A line of strong thunderstorms could bring damaging winds and even a few tornadoes to the Midlands and Lowcountry Thursday as a powerful cold front moves through the Palmetto State.
Surface analysis Wednesday afternoon depicts a large low pressure area centered in the eastern Dakotas with a secondary low moving through the mid-Mississippi River Valley. Stretching east from the southern low is a warm front that reaches the South Carolina-Georgia border near Savannah. South of this feature, dew points in the Florida Panhandle are in the middle and upper 60s. The warm front is forecast to lift northward overnight Wednesday into Thursday, bringing warm and unstable air to South Carolina ahead of the passage of a cold front. The increase in atmospheric moisture in conjunction with a strong cold front providing ample lift will result in a broken line of strong and severe thunderstorms across the eastern half of the state.
High-resolution weather models indicate the most instability will be found along and east of a line from Augusta, to Columbia, to Darlington. Widespread rain and a few embedded stronger cells are possible early Thursday morning, but daytime heating will result in more substantial convection developing by midday Thursday. The risk of severe weather will stick around through early Thursday evening until the cold front slides across the state, pushing thunderstorm activity offshore by midnight Friday.
The Storm Prediction Center has a "marginal" and "slight" risk for severe weather in portions of the Midlands and Lowcountry. These classifications represent a 1 and a 2 on a severe weather scale of 1-to-5 respectively and mean that a few widely scattered severe thunderstorms are possible. Unlike Wednesday's extremely volatile environment along the Gulf Coast, the severe weather setup will not likely be as supportive for large and numerous tornadoes. Nonetheless, the upper-level wind pattern will support the risk of a few rotating supercells capable of producing tornadoes. Aside from the tornado risk, damaging winds gusts of up to 70 miles per hour will also be possible.
There is the potential for watches and warnings to be issued Thursday. If a watch is issued, it means that the ingredients for severe weather or tornadoes are present in the atmosphere. Watches are typically issued before the weather turns severe and tend to cover a fairly large geographic area for several hours. A warning on the other hand is issued when severe weather is ongoing for a specific location and is typically on a smaller geographic scale, typically covering only a few counties at a time. Warnings generally last an hour or less in any given location. Residents are encouraged to have multiple ways to receive severe weather alerts and to keep a close eye on the forecast over the next 24 hours.