Alert archive / Michigan / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 45, NWS Detroit, MI
NWS Detroit, MI issued this severe thunderstorm warning at Jul 20, 2021, 8:06 PM EDT for Washtenaw County, Michigan. It was in force for 54 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
- Jul 20, 2021, 8:06 PM EDT (00:06 UTC)
- Expired
- Jul 20, 2021, 9:00 PM EDT
- In force
- 54 min
- Issued by
- NWS Detroit, MI
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
County Washtenaw County, MI
The radar
The Detroit radar (KDTX), 61 km from the middle of the area, began a volume at 00:07 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 |
|---|---|---|---|
| Jul 20, 8:15 PM EDT | TSTM WND DMG | Chelsea, MI | LARGE TREE LIMB REPORTED DOWN. |
| Jul 20, 8:27 PM EDT | HAIL 0.75 | 1 Ssw Chelsea, MI |
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, 0.1 hours before the alert went out and 65 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
- 334 J/kg
- Mixed-layer CIN
- -53 J/kg
- Mixed-layer LCL
- 864 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- -125 m²/s²
- 0-3 km storm-relative helicity
- -74 m²/s²
- Significant tornado parameter
- -0.1
- Supercell composite
- -1.2
The text
As transmitted.
791
WUUS53 KDTX 210006
SVRDTX
MIC161-210100-
/O.NEW.KDTX.SV.W.0045.210721T0006Z-210721T0100Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Detroit/Pontiac MI
806 PM EDT Tue Jul 20 2021
The National Weather Service in Detroit/Pontiac has issued a
* Severe Thunderstorm Warning for...
Washtenaw County in southeastern Michigan...
* Until 900 PM EDT.
* At 806 PM EDT, severe thunderstorms were located along a line
extending from near Chelsea to near Dexter to near Canton, moving
southeast at 25 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* Severe thunderstorms will be near...
Salem around 810 PM EDT.
Ypsilanti around 815 PM EDT.
Ann Arbor and Dixboro around 820 PM EDT.
Other locations in the path of these severe thunderstorms include
Saline, Manchester, Willis and Milan.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4242 8413 4243 8355 4209 8354 4208 8397
4207 8413
TIME...MOT...LOC 0006Z 335DEG 23KT 4234 8411 4235 8382 4233 8352
HAIL...<.75IN
WIND...60MPH
$$
AM3 follow-up statements
388
WWUS53 KDTX 210020
SVSDTX
Severe Weather Statement
National Weather Service Detroit/Pontiac MI
820 PM EDT Tue Jul 20 2021
MIC161-210100-
/O.CON.KDTX.SV.W.0045.000000T0000Z-210721T0100Z/
Washtenaw MI-
820 PM EDT Tue Jul 20 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM EDT
FOR WASHTENAW COUNTY...
At 819 PM EDT, severe thunderstorms were located along a line
extending from near Chelsea to near Ann Arbor to near Ypsilanti,
moving southeast at 25 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
These severe storms will be near...
Ypsilanti around 825 PM EDT.
Saline around 830 PM EDT.
Willis around 835 PM EDT.
Milan around 850 PM EDT.
Other locations impacted by these severe thunderstorms include
Bridgewater, Pittsfield Township, Delhi Mills, Pleasant Lake,
Whittaker and Barton Hills.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4233 8413 4234 8355 4209 8354 4208 8397
4207 8413
TIME...MOT...LOC 0019Z 334DEG 23KT 4226 8406 4227 8377 4226 8355
HAIL...<.75IN
WIND...60MPH
$$
AM420
WWUS53 KDTX 210046
SVSDTX
Severe Weather Statement
National Weather Service Detroit/Pontiac MI
846 PM EDT Tue Jul 20 2021
MIC161-210100-
/O.CON.KDTX.SV.W.0045.000000T0000Z-210721T0100Z/
Washtenaw MI-
846 PM EDT Tue Jul 20 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM EDT
FOR SOUTHERN WASHTENAW COUNTY...
At 845 PM EDT, a severe thunderstorm was located over Manchester,
moving south at 15 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
southern Washtenaw County, including the following locations...
Bridgewater, Pittsfield Township, Pleasant Lake and Whittaker.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4230 8413 4219 8354 4209 8354 4208 8397
4207 8413
TIME...MOT...LOC 0045Z 356DEG 12KT 4216 8400
HAIL...<.75IN
WIND...60MPH
$$
DG197
WWUS53 KDTX 210059
SVSDTX
Severe Weather Statement
National Weather Service Detroit/Pontiac MI
859 PM EDT Tue Jul 20 2021
MIC161-210108-
/O.EXP.KDTX.SV.W.0045.000000T0000Z-210721T0100Z/
Washtenaw MI-
859 PM EDT Tue Jul 20 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN WASHTENAW COUNTY WILL
EXPIRE AT 900 PM EDT...
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However, gusty
winds are still possible with this thunderstorm.
LAT...LON 4230 8413 4219 8354 4209 8354 4208 8397
4207 8413
TIME...MOT...LOC 0058Z 335DEG 23KT 4209 8396
$$
DGThe office that day
Everything else NWS Detroit, MI issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 20, 8:31 PM EDT | Special Weather Statement | DTX | Lenawee, Monroe | 89 min |
| Jul 20, 8:58 PM EDT | Special Weather Statement | DTX | Lenawee | 62 min |
| Jul 21, 2:54 AM EDT | Beach Hazards Statement | DTX | Huron, Saint Clair, Sanilac | 17 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.