688
ACUS03 KWNS 251926
SWODY3
SPC AC 251925

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0125 PM CST Mon Nov 25 2024

Valid 271200Z - 281200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The risk for severe weather appears negligible through this period,
but widely scattered thunderstorms are possible across parts of the
lower Mississippi Valley into Tennessee Valley by late Wednesday
night.

...Synopsis...
Models suggest that mid/upper ridging across the subtropical eastern
Pacific into Gulf of Mexico will undergo suppression into and
through this forecast period, with some amplification of troughing
within the mid-latitude westerlies east of the Rockies into the
Atlantic Seaboard.  In the wake of a preceding perturbation, and
associated surface cold front forecast to stall across the northern
Gulf of Mexico through northern Florida, it appears that this will
include a consolidating mid-level short wave trough turning eastward
through the middle Mississippi Valley by late Wednesday night.

The spread among model output concerning this trailing perturbation
and related developments has been sizable.  However, it now appears
most probable that associated surface wave development, along a cold
front initially advancing southward to the lee of the southern
Rockies, will remain low in amplitude across the lower Mississippi
Valley through southern Appalachians/Mid Atlantic by early
Thanksgiving morning.

...Lower Mississippi Valley into Southeast...
Due to the lower-amplitude nature of the developing surface wave,
strengthening pre-frontal low-level wind fields are likely to
maintain a substantial westerly component.  This will probably slow
inland low-level moisture return off a relatively moist boundary
layer over the Gulf of Mexico.  In the wake of the stalling lead
front, initially near central/eastern Gulf coastal areas before
weakening and returning northward, NAM forecast soundings suggest
that at least a shallow residual surface-based layer may be
maintained inland of southeastern Louisiana and southern Mississippi
coastal areas through at least 12Z Thursday.  Farther aloft, it
appears that the low-level moisture return will (at least initially)
be capped by a substantive lower/mid-tropospheric warm layer, with
only a gradual erosion of the inhibition through the period.

While various model output suggests that lower/mid-tropospheric warm
advection might contribute to elevated convection capable of
producing lightning across parts of the lower Mississippi into
Tennessee Valleys Wednesday evening into Wednesday night, latest NAM
output indicates that potential for thunderstorm activity may remain
negligible until at least 09-12Z Thursday across parts of
southeastern Louisiana into southern Mississippi and Alabama.

..Kerr.. 11/25/2024

$$