Severe Storm Outlook Narrative (AC)
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000
ACUS02 KWNS 071730
SWODY2
SPC AC 071728

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CST Tue Feb 07 2023

Valid 081200Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
MISSISSIPPI VALLEY...

...SUMMARY...
Severe thunderstorms are possible Wednesday and Wednesday night
across the Lower Mississippi Valley. This includes the potential for
damaging winds, a few tornadoes, and possibly some hail.

...Synopsis...
A mid-level trough will become negatively tilted Wednesday morning
across the southern High Plains and move northeast to near the
Ozarks by 06Z Thursday. A surface low will develop along a front in
eastern Texas Wednesday morning and deepen as it moves northward
into the Ozarks by 12Z Thursday.

...Lower Mississippi Valley...
As the surface low deepens during the day Wednesday, low-level flow
will strengthen and advect moisture northward across the Lower
Mississippi Valley. Mid 60s dewpoints may advect as far north as
southern Arkansas/northern Mississippi by Wednesday evening. The
warm sector will be mostly capped Wednesday morning, but inhibition
is expected to erode by mid day as mid-level temperatures cool ahead
of the advancing trough. Despite the uncapped warm sector, most CAM
guidance has limited convection across Louisiana during the day. The
ECMWF has more widespread convection Wednesday afternoon and seems
like the more likely solution given the height falls and the
uncapped warm sector by early afternoon. However, these storms may
remain more multi-cellular and only marginally severe as warm sector
effective shear is only expected to be 20-25 knots during the day.

Most guidance shows a low-level wave moving northward across the
western Gulf tomorrow afternoon. This can be seen in both PWAT and
850mb wind fields and appears to be the impetus for western Gulf
convection, apparent on most guidance. As this feature moves into
eastern Louisiana/western Mississippi Wednesday evening, expect a
more concentrated convective risk to develop along the I-20 corridor
from eastern Louisiana to central Mississippi. Most guidance shows
the low-level jet strengthening from 35 to 55 knots between 23Z and
04Z which will elongate hodographs across the warm sector. During
this period, convergence is forecast to increase along the cold
front and ascent associated with the mid-level trough is expected to
overspread the warm sector. A greater tornado threat could persist
from evening to early overnight, both from any pre-frontal
supercells and any line embedded supercells/QLCS vorticies
associated with the front.

Damaging winds will also be possible with the developing squall line
during this period as some residual instability remains before this
line moves east of the better instability after 06Z near the
Alabama/Mississippi Line. Given the strong wind field, some marginal
severe wind threat could persist into Alabama early Thursday
morning, but limited instability should mitigate a greater threat.

..Bentley.. 02/07/2023

$$


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