Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 1981
The Storm Prediction Center issued this mesoscale discussion at Dec 10, 2021, 4:20 PM CST for 6 counties in Arkansas; Choctaw County, McCurtain County, Oklahoma; 28 counties in Texas. It was in force for 85 min.
The area
The outline as issued.
The facts
- Issued
- Dec 10, 2021, 4:20 PM CST (22:20 UTC)
- Expired
- Dec 10, 2021, 5:45 PM CST
- In force
- 85 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 36 counties
Hempstead County, AR, Howard County, AR, Little River County, AR, Miller County, AR, Pike County, AR, Sevier County, AR, Choctaw County, OK, McCurtain County, OK, Bowie County, TX, Camp County, TX, Cass County, TX, Collin County, TX, Dallas County, TX, Delta County, TX, Ellis County, TX, Fannin County, TX, Franklin County, TX, Gregg County, TX, Henderson County, TX, Hill County, TX, Hopkins County, TX, Hunt County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Marion County, TX, Morris County, TX, Navarro County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 169 km from the middle of the area, began a volume at 22:22 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 12:00Z, 10.3 hours before the alert went out and 159 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
- 162 J/kg
- Mixed-layer CIN
- -424 J/kg
- Mixed-layer LCL
- 1084 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 208 m²/s²
- 0-3 km storm-relative helicity
- 263 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
029
ACUS11 KWNS 102221
SWOMCD
SPC MCD 102220
ARZ000-LAZ000-TXZ000-OKZ000-102345-
Mesoscale Discussion 1981
NWS Storm Prediction Center Norman OK
0420 PM CST Fri Dec 10 2021
Areas affected...Northeast Texas...far southeast Oklahoma...and far
southwest Arkansas
Concerning...Severe potential...Watch possible
Valid 102220Z - 102345Z
Probability of Watch Issuance...40 percent
SUMMARY...Isolated to widely scattered severe storms are possible
across portions of the Arklatex.
DISCUSSION...High based showers have developed along a dryline which
has recently passed through Dallas. These showers are now moving
into a more moisture rich airmass with dewpoints in the mid 60s.
This is yielding MLCAPE around 1500 to 2000 J/kg beneath strong
mid-level flow and effective shear in excess of 60 knots. Therefore,
further intensification of these showers are possible. The threat
will likely remain isolated, but the environment is quite favorable
for supercells with an initial large hail threat with an increasing
tornado threat with eastward extent. The isolated nature of any
storm development may preclude the need for a watch, but if storm
intensity is great enough or if more storms develop, a watch may be
needed.
..Bentley/Grams.. 12/10/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LZK...SHV...TSA...FWD...OUN...
LAT...LON 33279692 34019584 34579457 34189338 33319365 32189491
31809694 31979759 33279692SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 10, 1:35 PM CST | Mesoscale Discussion | SPC | Baxter, Clay, Cleburne, Conway, Craighead, Cross and 22 more | 2 hr |
| Dec 10, 3:07 PM CST | Tornado Watch | SPC | Arkansas, Clark, Clay, Cleburne, Cleveland, Conway and 37 more | 11 hr |
| Dec 10, 4:45 PM CST | Mesoscale Discussion | SPC | Arkansas, Clay, Craighead, Crittenden, Cross, Grant and 17 more | 90 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.