Alert archive / Wisconsin / Tornado Watches in 2003

Tornado Watch 876

August 20, 2003Gogebic County, Iron County, Ontonagon County, Michigan; 8 counties in Minnesota; 35 counties in Wisconsin

The Storm Prediction Center issued this tornado watch at Aug 20, 2003, 3:45 PM CDT for Gogebic County, Iron County, Ontonagon County, Michigan; 8 counties in Minnesota; 35 counties in Wisconsin. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Aug 20, 2003, 3:45 PM CDT (20:45 UTC)
Expired: Aug 20, 2003, 9:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 46 counties

Gogebic County, MI, Iron County, MI, Ontonagon County, MI, Aitkin County, MN, Carlton County, MN, Chisago County, MN, Itasca County, MN, Kanabec County, MN, Lake County, MN, Pine County, MN, Washington County, MN, Ashland County, WI, Barron County, WI, Bayfield County, WI, Brown County, WI, Buffalo County, WI, Burnett County, WI, Chippewa County, WI, Clark County, WI, Douglas County, WI, Dunn County, WI, Eau Claire County, WI, Florence County, WI, Forest County, WI, Iron County, WI, Langlade County, WI, Lincoln County, WI, Marathon County, WI, Menominee County, WI, Oconto County, WI, Oneida County, WI, Outagamie County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Portage County, WI, Price County, WI, Rusk County, WI, Saint Croix County, WI, Sawyer County, WI, Shawano County, WI, Taylor County, WI, Vilas County, WI, Washburn County, WI, Waupaca County, WI, Wood County, WI

The radar

The Duluth radar (KDLH), 146 km from the middle of the area, began a volume at 20:47 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.

Warnings issued inside it

4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Aug 20, 6:44 PM CDT	Severe Thunderstorm Warning	DLH	Aitkin	61 min
Aug 20, 7:52 PM CDT	Severe Thunderstorm Warning	DLH	Aitkin, Carlton, Saint Louis	53 min
Aug 20, 7:56 PM CDT	Tornado Warning	DLH	Lake, Saint Louis	64 min
Aug 20, 8:20 PM CDT	Severe Thunderstorm Warning	DLH	Douglas	55 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Green Bay/Straub, WI (KGRB), launched 12:00Z, 8.8 hours before the alert went out and 274 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: 50 J/kg
Mixed-layer CIN: -263 J/kg
Mixed-layer LCL: 949 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 132 m²/s²
0-3 km storm-relative helicity: 128 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.

000 
WWUS20 KWNS 202047
SEL6  
SPC WW 202045
MIZ000-MNZ000-WIZ000-LMZ000-LSZ000-210200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 876 
NWS STORM PREDICTION CENTER NORMAN OK 
345 PM CDT WED AUG 20 2003

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       WESTERN UPPER MICHIGAN
       NORTHERN AND EASTERN MINNESOTA
       WESTERN AND NORTHERN WISCONSIN
       LAKE MICHIGAN
       LAKE SUPERIOR

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 345 PM UNTIL
900 PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 120 STATUTE MILES EAST AND
WEST OF A LINE FROM 65 MILES EAST NORTHEAST OF HIBBING MINNESOTA
TO 40 MILES SOUTHWEST OF MOSINEE WISCONSIN.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.


OTHER WATCH INFORMATION...CONTINUE...WW 875...


DISCUSSION...THUNDERSTORMS EXPECTED TO DEVELOP/SPREAD NEWD INTO WW
DURING THE NEXT FEW HOURS AS HEATING CONTINUES DOWNSTREAM FROM UPPER
IMPULSE NOW ENTERING SW IA...AND AHEAD OF UPPER VORT EDGING E FROM
NW MN. LOW LEVEL WIND/CONVERGENCE FIELDS LIKELY TO REMAIN WEAK AS
EXISTING OUTFLOW BOUNDARY CONTINUES TO WEAKEN OVER CNTRL/NRN WI. BUT
DEEP SHEAR SHOULD BE SUFFICIENT FOR A FEW SUPERCELLS.  RICH BOUNDARY
LAYER MOISTURE AND RESIDUAL BACKING OF NEAR-SURFACE FLOW SUGGEST
POSSIBILITY FOR A TORNADO OR TWO WITH ANY SUSTAINED STORMS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550.
MEAN STORM MOTION VECTOR 22035.


...CORFIDI

474,0885 442,0874 442,0923 474,0940

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 20, 2:11 PM CDT	Mesoscale Discussion	SPC	Gogebic, Iron	2 hr
Aug 20, 2:15 PM CDT	Mesoscale Discussion	SPC	Mower	90 min
Aug 20, 2:50 PM CDT	Severe Thunderstorm Watch	SPC	Dodge, Fillmore, Houston, Mower, Olmsted, Wabasha and 1 more	5 hr
Aug 20, 6:09 PM CDT	Mesoscale Discussion	SPC	Dodge, Fillmore, Houston, Mower, Olmsted, Wabasha and 1 more	2 hr

Nearby

Tornado Watches in Wisconsin, 2003 Tornado Watches in Minnesota, 2003 Tornado Watches in Michigan, 2003 Every tornado watch in 2003

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.