Alert archive / Montana / Mesoscale Discussions in 2006

Mesoscale Discussion 908

May 20, 200619 counties in Montana; 13 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at May 20, 2006, 2:53 PM MDT for 19 counties in Montana; 13 counties in Wyoming. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 20, 2006, 2:53 PM MDT (20:53 UTC)
Expired: May 20, 2006, 5:00 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 32 counties

Big Horn County, MT, Broadwater County, MT, Carbon County, MT, Cascade County, MT, Fergus County, MT, Gallatin County, MT, Golden Valley County, MT, Judith Basin County, MT, Meagher County, MT, Musselshell County, MT, Park County, MT, Petroleum County, MT, Powder River County, MT, Rosebud County, MT, Stillwater County, MT, Sweet Grass County, MT, Treasure County, MT, Wheatland County, MT, Yellowstone County, MT, Big Horn County, WY, Campbell County, WY, Converse County, WY, Crook County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Niobrara County, WY, Park County, WY, Platte County, WY, Sheridan County, WY, Washakie County, WY, Weston County, WY

The radar

The Billings radar (KBLX), 91 km from the middle of the area, began a volume at 20:54 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

Riverton, WY (KRIW), launched 12:00Z, 8.9 hours before the alert went out and 223 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: 2014 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 145 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
May 19, 6:47 PM MDT	Mesoscale Discussion	SPC	Mineral, Sanders	88 min
May 20, 11:42 AM MDT	Mesoscale Discussion	SPC	Big Horn, Broadwater, Carbon, Cascade, Chouteau, Fergus and 16 more	2 hr
May 20, 12:24 PM MDT	Severe Thunderstorm Watch	SPC	Big Horn, Broadwater, Carbon, Cascade, Chouteau, Fergus and 16 more	8 hr

Nearby

Mesoscale Discussions in Montana, 2006 Mesoscale Discussions in Wyoming, 2006 Every mesoscale discussion in 2006

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.