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.
Anomalously strong high pressure builds in aloft starting Friday, bringing about the hottest weather of the year. We’ll challenge record high temperatures as well as record warm low temperatures, with heat advisories and even Extreme Heat Warnings a likelihood.
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.
The story for Friday and the weekend will be the potential for dangerous heat as high pressure ridges in overhead and at the surface while dewpoints continue to run in the low-to-mid-70s, helping to keep overnight lows elevated to near record-warm levels and storm chances suppressed, worsening the risk for heat stress as a result.
Storms will be more hit-or-miss on Thursday as high pressure aloft starts to rebuild, which will heat things up for the weekend. Temperatures will start in the mid-to-upper 70s, with lows possibly not getting below 80° at the beaches. We’ll warm to the low-to-mid-90s in the afternoon, and with limited storm coverage, heat indices should have no trouble getting into the low-to-mid-100s, especially post-seabreeze.
We should see more thunderstorms on Friday as mid-level energy continues to affect the area for one more day. High pressure then ridges in aloft for the weekend, warming temperatures up and taking storm chances down a notch.
A fairly standard summer setup will take shape for Friday and the weekend as high pressure in the Atlantic ridges westward across the area, keeping temperatures warm and humid with daily storm chances. We can generally expect temperatures to start in the mid-70s each morning, with temperatures warming to the low to mid-90s each afternoon as our run of 90° days dating back to June 14 continues. Dewpoints ahead of the seabreeze will mix out with some drier air aloft to keep heat indices from getting too far out of hand, with apparent temperatures running just 3 or 4° warmer than air temperatures. Still, if you have vulnerability to the heat, be mindful of too much strenuous activity during the afternoons.
We should see isolated to scattered showers and thunderstorms fire along and ahead of the seabreeze each afternoon. The risk for severe weather is very low, but there’s always the risk for a storm or two to briefly turn strong to severe especially where thunderstorm outflow boundaries collide. Remember, all thunderstorms are dangerous because of the lightning they produce. When thunder roars, go indoors!
The high heat of the past couple days — we hit 98° again on Wednesday, just one degree off the record high — will let up on Thursday as high pressure aloft continues to weaken. Don’t misunderstand: it’ll still be plenty hot, but not to the Advisory-level thresholds we’ve hit recently. After a start in the mid-70s, likely in the wake of thunderstorms that are expected late tonight into early Thursday morning, temperatures in the afternoon warm to the low 90s. Dewpoints will mix down to around 70°, so heat indices should stay relatively tame, with a brief spike into the upper 90s possible as the seabreeze pushes inland. A few showers and thunderstorms could pop on the seabreeze, as is often the case this time of year, but nothing out-of-bounds is expected.
As we reach the summer solstice late Friday night (10:20 PM, to be exact), the weather will be seasonally appropriate. We can generally expect temperature in the low to mid-90s each afternoon after muggy starts in the mid-70s. Showers and thunderstorms will be possible particularly Friday and Saturday afternoons along and ahead of the seabreeze, though updrafts will struggle against high pressure building in aloft. In fact, we should generally see a lid on things for Sunday, making for a mostly sunny day. Heat indices will still run in the upper 90s to around 100°, so be sure you’re getting plenty of water and rest if you’re working or playing outside.
More heat and humidity are on tap for Thursday, but with a slightly better chance of storms in the afternoon especially as a front gets closer to the area. We’ll start the day in the mid-70s once again, warming back to the mid-90s in the afternoon. We’ll be keeping an eye on a line of thunderstorms to our northwest, which could help induce some stronger storms in the metro later in the afternoon through the evening hours. Damaging wind gusts would be the primary concern in the strongest storms, though the risk for severe weather is generally low (but not zero) across the area.
