Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 244
The Storm Prediction Center issued this mesoscale discussion at Mar 24, 2021, 7:37 PM CDT for Little River County, Miller County, Sevier County, Arkansas; Bryan County, Choctaw County, McCurtain County, Oklahoma; 29 counties in Texas. It was in force for 53 min.
The area
The outline as issued.
The facts
- Issued
- Mar 24, 2021, 7:37 PM CDT (00:37 UTC)
- Expired
- Mar 24, 2021, 8:30 PM CDT
- In force
- 53 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 48
All 35 counties
Little River County, AR, Miller County, AR, Sevier County, AR, Bryan County, OK, Choctaw County, OK, McCurtain County, OK, Bowie County, TX, Camp County, TX, Cass 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, Gregg County, TX, Harrison County, TX, Hopkins County, TX, Hunt County, TX, Kaufman County, TX, Lamar County, TX, Marion 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, Van Zandt County, TX, Wise County, TX, Wood County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 163 km from the middle of the area, began a volume at 00:40 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
Shreveport, LA (KSHV), launched 00:00Z, 0.6 hours before the alert went out and 207 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
- 281 J/kg
- Mixed-layer CIN
- -75 J/kg
- Mixed-layer LCL
- 1372 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 54 m²/s²
- 0-3 km storm-relative helicity
- 112 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.9
The text
As transmitted.
293
ACUS11 KWNS 250037
SWOMCD
SPC MCD 250037
LAZ000-ARZ000-TXZ000-OKZ000-250130-
Mesoscale Discussion 0244
NWS Storm Prediction Center Norman OK
0737 PM CDT Wed Mar 24 2021
Areas affected...northeast Texas into the ArkLaTex and far
southeastern Oklahoma
Concerning...Severe Thunderstorm Watch 48...
Valid 250037Z - 250130Z
The severe weather threat for Severe Thunderstorm Watch 48
continues.
SUMMARY...The greatest severe threat in the near term is across the
eastern half of WW 48 and areas downstream.
DISCUSSION...An ongoing cluster of thunderstorms (a few with
marginally strong supercellular structures) continues to migrate
northeastward across the eastern half of WW 48. Hail as large as
1.75 inches in diameter was reported with one dominant cell over Van
Zandt County earlier. Most of the severe threat exists with cells
that can acquire rotation, with pressure perturbations processes
amid weak to moderate instability fostering hail production. These
cells are also lifting northeastward in tandem with a warm front
subjectively analyzed near the I-30 corridor in northeast Texas.
Cells that interact favorably with this boundary will continue to
pose a hail/wind and brief tornado risk. Furthermore, increasing
low-level flow may aid in maintenance of ongoing cells despite a
general tendency toward more elevated convection over time. This
could maintain a hail risk just beyond the confines of WW 48 over
time.
Western portions of WW 48 (generally west of I-35) are currently
experiencing a lull in the severe weather risk. Despite
appreciable deep shear, relatively meager mid-level lapse rates seem
to be the primary limiting factor for a more robust threat. This
may change over the next couple of hours as ascent now approaching
the Texas Big Country/southwest Texas vicinity approaches the region
later tonight.
..Cook/Grams.. 03/25/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SHV...TSA...FWD...OUN...
LAT...LON 33849743 34029625 34199505 34129410 33619369 32919371
32529394 32469460 32469563 32639712 32649793 33139799
33849743SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 24, 11:37 PM CDT | Mesoscale Discussion | SPC | Calhoun, Clark, Cleveland, Columbia, Dallas, Garland and 19 more | 53 min |
| Mar 24, 8:15 PM CDT | Mesoscale Discussion | SPC | Bandera, Bell, Blanco, Bosque, Brown, Burnet and 29 more | 2 hr |
| Mar 24, 9:52 PM CDT | Tornado Watch | SPC | Bandera, Bell, Bexar, Blanco, Bosque, Burnet and 37 more | 6 hr |
| Mar 24, 10:28 PM CDT | Mesoscale Discussion | SPC | Edwards, Kimble | 62 min |
| Mar 24, 11:42 PM CDT | Mesoscale Discussion | SPC | Burnet, Coryell, Lampasas, Llano, Mason, San Saba | 93 min |
| Mar 25, 1:40 AM CDT | Mesoscale Discussion | SPC | Anderson, Bandera, Bell, Bexar, Blanco, Bosque and 40 more | 95 min |
Nearby
Mesoscale Discussions in Texas, 2021Mesoscale Discussions in Arkansas, 2021Mesoscale Discussions in Oklahoma, 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.