Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 29
The Storm Prediction Center issued this mesoscale discussion at Jan 25, 2021, 7:38 AM CST for 10 counties in Arkansas; McCurtain County, Oklahoma; 17 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jan 25, 2021, 7:38 AM CST (13:38 UTC)
- Expired
- Jan 25, 2021, 9:45 AM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
All 28 counties
Clark County, AR, Garland County, AR, Hempstead County, AR, Howard County, AR, Little River County, AR, Miller County, AR, Montgomery County, AR, Pike County, AR, Polk County, AR, Sevier County, AR, McCurtain County, OK, Anderson County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Marion County, TX, Morris County, TX, Red River County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX
The radar
The Shreveport radar (KSHV), 129 km from the middle of the area, began a volume at 13:41 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
Shreveport, LA (KSHV), launched 12:00Z, 1.6 hours before the alert went out and 131 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
- 964 J/kg
- Mixed-layer CIN
- -75 J/kg
- Mixed-layer LCL
- 548 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 424 m²/s²
- 0-3 km storm-relative helicity
- 543 m²/s²
- Significant tornado parameter
- 2.9
- Supercell composite
- 8.7
The text
As transmitted.
512
ACUS11 KWNS 251339
SWOMCD
SPC MCD 251338
ARZ000-LAZ000-TXZ000-OKZ000-251545-
Mesoscale Discussion 0029
NWS Storm Prediction Center Norman OK
0738 AM CST Mon Jan 25 2021
Areas affected...Portions of northeast TX...extreme southeastern
OK...western AR...and far northwestern LA
Concerning...Severe potential...Watch unlikely
Valid 251338Z - 251545Z
Probability of Watch Issuance...20 percent
SUMMARY...An isolated threat for large hail and strong/gusty winds
should continue in the short term. Watch issuance remains unlikely.
DISCUSSION...A line of storms along a cold front will move generally
east-northeastward across the Arklatex region this morning. Strong
effective bulk shear of 50-60 kt should continue to foster storm
organization, with a supercell embedded on the southern flank of the
line. The 12Z sounding from SHV shows a sharp inversion around 750
mb. It appears likely that this cap will not substantially erode
this morning. Accordingly, the ongoing strong to severe storms
should tend to weaken over the next couple of hours as they move
eastward into a less unstable airmass. But in the short term, an
isolated threat for large hail will continue with the ongoing
supercell. Occasional strong/gusty winds generally below severe
limits (35-45 kt) may also occur. Current expectations are for the
overall severe threat to remain too isolated/marginal to justify
watch issuance.
..Gleason/Edwards.. 01/25/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LZK...SHV...TSA...FWD...
LAT...LON 32209619 33189548 33899494 34569455 34919382 34879335
34679303 34399302 33909321 32759411 31739519 31779572
32209619SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 24, 6:40 PM CST | Mesoscale Discussion | SPC | Jackson, Tillman | 3 hr |
| Jan 25, 12:42 AM CST | Mesoscale Discussion | SPC | Atoka, Bryan, Carter, Choctaw, Cleveland, Coal and 23 more | 2 hr |
| Jan 25, 3:30 AM CST | Mesoscale Discussion | SPC | Atoka, Bryan, Choctaw, Coal, Johnston, Love and 1 more | 2 hr |
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.