Valid 2026-10-10 13:00 UTC – 2026-10-11 12:00 UTC

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN GEORGIA INTO WESTERN/SOUTHERN SOUTH CAROLINA

Thunderstorms associated with a tornado threat will be possible today from eastern Georgia into western/southern South Carolina. A few severe wind gusts may also occur in parts of the Desert Southwest.

Eastern Florida Panhandle/Georgia/Carolinas

Isaias underwent a rapid transition to a post-tropical cyclone after landfall Friday evening, with a notable baroclinic zone now in place throughout its eastern periphery. The low-level center of this system is currently over southeast AL, with a warm front extending east-northeastward from this center across central GA, central SC, and eastern NC. General expectation is for this former tropical cyclone to spend the first half of the period completing its transition to a mid-latitude cyclone over MS/AL before then progressing northeastward across the TN Valley later tonight. The surface low is expected to drift northeastward as the system matures, centering over northern AL by 00Z. As it does, its warm sector, which is characterized by low to mid 70s dewpoints, will expand northwestward into more of GA and the Carolinas. This increase in low-level moisture will support moderate buoyancy (i.e. MLCAPE around 1500 J/kg) despite widespread cloudiness and limited heating. Low-level confluence within the warm sector, augmented by modest but persistent large-scale ascent, is expected to support thunderstorm development throughout the period, particularly during the afternoon.

The stronger low to mid-level flow will be displaced west of the greater low-level moisture and associated buoyancy. Even so, southeasterly low-level flow veering to southerly in the mid/upper levels will result in moderate vertical shear and the potential for occasional organization/intensification of the predominantly multicellular structures. Several brief tornadoes could result within any of these more organized storms. Convectively augmented damaging wind gusts are possible as well. Greatest severe potential is expected along the GA/SC border vicinity between 21Z and 00Z.

Lower CO River Valley into South-Central AZ

Complex synoptic evolution is anticipated over the eastern Pacific Ocean, just upstream of southern CA and the Baja Peninsula, as Tropical Storm Rachel interacts with a compact mid-latitude cyclone. The interaction will increase the northeastward motion of the tropical cyclone, while also resulting an expanded low to mid-level wind field. Additionally, this evolution will favor advection of notable low-level moisture into the Lower CO River Valley and adjacent southern/central AZ. Overall thunderstorm coverage is expected to increase throughout the day into tonight. Deep-layer vertical shear will be stronger enough for supercells, a few of which could produce strong wind gusts. Additionally, surface low associated with the tropical cyclone is forecast to move into the Lower CO River Valley region after 06Z. Increase low-level winds and moisture will support a low-probability tornado threat.

Mosier/Wendt · 10/10/2026