Alert archive / Michigan / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 30, NWS Grand Rapids, MI

August 9, 2009Gratiot County, Michigan

NWS Grand Rapids, MI issued this severe thunderstorm warning at Aug 9, 2009, 1:33 AM EDT for Gratiot County, Michigan. It was in force for 27 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 9, 2009, 1:33 AM EDT (05:33 UTC)
Expired: Aug 9, 2009, 2:00 AM EDT
In force: 27 min
Issued by: NWS Grand Rapids, MI
Area: Storm-based polygon

County Gratiot County, MI

The radar

The Grand Rapids radar (KGRR), 88 km from the middle of the area, began a volume at 05:34 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 nearest sounding before it

Detroit, MI (KDTX), launched 00:00Z, 5.6 hours before the alert went out and 115 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 834 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 628 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 353 m²/s²
0-3 km storm-relative helicity: 474 m²/s²
Significant tornado parameter: 2.0
Supercell composite: 15.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Grand Rapids, MI wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 8, 10:11 PM EDT, 3 hours 22 minutes earlier.

Area forecast discussion, Aug 8, 10:11 PM EDT, 3 hours 22 minutes before

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Hazardous weather outlook, Aug 8, 4:34 PM EDT, 8 hours 59 minutes before

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In the hours before

Local storm report, Aug 8, 7:45 PM EDT, 5 hours 48 minutes before

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Local storm report, Aug 8, 8:25 PM EDT, 5 hours 8 minutes before

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Special weather statement, Aug 8, 11:16 PM EDT, 2 hours 17 minutes before

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Special weather statement, Aug 9, 12:10 AM EDT, 1 hour 23 minutes before

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Special weather statement, Aug 9, 1:10 AM EDT, 23 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 8, 9:58 PM EDT	Special Marine Warning	GRR		92 min
Aug 8, 11:16 PM EDT	Special Weather Statement	GRR	Lake, Mason, Newaygo	59 min
Aug 9, 12:10 AM EDT	Special Weather Statement	GRR	Isabella, Mecosta, Montcalm, Muskegon, Newaygo, Oceana	65 min
Aug 9, 1:10 AM EDT	Special Weather Statement	GRR	Clinton, Gratiot, Kent, Montcalm	65 min
Aug 9, 2:05 AM EDT	Special Weather Statement	GRR	Eaton, Ingham	55 min
Aug 9, 3:06 PM EDT	Heat Advisory	GRR	Allegan, Barry, Calhoun, Eaton, Ingham, Jackson and 2 more	5 hr
Aug 9, 5:26 PM EDT	Special Marine Warning	GRR		74 min
Aug 9, 5:47 PM EDT	Special Marine Warning	GRR		41 min
Aug 9, 6:01 PM EDT	Severe Thunderstorm Warning	GRR	Kent, Muskegon, Newaygo, Ottawa	66 min
Aug 9, 6:35 PM EDT	Special Weather Statement	GRR	Barry, Calhoun, Eaton, Ingham, Jackson, Kalamazoo	70 min
Aug 9, 6:45 PM EDT	Severe Thunderstorm Warning	GRR	Ionia, Kent, Mecosta, Montcalm, Muskegon, Newaygo and 1 more	60 min
Aug 9, 7:10 PM EDT	Severe Thunderstorm Warning	GRR	Allegan, Barry, Calhoun, Clinton, Eaton, Ingham and 5 more	65 min
Aug 9, 7:17 PM EDT	Special Marine Warning	GRR		49 min
Aug 9, 7:40 PM EDT	Severe Thunderstorm Warning	GRR	Clinton, Eaton, Gratiot, Ingham, Ionia, Isabella and 2 more	65 min
Aug 9, 7:49 PM EDT	Severe Thunderstorm Warning	GRR	Calhoun, Ingham, Jackson	56 min

Nearby

Severe Thunderstorm Warnings in Michigan, 2009 Every severe thunderstorm warning in 2009

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.