Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 1591

August 28, 2017Jefferson County, Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2017, 3:00 AM CDT for Jefferson County, Texas. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Aug 28, 2017, 3:00 AM CDT (08:00 UTC)
Expired: Aug 28, 2017, 4:00 AM CDT
In force: 60 min
Issued by: the Storm Prediction Center

County Jefferson County, TX

The radar

The Houston radar (KHGX), 100 km from the middle of the area, began a volume at 08:03 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

Lake Charles Mun, LA (KLCH), launched 00:00Z, 8.0 hours before the alert went out and 101 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: 311 J/kg
Mixed-layer CIN: -31 J/kg
Mixed-layer LCL: 714 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 148 m²/s²
0-3 km storm-relative helicity: 253 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.4

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 27, 7:45 PM CDT	Mesoscale Discussion	SPC	Carson, Dallam, Hansford, Hartley, Hutchinson, Moore and 3 more	2 hr
Aug 27, 9:50 PM CDT	Mesoscale Discussion	SPC	Brazoria, Chambers, Fort Bend, Galveston, Harris, Jefferson and 2 more	115 min
Aug 28, 1:51 AM CDT	Tornado Watch	SPC	Chambers, Hardin, Jefferson, Liberty, Orange	10 hr
Aug 28, 11:37 AM CDT	Mesoscale Discussion	SPC	Chambers, Galveston, Jefferson, Orange	83 min
Aug 28, 12:16 PM CDT	Tornado Watch	SPC	Jefferson, Orange	12 hr
Aug 28, 3:58 PM CDT	Mesoscale Discussion	SPC	Jefferson, Orange	92 min
Aug 28, 6:49 PM CDT	Mesoscale Discussion	SPC	Jefferson, Orange	116 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.