SPC Dec 20, 2023 0600 UTC Day 1 Convective Outlook

[NorthGeorgiaWX]

SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1143 PM CST Tue Dec 19 2023

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated thunderstorms will be possible across parts of
southern/central California and over portions of the Southwest. The
severe-thunderstorm threat appears low.

...Synopsis...
A deep-layer cyclone is forecast to move slowly southward off of the
CA coast through the day. Downstream of this cyclone, a
low-amplitude midlevel shortwave trough is forecast to move across
parts of the Southwest and southern Rockies. An expansive surface
ridge will cover much of the central/eastern CONUS, which should
generally preclude thunderstorm development east of the Rockies. 

Midlevel moistening in advance of the Southwest shortwave will
support elevated convection and perhaps sporadic lightning flashes
across parts of AZ/NM. Somewhat more vigorous convection and greater
thunderstorm coverage will be possible across parts of CA, in
association with the offshore low.

...California...
Deep southerly flow to the east of the offshore low will maintain
modest low/midlevel moisture across near-coastal areas of
southern/central CA. While the low will remain offshore through the
period, a band of convection may move onshore during the day and
possibly persist into the evening, in association with gradual
cooling aloft and favorably difluent upper-level flow. Inland
destabilization will likely remain quite limited, but increasing
vertical shear may support modestly organized convection at times. A
couple strong storms will be possible as stronger offshore
convection approaches the coast, but instability currently appears
too weak to support an organized severe-thunderstorm threat.

..Dean/Squitieri.. 12/20/2023

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