Alert archive / Michigan / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 78, NWS Detroit, MI

August 12, 20214 counties in Michigan

NWS Detroit, MI issued this severe thunderstorm warning at Aug 12, 2021, 7:09 AM EDT for 4 counties in Michigan. It was in force for 45 min. 2 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 12, 2021, 7:09 AM EDT (11:09 UTC)
Expired
Aug 12, 2021, 7:54 AM EDT
In force
45 min
Issued by
NWS Detroit, MI
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Macomb County, MI, Monroe County, MI, Oakland County, MI, Wayne County, MI

The radar

The Detroit radar (KDTX), 53 km from the middle of the area, began a volume at 11:13 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 12, 7:15 AM EDTTSTM WND DMG3 Ssw Canton, MI8 INCH DIAMTER TREE LIMB DOWN.
Aug 12, 7:24 AM EDTTSTM WND DMG2 Wnw Romulus, MIPUBLIC REPORT OF APPROX 6 INCH DIAMETER HEALTHY TREE LIMBS DOWN ALONG TYLER RD BETWEEN COGSWELL AND OZGA RDS.

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, 11.2 hours before the alert went out and 54 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 2021-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 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 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 243 square meters per square second.19395878Sfc1 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
12 J/kg
Mixed-layer CIN
-458 J/kg
Mixed-layer LCL
1474 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
243 m²/s²
0-3 km storm-relative helicity
373 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

955 
WUUS53 KDTX 121109
SVRDTX
MIC099-115-125-163-121215-
/O.NEW.KDTX.SV.W.0078.210812T1109Z-210812T1215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Detroit/Pontiac MI
709 AM EDT Thu Aug 12 2021

The National Weather Service in Detroit/Pontiac has issued a

* Severe Thunderstorm Warning for...
  Northern Monroe County in southeastern Michigan...
  Wayne County in southeastern Michigan...
  Southeastern Oakland County in southeastern Michigan...
  Southwestern Macomb County in southeastern Michigan...

* Until 815 AM EDT.

* At 708 AM EDT, a severe thunderstorm was located near Ypsilanti,
  moving northeast at 65 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* This severe thunderstorm will be near...
  Romulus around 720 AM EDT.
  Livonia, Taylor and Greenfield Village around 725 AM EDT.
  Southfield, Detroit, Dearborn and Detroit Zoo around 730 AM EDT.
  Warren, Downtown Detroit and Belle Isle around 735 AM EDT.
  Grosse Pointe around 740 AM EDT.
  St. Clair Shores around 745 AM EDT.

Other locations impacted by this severe thunderstorm include
Melvindale, Gibraltar, Roseville, New Boston, Rockwood, Harper Woods,
Pleasant Ridge, Westland, Grosse Pointe Shores and Ecorse.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4237 8288 4230 8309 4224 8313 4213 8312
      4204 8315 4202 8377 4209 8354 4243 8355
      4254 8287 4253 8282
TIME...MOT...LOC 1108Z 246DEG 58KT 4228 8358 

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

$$

AM
2 follow-up statements
750 
WWUS53 KDTX 121132
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
732 AM EDT Thu Aug 12 2021

MIC115-121142-
/O.CAN.KDTX.SV.W.0078.000000T0000Z-210812T1215Z/
Monroe MI-
732 AM EDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN MONROE 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 4237 8288 4234 8296 4232 8306 4230 8309
      4213 8319 4212 8339 4246 8339 4254 8288
      4253 8282
TIME...MOT...LOC 1132Z 249DEG 39KT 4234 8323 

$$

MIC099-125-163-121215-
/O.CON.KDTX.SV.W.0078.000000T0000Z-210812T1215Z/
Wayne MI-Oakland MI-Macomb MI-
732 AM EDT Thu Aug 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 AM EDT
FOR WAYNE...SOUTHEASTERN OAKLAND AND SOUTHWESTERN MACOMB COUNTIES...

At 732 AM EDT, a severe thunderstorm was located over Dearborn, or 8
miles southeast of Livonia, moving east at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

This severe storm will be near...
  Detroit and Detroit Zoo around 740 AM EDT.
  Downtown Detroit around 745 AM EDT.
  Belle Isle around 750 AM EDT.
  Grosse Pointe around 755 AM EDT.
  St. Clair Shores around 805 AM EDT.

Other locations impacted by this severe thunderstorm include
Melvindale, Roseville, Harper Woods, Pleasant Ridge, Westland, Grosse
Pointe Shores, Ecorse, Center Line, Huntington Woods and Grosse
Pointe Woods.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4237 8288 4234 8296 4232 8306 4230 8309
      4213 8319 4212 8339 4246 8339 4254 8288
      4253 8282
TIME...MOT...LOC 1132Z 249DEG 39KT 4234 8323 

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

$$

AM
864 
WWUS53 KDTX 121154
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
754 AM EDT Thu Aug 12 2021

MIC099-125-163-121204-
/O.CAN.KDTX.SV.W.0078.000000T0000Z-210812T1215Z/
Wayne MI-Oakland MI-Macomb MI-
754 AM EDT Thu Aug 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR WAYNE...SOUTHEASTERN OAKLAND
AND SOUTHWESTERN MACOMB COUNTIES IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

LAT...LON 4237 8288 4234 8296 4232 8306 4230 8309
      4213 8319 4212 8339 4246 8339 4254 8288
      4253 8282
TIME...MOT...LOC 1152Z 246DEG 58KT 4248 8279 

$$

AM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 10:42 PM EDTSpecial Weather StatementDTXGenesee, Lapeer, Livingston, Oakland, Shiawassee63 min
Aug 11, 11:00 PM EDTSpecial Weather StatementDTXLenawee, Washtenaw60 min
Aug 11, 11:34 PM EDTSpecial Weather StatementDTXMacomb, Monroe, Saint Clair, Wayne56 min
Aug 12, 12:47 AM EDTSpecial Weather StatementDTXTuscola43 min
Aug 12, 1:14 AM EDTSpecial Weather StatementDTXGenesee, Shiawassee46 min
Aug 12, 2:04 AM EDTAreal Flood AdvisoryDTXLivingston2 hr
Aug 12, 2:36 AM EDTSpecial Weather StatementDTXWayne54 min
Aug 12, 3:08 AM EDTAreal Flood AdvisoryDTXWayne4 hr
Aug 12, 4:33 AM EDTFlash Flood WarningDTXLivingston2 hr
Aug 12, 5:18 AM EDTAreal Flood AdvisoryDTXMacomb, Oakland3 hr
Aug 12, 5:41 AM EDTFlash Flood WarningDTXMacomb, Oakland, Wayne3 hr
Aug 12, 6:31 AM EDTSevere Thunderstorm WarningDTXLenawee, Livingston, Monroe, Washtenaw59 min
Aug 12, 6:43 AM EDTAreal Flood WarningDTXLivingston2 hr
Aug 12, 7:18 AM EDTSpecial Weather StatementDTXMonroe42 min
Aug 12, 7:27 AM EDTSpecial Marine WarningDTX34 min
Aug 12, 7:35 AM EDTRiver Flood WarningDTXLivingston18 days
Aug 12, 8:42 AM EDTAreal Flood AdvisoryDTXMacomb, Oakland, Wayne3 hr
Aug 12, 11:53 AM EDTRiver Flood WarningDTXMacomb7 hr
Aug 12, 6:08 PM EDTRiver Flood WarningDTXWayne15 hr

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.