Alert archive / Michigan / Mesoscale Discussions in 2013
Mesoscale Discussion 520
The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2013, 9:48 AM EDT for 35 counties in Michigan. It was in force for 27 min.
The area
The outline as issued.
The facts
- Issued
- Apr 18, 2013, 9:48 AM EDT (13:48 UTC)
- Expired
- Apr 18, 2013, 10:15 AM EDT
- In force
- 27 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 95%
All 35 counties
Allegan County, MI, Barry County, MI, Bay County, MI, Calhoun County, MI, Clinton County, MI, Eaton County, MI, Genesee County, MI, Gratiot County, MI, Hillsdale County, MI, Huron County, MI, Ingham County, MI, Ionia County, MI, Isabella County, MI, Jackson County, MI, Kalamazoo County, MI, Kent County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Mecosta County, MI, Midland County, MI, Monroe County, MI, Montcalm County, MI, Newaygo County, MI, Oakland County, MI, Ottawa County, MI, Saginaw County, MI, Saint Clair County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Van Buren County, MI, Washtenaw County, MI, Wayne County, MI
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Detroit, MI (KDTX), launched 12:00Z, 1.8 hours before the alert went out and 77 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
- 42 J/kg
- Mixed-layer CIN
- -226 J/kg
- Mixed-layer LCL
- 609 m above ground
- 0-6 km bulk shear
- 64 kt
- 0-1 km storm-relative helicity
- 476 m²/s²
- 0-3 km storm-relative helicity
- 516 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.9
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 18, 8:25 AM EDT | Mesoscale Discussion | SPC | Berrien, Cass, Kalamazoo, Saint Joseph | 95 min |
| Apr 18, 9:31 AM EDT | Tornado Watch | SPC | Berrien, Branch, Cass, Hillsdale, Saint Joseph | 7 hr |
| Apr 18, 10:06 AM EDT | Tornado Watch | SPC | Allegan, Barry, Bay, Calhoun, Clinton, Eaton and 30 more | 6 hr |
| Apr 18, 12:14 PM EDT | Mesoscale Discussion | SPC | Barry, Bay, Branch, Calhoun, Clinton, Eaton and 26 more | 2 hr |
Nearby
Mesoscale Discussions in Michigan, 2013Every mesoscale discussion in 2013
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.