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.