Alert archive / Michigan / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 84, NWS Detroit, MI

August 24, 2021Genesee County, Michigan

NWS Detroit, MI issued this severe thunderstorm warning at Aug 24, 2021, 7:30 PM EDT for Genesee County, 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 24, 2021, 7:30 PM EDT (23:30 UTC)
Expired
Aug 24, 2021, 8:15 PM EDT
In force
45 min
Issued by
NWS Detroit, MI
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Genesee County, MI

The radar

The Detroit radar (KDTX), 36 km from the middle of the area, began a volume at 23:33 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 24, 7:52 PM EDTTSTM WND DMG2 Ssw Flint, MILARGE TREE BRANCH APPROXIMATELY 8 INCH DIAMETER DOWN IN NORTHEAST CORNER OF BROOME PARK
Aug 24, 7:55 PM EDTTSTM WND DMG6 S Flint, MIREPORT OF A TREE DOWN BLOCKING TRAFFIC ON VAN SLYKE AND W HILL ROAD

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, 11.5 hours before the alert went out and 36 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 2021-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 298 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 2021-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -57 square meters per square second.1939Sfc1 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
298 J/kg
Mixed-layer CIN
-182 J/kg
Mixed-layer LCL
1140 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-57 m²/s²
0-3 km storm-relative helicity
-89 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

613 
WUUS53 KDTX 242330
SVRDTX
MIC049-250015-
/O.NEW.KDTX.SV.W.0084.210824T2330Z-210825T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Detroit/Pontiac MI
730 PM EDT Tue Aug 24 2021

The National Weather Service in Detroit/Pontiac has issued a

* Severe Thunderstorm Warning for...
  Genesee County in southeastern Michigan...

* Until 815 PM EDT.

* At 730 PM EDT, severe thunderstorms were located along a line
  extending from Montrose to near Swartz Creek to 6 miles southeast
  of Morrice, moving east at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Severe thunderstorms will be near...
  Swartz Creek and Montrose around 735 PM EDT.
  Clio, Mount Morris and Beecher around 740 PM EDT.
  Grand Blanc around 750 PM EDT.
  Fenton, Burton, Linden and Otisville around 755 PM EDT.
  Davison, Otter Lake and Lake Fenton around 800 PM EDT.
  Goodrich around 815 PM EDT.

Other locations impacted by these severe thunderstorms include Atlas,
Thetford Township, Argentine, Rankin and Genesee.

People attending Ally Golf Tournament 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 4322 8346 4288 8345 4287 8369 4278 8369
      4278 8392 4322 8393
TIME...MOT...LOC 2330Z 259DEG 35KT 4319 8388 4292 8388 4278 8408 

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

$$

DG
2 follow-up statements
240 
WWUS53 KDTX 242355
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
755 PM EDT Tue Aug 24 2021

MIC049-250015-
/O.CON.KDTX.SV.W.0084.000000T0000Z-210825T0015Z/
Genesee MI-
755 PM EDT Tue Aug 24 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR GENESEE COUNTY...

At 755 PM EDT, severe thunderstorms were located along a line
extending from near Millington to near Grand Blanc to Linden, moving
east at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

These severe storms will be near...
  Davison and Otisville around 800 PM EDT.
  Otter Lake around 805 PM EDT.
  Goodrich around 815 PM EDT.

Other locations impacted by these severe thunderstorms include Atlas,
Thetford Township, Argentine, Rankin and Genesee.

People attending Ally Golf Tournament 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 4322 8346 4288 8345 4287 8369 4278 8369
      4278 8392 4314 8393
TIME...MOT...LOC 2355Z 259DEG 35KT 4323 8359 4296 8359 4282 8379 

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

$$

Mann
444 
WWUS53 KDTX 250016
SVSDTX

Severe Weather Statement
National Weather Service Detroit/Pontiac MI
816 PM EDT Tue Aug 24 2021

MIC049-250026-
/O.EXP.KDTX.SV.W.0084.000000T0000Z-210825T0015Z/
Genesee MI-
816 PM EDT Tue Aug 24 2021

...THE SEVERE THUNDERSTORM WARNING FOR GENESEE COUNTY HAS EXPIRED...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning has been allowed to expire.  However gusty
winds and heavy rain are still possible with these thunderstorms.

LAT...LON 4322 8346 4288 8345 4287 8369 4278 8369
      4278 8392 4314 8393
TIME...MOT...LOC 0016Z 259DEG 35KT 4323 8359 4296 8359 4282 8379 

$$

Mann

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 6:01 PM EDTSpecial Weather StatementDTXBay, Midland, Saginaw89 min
Aug 24, 6:07 PM EDTSevere Thunderstorm WarningDTXMidland53 min
Aug 24, 6:38 PM EDTSpecial Weather StatementDTXBay, Saginaw52 min
Aug 24, 6:42 PM EDTSpecial Marine WarningDTX93 min
Aug 24, 6:47 PM EDTSevere Thunderstorm WarningDTXBay28 min
Aug 24, 6:52 PM EDTSevere Thunderstorm WarningDTXSaginaw53 min
Aug 24, 7:08 PM EDTSpecial Weather StatementDTXShiawassee67 min
Aug 24, 7:13 PM EDTSevere Thunderstorm WarningDTXShiawassee62 min
Aug 24, 7:45 PM EDTSevere Thunderstorm WarningDTXLivingston35 min
Aug 24, 7:52 PM EDTSpecial Weather StatementDTXHuron, Sanilac53 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.