Mesoscale Discussion 2079

Issued

Dec 29, 2021, 4:44 PM CST (22:44 UTC)

Expired

Dec 29, 2021, 6:45 PM CST

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

Counties Clark County, AR, Columbia County, AR, Hempstead County, AR, Lafayette County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, Webster Parish, LA, Bowie County, TX, Camp County, TX, Cass County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Smith County, TX, Upshur County, TX

The Shreveport radar (KSHV), 59 km from the middle of the area, began a volume at 22:47 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.

665 
ACUS11 KWNS 292244
SWOMCD
SPC MCD 292244 
ARZ000-LAZ000-TXZ000-300045-

Mesoscale Discussion 2079
NWS Storm Prediction Center Norman OK
0444 PM CST Wed Dec 29 2021

Areas affected...The Texarkana area

Concerning...Severe potential...Watch unlikely 

Valid 292244Z - 300045Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms moving into southern AR have shown signs of
intensification over the past hour and may pose a severe hail threat
through the evening hours.

DISCUSSION...IR imagery and lightning data have shown an
intensifying trend in convection across the Texarkana area over the
past 30-60 minutes. This activity is maturing in an environment with
sufficient MLCAPE (around 500-1000 J/kg) and 50-60 knots of
effective bulk shear. Given the recent convective trends and
downstream environment, storms will likely continue to intensify
over the next 1-2 hours. However, this convection has developed
along and just ahead of a residual outflow boundary with surface
temperatures quickly dropping off into the 60s with northern extent.
This is indicative of a shallow cold layer that will likely favor
elevated storms. Nonetheless, long, straight hodographs will favor
the potential for supercellular structures that may pose a severe
hail threat through the evening hours across the Texarkana region.
The severe threat may be heightened, including a damaging wind
potential, for any storms that remain along or south of the outflow
boundary. Given the elevated and relatively isolated nature of this
activity, a watch is not expected.

..Moore/Bunting.. 12/29/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LZK...SHV...FWD...

LAT...LON   32419561 33109498 33709404 34069320 33979270 33639256
            33259271 32659306 32399369 32299439 32209495 32189541
            32419561

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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.