Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 513
The Storm Prediction Center issued this mesoscale discussion at May 3, 2021, 9:52 PM CDT for 18 counties in Texas. It was in force for 53 min.
The area
The outline as issued.
The facts
- Issued
- May 3, 2021, 9:52 PM CDT (02:52 UTC)
- Expired
- May 3, 2021, 10:45 PM CDT
- In force
- 53 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 133
Counties Anderson County, TX, Bell County, TX, Coryell County, TX, Ellis County, TX, Falls County, TX, Freestone County, TX, Henderson County, TX, Hill County, TX, Hunt County, TX, Kaufman County, TX, Limestone County, TX, McLennan County, TX, Milam County, TX, Navarro County, TX, Rains County, TX, Robertson County, TX, Rockwall County, TX, Van Zandt County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 92 km from the middle of the area, began a volume at 02:56 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, 2.9 hours before the alert went out and 114 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
- 3299 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 1213 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 150 m²/s²
- 0-3 km storm-relative helicity
- 143 m²/s²
- Significant tornado parameter
- 2.6
- Supercell composite
- 13.9
The text
As transmitted.
839
ACUS11 KWNS 040252
SWOMCD
SPC MCD 040252
TXZ000-040345-
Mesoscale Discussion 0513
NWS Storm Prediction Center Norman OK
0952 PM CDT Mon May 03 2021
Areas affected...Portions of north-central into central TX
Concerning...Tornado Watch 133...
Valid 040252Z - 040345Z
The severe weather threat for Tornado Watch 133 continues.
SUMMARY...Primary severe risks are transitioning to scattered
damaging winds and isolated large hail this evening. Either an
extension in area to WW 134 or a new Severe Thunderstorm Watch will
likely be needed before the scheduled 04Z expiration of WW 133.
DISCUSSION...Storms have recently grown upscale into a broken line
in north-central TX along a composite cold front/dryline. Strong
outbound velocities have been observed in/near Ellis County TX from
KFWS. Given the increasingly linear nature to most of the convection
across this region, scattered severe/damaging wind gusts should
become the primary concern in the short term. But, isolated large
hail and perhaps a brief tornado may still occur with any embedded
supercells. Around 2000-2500 J/kg of MLCAPE remains present
downstream of ongoing convection, along with strong deep-layer
shear. Even with the loss of daytime heating, this favorable
environment will likely allow for a continued severe wind/hail
threat to persist beyond the scheduled 04Z expiration of WW 133.
Either a new Severe Thunderstorm Watch or extension in area of WW
134 to the east will likely be needed.
..Gleason.. 05/04/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...
LAT...LON 31119807 31959748 32869653 33269599 33229578 33009570
32129556 31629571 30919661 30729714 31119807SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 3, 7:01 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Bandera, Bexar, Blanco, Burnet, Comal and 9 more | 4 hr |
| May 3, 7:38 PM CDT | Mesoscale Discussion | SPC | Bosque, Collin, Dallas, Denton, Ellis, Fannin and 6 more | 97 min |
| May 3, 8:30 PM CDT | Mesoscale Discussion | SPC | Bexar, Blanco, Comal, Guadalupe, Hays, Kendall | 60 min |
| May 3, 8:38 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Gregg, Marion, Morris and 4 more | 2 hr |
| May 3, 9:10 PM CDT | Mesoscale Discussion | SPC | Callahan, Eastland, Fisher, Haskell, Jones, Nolan and 6 more | 95 min |
| May 3, 9:10 PM CDT | Severe Thunderstorm Watch | SPC | Bowie, Camp, Cass, Cherokee, Franklin, Gregg and 10 more | 7 hr |
| May 3, 10:22 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bell, Collin, Cooke, Dallas, Delta and 28 more | 5 hr |
| May 3, 11:34 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Falls, Franklin, Freestone and 12 more | 86 min |
| May 4, 6:44 AM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Brazos, Burleson, Camp, Cass and 23 more | 2 hr |
| May 4, 8:11 AM CDT | Severe Thunderstorm Watch | SPC | Angelina, Austin, Brazos, Burleson, Chambers, Colorado and 22 more | 8 hr |
Nearby
Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021
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.