ACUS03 KWNS 101922
SWODY3
SPC AC 101921
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0121 PM CST Mon Feb 10 2025
Valid 121200Z - 131200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
EASTERN LOUISIANA INTO CENTRAL/SOUTHERN MISSISSIPPI AND FAR WESTERN
ALABAMA...
...SUMMARY...
Severe storms will be possible Wednesday afternoon into Wednesday
night from the Sabine Valley vicinity into far western Georgia.
...Lower MS Valley/Central Gulf Coast States...
A large-scale upper trough will be located over the Plains/central
U.S. Wednesday. A shortwave embedded within the larger-scale trough
will rotated from the Plains to the Midwest/Great Lakes, resulting
in a large swath of strong deep-layer southwesterly flow across the
region. At the surface, low pressure will develop near the Sabine
River during the morning, and deepen as the low lifts northeast
through the period. Southerly low-level flow will maintain 60s F
dewpoints across the Lower MS Valley and Gulf Coast states ahead of southeastward-advancing cold front. While widespread cloud cover and
ongoing precipitation will limit stronger destabilization, and adds
to uncertainty for this event, the overall large-scale pattern
suggests some severe thunderstorm potential is likely from extreme
southeast TX into MS/AL Wednesday afternoon into the overnight
hours.
Mid to upper 60s F dewpoints will approach the I-20 corridor by
afternoon as the surface low develop northeast into TN/KY by 00z.
Additionally, strong shear will overspread the region for much of
the period (decreasing from west to east with time). Large-scale
ascent will be somewhat offset to the north of the better low-level
moisture, but a glancing influence coupled with the sharpening of
the southeast-advancing cold front will be sufficient to sustain
convection in a strong warm advection regime.
Forecast soundings indicate enlarged low-level hodographs becoming
elongated above 2-3 km, typical of supercell/QLCS environments and
aided by a 45-60 kt low-level jet. However, low-level lapse rates
are expected to remain poor given limited heating, and midlevel
lapse rates also are expected to remain modest. MUCAPE around
500-1000 J/kg is evident in most forecast guidance, though
surface-based instability is likely to remain muted. With shear
vectors oriented parallel to the surface boundary, convection is
likely to mostly be to the cool side of the boundary. However, given
strength of shear and modest instability, some strong/severe wind
potential is possible with organized line segments. While low-level
lapse rates and instability are expected to remain poor, limiting
overall tornado potential, a couple of mesovortex spin-ups within
linear convection may still be possible given very favorable shear
environment and any mesoscale pockets of greater instability.
Currently, it is uncertain if convection will be able to develop
ahead of the cold front in the open warm sector. Given the somewhat
northward offset of stronger ascent and orientation of shear vectors
to the initiating boundary, it appears low probability at this time
that convection will be able to sufficiently deepen within the
pre-frontal warm advection regime. However, if this occurs, a
conditional risk for severe gusts and a couple of tornadoes with
supercells will exist.
The severe risk should gradually lessen overnight with north and
east extent as instability decreases and large-scale ascent
continues to lift to the northeast of the region.
..Leitman.. 02/10/2025
$$
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