Alert archive / Michigan / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 64, NWS Detroit, MI

August 9, 2021Livingston County, Oakland County, Washtenaw County, Michigan

NWS Detroit, MI issued this severe thunderstorm warning at Aug 9, 2021, 1:49 PM EDT for Livingston County, Oakland County, Washtenaw County, Michigan. It was in force for 30 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 9, 2021, 1:49 PM EDT (17:49 UTC)
Expired
Aug 9, 2021, 2:19 PM EDT
In force
30 min
Issued by
NWS Detroit, MI
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Livingston County, MI, Oakland County, MI, Washtenaw County, MI

The radar

The Detroit radar (KDTX), 34 km from the middle of the area, began a volume at 17:52 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 9, 1:52 PM EDTTSTM WND DMG3 N South Lyon, MIREPORT OF A TREE DOWN.

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 12:00Z, 5.8 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 12:00Z on 2021-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 515 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 12:00Z on 2021-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 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
515 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
948 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

191 
WUUS53 KDTX 091749
SVRDTX
MIC093-125-161-091845-
/O.NEW.KDTX.SV.W.0064.210809T1749Z-210809T1845Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Detroit/Pontiac MI
149 PM EDT Mon Aug 9 2021

The National Weather Service in Detroit/Pontiac has issued a

* Severe Thunderstorm Warning for...
  Southwestern Oakland County in southeastern Michigan...
  Southeastern Livingston County in southeastern Michigan...
  Northeastern Washtenaw County in southeastern Michigan...

* Until 245 PM EDT.

* At 149 PM EDT, a severe thunderstorm was located over Whitmore
  Lake, or 7 miles south of Brighton, moving north at 30 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

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

* This severe thunderstorm will be near...
  South Lyon around 200 PM EDT.
  Brighton around 205 PM EDT.
  Milford around 215 PM EDT.
  Hartland around 220 PM EDT.

Other locations impacted by this severe thunderstorm include
Lakeland, White Lake, Island Lake State Recreation Area, Chilson,
Delhi Mills, New Hudson, Barton Hills and Wixom.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with this storm. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4228 8362 4231 8389 4269 8388 4267 8349
TIME...MOT...LOC 1749Z 198DEG 27KT 4242 8373 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

IRL
4 follow-up statements
103 
WWUS53 KDTX 091755
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
155 PM EDT Mon Aug 9 2021

MIC161-091805-
/O.CAN.KDTX.SV.W.0064.000000T0000Z-210809T1845Z/
Washtenaw MI-
155 PM EDT Mon Aug 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN WASHTENAW COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4269 8388 4267 8349 4243 8357 4243 8389
TIME...MOT...LOC 1755Z 198DEG 27KT 4247 8371 

$$

MIC093-125-091845-
/O.CON.KDTX.SV.W.0064.000000T0000Z-210809T1845Z/
Oakland MI-Livingston MI-
155 PM EDT Mon Aug 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR SOUTHWESTERN OAKLAND AND SOUTHEASTERN LIVINGSTON COUNTIES...

At 155 PM EDT, a severe thunderstorm was located near South Lyon, or
near Brighton, moving north at 30 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

This severe storm will be near...
  Brighton around 205 PM EDT.
  Milford around 215 PM EDT.
  Hartland around 220 PM EDT.

Other locations impacted by this severe thunderstorm include Island
Lake State Recreation Area, Chilson, New Hudson, Lakeland, White Lake
and Wixom.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4269 8388 4267 8349 4243 8357 4243 8389
TIME...MOT...LOC 1755Z 198DEG 27KT 4247 8371 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

IRL
431 
WWUS53 KDTX 091801
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
201 PM EDT Mon Aug 9 2021

MIC093-125-091845-
/O.CON.KDTX.SV.W.0064.000000T0000Z-210809T1845Z/
Oakland MI-Livingston MI-
201 PM EDT Mon Aug 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR SOUTHWESTERN OAKLAND AND SOUTHEASTERN LIVINGSTON COUNTIES...

At 201 PM EDT, a severe thunderstorm was located near South Lyon, or
near Milford, moving north at 30 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

This severe storm will be near...
  Milford around 215 PM EDT.

Other locations impacted by this severe thunderstorm include Island
Lake State Recreation Area, New Hudson, White Lake and Wixom.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4268 8373 4267 8349 4243 8357 4245 8382
TIME...MOT...LOC 1801Z 201DEG 27KT 4251 8366 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

IRL
013 
WWUS53 KDTX 091810
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
210 PM EDT Mon Aug 9 2021

MIC093-091820-
/O.CAN.KDTX.SV.W.0064.000000T0000Z-210809T1845Z/
Livingston MI-
210 PM EDT Mon Aug 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN LIVINGSTON COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4267 8349 4249 8355 4251 8367 4268 8368
TIME...MOT...LOC 1810Z 203DEG 29KT 4259 8357 

$$

MIC125-091845-
/O.CON.KDTX.SV.W.0064.000000T0000Z-210809T1845Z/
Oakland MI-
210 PM EDT Mon Aug 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR SOUTHWESTERN OAKLAND COUNTY...

At 210 PM EDT, a severe thunderstorm was located over Milford, moving
northeast at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

This severe thunderstorm will remain over mainly rural areas of
southwestern Oakland County, including the following locations... New
Hudson, White Lake and Wixom.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4267 8349 4249 8355 4251 8367 4268 8368
TIME...MOT...LOC 1810Z 203DEG 29KT 4259 8357 

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

$$

IRL
664 
WWUS53 KDTX 091819
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
219 PM EDT Mon Aug 9 2021

MIC125-091828-
/O.CAN.KDTX.SV.W.0064.000000T0000Z-210809T1845Z/
Oakland MI-
219 PM EDT Mon Aug 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN OAKLAND COUNTY IS
CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.  However gusty winds are 
still possible with this thunderstorm. A Special Weather Statement 
is in effect until 3 PM for portions of Oakland County for wind 
gusts to 50 mph.

LAT...LON 4267 8349 4249 8355 4251 8367 4268 8368
TIME...MOT...LOC 1814Z 198DEG 27KT 4265 8354 

$$

IRL

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 9, 1:29 PM EDTSpecial Weather StatementDTXLivingston, Washtenaw46 min
Aug 9, 2:08 PM EDTSpecial Weather StatementDTXWayne67 min
Aug 9, 2:18 PM EDTSpecial Weather StatementDTXOakland42 min
Aug 9, 3:11 PM EDTSpecial Marine WarningDTX76 min
Aug 9, 3:12 PM EDTAreal Flood AdvisoryDTXMacomb, Oakland, Wayne101 min
Aug 9, 3:13 PM EDTSevere Thunderstorm WarningDTXMacomb, Wayne44 min
Aug 9, 3:34 PM EDTSevere Thunderstorm WarningDTXSaint Clair56 min
Aug 9, 3:48 PM EDTSpecial Weather StatementDTXSanilac57 min
Aug 9, 3:59 PM EDTSpecial Marine WarningDTX62 min
Aug 9, 4:09 PM EDTSpecial Weather StatementDTXHuron51 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.