Alert archive / Michigan / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 33, NWS Detroit, MI

July 7, 2021Saint Clair County, Michigan

NWS Detroit, MI issued this severe thunderstorm warning at Jul 7, 2021, 3:10 PM EDT for Saint Clair County, Michigan. It was in force for 65 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 7, 2021, 3:10 PM EDT (19:10 UTC)
Expired
Jul 7, 2021, 4:15 PM EDT
In force
65 min
Issued by
NWS Detroit, MI
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Saint Clair County, MI

The radar

The Detroit radar (KDTX), 71 km from the middle of the area, began a volume at 19:10 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 7, 1:31 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Detroit, MI (KDTX), launched 12:00Z, 7.2 hours before the alert went out and 68 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 2021-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1092 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 2021-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 54 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
1092 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
779 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
123 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted.

199 
WUUS53 KDTX 071910
SVRDTX
MIC147-072015-
/O.NEW.KDTX.SV.W.0033.210707T1910Z-210707T2015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Detroit/Pontiac MI
310 PM EDT Wed Jul 7 2021

The National Weather Service in Detroit/Pontiac has issued a

* Severe Thunderstorm Warning for...
  Southeastern St. Clair County in southeastern Michigan...

* Until 415 PM EDT.

* At 309 PM EDT, a severe thunderstorm was located near New
  Baltimore, moving east at 25 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...
  Algonac around 320 PM EDT.
  St. Clair and Marine City around 325 PM EDT.

Other locations impacted by this severe thunderstorm include
Anchorville, Adair, Columbus, Rattle Run, Pearl Beach, Smiths Creek
and Fair Haven.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4281 8248 4276 8247 4267 8251 4262 8251
      4255 8258 4255 8260 4256 8262 4255 8266
      4268 8273 4268 8271 4269 8271 4271 8273
      4291 8274 4293 8246
TIME...MOT...LOC 1909Z 267DEG 27KT 4273 8263 

HAIL...0.75IN
WIND...60MPH
 
$$

DG
3 follow-up statements
543 
WWUS53 KDTX 071922
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
322 PM EDT Wed Jul 7 2021

MIC147-072015-
/O.CON.KDTX.SV.W.0033.000000T0000Z-210707T2015Z/
St. Clair MI-
322 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR SOUTHEASTERN ST. CLAIR COUNTY...

At 322 PM EDT, a severe thunderstorm was located near Marine City, or
7 miles north of Algonac, moving east at 25 mph.

HAZARD...60 mph wind gusts and half dollar size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

This severe storm will be near...
  Algonac around 325 PM EDT.
  St. Clair and Marine City around 330 PM EDT.

Other locations impacted by this severe thunderstorm include
Anchorville, Adair, Columbus, Rattle Run, Pearl Beach, Smiths Creek
and Fair Haven.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and deadly cloud to ground
lightning. Seek shelter inside a well-built structure. Stay away from
windows.

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.

&&

LAT...LON 4281 8248 4276 8247 4267 8251 4262 8251
      4255 8258 4255 8260 4256 8262 4255 8266
      4268 8273 4268 8271 4269 8271 4271 8273
      4291 8274 4293 8246
TIME...MOT...LOC 1922Z 268DEG 22KT 4273 8256 

HAIL...1.25IN
WIND...60MPH
 
$$

IRL
422 
WWUS53 KDTX 071933
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
333 PM EDT Wed Jul 7 2021

MIC147-072015-
/O.CON.KDTX.SV.W.0033.000000T0000Z-210707T2015Z/
St. Clair MI-
333 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR SOUTHEASTERN ST. CLAIR COUNTY...

At 333 PM EDT, a severe thunderstorm was located over Marine City, or
near St. Clair, moving east at 30 mph.

HAZARD...60 mph wind gusts and half dollar size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

This severe thunderstorm will remain over mainly rural areas of
southeastern St. Clair County, including the following locations...
Anchorville, Columbus, Rattle Run, Pearl Beach, Adair and Fair Haven.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Prepare immediately for large hail and deadly cloud to ground
lightning. Seek shelter inside a well-built structure. Stay away from
windows.

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 4281 8248 4275 8247 4267 8251 4261 8252
      4255 8259 4256 8263 4255 8266 4267 8273
      4267 8271 4269 8271 4271 8273 4273 8273
      4290 8274 4292 8246
TIME...MOT...LOC 1933Z 265DEG 25KT 4274 8247 

HAIL...1.25IN
WIND...60MPH
 
$$

IRL
945 
WWUS53 KDTX 071956
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
356 PM EDT Wed Jul 7 2021

MIC147-072015-
/O.CON.KDTX.SV.W.0033.000000T0000Z-210707T2015Z/
St. Clair MI-
356 PM EDT Wed Jul 7 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR SOUTHEASTERN ST. CLAIR COUNTY...

At 356 PM EDT, a severe thunderstorm was located 12 miles east of
Marine City, or 12 miles southeast of St. Clair, moving east at 30
mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
New Baltimore, Algonac, Marine City, Harsens Island, Anchorville,
Adair, Pearl Beach and Fair Haven.

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 8251 4261 8252 4257 8257 4255 8259
      4256 8263 4255 8266 4267 8273 4267 8271
      4269 8271 4271 8273 4280 8273 4281 8248
      4275 8247
TIME...MOT...LOC 1956Z 267DEG 27KT 4275 8226 

HAIL...0.75IN
WIND...60MPH
 
$$

IRL

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 8:06 PM EDTSpecial Weather StatementDTXSaint Clair54 min
Jul 6, 8:07 PM EDTSpecial Marine WarningDTX53 min
Jul 6, 8:26 PM EDTSpecial Marine WarningDTX79 min
Jul 6, 9:22 PM EDTSpecial Weather StatementDTXSaginaw53 min
Jul 6, 9:31 PM EDTSevere Thunderstorm WarningDTXSaginaw25 min
Jul 6, 9:37 PM EDTSpecial Marine WarningDTX21 min
Jul 6, 9:45 PM EDTSevere Thunderstorm WarningDTXHuron41 min
Jul 6, 10:13 PM EDTSpecial Weather StatementDTXOakland62 min
Jul 6, 10:16 PM EDTSevere Thunderstorm WarningDTXLapeer, Tuscola45 min
Jul 6, 10:49 PM EDTSevere Thunderstorm WarningDTXSanilac32 min
Jul 6, 10:51 PM EDTSpecial Weather StatementDTXOakland24 min
Jul 6, 11:00 PM EDTSpecial Weather StatementDTXSaginaw30 min
Jul 7, 3:38 AM EDTSmall Craft AdvisoryDTX24 hr
Jul 7, 12:35 PM EDTSpecial Weather StatementDTXHuron70 min
Jul 7, 1:43 PM EDTSpecial Weather StatementDTXHuron47 min
Jul 7, 1:49 PM EDTSevere Thunderstorm WarningDTXShiawassee41 min
Jul 7, 1:54 PM EDTSpecial Weather StatementDTXLivingston51 min
Jul 7, 2:08 PM EDTSpecial Weather StatementDTXLenawee52 min
Jul 7, 2:24 PM EDTSpecial Marine WarningDTX48 min
Jul 7, 2:39 PM EDTSevere Thunderstorm WarningDTXMonroe50 min
Jul 7, 2:41 PM EDTSpecial Marine WarningDTX65 min
Jul 7, 2:47 PM EDTSpecial Weather StatementDTXOakland43 min
Jul 7, 2:47 PM EDTSevere Thunderstorm WarningDTXLapeer, Oakland58 min
Jul 7, 2:53 PM EDTSpecial Weather StatementDTXSaint Clair37 min
Jul 7, 2:54 PM EDTSevere Thunderstorm WarningDTXOakland46 min
Jul 7, 3:11 PM EDTSpecial Marine WarningDTX105 min
Jul 7, 3:26 PM EDTSevere Thunderstorm WarningDTXMacomb49 min
Jul 7, 3:38 PM EDTSevere Thunderstorm WarningDTXLivingston, Washtenaw67 min
Jul 7, 3:51 PM EDTSpecial Weather StatementDTXOakland84 min
Jul 7, 4:15 PM EDTSevere Thunderstorm WarningDTXSaint Clair30 min
Jul 7, 4:18 PM EDTSevere Thunderstorm WarningDTXOakland57 min
Jul 7, 5:07 PM EDTSpecial Weather StatementDTXWayne53 min
Jul 7, 5:08 PM EDTSpecial Marine WarningDTX68 min
Jul 7, 5:09 PM EDTSevere Thunderstorm WarningDTXMacomb51 min
Jul 7, 5:31 PM EDTAreal Flood AdvisoryDTXMacomb, Oakland112 min
Jul 7, 5:44 PM EDTSpecial Weather StatementDTXMacomb31 min
Jul 7, 7:07 PM EDTSpecial Weather StatementDTXMonroe53 min
Jul 7, 7:22 PM EDTAreal Flood AdvisoryDTXGenesee99 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.