The forecast for the rest of the work week is generally on track: Temperatures in the mid-90s will continue through Thursday with peak heat indices around 100° thanks to some, but not too much, humidity. Skies will generally run partly cloudy to mostly sunny. Storm chances don’t return to the picture until Friday, and even then, it looks like coverage will be more on the isolated side. The weaker ridge will keep temperatures running a little lower (low 90s) on Friday, but above-normal temperatures look to continue heading into the weekend despite steadily increasing storm chances as a front arrives and stalls out nearby. (Remember, normal is looking a little lower these days: normal highs for this week generally run around 87°.)
Plenty of sunshine is in the offing for the rest of the work week as high pressure remains the primary driving force for our weather. Temperatures climbed back into the low 90s on Labor Day, and this will continue as we head into the rest of the week, with mid-90s expected by mid-week. Dewpoints in the mid-60s will keep heat indices in the mid-90s on Tuesday, but as dewpoints creep up throughout the week, so it shall be with the heat index as well. Feels-like temperatures will be flirting with 100° again starting Wednesday through the rest of the week.
There’s not much in the way of rainfall to report on for much of the week with high pressure in control, but we start to see some cracks in the armor on Friday as a few storms should pop on the seabreeze, with slightly better coverage of showers and storms each afternoon this weekend.
Tuesday will be another warm and muggy day as we prepare for Idalia’s arrival in the Lowcountry. We start the day in the mid-70s and warm to around 90° with heat indices approaching 100° within the increasingly tropical airmass. Showers and thunderstorms should begin to fire along the seabreeze in the afternoon and become somewhat numerous at times. Heavy rain capable of minor flooding will be possible. We’ll also need to watch the risk for coastal flooding in the evening, with minor to moderate flooding possible as water levels approaching 7.5′ with the 7:31 PM high tide. Due to the Storm Surge Watch in effect, there will be no Coastal Flood Advisory, so keep that in mind.
The air on Wednesday evening is fairly glorious — dewpoints in the mid-60s behind the seabreeze, with even some 50s dewpoints ahead of it — thanks to a cold front that pushed through earlier in the day. We’ll keep some of this dry air around for Thursday, which will keep the high of 92° feeling closer to 93-94°. We’ll see a few clouds across the area, but otherwise, it’ll be another reasonably pleasant late-August day.
After another very warm day Tuesday, a cold front will get through the area overnight and into early Wednesday, bringing an all-too-brief round of much drier air to the area. (A few showers are possible too.) We start the day in the mid-70s, but as the somewhat cooler and drier air moves in, we’ll find highs will top out generally in the upper 80s. Lower dewpoints, though, are what will make upper 80s to around 90° much more tolerable. We should see dewpoints mix down to the low 60s for the first time since June. Heat index won’t be a factor, and it should overall be a comparatively nice afternoon to do some things outside for a change.
Tuesday will be another rather warm day across the Lowcountry. After we topped out at 95° on Monday, temperatures should head a little higher on Tuesday, back into the mid-90s once again under partly cloudy skies. Peak heat indices will range from near 105° inland to around 108° closer to the coast where the higher-dewpoint air will be found. This is in the range where heat illness becomes an escalated concern, so be sure to take the normal heat precautions if you’re out and about Tuesday afternoon. Showers and thunderstorms are unlikely given ridging aloft, but a stray shower can never be totally ruled out.
A stalling front and deep moisture will keep showers and thunderstorms figuring prominently in the forecast for the next couple days, bringing an end to this string of excessive heat (though it’ll still be plenty warm before storms get going). Wednesday could feature a scattering of storms at any point during the day, but the best chances will be found in the afternoon as daytime heating gets going. Some spots may see some heavy rain given deep moisture and occasionally lackadaisical storm motions. Keep an ear out for flood advisories.
Thursday looks rather similar, though we should start to see the deeper moisture get shunted away from the area late in the day. Temperatures once again start in the mid-70s before peaking around 90-91° ahead of another round of showers and thunderstorms developing across the area. Once again, the main threat is heavy rain, but a couple storms still could produce some gusty winds.
The front falls apart Friday as high pressure begins to ridge back in, and that will drive storm chances down and temperatures back up into the mid-90s. Despite generally southwesterly winds at the surface, dewpoints should mix down into the upper 60s to around 70° around peak heating, keeping the heat index at least a little in check. An isolated shower or storm will be possible on the seabreeze, but much of us get Friday in rain-free.
We have one more day of Heat Advisory-level warmth on Tuesday before a front starts to usher in changes later in the day in the way of showers and thunderstorms. First, though, we start the day in the upper 70s to around 80° in the morning before highs head back into the mid-90s in the afternoon. Mid-70s dewpoints will yield heat indices around 110° for at least a couple hours. From there, showers and thunderstorms should develop in the afternoon, with more widespread coverage arriving late afternoon and evening as the front gets closer. A few storms could be on the strong to severe side with damaging wind gusts the main concern. Otherwise, heavy rain and frequent lightning are the other main concerns.
We look to get a break from the rain on Wednesday as some slightly drier air works into the area for a spell. It’ll still be plenty hot, though — lows start in the mid-70s away from the warmer coastline to head to the mid-90s in the afternoon as persistent westerly winds delay the seabreeze once again. Expect heat indices in the upper 90s to around 100° with dewpoints suppressed to the upper 60s.
From there, moisture returns to the area and our thunderstorm chances respond in kind as disturbances swing through the trough aloft. There’s a small chance we could deal with a thunderstorm complex in the morning before more thunderstorms fire later Thursday toward peak heating. So it shall be on Friday as well, with a slightly better chance of storms in the afternoon given slightly richer surface dewpoints. A few storms could be on the strong to severe side with damaging wind gusts the main concern. Temperature-wise, expect highs to top out in the mid-90s each day after starting out in the upper 70s. Heat indices will head north of 105° again and could creep toward 110°, so be ready to take heat safety precautions during the afternoons before thunderstorms get going.
After the fourth-warmest July on record at North Charleston, we catch a bit of a break from the high heat as we get over the hump into the rest of the work week as highs only look to get into the mid-to-upper 80s through Friday. The drier air will be quite noticeable especially Wednesday and Thursday mornings as lows look to dip into the low 70s. The drier air will also act to keep shower and thunderstorm chances to a minimum Wednesday and Thursday, with maybe a popup or two on the inland-moving seabreeze in the afternoons.
Rain chances head back up on Friday as high pressure weakens and moisture surges back into the area. We’ll likely see off and on showers and storms break out with just a little sunshine, continuing throughout the day. Some very heavy rain will be possible at times, and we’ll need to watch for the risk for flooding in a few spots with fairly slow storm motions expected.
Finally, onshore flow with the recent full moon will continue to drive tides into flood stage over the next couple nights. The water level peaked at 7.93′ at 8:48 PM on Tuesday evening, and water levels between 7.6-7.8′ look probable for Wednesday evening. Expect road closures downtown as a result. Keep an ear out for Coastal Flood Advisories from the National Weather Service.
