Alert archive / Texas / Mesoscale Discussions in 2007

Mesoscale Discussion 273

March 12, 200719 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Mar 12, 2007, 1:39 AM CDT for 19 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 12, 2007, 1:39 AM CDT (06:39 UTC)
Expired: Mar 12, 2007, 3:45 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Austin County, TX, Bastrop County, TX, Bee County, TX, Colorado County, TX, DeWitt County, TX, Fayette County, TX, Fort Bend County, TX, Goliad County, TX, Gonzales County, TX, Harris County, TX, Jackson County, TX, Karnes County, TX, Lavaca County, TX, Lee County, TX, Refugio County, TX, Victoria County, TX, Waller County, TX, Washington County, TX, Wharton County, TX

The radar

The Austin/San Antonio radar (KEWX), 101 km from the middle of the area, began a volume at 06:41 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.

Tornado Watch 59Mar 12, 4:05 AM CDT

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 00:00Z, 6.7 hours before the alert went out and 183 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: 767 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 611 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 244 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 4.6

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
Mar 11, 9:09 PM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Bexar, Blanco, Burnet, Caldwell and 19 more	2 hr
Mar 11, 11:16 PM CDT	Mesoscale Discussion	SPC	Atascosa, Bexar, Caldwell, Comal, Dimmit, Frio and 8 more	89 min
Mar 12, 4:01 AM CDT	Tornado Watch	SPC	Austin, Brazoria, Chambers, Fort Bend, Galveston, Harris and 5 more	4 hr
Mar 12, 5:09 AM CDT	Mesoscale Discussion	SPC	Austin, Brazoria, Chambers, Colorado, Fort Bend, Galveston and 10 more	96 min
Mar 12, 6:10 AM CDT	Mesoscale Discussion	SPC	Hardin, Jasper, Jefferson, Newton, Orange	95 min

Nearby

Mesoscale Discussions in Texas, 2007 Every mesoscale discussion in 2007

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.