Alert archive / South Dakota / Mesoscale Discussions in 2003

Mesoscale Discussion 1820

July 13, 200310 counties in Nebraska; 13 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 13, 2003, 5:47 PM CDT for 10 counties in Nebraska; 13 counties in South Dakota. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued: Jul 13, 2003, 5:47 PM CDT (22:47 UTC)
Expired: Jul 13, 2003, 7:45 PM CDT
In force: 118 min
Issued by: the Storm Prediction Center

All 23 counties

Blaine County, NE, Box Butte County, NE, Cherry County, NE, Dawes County, NE, Grant County, NE, Hooker County, NE, Logan County, NE, McPherson County, NE, Sheridan County, NE, Thomas County, NE, Bennett County, SD, Corson County, SD, Dewey County, SD, Haakon County, SD, Jackson County, SD, Jones County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Stanley County, SD, Todd County, SD, Ziebach County, SD

The watches that followed

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

Severe Thunderstorm Watch 742Jul 13, 8:20 PM CDT

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 10.8 hours before the alert went out and 130 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: 244 J/kg
Mixed-layer CIN: -400 J/kg
Mixed-layer LCL: 2673 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 94 m²/s²
0-3 km storm-relative helicity: 85 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 12, 7:10 PM CDT	Mesoscale Discussion	SPC	Arthur, Banner, Box Butte, Cheyenne, Dawes, Deuel and 8 more	2 hr
Jul 12, 9:02 PM CDT	Mesoscale Discussion	SPC	Arthur, Chase, Dawes, Deuel, Dundy, Garden and 6 more	118 min
Jul 13, 3:13 PM CDT	Mesoscale Discussion	SPC	Perkins	2 hr

Nearby

Mesoscale Discussions in South Dakota, 2003 Mesoscale Discussions in Nebraska, 2003 Every mesoscale discussion 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.