Alert archive / Wyoming / Mesoscale Discussions in 2009

Mesoscale Discussion 1549

July 13, 200914 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at Jul 13, 2009, 1:18 PM MDT for 14 counties in Wyoming. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Jul 13, 2009, 1:18 PM MDT (19:18 UTC)
Expired: Jul 13, 2009, 2:45 PM MDT
In force: 87 min
Issued by: the Storm Prediction Center

Counties Big Horn County, WY, Campbell County, WY, Converse County, WY, Fremont County, WY, Hot Springs County, WY, Johnson County, WY, Natrona County, WY, Niobrara County, WY, Park County, WY, Sheridan County, WY, Sublette County, WY, Teton County, WY, Washakie County, WY, Weston County, WY

The radar

The Riverton/Lander radar (KRIW), 114 km from the middle of the area, began a volume at 19:21 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 579Jul 13, 1:45 PM MDT

The nearest sounding before it

Rapid City, SD (KUNR), launched 12:00Z, 7.3 hours before the alert went out and 354 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: 1159 J/kg
Mixed-layer CIN: -194 J/kg
Mixed-layer LCL: 941 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 115 m²/s²
0-3 km storm-relative helicity: 181 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.6

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
Jul 13, 12:34 PM MDT	Tornado Watch	SPC	Campbell, Crook, Weston	8 hr
Jul 13, 1:02 PM MDT	Severe Thunderstorm Watch	SPC	Sheridan	9 hr
Jul 13, 1:45 PM MDT	Severe Thunderstorm Watch	SPC	Goshen, Laramie	6 hr
Jul 13, 5:05 PM MDT	Mesoscale Discussion	SPC	Crook	55 min

Nearby

Mesoscale Discussions in Wyoming, 2009 Every mesoscale discussion in 2009

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.