Alert archive / Texas / Mesoscale Discussions in 2009

Mesoscale Discussion 643

April 30, 20094 counties in Oklahoma; 32 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2009, 3:13 AM CDT for 4 counties in Oklahoma; 32 counties in Texas. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: Apr 30, 2009, 3:13 AM CDT (08:13 UTC)
Expired: Apr 30, 2009, 4:45 AM CDT
In force: 92 min
Issued by: the Storm Prediction Center

All 36 counties

Cotton County, OK, Jefferson County, OK, Love County, OK, Tillman County, OK, Archer County, TX, Baylor County, TX, Clay County, TX, Collin County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Ellis County, TX, Erath County, TX, Fannin County, TX, Grayson County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Johnson County, TX, Kaufman County, TX, Montague County, TX, Palo Pinto County, TX, Parker County, TX, Rains County, TX, Rockwall County, TX, Somervell County, TX, Stephens County, TX, Tarrant County, TX, Throckmorton County, TX, Van Zandt County, TX, Wichita County, TX, Wilbarger County, TX, Wise County, TX, Young County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 95 km from the middle of the area, began a volume at 08:13 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

Fort Worth, TX (KFWD), launched 00:00Z, 8.2 hours before the alert went out and 71 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: 2590 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 517 m above ground
0-6 km bulk shear: 53 kt
0-1 km storm-relative helicity: 240 m²/s²
0-3 km storm-relative helicity: 296 m²/s²
Significant tornado parameter: 5.0
Supercell composite: 17.6

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
Apr 29, 9:27 PM CDT	Severe Thunderstorm Watch	SPC	Beckham, Bryan, Carter, Comanche, Cotton, Greer and 10 more	4 hr
Apr 29, 11:54 PM CDT	Mesoscale Discussion	SPC	Beckham, Carter, Comanche, Cotton, Greer, Harmon and 7 more	96 min
Apr 30, 1:15 AM CDT	Severe Thunderstorm Watch	SPC	Atoka, Bryan, Carter, Cotton, Harmon, Jackson and 5 more	6 hr
Apr 30, 1:55 PM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Craig, Delaware, Haskell, McIntosh and 9 more	2 hr
Apr 30, 5:13 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Blaine, Canadian, Cleveland, Creek, Dewey and 15 more	92 min
Apr 30, 5:26 PM CDT	Mesoscale Discussion	SPC	Beckham, Greer, Harmon, Jackson, Roger Mills	64 min
Apr 29, 7:06 PM CDT	Mesoscale Discussion	SPC	Coke, Concho, Crockett, Edwards, Glasscock, Irion and 13 more	84 min
Apr 30, 1:23 AM CDT	Mesoscale Discussion	SPC	Jim Hogg, Webb, Zapata	97 min

Nearby

Mesoscale Discussions in Texas, 2009 Mesoscale Discussions in Oklahoma, 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.