Alert archive / Texas / Mesoscale Discussions in 2015

Mesoscale Discussion 346

April 17, 2015Chambers County, Galveston County, Jefferson County, Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2015, 7:39 PM CDT for Chambers County, Galveston County, Jefferson County, Texas. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Apr 17, 2015, 7:39 PM CDT (00:39 UTC)
Expired: Apr 17, 2015, 9:15 PM CDT
In force: 96 min
Issued by: the Storm Prediction Center

Counties Chambers County, TX, Galveston County, TX, Jefferson County, TX

The radar

The Houston radar (KHGX), 24 km from the middle of the area, began a volume at 00:40 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.

Severe Thunderstorm Watch 71Apr 17, 9:05 PM CDT

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 00:00Z, 0.7 hours before the alert went out and 175 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: 1637 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 835 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 136 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 17, 7:26 PM CDT	Mesoscale Discussion	SPC	Carson, Hansford, Hutchinson, Ochiltree, Roberts	2 hr
Apr 17, 9:10 PM CDT	Mesoscale Discussion	SPC	Aransas, Brooks, Calhoun, Duval, Hidalgo, Jim Hogg and 7 more	95 min
Apr 17, 9:13 PM CDT	Severe Thunderstorm Watch	SPC	Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris and 4 more	5 hr
Apr 17, 10:59 PM CDT	Mesoscale Discussion	SPC	Aransas, Brooks, Hidalgo, Kenedy, Kleberg, Nueces	91 min
Apr 17, 11:31 PM CDT	Mesoscale Discussion	SPC	Chambers, Galveston, Jefferson, Orange	59 min
Apr 18, 1:52 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Brown, Callahan, Clay, Coleman and 23 more	113 min
Apr 18, 2:13 PM CDT	Severe Thunderstorm Watch	SPC	Bandera, Bastrop, Bexar, Blanco, Bosque, Brown and 58 more	8 hr
Apr 18, 2:27 PM CDT	Tornado Watch	SPC	Archer, Baylor, Childress, Clay, Collingsworth, Cottle and 9 more	6 hr
Apr 18, 4:32 PM CDT	Mesoscale Discussion	SPC	Atascosa, Bastrop, Bexar, Caldwell, Comal, Dimmit and 11 more	2 hr
Apr 18, 4:48 PM CDT	Mesoscale Discussion	SPC	Hidalgo, Kenedy, Kleberg, Willacy	2 hr
Apr 18, 5:23 PM CDT	Mesoscale Discussion	SPC	Collin, Dallas, Ellis, Falls, Hill, Kaufman and 6 more	3 hr
Apr 18, 5:46 PM CDT	Severe Thunderstorm Watch	SPC	Anderson, Bell, Collin, Cooke, Dallas, Denton and 20 more	5 hr
Apr 18, 6:03 PM CDT	Mesoscale Discussion	SPC	Baylor, Childress, Collingsworth, Cottle, Foard, Hardeman and 3 more	87 min
Apr 18, 6:40 PM CDT	Mesoscale Discussion	SPC	Bandera, Bell, Blanco, Bosque, Brown, Burnet and 48 more	95 min

Nearby

Mesoscale Discussions in Texas, 2015 Every mesoscale discussion in 2015

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.