Alert archive / Wisconsin / Mesoscale Discussions in 2012

Mesoscale Discussion 1652

July 30, 20127 counties in Michigan; 18 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 30, 2012, 4:49 PM EDT for 7 counties in Michigan; 18 counties in Wisconsin. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Jul 30, 2012, 4:49 PM EDT (20:49 UTC)
Expired: Jul 30, 2012, 5:45 PM EDT
In force: 56 min
Issued by: the Storm Prediction Center

All 25 counties

Alger County, MI, Delta County, MI, Dickinson County, MI, Iron County, MI, Marquette County, MI, Menominee County, MI, Schoolcraft County, MI, Adams County, WI, Brown County, WI, Calumet County, WI, Door County, WI, Florence County, WI, Forest County, WI, Kewaunee County, WI, Langlade County, WI, Manitowoc County, WI, Marinette County, WI, Menominee County, WI, Oconto County, WI, Outagamie County, WI, Portage County, WI, Shawano County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI

The radar

The Marquette radar (KMQT), 99 km from the middle of the area, began a volume at 20:50 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 12:00Z, 8.8 hours before the alert went out and 140 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: 455 J/kg
Mixed-layer CIN: -119 J/kg
Mixed-layer LCL: 805 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 132 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

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

292 
ACUS11 KWNS 302049
SWOMCD
SPC MCD 302049 
MIZ000-WIZ000-302145-

MESOSCALE DISCUSSION 1652
NWS STORM PREDICTION CENTER NORMAN OK
0349 PM CDT MON JUL 30 2012

AREAS AFFECTED...WI...MI

CONCERNING...SEVERE THUNDERSTORM WATCH 540...

VALID 302049Z - 302145Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 540
CONTINUES.

SUMMARY...STORM DEVELOPMENT HAS BEEN SLOW TO OCCUR ACROSS THE WATCH
AREA THROUGH LATE AFTERNOON. HOWEVER...THE CHANCE FOR SEVERE WEATHER
AHEAD OF AN ADVANCING COLD FRONT OVER THE AREA REMAINS A CONCERN AS
STRONGER UPDRAFTS ARE NOW OCCURRING NEAR THE WI/MI BORDER IN
FLORENCE COUNTY WI AND DICKINSON COUNTY MI.

DISCUSSION...DESPITE REMOVAL OF REMAINING CONVECTIVE INHIBITION
ACROSS NRN WI AND THE CENTRAL PORTIONS OF THE U.P. OF MI...TSTM
INITIATION HAS BEEN HINDERED AHEAD OF A WEAKLY CONVERGENT COLD FRONT
SITUATED FROM LAKE SUPERIOR SWWD ACROSS WI. WITH TEMPERATURES NOW
WELL INTO THE 80S F NORTH AND OVER 90 F IN THE SRN PORTION OF THE
WATCH...EXPECT ADDITIONAL STORM DEVELOPMENT TO OCCUR WITHIN THE
RESULTING INSTABILITY AXIS AHEAD OF THE FRONT THROUGH LATE THIS
AFTERNOON. RECENT DEVELOPMENT APPEARS TO BE DISCRETE IN NATURE AND
COULD ACQUIRE SUPERCELL STRUCTURE GIVEN EFFECTIVE SHEAR MAGNITUDES
IN EXCESS OF 30KT. THE THREAT FOR LARGE HAIL WILL EVOLVE WITH THESE
STORMS. EVENTUALLY...STORMS SHOULD CONCENTRATE IN A MORE LINEAR
FASHION ALONG THE ADVANCING FRONT WITH AN INCREASING CHANCE FOR
DAMAGING WINDS IF A SQUALL LINE EVOLVES INTO THE EARLY EVENING.

..CARBIN.. 07/30/2012

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

ATTN...WFO...APX...MQT...GRB...MKX...ARX...

LAT...LON   46658875 46718551 43808682 43969020 46668881 46658875

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 30, 1:26 PM EDT	Mesoscale Discussion	SPC	Alger, Baraga, Benzie, Charlevoix, Delta, Dickinson and 7 more	64 min
Jul 30, 2:28 PM EDT	Severe Thunderstorm Watch	SPC	Alger, Delta, Dickinson, Iron, Luce, Marquette and 2 more	8 hr
Jul 30, 7:16 PM EDT	Mesoscale Discussion	SPC	Antrim, Benzie, Charlevoix, Delta, Emmet, Grand Traverse and 8 more	59 min

Nearby

Mesoscale Discussions in Wisconsin, 2012 Mesoscale Discussions in Michigan, 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.