Alert archive / Texas / Mesoscale Discussions in 2017
Mesoscale Discussion 542
The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2017, 9:28 PM CDT for 11 counties in Arkansas; 7 counties in Oklahoma; 44 counties in Texas. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Apr 21, 2017, 9:28 PM CDT (02:28 UTC)
- Expired
- Apr 21, 2017, 11:00 PM CDT
- In force
- 92 min
- Issued by
- the Storm Prediction Center
All 62 counties
Garland County, AR, Hempstead County, AR, Howard County, AR, Little River County, AR, Miller County, AR, Montgomery County, AR, Pike County, AR, Polk County, AR, Scott County, AR, Sevier County, AR, Yell County, AR, Atoka County, OK, Bryan County, OK, Choctaw County, OK, Latimer County, OK, LeFlore County, OK, McCurtain County, OK, Pushmataha County, OK, Bosque County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Collin County, TX, Comanche County, TX, Cooke County, TX, Coryell County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Ellis County, TX, Erath County, TX, Fannin County, TX, Franklin County, TX, Grayson County, TX, Gregg County, TX, Hamilton County, TX, Henderson County, TX, Hill County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Marion County, TX, McLennan County, TX, Mills County, TX, Morris County, TX, Navarro County, TX, Palo Pinto County, TX, Parker County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Smith County, TX, Somervell 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), 137 km from the middle of the area, began a volume at 02:31 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 00:00Z, 2.5 hours before the alert went out and 128 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
- 1220 J/kg
- Mixed-layer CIN
- -102 J/kg
- Mixed-layer LCL
- 1576 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- 203 m²/s²
- 0-3 km storm-relative helicity
- 219 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 12.5
The text
As transmitted.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 21, 7:11 PM CDT | Mesoscale Discussion | SPC | Howard, Little River, Montgomery, Pike, Polk, Scott and 3 more | 94 min |
| Apr 21, 11:39 PM CDT | Mesoscale Discussion | SPC | Calhoun, Clark, Columbia, Dallas, Garland, Hempstead and 13 more | 96 min |
| Apr 22, 12:41 AM CDT | Severe Thunderstorm Watch | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 22 more | 6 hr |
| Apr 22, 4:16 AM CDT | Mesoscale Discussion | SPC | Ashley, Bradley, Calhoun, Chicot, Columbia, Desha and 3 more | 89 min |
| Apr 22, 12:51 PM CDT | Mesoscale Discussion | SPC | Chicot | 114 min |
Nearby
Mesoscale Discussions in Texas, 2017Mesoscale Discussions in Arkansas, 2017Mesoscale Discussions in Oklahoma, 2017Every mesoscale discussion in 2017
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.