Alert archive / Michigan / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 68, NWS Detroit, MI

August 11, 20215 counties in Michigan

NWS Detroit, MI issued this severe thunderstorm warning at Aug 11, 2021, 12:02 AM EDT for 5 counties in Michigan. It was in force for 58 min. 1 report 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 11, 2021, 12:02 AM EDT (04:02 UTC)
Expired
Aug 11, 2021, 1:00 AM EDT
In force
58 min
Issued by
NWS Detroit, MI
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Genesee County, MI, Livingston County, MI, Oakland County, MI, Shiawassee County, MI, Washtenaw County, MI

The radar

The Detroit radar (KDTX), 35 km from the middle of the area, began a volume at 04:03 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 11, 12:06 AM EDTTSTM WND DMG4 Wsw Owosso, MITREES DOWN. TIME ESTIMATED FROM RADAR.

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

The nearest sounding before it

Detroit, MI (KDTX), launched 00:00Z, 4.0 hours before the alert went out and 38 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, Detroit, MI at 00:00Z on 2021-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2462 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, Detroit, MI at 00:00Z on 2021-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 square meters per square second.1939Sfc1 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
2462 J/kg
Mixed-layer CIN
-27 J/kg
Mixed-layer LCL
962 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
207 m²/s²
Significant tornado parameter
0.7
Supercell composite
3.7

Open this sounding in Storm Lab

The text

As transmitted.

065 
WUUS53 KDTX 110402
SVRDTX
MIC049-093-125-155-161-110500-
/O.NEW.KDTX.SV.W.0068.210811T0402Z-210811T0500Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Detroit/Pontiac MI
1202 AM EDT Wed Aug 11 2021

The National Weather Service in Detroit/Pontiac has issued a

* Severe Thunderstorm Warning for...
  Western Oakland County in southeastern Michigan...
  Shiawassee County in southeastern Michigan...
  Livingston County in southeastern Michigan...
  Genesee County in southeastern Michigan...
  Washtenaw County in southeastern Michigan...

* Until 100 AM EDT.

* At 1202 AM EDT, severe thunderstorms were located along a line
  extending from 6 miles northeast of Elsie to near Williamston to
  near Vandercook Lake, moving east at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Severe thunderstorms will be near...
  Henderson around 1210 AM EDT.
  Fowlerville around 1215 AM EDT.
  Howell, New Lothrop and Oak Grove around 1225 AM EDT.
  Manchester and Montrose around 1230 AM EDT.
  Flushing and Brighton around 1235 AM EDT.
  Hartland, Clio, Mount Morris and Beecher around 1240 AM EDT.
  Ann Arbor, Flint, Saline and Crossroads Village around 1245 AM 
  EDT.
  Milford and Burton around 1250 AM EDT.

Other locations impacted by these severe thunderstorms include
Whittaker, Plainfield, Rankin, Hudson Mills Metropark, Holly State
Recreation Area, Commerce, Delhi Mills, Pleasant Lake, Rose Center
and Pinckney State Recreation Area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4313 8435 4313 8393 4322 8393 4322 8346
      4259 8344 4244 8347 4243 8355 4209 8354
      4209 8413 4277 8416 4278 8435
TIME...MOT...LOC 0402Z 273DEG 40KT 4314 8430 4263 8430 4220 8443 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

TF
3 follow-up statements
171 
WWUS53 KDTX 110421
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
1221 AM EDT Wed Aug 11 2021

MIC049-093-125-155-161-110500-
/O.CON.KDTX.SV.W.0068.000000T0000Z-210811T0500Z/
Oakland MI-Shiawassee MI-Livingston MI-Genesee MI-Washtenaw MI-
1221 AM EDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 100 AM EDT
FOR WESTERN OAKLAND...SHIAWASSEE...LIVINGSTON...GENESEE AND WASHTENAW
COUNTIES...

At 1217 AM EDT, a gusty outflow boundary was located along a line 
extending from near New Lothrop to near Howell to near Grass Lake, 
moving east at 50 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

This gusty boundary will be near...   
  Montrose around 1225 AM EDT.
  Flushing and Brighton around 1230 AM EDT.
  Hartland, Clio, Mount Morris and Beecher around 1235 AM EDT.
  Ann Arbor, Flint, Saline, Milford, Burton and Crossroads Village 
  around 1240 AM EDT.
  Milan, Davison and Otisville around 1245 AM EDT.
  Novi, Ypsilanti and Otter Lake around 1250 AM EDT.
  Willis around 1255 AM EDT.

Other locations impacted by these gusty winds include Whittaker, 
Plainfield, Rankin, Hudson Mills Metropark, Holly State Recreation 
Area, Commerce, Delhi Mills, Pleasant Lake, Rose Center and Pinckney 
State Recreation Area.

This outflow boundary has a history of producing 60 mph winds and 
tree damage in Ingham County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4313 8435 4313 8393 4322 8393 4322 8346
      4259 8344 4244 8347 4243 8355 4209 8354
      4209 8413 4277 8416 4278 8435
TIME...MOT...LOC 0417Z 272DEG 45KT 4313 8401 4262 8401 4219 8414 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

TF
568 
WWUS53 KDTX 110437
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
1237 AM EDT Wed Aug 11 2021

MIC093-125-161-110446-
/O.CAN.KDTX.SV.W.0068.000000T0000Z-210811T0500Z/
Oakland MI-Livingston MI-Washtenaw MI-
1237 AM EDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN OAKLAND...LIVINGSTON
AND WASHTENAW COUNTIES IS CANCELLED...

The storms which prompted the warning have weakened. Therefore, the 
warning has been cancelled.

LAT...LON 4313 8412 4313 8393 4322 8393 4322 8346
      4288 8345 4287 8369 4278 8369 4278 8410
TIME...MOT...LOC 0436Z 253DEG 40KT 4324 8379 4300 8382 4276 8388 

$$

MIC049-155-110500-
/O.CON.KDTX.SV.W.0068.000000T0000Z-210811T0500Z/
Shiawassee MI-Genesee MI-
1237 AM EDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 100 AM EDT
FOR EASTERN SHIAWASSEE AND GENESEE COUNTIES...

At 1236 AM EDT, severe thunderstorms were located along a line
extending from Birch Run to near Swartz Creek to near Cohoctah,
moving east at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

These severe storms will be near...
  Clio around 1240 AM EDT.
  Mount Morris and Beecher around 1245 AM EDT.
  Flint, Burton, Crossroads Village and Lake Fenton around 1250 AM 
  EDT.
  Davison and Otter Lake around 1255 AM EDT.
  Grand Blanc and Otisville around 100 AM EDT.
  Goodrich around 105 AM EDT.

Other locations impacted by these severe thunderstorms include Atlas,
Juddville, Rankin, Thetford Township, Argentine, Genesee and Vernon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4313 8412 4313 8393 4322 8393 4322 8346
      4288 8345 4287 8369 4278 8369 4278 8410
TIME...MOT...LOC 0436Z 253DEG 40KT 4324 8379 4300 8382 4276 8388 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

TF
521 
WWUS53 KDTX 110450
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
1250 AM EDT Wed Aug 11 2021

MIC049-155-110500-
/O.EXP.KDTX.SV.W.0068.000000T0000Z-210811T0500Z/
Shiawassee MI-Genesee MI-
1250 AM EDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN SHIAWASSEE AND GENESEE
COUNTIES WILL EXPIRE AT 100 AM EDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

LAT...LON 4313 8412 4313 8393 4322 8393 4322 8346
      4288 8345 4287 8369 4278 8369 4278 8410
TIME...MOT...LOC 0450Z 273DEG 40KT 4323 8363 4299 8366 4275 8372 

$$

TF

The office that day

Everything else NWS Detroit, MI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 10, 11:43 PM EDTSevere Thunderstorm WarningDTXBay, Midland, Saginaw62 min
Aug 10, 11:53 PM EDTSpecial Weather StatementDTXGenesee, Livingston, Shiawassee, Washtenaw52 min
Aug 10, 11:58 PM EDTSpecial Marine WarningDTX92 min
Aug 11, 12:43 AM EDTSevere Thunderstorm WarningDTXBay, Huron, Saginaw, Tuscola47 min
Aug 11, 1:09 AM EDTSpecial Marine WarningDTX81 min
Aug 11, 1:11 AM EDTSpecial Weather StatementDTXHuron49 min
Aug 11, 1:29 AM EDTSpecial Marine WarningDTX46 min
Aug 11, 4:04 AM EDTHeat AdvisoryDTXLenawee, Livingston, Macomb, Monroe, Oakland, Washtenaw and 1 more13 hr
Aug 11, 2:22 PM EDTSevere Thunderstorm WarningDTXLenawee, Washtenaw68 min
Aug 11, 2:31 PM EDTSevere Thunderstorm WarningDTXSaginaw42 min
Aug 11, 2:42 PM EDTSevere Thunderstorm WarningDTXLivingston63 min
Aug 11, 2:59 PM EDTSevere Thunderstorm WarningDTXMonroe, Wayne76 min
Aug 11, 3:02 PM EDTSpecial Weather StatementDTXGenesee58 min
Aug 11, 3:09 PM EDTSevere Thunderstorm WarningDTXOakland66 min
Aug 11, 3:16 PM EDTSevere Thunderstorm WarningDTXGenesee, Shiawassee59 min
Aug 11, 3:17 PM EDTSpecial Marine WarningDTX88 min
Aug 11, 3:36 PM EDTSpecial Marine WarningDTX84 min
Aug 11, 3:36 PM EDTSevere Thunderstorm WarningDTXLapeer, Macomb, Saint Clair, Sanilac69 min

Nearby

Severe Thunderstorm Warnings in Michigan, 2021Every severe thunderstorm 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.