SPC Jan 21, 2025 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0132 PM CST Tue Jan 21 2025

Valid 212000Z - 221200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The risk for thunderstorms appears negligible across the U.S.
through tonight.

...20z...
No changes were made. Widespread winter precipitation is ongoing
along the Gulf Coast. High pressure over the interior of the central
CONUS will continue to support very cold, dry and stable conditions
with offshore flow. This will negate sufficient buoyancy for
thunderstorm potential. See the prior outlook for more info.

..Lyons.. 01/21/2025

.PREV DISCUSSION... /ISSUED 1012 AM CST Tue Jan 21 2025/

...Synopsis...
Expansive high pressure associated with a polar airmass is in place
across is in place east of Rockies. This high, which is currently
centered over eastern OK/western AR, is expected to shift
eastward/northeastward throughout the day, ending the period over
the Ohio Valley. Associated cold, dry, and stable conditions will
preclude thunderstorm development. A similar environment is
anticipated across the western CONUS, with high pressure and
associated stability dominating the sensible weather.

A deepening surface low will continue to shift eastward across the
Gulf of Mexico, with strong warm-air advection throughout its warm
sector contributing to a broad precipitation field across the Gulf
Coast. A few lightning flashes were observed over Acadia Parish in
south-central LA over the past hour, but these flashes were most
likely created by the self-initiated upward leader process. Given
the continuing windy conditions and potential for mixed-phase
hydrometeors at low levels, some additional self-initiated flashes
are possible throughout the period.

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