Alert archive / Montana / Mesoscale Discussions in 2003

Mesoscale Discussion 2120

August 7, 200320 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Aug 7, 2003, 5:56 PM MDT for 20 counties in Montana. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 7, 2003, 5:56 PM MDT (23:56 UTC)
Expired: Aug 7, 2003, 8:00 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Blaine County, MT, Chouteau County, MT, Daniels County, MT, Dawson County, MT, Fergus County, MT, Garfield County, MT, Hill County, MT, Judith Basin County, MT, McCone County, MT, Meagher County, MT, Musselshell County, MT, Petroleum County, MT, Phillips County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT, Wheatland County, MT, Wibaux County, MT

The radar

The Glasgow radar (KGGW), 148 km from the middle of the area, began a volume at 23:59 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

Great_falls, MT (KTFX), launched 12:00Z, 11.9 hours before the alert went out and 177 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: 2439 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: -81 m²/s²
0-3 km storm-relative helicity: 39 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 6, 7:25 PM MDT	Mesoscale Discussion	SPC	Blaine, Fergus, Garfield, Golden Valley, Musselshell, Petroleum and 2 more	2 hr
Aug 7, 12:16 AM MDT	Mesoscale Discussion	SPC	McCone, Richland	59 min
Aug 7, 2:18 PM MDT	Mesoscale Discussion	SPC	Broadwater, Cascade, Chouteau, Deer Lodge, Gallatin, Granite and 12 more	117 min
Aug 7, 3:45 PM MDT	Severe Thunderstorm Watch	SPC	Blaine, Chouteau, Daniels, Dawson, Fergus, Garfield and 14 more	6 hr

Nearby

Mesoscale Discussions in Montana, 2003 Every mesoscale discussion in 2003

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.