Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 689

May 18, 201514 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 18, 2015, 2:16 PM CDT for 14 counties in Texas. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: May 18, 2015, 2:16 PM CDT (19:16 UTC)
Expired: May 18, 2015, 3:15 PM CDT
In force: 59 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

Counties Andrews County, TX, Brewster County, TX, Crane County, TX, Ector County, TX, Jeff Davis County, TX, Loving County, TX, Midland County, TX, Pecos County, TX, Presidio County, TX, Reeves County, TX, Terrell County, TX, Upton County, TX, Ward County, TX, Winkler County, TX

The radar

The Midland/Odessa radar (KMAF), 186 km from the middle of the area, began a volume at 19:31 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 188May 18, 2:35 PM CDT

The nearest sounding before it

Midland Regional, TX (KMAF), launched 12:00Z, 7.3 hours before the alert went out and 186 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: 290 J/kg
Mixed-layer CIN: -219 J/kg
Mixed-layer LCL: 1231 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 28 m²/s²
0-3 km storm-relative helicity: -9 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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
May 18, 1:07 PM CDT	Mesoscale Discussion	SPC	Clay, Montague, Wichita	53 min
May 18, 2:36 PM CDT	Severe Thunderstorm Watch	SPC	Andrews, Brewster, Crane, Ector, Jeff Davis, Loving and 7 more	7 hr
May 18, 2:58 PM CDT	Mesoscale Discussion	SPC	Archer, Bell, Blanco, Bosque, Brown, Burnet and 33 more	2 hr
May 18, 6:00 PM CDT	Mesoscale Discussion	SPC	Andrews, Brewster, Crane, Ector, Gaines, Jeff Davis and 8 more	2 hr

Nearby

Mesoscale Discussions in Texas, 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.