Alert archive / Montana / Mesoscale Discussions in 2014

Mesoscale Discussion 618

May 18, 20144 states

The Storm Prediction Center issued this mesoscale discussion at May 18, 2014, 7:44 PM MDT for 4 states. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: May 18, 2014, 7:44 PM MDT (01:44 UTC)
Expired: May 18, 2014, 8:45 PM MDT
In force: 61 min
Issued by: the Storm Prediction Center

All 34 counties

Carter County, MT, Custer County, MT, Dawson County, MT, Fallon County, MT, McCone County, MT, Powder River County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Rosebud County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, Hettinger County, ND, McKenzie County, ND, Mountrail County, ND, Slope County, ND, Stark County, ND, Williams County, ND, Butte County, SD, Custer County, SD, Fall River County, SD, Harding County, SD, Lawrence County, SD, Meade County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Campbell County, WY, Crook County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 204 km from the middle of the area, began a volume at 01:45 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 (KRAP), launched 00:00Z, 1.7 hours before the alert went out and 207 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: 197 J/kg
Mixed-layer CIN: -316 J/kg
Mixed-layer LCL: 2188 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 26 m²/s²
0-3 km storm-relative helicity: 123 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.

Issued	Product	Office	Counties	Lasted
May 18, 9:43 PM MDT	Mesoscale Discussion	SPC	Carter, Custer, Dawson, Fallon, McCone, Prairie and 2 more	62 min
May 19, 2:12 PM MDT	Mesoscale Discussion	SPC	Bennett, Mellette, Todd, Tripp	2 hr

Nearby

Mesoscale Discussions in Montana, 2014 Mesoscale Discussions in North Dakota, 2014 Mesoscale Discussions in South Dakota, 2014 Every mesoscale discussion in 2014

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.