SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1112 AM CST Mon Dec 22 2025 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not currently forecast across the contiguous United States on Tuesday or Tuesday night. ...Synopsis... An expansive and unseasonably strong upper ridge will dominate the mid and upper-level flow pattern across the CONUS Day2/Tuesday. As the ridge intensifies, troughing on the flanks of the ridge will also strengthen. The western most trough, and a mid-level shortwave trough embedded within it will likely reach the central and northern CA coastal areas late Tuesday night. Strong ascent and flow aloft will support a deepening surface low which will support onshore flow and some thunderstorm potential over much of coastal CA/OR. ...West Coast... As the upper trough deepens over the West Coast, strong onshore flow will develop and support inland transport of low-level moisture across much of coast and the CA central Valley. Cooling mid-level temperatures and strong ascent associated with the embedded shortwave will overspread this air mass contributing to weak destabilization late Tuesday through early Wednesday. Low-topped convection, capable of occasional lightning, is expected to increase in coverage overnight. While a stronger storm is possible, especially along and ahead of the surface cold front, the scant buoyancy and overnight timing suggest severe potential is very low. Elsewhere, moisture advection is likely over parts of the southern Plains and far south TX beneath the upper ridge as the surface reflection shifts eastward. Despite persistent southerly flow and increasing surface dewpoints, little to no ascent and warm mid-level temperatures should preclude thunderstorm development outside of far south TX. ..Lyons.. 12/22/2025
