Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 1487

August 13, 20175 states

The Storm Prediction Center issued this mesoscale discussion at Aug 13, 2017, 1:50 PM MDT for 5 states. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: Aug 13, 2017, 1:50 PM MDT (19:50 UTC)
Expired: Aug 13, 2017, 3:15 PM MDT
In force: 85 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

Counties Baca County, CO, Morton County, KS, Colfax County, NM, Union County, NM, Cimarron County, OK, Texas County, OK, Dallam County, TX, Hansford County, TX, Hartley County, TX, Hutchinson County, TX, Moore County, TX, Ochiltree County, TX, Roberts County, TX, Sherman County, TX

The radar

The Amarillo radar (KAMA), 189 km from the middle of the area, began a volume at 19:50 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 450Aug 13, 2:40 PM MDT

The nearest sounding before it

Amarillo Airport, TX (KAMA), launched 12:00Z, 7.8 hours before the alert went out and 190 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: 553 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 527 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 140 m²/s²
0-3 km storm-relative helicity: 122 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 13, 2:41 PM MDT	Severe Thunderstorm Watch	SPC	Baca, Bent, Crowley, Kiowa, Las Animas, Otero and 1 more	8 hr
Aug 13, 3:00 PM MDT	Severe Thunderstorm Watch	SPC	Cheyenne, Kit Carson, Yuma	11 hr
Aug 13, 5:03 PM MDT	Mesoscale Discussion	SPC	Quay	87 min

Nearby

Mesoscale Discussions in Texas, 2017 Mesoscale Discussions in New Mexico, 2017 Mesoscale Discussions in Oklahoma, 2017 Every mesoscale discussion in 2017

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.