Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 755

May 18, 201743 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 18, 2017, 12:03 PM CDT for 43 counties in Texas. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: May 18, 2017, 12:03 PM CDT (17:03 UTC)
Expired: May 18, 2017, 2:00 PM CDT
In force: 117 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

All 43 counties

Archer County, TX, Baylor County, TX, Brown County, TX, Callahan County, TX, Clay County, TX, Coke County, TX, Coleman County, TX, Comanche County, TX, Concho County, TX, Cottle County, TX, Dickens County, TX, Eastland County, TX, Erath County, TX, Fisher County, TX, Foard County, TX, Hamilton County, TX, Hardeman County, TX, Haskell County, TX, Hood County, TX, Jack County, TX, Jones County, TX, Kent County, TX, King County, TX, Knox County, TX, Mills County, TX, Mitchell County, TX, Motley County, TX, Nolan County, TX, Palo Pinto County, TX, Parker County, TX, Runnels County, TX, Scurry County, TX, Shackelford County, TX, Somervell County, TX, Stephens County, TX, Sterling County, TX, Stonewall County, TX, Taylor County, TX, Throckmorton County, TX, Tom Green County, TX, Wichita County, TX, Wilbarger County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 50 km from the middle of the area, began a volume at 17:08 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.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 5.1 hours before the alert went out and 233 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: 2097 J/kg
Mixed-layer CIN: -180 J/kg
Mixed-layer LCL: 785 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 93 m²/s²
0-3 km storm-relative helicity: 71 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 2.3

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
May 18, 12:59 PM CDT	Mesoscale Discussion	SPC	Childress, Collingsworth, Cottle, Hardeman, Wichita, Wilbarger	2 hr
May 18, 1:18 PM CDT	Tornado Watch PDS	SPC	Archer, Baylor, Childress, Clay, Collingsworth, Cottle and 12 more	7 hr
May 18, 1:55 PM CDT	Tornado Watch	SPC	Bosque, Brown, Callahan, Coke, Coleman, Collin and 40 more	10 hr
May 18, 3:02 PM CDT	Mesoscale Discussion	SPC	Baylor, Foard, Hardeman, Knox, Wichita, Wilbarger	88 min
May 18, 4:55 PM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Callahan, Coke, Coleman, Collin and 39 more	95 min

Nearby

Mesoscale Discussions in Texas, 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.