After an uncharacteristically quiet Monday (weather-wise, anyway), Tuesday should feature a few more storms as a little energy aloft moves through and interacts with the afternoon seabreeze. Temperatures start in the mid-70s, warming to the upper 80s to around 90° before thunderstorms disrupt the temperature curve for some of us. Models do indicate some isolated heavy downpours, though with less in the way of deep moisture, the flooding threat shouldn’t be terribly high.
Thursday will be a fairly typical mid-August day across the area. We’ll start in the mid-to-upper 70s, warming to around 90° in the afternoon with heat indices generally running in the low to mid-100s given continued dewpoints in the mid-to-upper-70s, highest downtown and along the coast with closer proximity to the water. Once again, showers and thunderstorms should fire on the seabreeze in the afternoon, and a couple of those could be on the strong side with frequent lightning and gusty winds. Winds out of the west will drive showers and storms coastward, so keep an eye on this if you’re taking a day at the beach (you lucky duck).
After a rambunctious Monday that featured widespread showers and thunderstorms leading to flash flooding downtown as well as a lightning strike caught on camera in Mt. Pleasant, the weather will return to a more traditional summertime pattern beginning Tuesday as Charleston County heads back to class. Temperatures will start on the mild side, generally in the mid-to-upper 70s, warming to the upper 80s in the afternoon. Mix in the continued humidity, and it’ll feel closer to 98°. Scattered showers and storms should fire again in the afternoon along and ahead of the seabreeze, and yes, there is a risk of heavy rain with these storms, but the risk for flash flooding will be a bit lower especially as storm motions should be a bit faster.
With the stalled front back offshore, northeasterly winds will be back in play and turning temperatures down a bit once again starting Thursday. Expect lows in the low 70s to start the day with some broken clouds and some sunshine as well. We should see showers and storms kick off with the seabreeze in the afternoon, though, which could pack some heavy downpours as deep moisture remains in place. These storms will follow the surface northeasterly winds down the coast. Be ready for periods of heavy rain and perhaps the risk for some flooding in a few spots as well.
We remain on the cool side of normal on Tuesday, though a few more breaks in the clouds should allow temperatures to turn warmer, with highs approaching the mid-to-upper 80s in the afternoon after starting the day in the low 70s. Periods of showers and maybe a few thunderstorms will continue to be possible, though it won’t rain all the time. Some guidance suggests storms kicking off on the seabreeze later in the afternoon, which could produce some heavy downpours considering the continued feed of moisture and energy from the southwest. Severe weather is not expected, though.
The heat wave rolls on into Thursday as we continue to sit between low pressure to the west and high pressure over the Atlantic, funneling warm and humid air into the area. We once again look to get off to a very warm and humid start with lows topping out in the upper 70s inland to low 80s near the coast. Temperatures will then warm to the low-to-mid-90s in the afternoon before showers and thunderstorms kick off, cooling some spots down. Daytime heating combined with mid-to-upper-70s dewpoints will drive heat indices to around 108-112° inland and approaching 116° closer to the coast. This has prompted an Extreme Heat Warning for Charleston and southern portions of Berkeley County (Hanahan, Daniel Island) along with an expansion of the heat advisory inland to the rest of Berkeley and Dorchester counties from 11am-8pm. Get plenty of hydration and be sure to take frequent breaks indoors or in the shade if you are working outdoors during the heat of the day!
Expect showers and storms to kick off in the noon-2pm timeframe. Slow-moving storms are again expected, with the potential for training of rainfall over some of the same areas, yielding some heavy rain and perhaps a few more flood advisories. Lightning will also be prevalent once again, so be ready to head inside if thunderstorms approach. It won’t rain all day at any one spot, though.
The heat wave continues on Tuesday, but we will be getting past its peak as the high pressure ridge aloft continues to migrate westward, allowing for more shower and thunderstorm activity to develop in the afternoon. We’ll still be hot enough for a Heat Advisory, with low temperatures in the upper 70s to low 80s yielding to highs in the mid-90s. Mix in mid-to-upper-70s dewpoints and you get heat indices topping out around 110° or so before showers and thunderstorms develop. Guidance generally keeps things dry through about 1-2 PM before numerous storms kick off generally away from the coast. Widespread severe weather isn’t expected, but a couple storms could produce some strong winds, and there will be a risk for flooding if storms train. Remember, every thunderstorm is dangerous because of the lightning it produces, so be sure to head indoors if a storm threatens your area.
Sunday’s going to be a very hot day across the area, with extreme heat expected across the Charleston metro especially as we get into the afternoon. The overnight and morning really won’t offer much relief, with air temperatures in the upper 70s to low 80s for lows expected. This could keep heat indices over 90° especially closer to the coast, including downtown, for much of the night. Once the sun comes up, we’ll warm up very quickly; heat indices should be over 100° by 10-11am. Air temperatures should peak near 100° in the afternoon, and if we reach the triple digits at the airport, it’ll at least tie a record high (100°, set in 2005) as well as the first time since May 27, 2019 that the high temperature reached the century mark in Charleston. Mix in humidity and it will feel like 115° and perhaps even hotter, especially in the wake of the seabreeze as dewpoints surge behind it. The strong ridge of high pressure will put the kibosh on any thunderstorm activity, so don’t look for any relief from Mother Nature on Sunday.
Heat indices over 110° are dangerous to everyone. Make sure you’re getting any exercise in during the early hours, get plenty of fluids if you must be outdoors, and take frequent breaks.
The stationary front that’s been lingering nearby will begin to fall apart on Thursday as high pressure begins to build in, bringing storm chances down and temperatures up especially as we head into the weekend, which looks particularly hot.
