Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 461
The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2021, 7:31 PM CDT for 30 counties in Texas. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- Apr 28, 2021, 7:31 PM CDT (00:31 UTC)
- Expired
- Apr 28, 2021, 9:30 PM CDT
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 119
All 30 counties
Callahan County, TX, Coleman County, TX, Collin County, TX, Comanche County, TX, Cooke County, TX, Dallas County, TX, Denton County, TX, Eastland County, TX, Ellis County, TX, Erath County, TX, Fannin County, TX, Grayson County, TX, Haskell County, TX, Hood County, TX, Hunt County, TX, Jack County, TX, Johnson County, TX, Jones County, TX, Montague County, TX, Palo Pinto County, TX, Parker County, TX, Rockwall County, TX, Shackelford County, TX, Somervell County, TX, Stephens County, TX, Tarrant County, TX, Taylor County, TX, Throckmorton County, TX, Wise County, TX, Young County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 92 km from the middle of the area, began a volume at 00:31 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, 0.5 hours before the alert went out and 90 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
- 1526 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 1058 m above ground
- 0-6 km bulk shear
- 73 kt
- 0-1 km storm-relative helicity
- 191 m²/s²
- 0-3 km storm-relative helicity
- 154 m²/s²
- Significant tornado parameter
- 2.2
- Supercell composite
- 9.4
The text
As transmitted.
226
ACUS11 KWNS 290031
SWOMCD
SPC MCD 290031
TXZ000-OKZ000-290230-
Mesoscale Discussion 0461
NWS Storm Prediction Center Norman OK
0731 PM CDT Wed Apr 28 2021
Areas affected...North-central and Northeast Texas
Concerning...Tornado Watch 119...
Valid 290031Z - 290230Z
The severe weather threat for Tornado Watch 119 continues.
SUMMARY...Large hail, wind damage and an isolated tornado threat is
expected across parts of north-central Texas early this evening. A
new watch may be needed to the east of WW 119.
DISCUSSION...The latest radar imagery from Fort Worth shows a
cluster of strong to severe thunderstorms to the west and southwest
of Fort Worth. These storms are located along the western edge of a
very moist airmass. Surface dewpoints are near 70 F across the
Dallas/Fort Worth Metro extending eastward across much of northeast
Texas, where the RAP is analyzing MLCAPE in the 1500 to 2000 J/kg
range. This combined with 60 kt of deep-layer shear will be
favorable for supercells early this evening. Supercells may produce
large hail and wind damage. In addition, the storms will move
eastward toward a strengthening low-level jet. For this reason, a
tornado threat may develops with the stronger supercells. The threat
is expected to move to the east of WW 119 where a new weather watch
may be need to be issued within the next hour or so.
..Broyles/Guyer.. 04/29/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...OUN...SJT...LUB...
LAT...LON 31869855 32369667 32819596 33319579 33629597 33809642
33709788 33469965 33210011 32840027 32460025 32120002
31819940 31869855SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 7:01 PM CDT | Mesoscale Discussion | SPC | Bastrop, Bexar, Caldwell, Comal, Gonzales, Guadalupe and 4 more | 89 min |
| Apr 28, 7:55 PM CDT | Tornado Watch | SPC | Bosque, Collin, Comanche, Dallas, Delta, Denton and 29 more | 6 hr |
| Apr 28, 9:13 PM CDT | Mesoscale Discussion | SPC | Bastrop, Bexar, Caldwell, Colorado, Comal, Fayette and 4 more | 92 min |
| Apr 28, 9:19 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Collin, Dallas, Delta and 18 more | 116 min |
| Apr 28, 10:22 PM CDT | Tornado Watch | SPC | Atascosa, Bandera, Bastrop, Bexar, Blanco, Burnet and 27 more | 7 hr |
| Apr 28, 11:03 PM CDT | Mesoscale Discussion | SPC | Atascosa, Bandera, Bastrop, Bell, Bexar, Blanco and 37 more | 117 min |
| Apr 29, 1:09 AM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Collin, Dallas, Delta and 22 more | 2 hr |
| Apr 29, 2:01 AM CDT | Tornado Watch | SPC | Bowie, Camp, Cass, Delta, Franklin, Gregg and 15 more | 6 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.