Alert archive / Texas / Mesoscale Discussions in 2011
Mesoscale Discussion 506
The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2011, 3:23 PM CDT for 31 counties in Texas. It was in force for 67 min.
The area
The outline as issued.
The facts
- Issued
- Apr 21, 2011, 3:23 PM CDT (20:23 UTC)
- Expired
- Apr 21, 2011, 4:30 PM CDT
- In force
- 67 min
- Issued by
- the Storm Prediction Center
All 31 counties
Camp County, TX, Collin County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Ellis County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Gregg County, TX, Henderson County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Johnson County, TX, Kaufman County, TX, Montague County, TX, Morris County, TX, Palo Pinto County, TX, Parker County, TX, Rains County, TX, Rockwall County, TX, Smith County, TX, Tarrant County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wise County, TX, Wood County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 100 km from the middle of the area, began a volume at 20:24 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
Shreveport, LA (KSHV), launched 12:00Z, 8.4 hours before the alert went out and 241 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.
- Mixed-layer CAPE
- 518 J/kg
- Mixed-layer CIN
- -94 J/kg
- Mixed-layer LCL
- 542 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 233 m²/s²
- 0-3 km storm-relative helicity
- 296 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 6.7
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 7:00 PM CDT | Mesoscale Discussion | SPC | Archer, Callahan, Coleman, Eastland, Jack, Palo Pinto and 5 more | 60 min |
| Apr 21, 2:19 PM CDT | Mesoscale Discussion | SPC | Coke, Crane, Crockett, Fisher, Glasscock, Howard and 16 more | 56 min |
| Apr 21, 3:03 PM CDT | Severe Thunderstorm Watch | SPC | Borden, Brewster, Brown, Callahan, Coke, Coleman and 23 more | 7 hr |
| Apr 21, 5:10 PM CDT | Mesoscale Discussion | SPC | Borden, Brewster, Coke, Crockett, Fisher, Glasscock and 21 more | 65 min |
Nearby
Mesoscale Discussions in Texas, 2011Every mesoscale discussion in 2011
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.