SUMMARY…Risk for damaging wind gusts may continue another several hours with convection spreading into the southern Appalachians. An isolated tornado may still not be out of the question, but this risk seems to be in the process of diminishing.
DISCUSSION…The most vigorous convection is generally east of the mid-level trough axis, on the southern periphery of the stronger height falls, and near the nose of the plume of weakly unstable boundary layer air supported by upper 60s/near 70s surface dew points. As the upper forcing shifts northeastward through daybreak, large-scale ascent supporting this activity will gradually weaken. Despite the likelihood of at least some further low-level moistening ahead of the convection as it spreads across the southern portion of the Cumberland Plateau into the Smoky Mountains through 09-11Z, models suggest that destabilization will be weak, and it remains unclear whether this will be surface-based. Any residual near surface stable layer should mitigate the risk for tornadoes, but stronger convection could still locally aid the downward transfer of higher momentum (associated with 50+ kt 850 mb flow) to the surface, contributing to potentially damaging surface gusts. However, the intensity of the convection seems likely to diminish as advances into/across the southern Appalachians.
