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ACUS02 KWNS 090558

SWODY2

SPC AC 090557



Day 2 Convective Outlook  

NWS Storm Prediction Center Norman OK

1257 AM CDT Tue Apr 09 2024



Valid 101200Z - 111200Z



...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN CENTRAL AND

SOUTHERN MS...EASTERN LA...AND SOUTHWEST AL...



...SUMMARY...

Numerous to widespread severe thunderstorms are probable beginning

Wednesday morning across parts of the central Gulf Coast States.

These will include potential for both many tornadoes, some of which

should be strong (EF2-EF3 caliber), and widespread damaging wind

swaths with embedded significant severe gusts.



...Synopsis...

Primary feature of interest will be a southern-stream shortwave

trough over west TX at 12Z Wednesday. This shortwave impulse should

begin to phase with a northern-stream wave digging into the Upper

Midwest, yielding a full-latitude amplified trough near the MS

Valley by 12Z Thursday. This will result in substantial flow

amplification through the troposphere, commencing by Wednesday

morning as a surface cyclone gradually deepens northeastward from

east TX towards the Lower OH Valley.



...Central Gulf Coast/Deep South...

A swath of numerous to widespread severe storms appears increasingly

likely on Wednesday morning to afternoon, highlighted within the

level 3-4/ENH-MDT risks. A nocturnal tornado/wind threat should

persist into Wednesday night across south AL, the FL Panhandle, and

southwest GA.



An MCS is expected to be ongoing from the Sabine to Lower MS Valleys

vicinity at 12Z Wednesday, with the southern portion potentially

already producing severe wind and tornadoes. Guidance is more

consistent with the indication of a plume of moderately steep

mid-level lapse rates ahead of this activity, emanating around the

MCS from the northwest Gulf. A renewed surge of rich western Gulf

moisture is progged to advect north-northeast just ahead of the

morning activity across LA, yielding moderate buoyancy across

convection-free areas of LA into south MS. 



Convective intensity should diurnally increase through late

morning/midday within already strong low-/deep-layer shear. The

initial thermodynamic environment coupled with further strengthening

of tropospheric wind fields should yield potential for an intense

QLCS spreading east-northeast into the afternoon. Embedded

supercells, with a possibility for semi-discrete ones just ahead of

the line along its southern flank, in addition to small-scale bowing

segments will be conducive to tornadoes and damaging wind swaths.

Primary uncertainty is just how far north-northeast this severe MCS

will extend, as both weaker mid and low-level lapse rates with

northeast extent and deep convection regenerating southwestward

towards the larger buoyancy plume, may yield a relatively pronounced

northern cutoff to the more widespread severe threat.



A tornado and severe wind threat should linger into Wednesday

evening/night, at least along the northeast Gulf coast region, with

regenerative offshore supercells moving inland. Guidance is

consistent in suggesting further increases of low-level

shear/hodograph curvature into the FL Panhandle vicinity through 12Z

Thursday, supporting a nocturnal strong tornado risk.



...Ark-La-Tex/Ark-La-Miss to the TN Valley...

A separate area of severe storms, primarily in the form of large

hail initially, should develop along a portion of the Red River

Valley near the Ark-La-Tex. This activity will be supported by a

plume of steep mid-level lapse rates near the cold-core region of

the mid-level low, and the northwest periphery of the residual Gulf

low-level moisture plume that will likely be modified by the

extensive MCS near the central Gulf Coast. 



Guidance has shown more variability with timing the east and

eventual northeast pivot of the mid-level low on Wednesday night,

yielding uncertainty in how far northeast at least a low-probability

severe threat will extend. There will be an attempt at overnight

airmass recovery northward from the central Gulf Coast to the TN

Valley in the wake of the large early-day MCS. Low-level shear

profiles will be supportive of rotating storms into early Wednesday,

with lower-probability tornado/wind threats.



..Grams.. 04/09/2024



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