMarine Dense Fog AdvisoryMKX10 hr

Nearby

Flash Flood Warnings in Wisconsin, 2018Every flash flood warning in 2018

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.