SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1249 AM CDT Mon Oct 20 2025 Valid 211200Z - 221200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms are possible over the Great Lakes, South Florida, and the northwest Gulf Coast regions Tuesday. Severe thunderstorms are not expected. ...Synopsis and Discussion... A strong upper low initially over the Midwest will continue to intensify as it moves eastward across the Great Lakes and into the Northeast Tuesday. As the upper low deepens, so too will a surface low over the Great Lakes. Residual surface moisture and cool mid-level temperatures beneath the upper low will likely support some weak buoyancy as lapse rates steepen through the day. With strong lift overspreading the weakly unstable air mass, isolated low-topped thunderstorms are possible across the Great Lakes and upper OH Valley Tuesday afternoon. Trailing the surface low, a cold front will sweep southeastward with strengthening surface high pressure behind it over the central US. Offshore winds will limit available moisture and buoyancy for much of the country. The exception will be across portions of the Northwest Gulf Coast and southern FL. Here, rich low-level moisture will allow for moderate diurnal destabilization. Still, weak forcing displaced to the north suggests only isolated thunderstorm coverage. Weak vertical shear and warm mid-level temperatures should limit severe potential. ..Lyons.. 10/20/2025
