Mesoscale Discussion 2084

Issued

Dec 30, 2021, 4:02 AM CST (10:02 UTC)

Expired

Dec 30, 2021, 6:30 AM CST

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The Birmingham radar (KBMX), 52 km from the middle of the area, began a volume at 10:02 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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680 
ACUS11 KWNS 301003
SWOMCD
SPC MCD 301002 
GAZ000-ALZ000-MSZ000-301230-

Mesoscale Discussion 2084
NWS Storm Prediction Center Norman OK
0402 AM CST Thu Dec 30 2021

Areas affected...Portions of southern/central MS into central AL and
central/eastern GA

Concerning...Severe potential...Watch unlikely 

Valid 301002Z - 301230Z

Probability of Watch Issuance...20 percent

SUMMARY...An isolated threat for hail, gusty winds, and perhaps a
brief tornado may persist over the next couple of hours. Watch
issuance appears unlikely at this time.

DISCUSSION...10Z surface observations show a convectively reinforced
boundary extending from northern LA into central MS/AL/GA. A recent
uptick in convective coverage has been noted across parts of
southern and central MS into central AL over the past hour or so.
Large-scale ascent across much of the Southeast remains nebulous
early this morning. But, modest low-level warm advection continues
over this region associated with a 25-35 kt southwesterly low-level
jet, which is likely aiding storms. The low-level flow is not overly
strong, and there is little veering with height in the low levels
per recent VWPs from area radars. Even so, strong deep-layer shear
of 45-50+ kt will be more than enough to support storm organization
if any storms can be sustained. There is also rich low-level
moisture and sufficient instability along/south of the boundary to
support surface-based storms.

Given the fairly long, straight hodographs in forecast soundings and
area VWPs, marginally severe hail would be possible if a supercell
can develop. Isolated strong/damaging winds could also occur with
any small bowing segments that can consolidate from ongoing
convection. The tornado threat is less clear given the previously
mentioned veered low-level flow, which is generally hampering 0-1-km
SRH. Regardless, a brief tornado still appears possible, with some
surface observations in east-central MS (KMEI) and central AL
(KSEM/KMGM) showing weak southerly surface winds. The overall severe
threat will probably remain more limited into central/eastern GA, as
MLCAPE gradually weakens with eastward extent. At this point, the
lack of more obvious large-scale forcing aloft may tend to keep the
overall severe threat isolated/marginal through the early morning
hours. Accordingly, watch issuance appears unlikely in the short
term.

..Gleason/Edwards.. 12/30/2021

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

ATTN...WFO...CAE...FFC...BMX...MOB...JAN...LIX...

LAT...LON   31079143 31179154 32259062 32608980 33528769 33718662
            33638581 33378427 33348339 33468289 33688254 33678229
            33218197 32798304 32758652 32088884 31379048 31079143

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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.