Alert archive / Montana / Mesoscale Discussions in 2006

Mesoscale Discussion 924

May 21, 20065 counties in Montana; 5 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at May 21, 2006, 2:09 PM MDT for 5 counties in Montana; 5 counties in Wyoming. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 21, 2006, 2:09 PM MDT (20:09 UTC)
Expired
May 21, 2006, 4:15 PM MDT
In force
2 hr
Issued by
the Storm Prediction Center

Counties Big Horn County, MT, Carbon County, MT, Powder River County, MT, Stillwater County, MT, Yellowstone County, MT, Big Horn County, WY, Campbell County, WY, Crook County, WY, Sheridan County, WY, Weston County, WY

The radar

The Billings radar (KBLX), 180 km from the middle of the area, began a volume at 20:10 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, 8.2 hours before the alert went out and 313 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 2006-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2006-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1335 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
116 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.

IssuedProductOfficeCountiesLasted
May 20, 6:04 PM MDTMesoscale DiscussionSPCBig Horn, Carbon, Carter, Custer, Garfield, Golden Valley and 12 more86 min
May 21, 1:20 PM MDTMesoscale DiscussionSPCGoshen, Niobrara, Weston115 min

Nearby

Mesoscale Discussions in Montana, 2006Mesoscale Discussions in Wyoming, 2006Every 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.