Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 1583

August 27, 20178 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 27, 2017, 4:04 AM CDT for 8 counties in Texas. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Aug 27, 2017, 4:04 AM CDT (09:04 UTC)
Expired: Aug 27, 2017, 5:00 AM CDT
In force: 56 min
Issued by: the Storm Prediction Center

Counties Brazoria County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Harris County, TX, Jefferson County, TX, Liberty County, TX, Montgomery County, TX

The radar

The Houston radar (KHGX), 17 km from the middle of the area, began a volume at 09:07 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

Corpus Christi, TX (KCRP), launched 00:00Z, 9.1 hours before the alert went out and 290 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: 104 J/kg
Mixed-layer CIN: -81 J/kg
Mixed-layer LCL: 905 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 50 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 26, 9:37 PM CDT	Mesoscale Discussion	SPC	Austin, Brazoria, Chambers, Colorado, Fort Bend, Galveston and 14 more	113 min
Aug 27, 1:50 AM CDT	Tornado Watch	SPC	Austin, Brazoria, Chambers, Fort Bend, Galveston, Harris and 5 more	11 hr
Aug 27, 10:54 AM CDT	Mesoscale Discussion	SPC	Austin, Brazoria, Chambers, Colorado, Fort Bend, Galveston and 14 more	3 hr
Aug 27, 12:40 PM CDT	Tornado Watch	SPC	Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris and 3 more	13 hr
Aug 27, 1:57 PM CDT	Mesoscale Discussion	SPC	Armstrong, Briscoe, Carson, Castro, Childress, Collingsworth and 17 more	3 hr
Aug 27, 3:07 PM CDT	Mesoscale Discussion	SPC	Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris and 5 more	113 min
Aug 27, 3:27 PM CDT	Severe Thunderstorm Watch	SPC	Armstrong, Carson, Collingsworth, Donley, Gray, Hansford and 10 more	8 hr
Aug 27, 6:04 PM CDT	Mesoscale Discussion	SPC	Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris and 3 more	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.