Alert archive / Texas / Mesoscale Discussions in 2009
Mesoscale Discussion 1939
The Storm Prediction Center issued this mesoscale discussion at Aug 20, 2009, 2:32 PM CDT for 4 states. It was in force for 88 min.
The area
The outline as issued.
The facts
- Issued
- Aug 20, 2009, 2:32 PM CDT (19:32 UTC)
- Expired
- Aug 20, 2009, 4:00 PM CDT
- In force
- 88 min
- Issued by
- the Storm Prediction Center
All 60 counties
Columbia County, AR, Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Sevier County, AR, Bossier Parish, LA, Caddo Parish, LA, Webster Parish, LA, Atoka County, OK, Bryan County, OK, Carter County, OK, Choctaw County, OK, Coal County, OK, Cotton County, OK, Garvin County, OK, Hughes County, OK, Jefferson County, OK, Johnston County, OK, Latimer County, OK, Love County, OK, Marshall County, OK, McCurtain County, OK, Murray County, OK, Pittsburg County, OK, Pontotoc County, OK, Pushmataha County, OK, Seminole County, OK, Stephens County, OK, Archer County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Clay County, TX, Collin County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Lamar County, TX, Marion County, TX, Montague County, TX, Morris County, TX, Parker County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Tarrant County, TX, Titus County, TX, Upshur County, TX, Wise County, TX, Wood County, TX, Young County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 188 km from the middle of the area, began a volume at 19:36 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.
The nearest sounding before it
Fort Worth, TX (KFWD), launched 12:00Z, 7.5 hours before the alert went out and 171 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
- 1880 J/kg
- Mixed-layer CIN
- -198 J/kg
- Mixed-layer LCL
- 1192 m above ground
- 0-6 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 56 m²/s²
- 0-3 km storm-relative helicity
- 121 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 |
|---|---|---|---|---|
| Aug 19, 8:48 PM CDT | Tornado Watch | SPC | Benton, Carroll, Madison, Washington | 7 hr |
| Aug 19, 11:11 PM CDT | Mesoscale Discussion | SPC | Boone, Carroll, Fulton | 64 min |
| Aug 19, 11:26 PM CDT | Severe Thunderstorm Watch | SPC | Baxter, Boone, Fulton, Marion | 9 hr |
| Aug 20, 1:47 AM CDT | Mesoscale Discussion | SPC | Benton | 88 min |
| Aug 20, 3:08 PM CDT | Severe Thunderstorm Watch | SPC | Hempstead, Howard, Lafayette, Little River, Miller, Nevada and 1 more | 7 hr |
| Aug 19, 8:14 PM CDT | Mesoscale Discussion | SPC | Ottawa | 61 min |
| Aug 19, 9:18 PM CDT | Mesoscale Discussion | SPC | Alfalfa, Blaine, Canadian, Creek, Dewey, Garfield and 13 more | 27 min |
| Aug 20, 1:10 AM CDT | Mesoscale Discussion | SPC | Alfalfa, Blaine, Caddo, Canadian, Cleveland, Custer and 14 more | 95 min |
Nearby
Mesoscale Discussions in Texas, 2009Mesoscale Discussions in Oklahoma, 2009Mesoscale Discussions in Arkansas, 2009Every 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.