SPC Jan 7, 2024 0700 UTC Day 2 Convective Outlook

[NorthGeorgiaWX]

SPC 0700Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1140 PM CST Sat Jan 06 2024

Valid 081200Z - 091200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS MONDAY INTO MONDAY
NIGHT ACROSS PARTS OF SOUTHEASTERN TEXAS...SOUTHERN
LOUISIANA...SOUTHERN MISSISSIPPI...SOUTHERN ALABAMA AND THE WESTERN
FLORIDA PANHANDLE...

...SUMMARY...
Severe thunderstorms, accompanied by a risk for damaging wind gusts
and tornadoes, are possible across parts of southern Louisiana and
southern Mississippi into southern Alabama and the Florida Panhandle
by late Monday night.

...Synopsis...
As initially amplified mid/upper ridging, within the prevailing
split flow across the eastern mid-latitude Pacific, is suppressed
further by another vigorous short wave trough approaching the
Pacific Northwest, a significant evolving downstream trough is
forecast to turn east of the Rockies through this period.  Models
indicate that it will take on a more neutral tilt, and come in
better phase with another perturbation within a belt of westerlies
emanating from the subtropical eastern Pacific, as it progresses
across the southern Great Plains Monday night.  

However, considerable spread is evident among the various model
output concerning the more specific details of this evolution, and
associated cyclogenesis, particularly late Monday into Monday night.
 It still appears that at least modest surface cyclogenesis may be
ongoing across the Texas Panhandle vicinity by late Monday morning,
but there may be little further deepening through the day as it
migrates east-northeastward across the southern Great Plains.  A
secondary frontal wave may form across and northeast of the upper
Texas coastal plain late Monday afternoon and evening, but more
rapid deepening of the primary surface cyclone may not commence
across the Ozark Plateau/Mid South vicinity until the overnight
hours.

Low-level moisture return off a modifying boundary layer over the
northern Gulf of Mexico may contribute to considerable cloud cover
and at least light precipitation across and well inland of Gulf
coastal areas through the day Monday.  By early Monday, stronger
mid-level cooling and forcing for ascent spreading east/southeast of
the Texas/Oklahoma Panhandle vicinity may already be contributing to
a developing line of storms, rooted above a relative deep
cold/stable surface-based layer. During the day, ascent driven by
low-level warm advection and, perhaps, forcing associated with the
subtropical perturbation, may contribute to increasing thunderstorm 
development near/offshore of upper Texas into central Gulf coastal
areas, prior to the inland advance of a destabilizing warm sector
boundary layer.  

...Gulf Coast...
As the leading edge of the stronger mid-level cooling advances
southeastward toward the northwestern Gulf coast/lower Mississippi
Valley, it appears that it may maintain the band of convection and
embedded thunderstorms, with some intensification possible as it
encounters better low-level moisture and instability.  At some point
across east/southeast Texas into western Louisiana, it is possible
that this activity could become capable of producing some hail and
gusty surface winds.  However, based on latest forecast soundings,
this appears likely to remain largely rooted above a saturated moist
adiabatic or more stable near surface layer, which may mitigate the
severe weather potential.

A window of opportunity may still exist for inland boundary-layer
destabilization across the upper Texas coastal plain into
southwestern Louisiana, where surface dew points may increase into
the mid/upper 60s.  Mixed-layer CAPE increasing up to 500-1000 J/kg
appears possible, in the presence of lower/mid-tropospheric warm
advection and strong deep-layer shear.  Prior to the onset of
mid-level subsidence, then a subsequent surface frontal passage,
organized thunderstorm development, including supercells, may not be
out of the question by late Monday afternoon.

Monday afternoon into Monday night, much will probably hinge on the
timing of the more rapid deepening of the primary surface cyclone,
which might be needed to allow for a destabilizing Gulf boundary
layer to advect inland across the northern Gulf coast.  However,
guidance continues to generally indicate that this may occur across
at least portions of southeastern Louisiana, southern Mississippi,
southwestern Alabama and the western Florida Panhandle by late
Monday night, if not earlier.  If this occurs, it appears likely to
coincide with intensifying wind fields and shear, including 50-70+
kt in the 850 mb layer, which could contribute to an environment
conducive to organizing convection with a risk for damaging wind
gusts and a couple of strong tornadoes.

..Kerr.. 01/07/2024

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