Alert archive / Texas / Mesoscale Discussions in 2004

Mesoscale Discussion 2409

November 17, 200417 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Nov 17, 2004, 12:26 PM CST for 17 counties in Texas. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Nov 17, 2004, 12:26 PM CST (18:26 UTC)
Expired: Nov 17, 2004, 2:00 PM CST
In force: 94 min
Issued by: the Storm Prediction Center

Counties Austin County, TX, Brazoria County, TX, Chambers County, TX, Colorado County, TX, Fort Bend County, TX, Galveston County, TX, Grimes County, TX, Harris County, TX, Jackson County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, San Jacinto County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 70 km from the middle of the area, began a volume at 18:27 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, 6.4 hours before the alert went out and 255 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: 800 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 738 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 167 m²/s²
0-3 km storm-relative helicity: 182 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 7.2

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
Nov 17, 1:11 AM CST	Mesoscale Discussion	SPC	Aransas, Bee, Calhoun, Goliad, Kleberg, Nueces and 3 more	94 min
Nov 17, 9:36 AM CST	Mesoscale Discussion	SPC	Aransas, Austin, Brazoria, Brazos, Burleson, Calhoun and 27 more	114 min
Nov 17, 10:05 AM CST	Tornado Watch	SPC	Austin, Brazoria, Brazos, Burleson, Chambers, Colorado and 12 more	6 hr
Nov 17, 3:10 PM CST	Mesoscale Discussion	SPC	Brazoria, Chambers, Fort Bend, Galveston, Hardin, Harris and 7 more	65 min

Nearby

Mesoscale Discussions in Texas, 2004 Every mesoscale discussion in 2004

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.