Alert archive / Wisconsin / Mesoscale Discussions in 2004

Mesoscale Discussion 673

May 12, 2004Allamakee County, Clayton County, Fayette County, Iowa; 8 counties in Michigan; 39 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 12, 2004, 5:22 PM CDT for Allamakee County, Clayton County, Fayette County, Iowa; 8 counties in Michigan; 39 counties in Wisconsin. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: May 12, 2004, 5:22 PM CDT (22:22 UTC)
Expired: May 12, 2004, 6:15 PM CDT
In force: 53 min
Issued by: the Storm Prediction Center

All 50 counties

Allamakee County, IA, Clayton County, IA, Fayette County, IA, Alger County, MI, Baraga County, MI, Delta County, MI, Dickinson County, MI, Houghton County, MI, Iron County, MI, Marquette County, MI, Menominee County, MI, Adams County, WI, Brown County, WI, Calumet County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Door County, WI, Florence County, WI, Fond du Lac County, WI, Forest County, WI, Grant County, WI, Green Lake County, WI, Iowa County, WI, Juneau County, WI, Kewaunee County, WI, La Crosse County, WI, Langlade County, WI, Manitowoc County, WI, Marathon County, WI, Marinette County, WI, Marquette County, WI, Menominee County, WI, Monroe County, WI, Oconto County, WI, Oneida County, WI, Outagamie County, WI, Ozaukee County, WI, Portage County, WI, Richland County, WI, Sauk County, WI, Shawano County, WI, Sheboygan County, WI, Vernon County, WI, Washington County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 10.4 hours before the alert went out and 72 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: 127 J/kg
Mixed-layer CIN: -116 J/kg
Mixed-layer LCL: 1117 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 107 m²/s²
0-3 km storm-relative helicity: 105 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

568 
ACUS11 KWNS 122222
SWOMCD
SPC MCD 122222 
MIZ000-WIZ000-IAZ000-MNZ000-122315-

MESOSCALE DISCUSSION 0673
NWS STORM PREDICTION CENTER NORMAN OK
0522 PM CDT WED MAY 12 2004

AREAS AFFECTED...CENTRAL/ERN WI/WRN UPPER MI

CONCERNING...SEVERE THUNDERSTORM WATCH 192...

VALID 122222Z - 122315Z

THREAT FOR ISOLATED DAMAGING WINDS AND HAIL WILL CONTINUE EWD ACROSS
THE VALID PORTIONS OF WW 192 FOR THE NEXT FEW HOURS...AND EWD INTO
ERN WI/WRN-MID UPPER MI THROUGH 02Z.  GIVEN ISOLATED NATURE OF
ADDITIONAL THREATS...NEW WW MAY NOT BE NECESSARY.

THUNDERSTORMS CONTINUE TO DEVELOP ALONG EWD MOVING COLD FRONT WHICH
EXTENDED FROM A SURFACE LOW OVER FAR WRN UPPER MI SWWD INTO NERN IA.
 SURFACE DEWPOINTS IN THE LOWER TO MID 60S AHEAD OF THIS FRONT ARE
SUPPORTING MODERATE INSTABILITY...WHILE OBJECTIVE ANALYSES INDICATE
ONLY MARGINAL DEEP LAYER SHEAR OF 25-30 KT.  THE SHEAR IS ORIENTED
NEARLY PARALLEL TO THE FRONT WHICH SUPPORTS LINEAR ORGANIZATION...AS
IS INDICATED BY REGIONAL RADARS.  SURFACE PRESSURE FALL/RISE COUPLET
OVER WI/UPPER MI SHOULD MAINTAIN EWD MOVING BOW SEGMENT OVER
NRN/CENTRAL WI FOR THE NEXT FEW HOURS...BUT WEAKENING INSTABILITY
BEYOND 02-03Z SHOULD LIMIT SEVERE POTENTIAL.  DAMAGING WINDS SHOULD
BE MARGINAL GIVEN TREND FOR WEAKENING INSTABILITY THIS EVENING...AND
EXPECT 20-30 KT EWD MOVEMENT OF STORMS SHOULD REMAIN THE SAME OR
SLOWLY DECREASE.

..PETERS.. 05/12/2004

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

ATTN...WFO...MQT...GRB...MKX...ARX...DMX...

43148804 42819036 42809209 44149096 44968982 45998951
46908896 47128861 46648659 45358666 43558777

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 12, 11:29 AM CDT	Mesoscale Discussion	SPC	Allamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 12 more	2 hr
May 12, 12:20 PM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Cerro Gordo, Chickasaw, Clayton, Fayette, Floyd and 5 more	6 hr
May 12, 2:22 PM CDT	Mesoscale Discussion	SPC	Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 8 more	83 min
May 12, 3:37 PM CDT	Mesoscale Discussion	SPC	Allamakee, Bremer, Butler, Cerro Gordo, Chickasaw, Clayton and 10 more	83 min

Nearby

Mesoscale Discussions in Wisconsin, 2004 Mesoscale Discussions in Michigan, 2004 Mesoscale Discussions in Iowa, 2004 Every mesoscale discussion in 2004

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.