Alert archive / South Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 1483

July 17, 2012Carter County, Fallon County, Montana; Butte County, Harding County, Lawrence County, South Dakota; Crook County, Weston County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jul 17, 2012, 12:44 PM MDT for Carter County, Fallon County, Montana; Butte County, Harding County, Lawrence County, South Dakota; Crook County, Weston County, Wyoming. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued
Jul 17, 2012, 12:44 PM MDT (18:44 UTC)
Expired
Jul 17, 2012, 1:45 PM MDT
In force
61 min
Issued by
the Storm Prediction Center
Chance of a watch
40%

Counties Carter County, MT, Fallon County, MT, Butte County, SD, Harding County, SD, Lawrence County, SD, Crook County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 147 km from the middle of the area, began a volume at 18:46 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

Rapid City, SD (KUNR), launched 12:00Z, 6.7 hours before the alert went out and 148 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, Rapid City, SD at 12:00Z on 2012-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 377 joules per kilogram.LCLLFCEL10008507005003002001001 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, Rapid City, SD at 12:00Z on 2012-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 square meters per square second.1939Sfc1 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
377 J/kg
Mixed-layer CIN
-263 J/kg
Mixed-layer LCL
906 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

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
Jul 16, 8:40 PM MDTMesoscale DiscussionSPCButte, Campbell, Corson, Dewey, Harding, Lawrence and 5 more65 min

Nearby

Mesoscale Discussions in South Dakota, 2012Mesoscale Discussions in Montana, 2012Mesoscale Discussions in Wyoming, 2012Every mesoscale discussion in 2012

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.