Alert archive / Texas / Mesoscale Discussions in 2020

Mesoscale Discussion 1887

December 29, 20209 counties in Oklahoma; 18 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Dec 29, 2020, 7:43 PM CST for 9 counties in Oklahoma; 18 counties in Texas. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Dec 29, 2020, 7:43 PM CST (01:43 UTC)
Expired: Dec 29, 2020, 10:15 PM CST
In force: 3 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 5%

All 27 counties

Beckham County, OK, Caddo County, OK, Comanche County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Kiowa County, OK, Tillman County, OK, Washita County, OK, Borden County, TX, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Crosby County, TX, Dawson County, TX, Dickens County, TX, Foard County, TX, Garza County, TX, Hall County, TX, Hardeman County, TX, Kent County, TX, King County, TX, Knox County, TX, Lynn County, TX, Motley County, TX, Stonewall County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 127 km from the middle of the area, began a volume at 01:46 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 nearest sounding before it

Midland Regional, TX (KMAF), launched 00:00Z, 1.7 hours before the alert went out and 289 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: 116 J/kg
Mixed-layer CIN: -69 J/kg
Mixed-layer LCL: 1492 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 6 m²/s²
0-3 km storm-relative helicity: 39 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

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
Dec 30, 4:48 PM CST	Mesoscale Discussion	SPC	Angelina, Brazoria, Calhoun, Chambers, Fort Bend, Galveston and 17 more	2 hr

Nearby

Mesoscale Discussions in Texas, 2020 Mesoscale Discussions in Oklahoma, 2020 Every mesoscale discussion in 2020

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.