Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 336
The Storm Prediction Center issued this mesoscale discussion at Apr 8, 2021, 9:58 PM CDT for 13 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 8, 2021, 9:58 PM CDT (02:58 UTC)
- Expired
- Apr 9, 2021, 12:00 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Anderson County, TX, Brazos County, TX, Cherokee County, TX, Freestone County, TX, Grimes County, TX, Henderson County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, Navarro County, TX, Robertson County, TX, Smith County, TX, Van Zandt County, TX
The radar
The Ft Hood radar (KGRK), 159 km from the middle of the area, began a volume at 03:00 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 00:00Z, 3.0 hours before the alert went out and 213 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
- 630 J/kg
- Mixed-layer CIN
- -62 J/kg
- Mixed-layer LCL
- 1855 m above ground
- 0-6 km bulk shear
- 68 kt
- 0-1 km storm-relative helicity
- 134 m²/s²
- 0-3 km storm-relative helicity
- 350 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 6.8
The text
As transmitted.
602
ACUS11 KWNS 090258
SWOMCD
SPC MCD 090258
TXZ000-090500-
Mesoscale Discussion 0336
NWS Storm Prediction Center Norman OK
0958 PM CDT Thu Apr 08 2021
Areas affected...Portions of east TX
Concerning...Severe potential...Watch unlikely
Valid 090258Z - 090500Z
Probability of Watch Issuance...20 percent
SUMMARY...A long-lived supercell may continue to produce large hail
in the short term, but it should continue weakening this evening.
Additional storms also posing an isolated large hail threat may
develop this evening across parts of east Texas.
DISCUSSION...A persistent supercell with a history of producing
large to very large hail (up to 2 inches in diameter) has weakened
some to the southeast of College Station TX. This weakening trend
will likely continue over the next couple of hours as it encounters
increasing MLCIN, but large hail may still be possible with this
supercell in the short term. Other convection is in the process of
deepening farther north in east TX as a south-southwesterly
low-level jet strengthens this evening. This activity may also pose
a threat for isolated large hail, with MUCAPE around 1000-1500 J/kg
and 50-60+ kt of deep-layer shear capable of supporting supercell
structures. Current expectations are for this hail threat to remain
too isolated for watch issuance this evening.
..Gleason/Grams.. 04/09/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...SHV...HGX...FWD...
LAT...LON 30339550 30149573 30199605 30679633 31539687 32029685
32389653 32639598 32609539 32479521 31699507 31399548
31039584 30699583 30339550SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 9:49 AM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Collin, Cooke, Delta and 20 more | 116 min |
| Apr 9, 12:07 PM CDT | Severe Thunderstorm Watch | SPC | Bowie, Camp, Cass, Gregg, Harrison, Marion and 5 more | 6 hr |
| Apr 9, 1:25 PM CDT | Mesoscale Discussion | SPC | Cherokee, Nacogdoches, Panola, Rusk, San Augustine, Shelby | 95 min |
| Apr 9, 3:14 PM CDT | Mesoscale Discussion | SPC | Cooke, Delta, Fannin, Grayson, Lamar, Montague and 1 more | 61 min |
| Apr 9, 3:59 PM CDT | Mesoscale Discussion | SPC | Bastrop, Bell, Blanco, Bosque, Burnet, Caldwell and 14 more | 2 hr |
| Apr 9, 4:27 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bell, Bosque, Collin, Cooke, Coryell and 26 more | 9 hr |
| Apr 9, 5:19 PM CDT | Mesoscale Discussion | SPC | Angelina, Cherokee, Nacogdoches, Sabine, San Augustine, Shelby | 116 min |
| Apr 9, 5:32 PM CDT | Severe Thunderstorm Watch | SPC | Angelina, Brazos, Burleson, Cherokee, Gregg, Grimes and 16 more | 7 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.