Alert archive / South Dakota / Mesoscale Discussions in 2005

Mesoscale Discussion 940

May 20, 2005Keya Paha County, Nebraska; 10 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 20, 2005, 6:36 PM CDT for Keya Paha County, Nebraska; 10 counties in South Dakota. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
May 20, 2005, 6:36 PM CDT (23:36 UTC)
Expired
May 20, 2005, 8:00 PM CDT
In force
84 min
Issued by
the Storm Prediction Center

Counties Keya Paha County, NE, Bennett County, SD, Haakon County, SD, Hughes County, SD, Jackson County, SD, Jones County, SD, Lyman County, SD, Mellette County, SD, Stanley County, SD, Todd County, SD, Tripp County, SD

The radar

The North Platte radar (KLNX), 175 km from the middle of the area, began a volume at 23:36 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 nearest sounding before it

Aberdeen, SD (KABR), launched 12:00Z, 11.6 hours before the alert went out and 232 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, Aberdeen, SD at 12:00Z on 2005-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Aberdeen, SD at 12:00Z on 2005-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 23 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1627 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
37 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.

IssuedProductOfficeCountiesLasted
May 20, 6:10 PM CDTSevere Thunderstorm WatchSPCCampbell, Corson, Harding, McPherson, Perkins8 hr

Nearby

Mesoscale Discussions in South Dakota, 2005Mesoscale Discussions in Nebraska, 2005Every mesoscale discussion in 2005

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.