Alert archive / Michigan / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 776
The Storm Prediction Center issued this severe thunderstorm watch at Aug 13, 2011, 5:28 PM EDT for 11 counties in Michigan; 8 counties in Ohio. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 13, 2011, 5:28 PM EDT (21:28 UTC)
- Expired
- Aug 13, 2011, 9:12 PM EDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
Counties Genesee County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Saint Clair County, MI, Shiawassee County, MI, Washtenaw County, MI, Wayne County, MI, Erie County, OH, Hancock County, OH, Huron County, OH, Lucas County, OH, Ottawa County, OH, Sandusky County, OH, Seneca County, OH, Wood County, OH
The radar
The Detroit radar (KDTX), 53 km from the middle of the area, began a volume at 21:30 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 SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 20%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 13, 6:15 PM EDT | Severe Thunderstorm Warning | DTX | Livingston, Washtenaw | 63 min |
| Aug 13, 6:57 PM EDT | Severe Thunderstorm Warning | DTX | Oakland, Wayne | 63 min |
| Aug 13, 7:37 PM EDT | Severe Thunderstorm Warning | DTX | Macomb, Saint Clair | 53 min |
| Aug 13, 8:18 PM EDT | Severe Thunderstorm Warning | DTX | Macomb, Saint Clair | 31 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Detroit, MI (KDTX), launched 12:00Z, 9.5 hours before the alert went out and 56 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 4981 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 133 m²/s²
- 0-3 km storm-relative helicity
- 132 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 13, 12:45 PM EDT | Mesoscale Discussion | SPC | Allegan, Berrien, Branch, Cass, Kalamazoo, Saint Joseph and 1 more | 60 min |
| Aug 13, 1:12 PM EDT | Severe Thunderstorm Watch | SPC | Allegan, Barry, Berrien, Branch, Calhoun, Cass and 11 more | 9 hr |
| Aug 13, 4:29 PM EDT | Mesoscale Discussion | SPC | Branch, Hillsdale, Jackson, Lenawee, Livingston, Saint Joseph | 91 min |
| Aug 13, 7:10 PM EDT | Mesoscale Discussion | SPC | Lenawee, Livingston, Macomb, Monroe, Oakland, Saint Clair and 2 more | 95 min |
| Aug 13, 6:30 PM EDT | Mesoscale Discussion | SPC | Adams, Brown, Clermont, Scioto | 90 min |
Nearby
Severe Thunderstorm Watches in Michigan, 2011Severe Thunderstorm Watches in Ohio, 2011Every severe thunderstorm watch in 2011
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.