Alert archive / South Dakota / Severe Thunderstorm Watches in 2001

Severe Thunderstorm Watch 643

July 30, 200113 counties in South Dakota

The Storm Prediction Center issued this severe thunderstorm watch at Jul 30, 2001, 7:00 PM MDT for 13 counties in South Dakota. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jul 30, 2001, 7:00 PM MDT (01:00 UTC)
Expired: Jul 31, 2001, 12:00 AM MDT
In force: 5 hr
Issued by: the Storm Prediction Center

Counties Butte County, SD, Corson County, SD, Custer County, SD, Dewey County, SD, Haakon County, SD, Harding County, SD, Jones County, SD, Lawrence County, SD, Meade County, SD, Pennington County, SD, Perkins County, SD, Stanley County, SD, Ziebach County, SD

The radar

The Rapid City radar (KUDX), 101 km from the middle of the area, began a volume at 01:03 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

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

Issued	Product	Office	Counties	Lasted
Jul 30, 7:23 PM MDT	Severe Thunderstorm Warning	UNR	Meade	52 min
Jul 30, 7:34 PM MDT	Severe Thunderstorm Warning	UNR	Pennington	41 min
Jul 30, 8:15 PM MDT	Severe Thunderstorm Warning	UNR	Haakon	45 min
Jul 30, 8:18 PM MDT	Severe Thunderstorm Warning	UNR	Meade	57 min
Jul 30, 8:40 PM MDT	Severe Thunderstorm Warning	UNR	Ziebach	65 min
Jul 30, 9:00 PM MDT	Severe Thunderstorm Warning	UNR	Haakon	60 min
Jul 30, 9:08 PM MDT	Severe Thunderstorm Warning	ABR	Dewey	67 min
Jul 30, 9:08 PM MDT	Severe Thunderstorm Warning	UNR	Pennington	67 min
Jul 30, 9:21 PM MDT	Severe Thunderstorm Warning	ABR	Stanley	39 min
Jul 30, 10:02 PM MDT	Severe Thunderstorm Warning	UNR	Meade	58 min
Jul 30, 10:15 PM MDT	Severe Thunderstorm Warning	ABR	Corson, Dewey, Walworth	60 min

The nearest sounding before it

Rapid City, SD (KUNR), launched 00:00Z, 1.0 hours before the alert went out and 108 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: 2241 J/kg
Mixed-layer CIN: -114 J/kg
Mixed-layer LCL: 2336 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 86 m²/s²
0-3 km storm-relative helicity: 210 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.4

Open this sounding in Storm Lab

The text

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

000 
WWUS9 KMKC 310046
MKC WW 310040
SDZ000-310600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 643
STORM PREDICTION CENTER NORMAN OK
640 PM MDT MON JUL 30 2001

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   WESTERN SOUTH DAKOTA                       

EFFECTIVE THIS MONDAY NIGHT FROM 700 PM UNTIL MIDNIGHT MDT.

HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 75 STATUTE MILES
NORTH AND SOUTH OF A LINE FROM 40 MILES SOUTH SOUTHWEST OF REDIG
SOUTH DAKOTA TO 30 MILES NORTH OF PIERRE SOUTH DAKOTA.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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.  SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE
TORNADOES.

OTHER WATCH INFORMATION...  CONTINUE...WW 641...WW 642...

DISCUSSION...SEVERE STORMS OVER EXTREME SWRN SD ARE EXPECTED TO
DEVELOP NEWD TONIGHT AS STRONG LOW LEVEL JET INTENSIFIES TOWARD THE
NRN PLAINS.  STORMS ARE EXPECTED TO DEVELOP ALONG LOW LEVEL
BOUNDARIES EXTENDING FROM SWRN ND INTO NORTH CENTRAL SD.  AIR MASS
BECOMES INCREASINGLY MOIST/UNSTABLE INTO NWRN AND CENTRAL SD WHERE
MLCAPE VALUES EXCEED 3500 J/KG...AND SUFFICIENT DEEP LAYER SHEAR IS
PRESENT TO ENHANCE ORGANIZED SEVERE THREAT. 


AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 3 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.  MEAN STORM
MOTION VECTOR 21030.


...WEISS

;454,1035 455,1001 434,1001 433,1035;

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 30, 10:45 PM MDT	Severe Thunderstorm Watch	SPC	Brown, Campbell, Edmunds, Faulk, Hughes, Hyde and 7 more	5 hr
Jul 31, 4:30 PM MDT	Severe Thunderstorm Watch	SPC	Aurora, Beadle, Bon Homme, Brown, Brule, Buffalo and 20 more	7 hr

Nearby

Severe Thunderstorm Watches in South Dakota, 2001 Every severe thunderstorm watch in 2001

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.