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SPC Mar 12, 2023 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook

Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1132 PM CST Sat Mar 11 2023

Valid 121200Z - 131200Z


Scattered severe thunderstorms capable of producing large hail,
damaging winds, and a couple tornadoes are possible Sunday across
parts of the Southeast. A few strong/severe storms are also possible
in the central valley region of California.


A few weak short-wave troughs will track east-southeast across the
Gulf States Sunday as the southern stream is suppressed a bit in
response to a strong digging short wave over the Great Lakes. In the
absence of meaningful height falls, weak surface low will advance
east across the lower MS Valley along the surging cold front into
southwest AL by early evening. Downstream, a secondary surface low
should evolve off the SC Coast during the latter half of the period,
as mid-level flow increases over the southern Appalachians. Surface
front and organized outflow boundaries should serve as the focus for
potentially organized, strong/severe convection.

Early this morning, an MCS has evolved over southern AR along/north
of a warm front draped across this region. This activity may also be
partially influenced by a weak short-wave trough that is currently
ejecting across the mid-MS Valley. Much of the northern Gulf States
remain cool/stable in the boundary layer with greater buoyancy
observed across east TX into LA/western MS. This MCS will continue
propagating southeast, likely expanding east into AL/northern GA by
the start of the day1 period. As a result, instability required for
robust convection should extend primarily across the southern Gulf
States into southern GA. 

Strong westerly flow and a surging cold front will encourage much of
the aforementioned convection to propagate toward northern FL.
Current thinking is a mixed storm mode, likely dominated by line
segments and multi-cell clusters, will spread across the Southeast
by late afternoon. Even so, strong shear should aid a few supercells
as abundant buoyancy will be in place prior to convection. Hail,
damaging winds, along with a few tornadoes can be expected with this

...Central Valley Region of CA...

The next within a series of speed maxima will advance inland across
southern CA after 18z. Lower 50s surface dew points are in place
across the central CA valley region, and this moisture should hold
through the day given the current flow regime. Given the cool
mid-level temperatures, afternoon convection should once again
develop within a favorably sheared environment for robust
convection. Forecast soundings suggest supercells are possible and
hail may approach severe levels with the strongest updrafts. Any
convection that develops will weaken with loss of daytime heating.

..Darrow/Moore.. 03/12/2023

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