Alert archive / Texas / Mesoscale Discussions in 2018

Mesoscale Discussion 135

March 18, 20188 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 18, 2018, 5:30 PM CDT for 8 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 18, 2018, 5:30 PM CDT (22:30 UTC)
Expired: Mar 18, 2018, 7:30 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Austin County, TX, Bastrop County, TX, Caldwell County, TX, Colorado County, TX, Fayette County, TX, Travis County, TX, Waller County, TX, Washington County, TX

The radar

The Ft Hood radar (KGRK), 88 km from the middle of the area, began a volume at 22:31 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 12:00Z, 10.5 hours before the alert went out and 256 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: 817 J/kg
Mixed-layer CIN: -303 J/kg
Mixed-layer LCL: 730 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: -1 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

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
Mar 17, 8:35 PM CDT	Mesoscale Discussion	SPC	Bell, Brazos, Falls, Houston, Leon, Madison and 2 more	55 min
Mar 18, 2:33 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Bosque, Brown, Callahan, Clay and 27 more	117 min
Mar 18, 3:31 PM CDT	Mesoscale Discussion	SPC	Anderson, Angelina, Austin, Bastrop, Bell, Brazos and 29 more	119 min
Mar 18, 4:06 PM CDT	Severe Thunderstorm Watch	SPC	Anderson, Angelina, Austin, Bastrop, Bell, Bosque and 68 more	6 hr
Mar 18, 6:27 PM CDT	Mesoscale Discussion	SPC	Hemphill, Lipscomb, Wheeler	3 hr

Nearby

Mesoscale Discussions in Texas, 2018 Every mesoscale discussion in 2018

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.