Alert archive / Texas / Mesoscale Discussions in 2008

Mesoscale Discussion 654

April 17, 20089 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2008, 7:06 PM CDT for 9 counties in Texas. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Apr 17, 2008, 7:06 PM CDT (00:06 UTC)
Expired: Apr 17, 2008, 8:00 PM CDT
In force: 54 min
Issued by: the Storm Prediction Center

Counties Collin County, TX, Cooke County, TX, Dallas County, TX, Denton County, TX, Grayson County, TX, Parker County, TX, Rockwall County, TX, Tarrant County, TX, Wise County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 53 km from the middle of the area, began a volume at 00:06 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 206Apr 17, 9:00 PM CDT

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 0.1 hours before the alert went out and 24 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: 822 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 1439 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 201 m²/s²
0-3 km storm-relative helicity: 234 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 6.8

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, 8:13 PM CDT	Mesoscale Discussion	SPC	Anderson, Bowie, Camp, Cass, Cherokee, Delta and 30 more	32 min
Apr 17, 8:57 PM CDT	Severe Thunderstorm Watch	SPC	Anderson, Bell, Camp, Cherokee, Collin, Dallas and 32 more	7 hr
Apr 17, 9:27 PM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Bastrop, Bell, Bexar, Blanco and 43 more	63 min
Apr 17, 11:55 PM CDT	Mesoscale Discussion	SPC	Anderson, Atascosa, Bandera, Bastrop, Bexar, Brazos and 46 more	65 min

Nearby

Mesoscale Discussions in Texas, 2008 Every mesoscale discussion in 2008

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.