Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 280

April 11, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2015, 2:11 PM MDT for 4 states. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Apr 11, 2015, 2:11 PM MDT (20:11 UTC)
Expired: Apr 11, 2015, 3:45 PM MDT
In force: 94 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 23 counties

Baca County, CO, Morton County, KS, Stevens County, KS, Cimarron County, OK, Texas County, OK, Armstrong County, TX, Briscoe County, TX, Carson County, TX, Castro County, TX, Dallam County, TX, Deaf Smith County, TX, Donley County, TX, Gray County, TX, Hansford County, TX, Hartley County, TX, Hutchinson County, TX, Moore County, TX, Oldham County, TX, Parmer County, TX, Potter County, TX, Randall County, TX, Sherman County, TX, Swisher County, TX

The radar

The Amarillo radar (KAMA), 61 km from the middle of the area, began a volume at 20:14 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 55Apr 11, 2:45 PM MDT

The nearest sounding before it

Amarillo Airport, TX (KAMA), launched 12:00Z, 8.2 hours before the alert went out and 62 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: 8 J/kg
Mixed-layer CIN: -416 J/kg
Mixed-layer LCL: 1063 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 173 m²/s²
0-3 km storm-relative helicity: 197 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

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
Apr 11, 2:43 PM MDT	Severe Thunderstorm Watch	SPC	Baca	7 hr
Apr 11, 5:31 PM MDT	Mesoscale Discussion	SPC	Grant, Hamilton, Haskell, Kearny, Meade, Morton and 3 more	89 min

Nearby

Mesoscale Discussions in Texas, 2015 Mesoscale Discussions in Kansas, 2015 Mesoscale Discussions in Oklahoma, 2015 Every mesoscale discussion in 2015

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.