Alert archive / South Dakota / Mesoscale Discussions in 2004

Mesoscale Discussion 1793

July 29, 200417 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 29, 2004, 3:20 PM MDT for 17 counties in South Dakota. It was in force for 25 min.

The area

The outline as issued.

The facts

Issued: Jul 29, 2004, 3:20 PM MDT (21:20 UTC)
Expired: Jul 29, 2004, 3:45 PM MDT
In force: 25 min
Issued by: the Storm Prediction Center

Counties Bennett County, SD, Butte County, SD, Custer County, SD, Dewey County, SD, Fall River County, SD, Haakon County, SD, Jackson County, SD, Jones County, SD, Lawrence County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Stanley County, SD, Sully County, SD, Todd County, SD, Ziebach County, SD

The radar

The Rapid City radar (KUDX), 45 km from the middle of the area, began a volume at 21:21 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 672Jul 29, 3:35 PM MDT

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 9.3 hours before the alert went out and 51 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1895 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 81 m²/s²
0-3 km storm-relative helicity: 114 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.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 29, 3:35 PM MDT	Severe Thunderstorm Watch	SPC	Bennett, Brule, Buffalo, Butte, Custer, Fall River and 17 more	5 hr
Jul 29, 4:30 PM MDT	Mesoscale Discussion	SPC	Bennett, Brule, Buffalo, Butte, Custer, Fall River and 17 more	30 min

Nearby

Mesoscale Discussions in South Dakota, 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; radar from the NEXRAD Level II archive.