Alert archive / Michigan / Mesoscale Discussions in 2011

Mesoscale Discussion 2168

September 12, 201110 counties in Michigan; Florence County, Forest County, Marinette County, Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Sep 12, 2011, 11:06 PM EDT for 10 counties in Michigan; Florence County, Forest County, Marinette County, Wisconsin. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Sep 12, 2011, 11:06 PM EDT (03:06 UTC)
Expired
Sep 13, 2011, 12:00 AM EDT
In force
54 min
Issued by
the Storm Prediction Center

Counties Alger County, MI, Baraga County, MI, Delta County, MI, Dickinson County, MI, Iron County, MI, Luce County, MI, Mackinac County, MI, Marquette County, MI, Menominee County, MI, Schoolcraft County, MI, Florence County, WI, Forest County, WI, Marinette County, WI

The radar

The Marquette radar (KMQT), 61 km from the middle of the area, began a volume at 03:07 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

Green Bay/Straub, WI (KGRB), launched 00:00Z, 3.1 hours before the alert went out and 173 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, Green Bay/Straub, WI at 00:00Z on 2011-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 893 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Green Bay/Straub, WI at 00:00Z on 2011-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 187 square meters per square second.19395878Sfc1 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
893 J/kg
Mixed-layer CIN
-98 J/kg
Mixed-layer LCL
1722 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
187 m²/s²
0-3 km storm-relative helicity
290 m²/s²
Significant tornado parameter
0.1
Supercell composite
2.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 12, 8:09 PM EDTSevere Thunderstorm WatchSPCAlger, Baraga, Delta, Dickinson, Gogebic, Houghton and 7 more4 hr

Nearby

Mesoscale Discussions in Michigan, 2011Mesoscale Discussions in Wisconsin, 2011Every mesoscale discussion 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.