Alert archive / Wyoming / Mesoscale Discussions in 2007

Mesoscale Discussion 1806

August 19, 20075 counties in Montana; 8 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at Aug 19, 2007, 5:01 PM MDT for 5 counties in Montana; 8 counties in Wyoming. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Aug 19, 2007, 5:01 PM MDT (23:01 UTC)
Expired: Aug 19, 2007, 6:30 PM MDT
In force: 89 min
Issued by: the Storm Prediction Center

Counties Carter County, MT, Custer County, MT, Fallon County, MT, Powder River County, MT, Rosebud County, MT, Campbell County, WY, Converse County, WY, Crook County, WY, Johnson County, WY, Natrona County, WY, Niobrara County, WY, Sheridan County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 250 km from the middle of the area, began a volume at 23:04 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 watches that followed

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

Severe Thunderstorm Watch 618Aug 19, 5:30 PM MDT

The nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 11.0 hours before the alert went out and 257 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: 2424 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 133 m²/s²
0-3 km storm-relative helicity: 108 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
Aug 19, 12:31 PM MDT	Mesoscale Discussion	SPC	Carbon, Fergus, Gallatin, Golden Valley, Judith Basin, Meagher and 6 more	119 min
Aug 19, 1:36 PM MDT	Severe Thunderstorm Watch	SPC	Beaverhead, Big Horn, Blaine, Broadwater, Carbon, Cascade and 17 more	6 hr
Aug 19, 5:30 PM MDT	Severe Thunderstorm Watch	SPC	Carter, Custer, Fallon, Powder River, Rosebud, Treasure	5 hr
Aug 18, 9:16 PM MDT	Mesoscale Discussion	SPC	Fremont, Johnson, Lincoln, Natrona, Sublette, Sweetwater and 2 more	59 min

Nearby

Mesoscale Discussions in Wyoming, 2007 Mesoscale Discussions in Montana, 2007 Every mesoscale discussion in 2007

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.