Alert archive / Michigan / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 77, NWS Detroit, MI
NWS Detroit, MI issued this severe thunderstorm warning at Aug 12, 2021, 6:31 AM EDT for 4 counties in Michigan. It was in force for 59 min. 4 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, 6:31 AM EDT (10:31 UTC)
- Expired
- Aug 12, 2021, 7:30 AM EDT
- In force
- 59 min
- Issued by
- NWS Detroit, MI
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Lenawee County, MI, Livingston County, MI, Monroe County, MI, Washtenaw County, MI
The radar
The Detroit radar (KDTX), 66 km from the middle of the area, began a volume at 10:35 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 12, 6:37 AM EDT | TSTM WND DMG | Manitou Beach, MI | SOCIAL MEDIA VIDEO OF MULTIPLE LARGE TREES SNAPPED AROUND DEVILS LAKE. |
| Aug 12, 6:47 AM EDT | TSTM WND DMG | 2 W Manchester, MI | POWER LINES DOWN OVER THE ROADWAY. |
| Aug 12, 7:00 AM EDT | TSTM WND DMG | 5 Sse Ann Arbor, MI | LARGE TREE DOWN NEAR TEXTILE RD AND MICHIGAN AVE. |
| Aug 12, 7:13 AM EDT | TSTM WND DMG | Ann Arbor, MI | SPOTTER REPORTS NUMEROUS 6 TO 12 INCH DIAMETER TREES AND BRANCHES DOWN ACROSS THE ANN ARBOR AREA. |
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, 10.5 hours before the alert went out and 70 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.
- 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
The text
As transmitted.
637
WUUS53 KDTX 121031
SVRDTX
MIC091-093-115-161-121130-
/O.NEW.KDTX.SV.W.0077.210812T1031Z-210812T1130Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Detroit/Pontiac MI
631 AM EDT Thu Aug 12 2021
The National Weather Service in Detroit/Pontiac has issued a
* Severe Thunderstorm Warning for...
Northwestern Monroe County in southeastern Michigan...
Northern Lenawee County in southeastern Michigan...
Southern Livingston County in southeastern Michigan...
Washtenaw County in southeastern Michigan...
* Until 730 AM EDT.
* At 630 AM EDT, a severe thunderstorm was located near Cement City,
or 8 miles south of Vandercook Lake, moving northeast at 65 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...
Manchester around 650 AM EDT.
Chelsea around 655 AM EDT.
Ann Arbor and Dexter around 700 AM EDT.
Hamburg around 705 AM EDT.
Dixboro and Whitmore Lake around 710 AM EDT.
South Lyon and Salem around 715 AM EDT.
Other locations impacted by this severe thunderstorm include Manitou
Beach-Devils Lake, Whittaker, Hudson Mills Metropark, Ridgeway, Delhi
Mills, Pleasant Lake, Pinckney State Recreation Area, Chilson,
Cambridge Junction and Unadilla.
People attending Manchester Community Fair should seek safe shelter
immediately!
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4207 8436 4207 8413 4248 8414 4269 8369
4243 8366 4243 8355 4209 8354 4184 8436
TIME...MOT...LOC 1030Z 241DEG 57KT 4208 8442
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
AM3 follow-up statements
374
WWUS53 KDTX 121053
SVSDTX
Severe Weather Statement
National Weather Service Detroit/Pontiac MI
653 AM EDT Thu Aug 12 2021
MIC093-121103-
/O.CAN.KDTX.SV.W.0077.000000T0000Z-210812T1130Z/
Livingston MI-
653 AM EDT Thu Aug 12 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN LIVINGSTON COUNTY IS
CANCELLED...
The severe thunderstorm which prompted the warning will stay south
of the warned area. Therefore, the warning has been cancelled.
LAT...LON 4207 8436 4207 8413 4242 8413 4243 8355
4209 8354 4184 8436
TIME...MOT...LOC 1053Z 241DEG 50KT 4222 8395
$$
MIC091-115-161-121130-
/O.CON.KDTX.SV.W.0077.000000T0000Z-210812T1130Z/
Monroe MI-Lenawee MI-Washtenaw MI-
653 AM EDT Thu Aug 12 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 AM EDT
FOR NORTHWESTERN MONROE...NORTHERN LENAWEE AND WASHTENAW COUNTIES...
At 653 AM EDT, a severe thunderstorm was located near Manchester,
moving northeast at 60 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
This severe storm will be near...
Ann Arbor and Saline around 700 AM EDT.
Ypsilanti and Dixboro around 710 AM EDT.
Salem around 715 AM EDT.
Other locations impacted by this severe thunderstorm include Manitou
Beach-Devils Lake, Pittsfield Township, Cone, Whittaker, Macon,
Hudson Mills Metropark, Bridgewater, Ridgeway, Delhi Mills and
Pleasant Lake.
People attending Manchester Community Fair should seek safe shelter
immediately!
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4207 8436 4207 8413 4242 8413 4243 8355
4209 8354 4184 8436
TIME...MOT...LOC 1053Z 241DEG 50KT 4222 8395
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
AM191
WWUS53 KDTX 121112
SVSDTX
Severe Weather Statement
National Weather Service Detroit/Pontiac MI
712 AM EDT Thu Aug 12 2021
MIC091-121122-
/O.CAN.KDTX.SV.W.0077.000000T0000Z-210812T1130Z/
Lenawee MI-
712 AM EDT Thu Aug 12 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN LENAWEE COUNTY IS
CANCELLED...
The severe thunderstorm which prompted the warning has moved out of
the warned area. Therefore, the warning has been cancelled.
LAT...LON 4208 8377 4208 8380 4242 8380 4243 8375
4243 8355 4209 8354 4202 8377
TIME...MOT...LOC 1112Z 247DEG 45KT 4229 8353
$$
MIC115-161-121130-
/O.CON.KDTX.SV.W.0077.000000T0000Z-210812T1130Z/
Monroe MI-Washtenaw MI-
712 AM EDT Thu Aug 12 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 AM EDT
FOR NORTHWESTERN MONROE AND EASTERN WASHTENAW COUNTIES...
At 712 AM EDT, a severe thunderstorm was located over Canton, moving
east at 50 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
northwestern Monroe and eastern Washtenaw Counties, including the
following locations... Oakville, Pittsfield Township, Cone, Whittaker
and Barton Hills.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4208 8377 4208 8380 4242 8380 4243 8375
4243 8355 4209 8354 4202 8377
TIME...MOT...LOC 1112Z 247DEG 45KT 4229 8353
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
AM168
WWUS53 KDTX 121120
SVSDTX
Severe Weather Statement
National Weather Service Detroit/Pontiac MI
720 AM EDT Thu Aug 12 2021
MIC115-161-121130-
/O.EXP.KDTX.SV.W.0077.000000T0000Z-210812T1130Z/
Monroe MI-Washtenaw MI-
720 AM EDT Thu Aug 12 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN MONROE AND
EASTERN WASHTENAW COUNTIES WILL EXPIRE AT 730 AM EDT...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However heavy rain
is still possible with this thunderstorm.
LAT...LON 4208 8377 4208 8380 4242 8380 4243 8375
4243 8355 4209 8354 4202 8377
TIME...MOT...LOC 1120Z 241DEG 57KT 4234 8340
$$
AMThe office that day
Everything else NWS Detroit, MI issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 11, 10:42 PM EDT | Special Weather Statement | DTX | Genesee, Lapeer, Livingston, Oakland, Shiawassee | 63 min |
| Aug 11, 11:00 PM EDT | Special Weather Statement | DTX | Lenawee, Washtenaw | 60 min |
| Aug 11, 11:34 PM EDT | Special Weather Statement | DTX | Macomb, Monroe, Saint Clair, Wayne | 56 min |
| Aug 12, 12:47 AM EDT | Special Weather Statement | DTX | Tuscola | 43 min |
| Aug 12, 1:14 AM EDT | Special Weather Statement | DTX | Genesee, Shiawassee | 46 min |
| Aug 12, 2:04 AM EDT | Areal Flood Advisory | DTX | Livingston | 2 hr |
| Aug 12, 2:36 AM EDT | Special Weather Statement | DTX | Wayne | 54 min |
| Aug 12, 3:08 AM EDT | Areal Flood Advisory | DTX | Wayne | 4 hr |
| Aug 12, 4:33 AM EDT | Flash Flood Warning | DTX | Livingston | 2 hr |
| Aug 12, 5:18 AM EDT | Areal Flood Advisory | DTX | Macomb, Oakland | 3 hr |
| Aug 12, 5:41 AM EDT | Flash Flood Warning | DTX | Macomb, Oakland, Wayne | 3 hr |
| Aug 12, 6:43 AM EDT | Areal Flood Warning | DTX | Livingston | 2 hr |
| Aug 12, 7:09 AM EDT | Severe Thunderstorm Warning | DTX | Macomb, Monroe, Oakland, Wayne | 45 min |
| Aug 12, 7:18 AM EDT | Special Weather Statement | DTX | Monroe | 42 min |
| Aug 12, 7:27 AM EDT | Special Marine Warning | DTX | 34 min | |
| Aug 12, 7:35 AM EDT | River Flood Warning | DTX | Livingston | 18 days |
| Aug 12, 8:42 AM EDT | Areal Flood Advisory | DTX | Macomb, Oakland, Wayne | 3 hr |
| Aug 12, 11:53 AM EDT | River Flood Warning | DTX | Macomb | 7 hr |
| Aug 12, 6:08 PM EDT | River Flood Warning | DTX | Wayne | 15 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.