SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0132 AM CST Thu Dec 11 2025 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Scattered, mostly weak, thunderstorm activity is possible across the Gulf Coast states Saturday into Saturday night. ...Discussion... Models indicate that the blocking high will generally maintain strength just to the north of Aleutians through this period. The evolution of a lower/mid-tropospheric cyclone to its east, across the northeastern Pacific, is more unclear, but guidance indicates that a downstream ridge will broaden eastward, inland of the British Columbia/Pacific Northwest coast through the southern Canadian Prairies and northern U.S. Great Plains. Farther east, it still appears that a vigorous digging short wave trough will once again contribute to larger-scale mid-level trough amplification across the Upper Midwest into Great Lakes and Ohio Valley Saturday through Saturday night. An increasingly confluent mid-level regime, in the wake of the amplifying trough, is forecast to support the southeastward development of an expanding cold surface ridge to the east of the Rockies, across much of the Great Plains and Mississippi Valley through western slopes of the Appalachians. By late Saturday night, a strengthening low-level baroclinic zone, near the leading edge of the colder air, is forecast to approach southern Mid Atlantic through Gulf coastal areas. In lower latitudes, beneath a weak branch of westerlies emanating from the subtropical eastern Pacific, a remnant preceding surface frontal zone may shift northward across the Florida Keys and southern peninsula by 12Z Sunday, downstream of broad mid-level troughing overspreading the Gulf Basin. ...Gulf Coast states... Although weak lapse rates and rather weak lower/mid-tropospheric wind fields seem likely to minimize the risk for severe weather, a substantive increase in boundary-layer moisture, in the presence of increasing large-scale forcing for ascent, may support increasing scattered thunderstorm development along the front, near the Florida Keys and southern peninsula, by late Saturday night. Elsewhere, guidance suggests that scattered thunderstorm development is possible near/offshore of lower through middle Texas coastal areas, at least early Saturday. Farther northeast, a narrow plume of elevated moisture return, off the modifying northwestern Gulf boundary layer, might contribute to weak destabilization sufficient for convection capable of producing lightning, mainly just ahead of the front as it approaches the Gulf coast late Saturday night. ..Kerr.. 12/11/2025
