SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1116 AM CST Tue Nov 04 2025 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN WEST OR/NORTHWEST CA AND THE NORTHEAST... CORRECTED FOR HEADLINE ...SUMMARY... Isolated severe thunderstorms are possible on Wednesday morning and afternoon in western Oregon and far northwest California. Damaging winds from showers and very isolated low-topped thunderstorms are possible during the afternoon to evening in the Northeast. ...Synopsis... A strong upper-level trough will overspread the Northwest on Wednesday with ridging building over the Rockies/Plains. A positively tilted trough will amplify across southeast Canada and the Great Lakes with a very strong mid-level jet strengthening from the southern Great Lakes to the Mid Atlantic during the afternoon/evening. This will result in a rapidly strengthening surface low during the day which moves from the northern Great Lakes to the Maine coast. ...Pacific Northwest into northwest California... Cool mid-level temperatures and relatively warm waters off the Pacific Northwest coast will result in weak instability ahead of a cold front as it approaches the coast on Wednesday morning. Some stronger storms may result in an isolated severe wind gust with the frontal passage. However, greater instability is forecast in the wake of this cold front as temperatures aloft continue to cool. Lower tropospheric flow will remain strong (50 knots at 1km) in the wake of the cold front, and an additional mid-level trough will likely be a focus for a second round of storms during the afternoon. This round will likely have the greatest threat for marginally large hail, isolated severe wind gusts, and perhaps a tornado threat, due to the greater instability and potential for low-topped supercells. This threat may also persist inland during the afternoon as some weak heating results in slightly greater instability during the afternoon. ...Eastern Great Lakes to parts of New England... As a surface low strengthens across the eastern Great Lakes Wednesday morning, a cold front will also sharpen and become the focus for convection by early afternoon. Limited moisture will result in weak to negligible instability and lightning will likely remain isolated. Nonetheless, very strong winds (greater than 50 knots at 1km) could easily mix to the surface and result in some damaging wind threat with a loosely organized line of convection along the cold front during the afternoon. ..Bentley.. 11/04/2025
