Alert archive / South Dakota / Tornado Watches in 2004

Tornado Watch 654

July 18, 200410 counties in Minnesota; 18 counties in South Dakota

The Storm Prediction Center issued this tornado watch at Jul 18, 2004, 8:00 PM CDT for 10 counties in Minnesota; 18 counties in South Dakota. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jul 18, 2004, 8:00 PM CDT (01:00 UTC)
Expired: Jul 19, 2004, 1:00 AM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 28 counties

Big Stone County, MN, Chippewa County, MN, Douglas County, MN, Grant County, MN, Lac qui Parle County, MN, Pope County, MN, Stevens County, MN, Swift County, MN, Traverse County, MN, Yellow Medicine County, MN, Brown County, SD, Campbell County, SD, Clark County, SD, Codington County, SD, Day County, SD, Deuel County, SD, Edmunds County, SD, Faulk County, SD, Grant County, SD, Hamlin County, SD, Hand County, SD, Hyde County, SD, Marshall County, SD, McPherson County, SD, Potter County, SD, Roberts County, SD, Spink County, SD, Walworth County, SD

The radar

The Aberdeen radar (KABR), 45 km from the middle of the area, began a volume at 01:01 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

Aberdeen, SD (KABR), launched 00:00Z, 1.0 hours before the alert went out and 27 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: 2541 J/kg
Mixed-layer CIN: -155 J/kg
Mixed-layer LCL: 1628 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 172 m²/s²
0-3 km storm-relative helicity: 230 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 5.9

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 190102
SEL4  
SPC WW 190100
MNZ000-SDZ000-190600-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 654
NWS STORM PREDICTION CENTER NORMAN OK
800 PM CDT SUN JUL 18 2004

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

       WESTERN MINNESOTA
       NORTHEAST SOUTH DAKOTA

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 800 PM UNTIL
100 AM 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 115 STATUTE MILES EAST AND
WEST OF A LINE FROM 50 MILES NORTHEAST OF ABERDEEN SOUTH DAKOTA TO
40 MILES SOUTHWEST OF WATERTOWN SOUTH DAKOTA.

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 653...

DISCUSSION...SUPERCELL NOW IN S CNTRL ND EXPECTED TO CONTINUE SEWD
INTO NRN SD SHORTLY...WITH ADDITIONAL STORMS EXPECTED TO DEVELOP IN
SE ND DURING THE NEXT 1-2 HRS DOING THE SAME.  WHILE NOTABLE CINH
EXIST IN NE SD /PER 00Z RAOB/...ENVIRONMENT DOES NOT APPEAR OVERLY
HOSTILE FOR EXISTING ROTATING STORMS.  ALSO...CONTINUED SEWD MOTION
OF MESOSCALE  TROUGH/AREA OF ASCENT MAY SOMEWHAT OFFSET DIURNAL
COOLING AND SUPPORT A RISK FOR ISOLATED TORNADOES IN ADDITION TO
HAIL/HIGH WIND.

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 34020.


...CORFIDI

455,0951 442,0952 442,1000 455,1000

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 19, 12:26 PM CDT	Mesoscale Discussion	SPC	Blue Earth, Dakota, Dodge, Faribault, Fillmore, Freeborn and 11 more	3 hr
Jul 18, 8:53 PM CDT	Mesoscale Discussion	SPC	Brule, Buffalo, Dewey, Gregory, Hughes, Hyde and 8 more	2 hr
Jul 18, 10:43 PM CDT	Mesoscale Discussion	SPC	Brule, Buffalo, Dewey, Gregory, Hughes, Hyde and 8 more	62 min
Jul 19, 4:09 PM CDT	Mesoscale Discussion	SPC	Bennett, Custer, Fall River, Lawrence, Oglala Lakota, Pennington	2 hr

Nearby

Tornado Watches in South Dakota, 2004 Tornado Watches in Minnesota, 2004 Every 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.