Alert archive / Texas / Mesoscale Discussions in 2020

Mesoscale Discussion 1639

August 29, 20207 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 29, 2020, 8:38 PM CDT for 7 counties in Texas. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Aug 29, 2020, 8:38 PM CDT (01:38 UTC)
Expired: Aug 29, 2020, 9:45 PM CDT
In force: 67 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 470

Counties Armstrong County, TX, Carson County, TX, Childress County, TX, Collingsworth County, TX, Donley County, TX, Gray County, TX, Hall County, TX

The radar

The Amarillo radar (KAMA), 77 km from the middle of the area, began a volume at 01:42 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

Norman, OK (KOUN), launched 00:00Z, 1.6 hours before the alert went out and 322 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: 2451 J/kg
Mixed-layer CIN: -114 J/kg
Mixed-layer LCL: 1167 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 99 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 29, 8:34 PM CDT	Severe Thunderstorm Watch	SPC	Briscoe, Childress, Collingsworth, Cottle, Donley, Floyd and 5 more	4 hr
Aug 29, 9:39 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Briscoe, Childress, Clay, Collingsworth and 12 more	2 hr
Aug 29, 10:08 PM CDT	Severe Thunderstorm Watch	SPC	Archer, Baylor, Clay, Foard, Hardeman, Wichita and 1 more	7 hr
Aug 29, 11:33 PM CDT	Mesoscale Discussion	SPC	Bowie, Camp, Cass, Delta, Fannin, Franklin and 5 more	87 min
Aug 30, 1:52 AM CDT	Mesoscale Discussion	SPC	Archer, Clay, Collin, Cooke, Dallas, Denton and 18 more	53 min

Nearby

Mesoscale Discussions in Texas, 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.