Another extremely hot day is on tap for Tuesday as temperatures take what should be one last shot at the 100° mark before sanity begins a slow return to the forecast. We’ll start the day near 80° inland of the coast, and we’re almost assuredly not getting below 80° at the coast and in downtown Charleston. From there, temperatures will soar into the upper 90s to near 100°, with the best risk of reaching the 100° mark inland of Highway 17. And then there are the dewpoints running in the mid-to-upper 70s, which will propel heat indices well into the mid-110s for many of us, with a few readings getting uncomfortably close to 120° in more rural spots. For the first time in this heat wave, an Extreme Heat Warning is in effect for the entire Tri-County, including Dorchester; to this point, we’ve only seen those warnings come out for Berkeley and Charleston. Continue to heed precautions for extreme heat: air conditioning if at all possible, but frequent breaks in the shade with water if you must be outdoors.

There will be a slightly better chance of thunderstorms Tuesday afternoon than we saw on Monday, which will cool some of us off. The price for this, though, is an elevated risk for strong and potentially damaging wind gusts, excessive lightning, and very heavy — perhaps flooding — rain in a few spots. Instability will be running on the high end of what we usually see around these parts, so any storm that can take advantage could take off like a rocket. The good news is that without much shear, storms will generally pop, rain for a while, and then collapse.

We have a few more days to go in the most dangerous part of this heat wave before the pattern finally begins to dislodge, allowing temperatures to trend back toward — but remain above — normal for mid-August.

Extreme Heat Warnings look to take a break on Sunday, but that is little solace with heat indices expected to continue to peak into the lower 110s in the afternoon, well into Heat Advisory criteria. Scattered showers and thunderstorms should develop again in the afternoon along the seabreeze, and a few of those could be on the strong side given plenty of instability once again. We’ll also see a risk for flooding, especially where storms train in the same areas, courtesy of a well-saturated atmosphere. Be ready for conditions to change quickly, particularly after 3-4 PM.

Dangerous heat will continue to be the main weather story as we head into Friday and the weekend, with an isolated to scattered afternoon thunderstorm the only real shot at bringing about any reprieve.

We’ll take the heat up a notch for Thursday as even hotter air temperatures in the upper 90s — perhaps approaching 100° in a few spots — combine with dewpoints in the mid-to-upper 70s to produce heat indices pushing 110-113°. This potential has prompted an Extreme Heat Warning for Charleston and tidal Berkeley counties (Daniel Island, Hanahan) from 11am-8pm. Elsewhere in Berkeley and Dorchester counties, a Heat Advisory will be in effect for the same time period. In these areas, heat indices should peak in the 108-110° range — still quite dangerous, but not nearly as intense as what folks will see closer to the coast, where the moisture-rich maritime air will make it that much harder for your body to cool down. If you must be outside during the advisory/warning period tomorrow, take frequent breaks in the shade with plenty of water.

There will be a risk for a few showers and thunderstorms in the afternoon as some energy ripples by aloft, riding around the periphery of a strong ridge of high pressure centered in the midsection of the continental US. If storms can get going, a stray strong storm or two won’t be out of the question given plenty of moisture to work with. However, don’t count on a thunderstorm to impart much, if any, relief from the extreme heat.

The weather story for the rest of the work week will be the intensifying heat wave across the area as high pressure building in aloft continues to strengthen, while southwesterly winds continue to pump in high-dewpoint air that will send heat indices over 110° in spots.

It’s a very toasty start to the school year for Charleston County on Tuesday as this week’s heat wave will begin in earnest as high pressure aloft takes hold. We’ll start the day on a very mild note, with lows in the mid-to-upper 70s warming to the mid-90s in the afternoon. Dewpoints will run in the low-to-mid-70s inland, while closer to the coast, they’ll run in the upper 70s. That will help drive heat indices solidly into the 100s, with the highest heat indices expected in the Highway 17 corridor and points east. A Heat Advisory will be in effect for Charleston County and the southern part of Berkeley County from 11am-8pm, when heat indices should exceed 108° and could top out near 111° as the seabreeze pushes by. The aforementioned high pressure will make it much harder for thunderstorms to develop, though a couple popup showers will be possible. With that in mind, though, don’t count on thunderstorms to impart any relief from the heat.

The main weather story this week will be the return of heat that will be reminiscent of what we experienced earlier in July, with another round of dangerous heat indices pushing 110-115° at times.

Overall, unsettled weather will continue over the weekend, though as is often the case in the summer, your plans won’t be completely washed out, either.

Showers and thunderstorms will remain in the forecast as we head into Friday and the weekend, with the best rain chances on Saturday as a slug of moisture moves ashore.