Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 409
The Storm Prediction Center issued this mesoscale discussion at Apr 23, 2021, 3:28 PM CDT for 17 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 23, 2021, 3:28 PM CDT (20:28 UTC)
- Expired
- Apr 23, 2021, 5:30 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 98
Counties Bosque County, TX, Brown County, TX, Comanche County, TX, Eastland County, TX, Erath County, TX, Hamilton County, TX, Hood County, TX, Jack County, TX, Johnson County, TX, Mills County, TX, Palo Pinto County, TX, Parker County, TX, San Saba County, TX, Somervell County, TX, Stephens County, TX, Tarrant County, TX, Wise County, TX
The radar
The Dyess AFB radar (KDYX), 97 km from the middle of the area, began a volume at 20:28 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
Fort Worth, TX (KFWD), launched 12:00Z, 8.5 hours before the alert went out and 121 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
- 14 J/kg
- Mixed-layer CIN
- -89 J/kg
- Mixed-layer LCL
- 578 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 397 m²/s²
- 0-3 km storm-relative helicity
- 249 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted.
512
ACUS11 KWNS 232029
SWOMCD
SPC MCD 232028
TXZ000-232230-
Mesoscale Discussion 0409
NWS Storm Prediction Center Norman OK
0328 PM CDT Fri Apr 23 2021
Areas affected...portions of west-central and north Texas
Concerning...Severe Thunderstorm Watch 98...
Valid 232028Z - 232230Z
The severe weather threat for Severe Thunderstorm Watch 98
continues.
SUMMARY...A few intense cells are possible the next 2-4 hours across
parts of northern/west-central Texas. Large hail and damaging gusts
are the main hazards expected with this activity.
DISCUSSION...Additional thunderstorms are develop and/or
strengthening just ahead of the eastward-advancing dryline this
afternoon. This activity is moving into an airmass that has seen
less thunderstorm activity early in the day compared to areas to the
east and south, and where dewpoints have climbed into the mid to
upper 60s. Increasing low level moisture beneath midlevel lapse
rates around 7.5-8.5 C/km is resulting in 1500-2000 J/kg MLCAPE,
supporting storm intensification. Furthermore, regional VWP data
suggest shear profiles have continued to improve/strengthen which
should allow for some better-organized cells. 20z experimental
Warn-on-Forecast ensemble guidance also indicates a few intense
cells are possible across the MCD area, including western portions
of the Fort Worth metro area, over the next 2-4 hours, potentially
producing large hail and damaging gusts.
..Leitman.. 04/23/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...SJT...
LAT...LON 31919933 32769901 33069876 33299824 33279762 33099736
32839725 32529730 32149738 32029747 31649766 31219824
31159877 31129904 31299931 31599932 31919933SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 23, 11:29 AM CDT | Mesoscale Discussion | SPC | Archer, Bastrop, Bell, Bexar, Blanco, Bosque and 52 more | 91 min |
| Apr 23, 12:37 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Archer, Bastrop, Bell, Blanco, Bosque and 53 more | 7 hr |
| Apr 23, 12:43 PM CDT | Mesoscale Discussion | SPC | Baylor, Childress, Collingsworth, Cottle, Foard, Hall and 2 more | 3 hr |
| Apr 23, 12:43 PM CDT | Mesoscale Discussion | SPC | Anderson, Angelina, Brazoria, Chambers, Cherokee, Fort Bend and 25 more | 2 hr |
| Apr 23, 2:00 PM CDT | Tornado Watch | SPC | Angelina, Austin, Brazos, Burleson, Chambers, Cherokee and 22 more | 7 hr |
| Apr 23, 3:14 PM CDT | Tornado Watch | SPC | Archer, Baylor, Childress, Clay, Collingsworth, Cottle and 7 more | 5 hr |
| Apr 23, 3:27 PM CDT | Mesoscale Discussion | SPC | Baylor, Foard, Hardeman, Wilbarger | 2 hr |
| Apr 23, 5:26 PM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Clay, Foard, Hardeman, Knox and 2 more | 2 hr |
| Apr 23, 5:36 PM CDT | Mesoscale Discussion | SPC | Angelina, Houston, Jasper, Nacogdoches, Newton, Polk and 7 more | 54 min |
| Apr 23, 6:46 PM CDT | Mesoscale Discussion | SPC | Atascosa, Bell, Bexar, Blanco, Bosque, Burnet and 19 more | 89 min |
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.