In the coming days, we'll have another robust cold front pushing farther south than usual for this time of year, reaching South Carolina and becoming stationary. Upper-level disturbances drifting through will work with the surface front to produce rounds of thunderstorms each day, at least through the first part of next week, with the potential for severe storms each day.
Starting with this afternoon, the plume of tropical moisture that brought us rain Wednesday remains over our Coastal Plain, so that's where our thunderstorm activity will be focused. We don't have a great setup for severe weather this afternoon as winds aloft are relatively weak, and we don't have much wind shear present. However, it will get unstable enough that the severe storm risk near our coast is non-zero. The Storm Prediction Center (SPC) outlook for today does not have any part of the Palmetto State in a severe storm risk area; we're only covered by a general thunderstorm area. So, only the strongest storms that we see pop up this afternoon would be capable of causing any damage, with very isolated damaging winds being the only mentionable threat, other than the usual downpours and lightning hazards that you see with all thunderstorms.
Our next cold front will approach Friday. Southwesterly winds ahead of it will push the tropical moisture away, and we'll see more sunshine than we're getting today. That will send our temperatures into the upper 80s and lower 90s, making it a summery day. However, the front will be over the southern Plains, middle Mississippi Valley, and Ohio Valley during the afternoon and evening. So, that's where the primary area of severe weather will be Friday into Friday night. A few intense storms could pop over the mountains during the afternoon and drift into the Upstate, and some leftovers from the activity further west may bring a second round of gusty storms later Friday night. With the activity centered to our northwest Friday into Friday night, SPC's outlook has only the Upstate and adjacent areas in the lowest level of severe storm risk for the period, and the risk is for isolated damaging winds with stronger storms.
On Saturday, the cold front will likely reach us toward the end of the day, which will increase our risk for severe storms. Storms likely erupt over the southern Appalachians and push southeastward during the late afternoon and evening, with temperatures again shooting up into the upper 80s and lower 90s ... perhaps middle 90s in the usual hot spots (some famously so).
I'll have to go on a brief tangent here; it will also be rather muggy so that the heat index will reach the middle to upper 90s Saturday afternoon. You'll have to exercise caution if working or playing out in the afternoon heat.
The heat and humidity will fuel thunderstorms, which will primarily bring a risk of locally damaging wind. The hail risk appears to be minimal, and while I never want to say never to an isolated tornado with intense thunderstorms, the tornado risk looks to be near zero on Saturday. The Storm Prediction Center has nearly all of South Carolina in a level 2 of 5 severe storm risk area on Saturday; the remaining bit is in a level 1 risk area.
The storms reaching the Upstate later in the day will march through during the afternoon and into the night and may not push offshore until after midnight.
The front will remain over us or nearby on Sunday while another disturbance moves in from the northwest, so another round of thunderstorms appears likely that day. Timing becomes more of a question at this range, but it looks like we'll see storms fire up near the I-20 Corridor during the afternoon and move across the Coastal Plain through the evening. Once again, we expect the primary risk to be locally damaging wind, with the hail and tornado threats both very low. SPC's outlook for Sunday mainly includes the Coastal Plain in its 15% severe storm risk area, which corresponds to the level 2 'slight' risk area on their outlooks for Days 1-3.
Looking ahead to Monday and Tuesday, we will keep the stationary front over the area for those days, and more upper-level disturbances will push through to cause additional rounds of thunderstorms. The severe storm risk will depend on the timing of those upper-level disturbances. Should they move through during the afternoon and evening when the atmosphere is warmest and most unstable, some of the storms will be severe with locally damaging wind. Otherwise, we'll only see a few severe storms, if any. Currently, SPC does not have any part of our state in a risk area for Monday or beyond, but this could change in time.
At least with good chances for rain from thunderstorms each day, we should continue to chip away at the remaining drought areas along our coast. Hopefully, in another week or two, we will be free of drought in South Carolina.
