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.
Much of the weather scuttlebutt this week will be about Tropical Storm Idalia, which increasingly looks like it’s going to have impacts on the area Wednesday into Thursday. We have a couple reasonably quiet days ahead before the weather begins to head downhill later Tuesday night. Expect highs on Monday to top out in the low 90s with just a slight chance of an afternoon shower or thunderstorm along the seabreeze; it’ll be a similar story for a good bit of Tuesday before moisture from Idalia potentially triggers a predecessor rain event along and ahead of a stalled front, which could bring very heavy rain to some spots and maybe even some flooding ahead of the storm’s arrival.
Sunday will be yet another warm and muggy late-August day across the Lowcountry. We’ll start the day in the mid-to-upper 70s before highs head to the low 90s in the afternoon. Heat indices should peak in the low 100s. From there, we should see a scattering of showers and thunderstorms along and ahead of the seabreeze. We may also see some activity from the north near a stalling cold front trying to infiltrate the area as well. The strongest storms will be capable of heavy rain and gusty winds, though widespread severe weather is far from in the cards. Overall, no washout of a day, just be ready to move outdoor activities inside if storms approach.
Saturday will be the peak of this stretch of hot weather as temperatures head to the mid-90s in the afternoon (though not quite as high as forecast earlier this week…good thing, too). Heat indices will get close to 109-110° in the afternoon. There’s no heat advisory as of this writing, and if trends continue, we’ll probably fall just short of criteria. Still, these kinds of heat indices still increase the risk for heat illness, so be getting plenty of water if you’re going to be exerting yourself outside in the afternoon. We should see a few storms fire along the seabreeze in the afternoon, which will bring some relief to a few of y’all.
More widespread showers and storms are expected Sunday (though not a complete washout, either) as a front sags southward and stalls out nearby. It’ll be another warm and humid day with air temperatures topping out in the low 90s and heat indices 100-103° before thunderstorms fire off and cool things down somewhat. The unsettled weather will continue into next week as the front hangs around and plays a big role in our weather.
Alas, Friday and the weekend will bring us back to reality a little bit after a couple fairly nice days for late August. Highs on Friday top back out in the mid-90s under mostly sunny skies as ridging holds on tight for at least one more day, suppressing afternoon thunderstorm chances (and, as such, any chance for relief). Heat indices look to peak around 102° or so — not quite advisory level, but not exactly pumpkin spice weather, either.
Saturday will be even hotter, as air temperatures head up into the upper 90s. Combine this with solidly mid-70s dewpoints and that’ll yield heat indices approaching the heat advisory threshold of 110°. As ridging aloft begins to weaken, the seabreeze may have a slightly easier time popping a storm or two, though coverage will continue to be primarily isolated in nature.
Storm chances tick up fairly decently for Sunday afternoon and evening as a front approaches the area and a trough sets in aloft. It’ll still be hot — expect mid-90s highs before storms kick in — and heat indices could still head north of the 105° danger zone (but should remain shy of advisory thresholds). This will usher in a more active period heading into next week, with rain chances becoming more likely as the aforementioned front stalls and hangs around for a few days.
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.
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.
We have a generally quiet week on tap as high pressure is the dominant weather player across the central and eastern US. It’s going to be warm, especially to start the week as dewpoints in the low-to-mid-70s combine with air temperatures in the mid-90s to yield heat indices around 102° on Monday and 105°+ on Tuesday under partly cloudy skies. A front might allow for a couple storms Wednesday before quiet weather resumes to close out the work week. It’ll be a little “cooler” and drier behind the front — dewpoints in the upper 60s to around 70° and air temperatures in the low 90s will still run above normal, but heat indices should remain in check as drier air mixes down and limits cloud cover. Isolated storm chances return Saturday afternoon, with a better chance of storms on Sunday as another front approaches the area.
Sunday’s forecast looks fairly similar to Saturday’s: We’ll start the day in the mid-70s and head toward around 90° in the afternoon under partly cloudy skies. Heat indices will top out around 100-101°, with perhaps locally higher values closer to the coast. A scattering of showers and thunderstorms will once again be possible as the seabreeze presses inland, with heavy rain a continued concern with decent low-level moisture still in place. Ridging developing aloft will keep a lid on widespread coverage of showers and storms.
After what ended up being quite a hot weekend, we have a day or two more of advisory-level heat (maybe even warning-level heat in a few spots) before a front moves into the area and brings some more unsettled weather for a few days.
