Alert archive / Texas / Mesoscale Discussions in 2009

Mesoscale Discussion 642

April 30, 2009Jim Hogg County, Webb County, Zapata County, Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2009, 1:23 AM CDT for Jim Hogg County, Webb County, Zapata County, Texas. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Apr 30, 2009, 1:23 AM CDT (06:23 UTC)
Expired: Apr 30, 2009, 3:00 AM CDT
In force: 97 min
Issued by: the Storm Prediction Center

Counties Jim Hogg County, TX, Webb County, TX, Zapata County, TX

The radar

The Corpus Christi radar (KCRP), 178 km from the middle of the area, began a volume at 06:23 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

Del Rio, TX (KDRT), launched 00:00Z, 6.4 hours before the alert went out and 246 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: 1940 J/kg
Mixed-layer CIN: -201 J/kg
Mixed-layer LCL: 1711 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 68 m²/s²
0-3 km storm-relative helicity: 149 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.0

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 29, 7:06 PM CDT	Mesoscale Discussion	SPC	Coke, Concho, Crockett, Edwards, Glasscock, Irion and 13 more	84 min
Apr 29, 9:27 PM CDT	Severe Thunderstorm Watch	SPC	Archer, Baylor, Clay, Cooke, Denton, Foard and 15 more	4 hr
Apr 29, 11:54 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Clay, Cooke, Denton, Foard and 15 more	96 min
Apr 30, 1:15 AM CDT	Severe Thunderstorm Watch	SPC	Archer, Baylor, Clay, Collin, Cooke, Dallas and 29 more	6 hr
Apr 30, 3:13 AM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Clay, Collin, Cooke, Dallas and 26 more	92 min
Apr 30, 5:26 PM CDT	Mesoscale Discussion	SPC	Childress, Collingsworth, Cottle, Dickens, Fisher, Foard and 9 more	64 min

Nearby

Mesoscale Discussions in Texas, 2009 Every mesoscale discussion in 2009

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.