SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0257 PM CDT Tue Sep 30 2025 Valid 302000Z - 011200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are unlikely through tonight. ...20Z Update... Only minor changes were made to the forecast with this update, including a slight expansion of the General Thunderstorm area in the Appalachians. See the previous discussion below for details. ..Weinman.. 09/30/2025 .PREV DISCUSSION... /ISSUED 1100 AM CDT Tue Sep 30 2025/ ...Synopsis and Discussion... Upper ridging will be maintained today across the Midwest and Great Lakes, while upstream troughing advances inland over the western states. Multiple embedded mid-level shortwave troughs will encourage thunderstorm development through the period from parts of the Great Basin into the northern/central Rockies and adjacent High Plains. Thunderstorms may also occur across parts of coastal WA with low-topped convection in close proximity to an upper low off the coast of British Columbia. Other isolated thunderstorms appear possible this afternoon over portions of the southern Appalachians and FL Atlantic Coast. For all these areas, weak instability and/or modest shear should preclude organized severe thunderstorms.
