Alert archive / Minnesota / Tornado Watches in 2004

Tornado Watch 678

August 1, 200427 counties in Minnesota; Sargent County, North Dakota; 11 counties in South Dakota

The Storm Prediction Center issued this tornado watch at Aug 1, 2004, 3:15 PM CDT for 27 counties in Minnesota; Sargent County, North Dakota; 11 counties in South Dakota. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Aug 1, 2004, 3:15 PM CDT (20:15 UTC)
Expired
Aug 1, 2004, 10:00 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
All 39 counties

Big Stone County, MN, Brown County, MN, Chippewa County, MN, Cottonwood County, MN, Douglas County, MN, Grant County, MN, Jackson County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, Lincoln County, MN, Lyon County, MN, Martin County, MN, Meeker County, MN, Murray County, MN, Nobles County, MN, Pipestone County, MN, Pope County, MN, Redwood County, MN, Renville County, MN, Rock County, MN, Stearns County, MN, Stevens County, MN, Swift County, MN, Todd County, MN, Traverse County, MN, Watonwan County, MN, Yellow Medicine County, MN, Sargent County, ND, Brookings County, SD, Codington County, SD, Day County, SD, Deuel County, SD, Grant County, SD, Hamlin County, SD, Lake County, SD, Marshall County, SD, Minnehaha County, SD, Moody County, SD, Roberts County, SD

The radar

The Minneapolis radar (KMPX), 168 km from the middle of the area, began a volume at 20:12 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.

Discussions around it

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

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 8.3 hours before the alert went out and 165 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, Minneapolis, MN at 12:00Z on 2004-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 665 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, Minneapolis, MN at 12:00Z on 2004-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 166 square meters per square second.193958Sfc1 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
665 J/kg
Mixed-layer CIN
-151 J/kg
Mixed-layer LCL
903 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
166 m²/s²
0-3 km storm-relative helicity
204 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The text

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

167 
WWUS20 KWNS 012016
SEL8  
SPC WW 012015
IAZ000-MNZ000-SDZ000-020300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 678
NWS STORM PREDICTION CENTER NORMAN OK
315 PM CDT SUN AUG 1 2004

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

       EXTREME NORTHWEST IOWA
       SOUTHWEST MINNESOTA
       EASTERN SOUTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 315 PM UNTIL 1000
PM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 75 STATUTE MILES EAST AND WEST
OF A LINE FROM 45 MILES WEST NORTHWEST OF ALEXANDRIA MINNESOTA TO
10 MILES SOUTH OF WORTHINGTON MINNESOTA.

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.

DISCUSSION...AIRMASS OVER EASTERN SD IS BECOMING VERY UNSTABLE WITH
DEWPOINTS NEAR 70F AND MLCAPE VALUES AROUND 3000 J/KG. COMBINATION
OF DAYTIME HEATING AND APPROACHING UPPER TROUGH WILL ERODE
CAP...LEADING TO ISOLATED SEVERE THUNDERSTORM DEVELOPMENT ACROSS WW
AREA IN THE NEXT 1-3 HOURS.  STORMS WILL LIKELY BECOME SUPERCELLULAR
WITH A RISK OF VERY LARGE HAIL AND ISOLATED TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 30030.


...HART

460,0944 432,0940 432,0970 460,0975

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 31, 8:19 PM CDTMesoscale DiscussionSPCBlue Earth, Brown, Cottonwood, Dodge, Faribault, Fillmore and 15 more56 min
Jul 31, 9:45 PM CDTSevere Thunderstorm WatchSPCBlue Earth, Brown, Cottonwood, Dakota, Dodge, Faribault and 22 more5 hr
Jul 31, 11:41 PM CDTMesoscale DiscussionSPCBlue Earth, Dakota, Dodge, Faribault, Fillmore, Freeborn and 14 more64 min
Aug 1, 5:56 AM CDTMesoscale DiscussionSPCFaribault, Freeborn, Jackson, Martin, Mower, Nobles94 min
Aug 1, 1:48 PM CDTMesoscale DiscussionSPCBig Stone, Brown, Chippewa, Cottonwood, Jackson, Kandiyohi and 20 more117 min
Aug 1, 3:41 PM CDTMesoscale DiscussionSPCKanabec, Mille Lacs, Morrison, Pine2 hr
Aug 1, 4:00 PM CDTSevere Thunderstorm WatchSPCAitkin, Benton, Chisago, Crow Wing, Isanti, Kanabec and 3 more5 hr
Aug 1, 3:43 AM CDTMesoscale DiscussionSPCGolden Valley92 min
Aug 1, 4:39 PM CDTMesoscale DiscussionSPCAdams, Benson, Burleigh, Dunn, Emmons, Grant and 13 more66 min
Aug 1, 5:00 PM CDTSevere Thunderstorm WatchSPCAdams, Benson, Bottineau, Burleigh, Cavalier, Eddy and 22 more5 hr
Jul 31, 10:27 PM CDTMesoscale DiscussionSPCBon Homme, Charles Mix, Douglas, Gregory, Hutchinson, Todd and 3 more93 min
Aug 1, 6:35 PM CDTSevere Thunderstorm WatchSPCBrown, Campbell, Corson, Dewey, Edmunds, Faulk and 4 more3 hr

Nearby

Tornado Watches in Minnesota, 2004Tornado Watches in South Dakota, 2004Tornado Watches in North Dakota, 2004Every tornado watch 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; radar from the NEXRAD Level II archive.