Our weather is about to turn unsettled for a few days. That's good because most of the state has been dry lately, and the severe thunderstorm risk will remain low. Most of the Lowcountry and the Grand Strand had plentiful rainfall over the last month, but those are the only exceptions.
This loop of visible satellite images (GOES-East Band 2) shows clouds associated with upper-level disturbances to our west, stretching back into Texas.
Imagery source: University of Wisconsin RealEarth
Through the rest of today and tonight, the first in a series of upper-level disturbances will move in, which will cause a scattering of showers and thunderstorms, mainly over the Upstate and Central Savannah River area. This activity will diminish this evening as it reaches the I-77 Corridor.
Another upper-level trough will move in toward daybreak on Saturday. This feature will be more robust and cause showers and thunderstorms across the Upstate all day, with mainly afternoon activity over the rest of the state. The severe storm risk will be minimal on Saturday. Highs will range from the middle 70s over the Upstate to the low 80s over the rest of the state.
We'll be between upper disturbances on Sunday, resulting in a less active and warmer day. However, we remain in a warm and muggy air mass, and a scattering of showers will pop up during the afternoon. A few places could see a thunderstorm. Highs will mainly be in the lower to middle 80s.
The last in the series of upper disturbances will pass through our area on Monday, so that will be a more unsettled day. Right now, it looks like the timing of this feature will bring showers and thunderstorms to the Upstate all day, while the rest of the state sees mainly afternoon and evening thunderstorms. That results in highs only near 80 in the Upstate but low to middle 80s over the rest of the state. While the severe storm threat will remain low, Monday will bring the best chance for isolated severe storms, especially along the Coastal Plain.
Rainfall through Monday will be concentrated over the Upstate, where it's needed most, and the least will fall over the Lowcountry, where it's not needed. That's just how I'd draw this play up if I were coaching the weather.
A plot of percent-of-normal rainfall over South Carolina over the last 30 days ending at 8 a.m. EDT Thursday.
Image Source: WeatherBELL
A plot of rainfall from 11 a.m. EDT Friday through 8 a.m. EDT Tuesday from the National Blend of Models. The usual caveat applies; this is model output and not an official forecast, but it gives a general idea of where the heaviest rainfall will occur.
Source: WeatherBELL
After Monday, the jet stream will shift northward for 2-3 days and take active weather northward with it. The downside of this will be that a bubble of hot air will build over Texas and the lower Mississippi Valley in the coming days, and this heat will get shunted into South Carolina starting around the middle of next week. Tuesday will feature a transition; it will be a warmer day with showers confined to the Coastal Plain, where the sea breeze can act as a trigger. Then Wednesday and Thursday look summery, with highs ranging from the upper 80s in the Upstate to the lower and middle 90s over the Midlands and Coastal Plain. Those days look mainly rain-free.
A cold front will move in later next week, but the timing is uncertain. The current best bet is for the front to move through next Friday. However, the front may move slower than expected and arrive later. It may move slowly enough that we're still dealing with unsettled weather into next Saturday. The most likely scenario is for the front to trigger a round of thunderstorms, and there might be severe storms to deal with. Cooler air will return next weekend behind this front.
It's only fitting that the first hot spell of the year appears in the forecast during our Heat Safety Week. You may think it's strange that we're doing this; after all, this is South Carolina, and intense heat is something we're known for. Well, there are two reasons to take a minute and think about dealing with our summertime heat. First, we have a lot of newcomers to the state who may not be well-acclimated to our simmering heat and humidity. Second, despite hot weather being the norm here from May to September, we still see some of our citizens succumb to heat-related illnesses each year. Often, complacency is to blame. So, please take a moment to check yourself before spending time out in the heat. Also, if you are out with children and pets, take a few seconds to check and make sure nobody gets left behind in a hot car. Always check the back seat! With Angry Sun beating down on your car, it doesn't have to be all that hot outside for your car to become an oven.
