Alert archive / Michigan / Mesoscale Discussions in 2012

Mesoscale Discussion 1392

July 4, 20126 counties in Michigan; Cook County, Lake County, Minnesota; Ashland County, Iron County, Vilas County, Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2012, 4:57 PM EDT for 6 counties in Michigan; Cook County, Lake County, Minnesota; Ashland County, Iron County, Vilas County, Wisconsin. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Jul 4, 2012, 4:57 PM EDT (20:57 UTC)
Expired: Jul 4, 2012, 6:30 PM EDT
In force: 93 min
Issued by: the Storm Prediction Center

Counties Baraga County, MI, Gogebic County, MI, Houghton County, MI, Iron County, MI, Keweenaw County, MI, Ontonagon County, MI, Cook County, MN, Lake County, MN, Ashland County, WI, Iron County, WI, Vilas County, WI

The radar

The Marquette radar (KMQT), 178 km from the middle of the area, began a volume at 20:59 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 464Jul 4, 8:30 PM EDT

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 9.0 hours before the alert went out and 314 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: 3032 J/kg
Mixed-layer CIN: -99 J/kg
Mixed-layer LCL: 1071 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 56 m²/s²
0-3 km storm-relative helicity: 117 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 7.1

Open this sounding in Storm Lab

The text

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

550 
ACUS11 KWNS 042057
SWOMCD
SPC MCD 042057 
MIZ000-WIZ000-MNZ000-042230-

MESOSCALE DISCUSSION 1392
NWS STORM PREDICTION CENTER NORMAN OK
0357 PM CDT WED JUL 04 2012

AREAS AFFECTED...NE MN...LAKE SUPERIOR...UPPER MI

CONCERNING...SEVERE THUNDERSTORM WATCH 460...

VALID 042057Z - 042230Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 460
CONTINUES.

SUMMARY...THE SEVERE THREAT LOCATED ACROSS NE MN WILL LIKELY
CONTINUE THIS AFTERNOON. THE PRIMARY THREATS SHOULD BE WIND DAMAGE
AND ISOLATED LARGE HAIL AS A LINE APPROACHES UPPER MI. WW ISSUANCE
MAY BE NECESSARY TO THE EAST OF WW 460 AS THE LINE APPROACHES THE
ERN EDGE OF THE WATCH.

DISCUSSION...A BOWING LINE SEGMENT NEAR THE ARROWHEAD OF MN IS
LOCATED ON A TIGHT GRADIENT OF MODERATE INSTABILITY AND IS BEING
SUPPORTED BY A SHORTWAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY.
MESOANALYSIS CURRENTLY SHOWS MLCAPE AROUND 1500 J/KG ACROSS NE MN
EXTENDING EWD ALONG THE SOUTH SHORT OF LAKE SUPERIOR. SOUTH OF LAKE
SUPERIOR ACROSS UPPER MI...STRONG INSTABILITY IS PRESENT WITH MLCAPE
ESTIMATED AROUND 4000 J/KG NEAR MARQUETTE. ALTHOUGH INSTABILITY IS
WEAKER OVER LAKE SUPERIOR...THE BOWING LINE SEGMENT APPEARS
WELL-DEVELOPED AND MAY REMAIN INTACT. IF THE BOWING LINE SEGMENT CAN
TURN ESEWD INTO THE GRADIENT OF STRONG INSTABILITY OVER UPPER
MI...THEN THE WIND DAMAGE THREAT COULD BECOME ENHANCED LATER THIS
AFTERNOON.

..BROYLES.. 07/04/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MQT...GRB...DLH...

LAT...LON   47128719 48219098 47789174 47069199 46409048 45688871
            47128719

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 4, 3:59 PM EDT	Mesoscale Discussion	SPC	Arenac, Bay, Clare, Genesee, Gladwin, Gratiot and 22 more	91 min
Jul 4, 4:42 PM EDT	Severe Thunderstorm Watch	SPC	Bay, Clare, Clinton, Genesee, Gratiot, Ingham and 19 more	5 hr
Jul 4, 6:36 PM EDT	Mesoscale Discussion	SPC	Alger, Baraga, Delta, Dickinson, Iron, Luce and 4 more	54 min
Jul 4, 7:08 PM EDT	Mesoscale Discussion	SPC	Monroe, Wayne	2 hr
Jul 4, 7:25 AM EDT	Mesoscale Discussion	SPC	Kittson, Lake of the Woods, Marshall, Pennington, Polk, Red Lake and 1 more	95 min
Jul 4, 7:53 AM EDT	Mesoscale Discussion	SPC	Ramsey, Washington	97 min
Jul 4, 9:10 AM EDT	Severe Thunderstorm Watch	SPC	Beltrami, Clearwater, Kittson, Lake of the Woods, Marshall, Pennington and 3 more	6 hr
Jul 4, 1:25 PM EDT	Mesoscale Discussion	SPC	Aitkin, Beltrami, Carlton, Clearwater, Itasca, Koochiching and 1 more	95 min
Jul 4, 1:34 PM EDT	Severe Thunderstorm Watch	SPC	Aitkin, Carlton, Cass, Cook, Crow Wing, Itasca and 4 more	7 hr

Nearby

Mesoscale Discussions in Michigan, 2012 Mesoscale Discussions in Wisconsin, 2012 Mesoscale Discussions in Minnesota, 2012 Every mesoscale discussion in 2012

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.