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.
Not too much to write home about in the weather department for the rest of the work week — just more in the way of heat, humidity, and a slight uptick in showers and storms as we head toward Friday.
Air temperature-wise, Wednesday will be the warmest day of the rest of the work week with highs topping out in the mid-90s. However, drier mid-level air will mix down to the surface during the heat of the day, and this will help keep heat indices around 100-101°. (Not great, but it could be worse.) The aforementioned dry mid-levels should keep most, if not all, shower and storm activity at bay, though you can never truly rule any stray shower or storm out during this point of the year.
Moisture starts to return Thursday, and this manifests itself with a little higher heat index in the afternoon — approaching 105° — and a slightly better (but still low) chance of seabreeze thunderstorms. Friday could see a little better coverage of afternoon thunderstorms as heat indices top out over 105° at peak heating. (Remember, heat advisory criteria for July 1 and beyond is 110° for two hours.) Overall, there’s nothing in this forecast that’s terribly out of bounds for this point in the year — just mind the heat and be ready to head inside if a thunderstorm gets close.
Tuesday’s forecast looks relatively benign across the area as partly cloudy skies dominate thanks to increasingly drier air aloft. We’ll start the day in the low 70s away from the coast before highs top out in the low-to-mid-90s in the afternoon. Heat indices should top out in the low 100s with low-70s dewpoints across the area. A shower or storm can’t be ruled out along the seabreeze, but most of us should get Tuesday in rain-free.
We’ll continue this hot stretch of weather as we get into Wednesday and through the rest of the work week. Expect highs in the mid-to-upper 90s each afternoon with heat indices peaking around 105-110° each day in many spots, with perhaps even higher heat indices closer to the coast where the higher-dewpoint air will be found. Lows won’t offer much in the way of relief — generally expect just upper 70s across much of the metro, with temperatures not going below 80° downtown and at the beaches over the next few days. With drier air aloft, it’ll be hard to get much in the way of thunderstorms to fire along the pinned seabreeze, and they likely won’t be deep enough to really overturn the atmosphere much, possibly leaving even muggier conditions behind them.
Wildfire smoke will once again cloud the sky a little bit on Wednesday, but not quite to the degree that we saw on Tuesday. The air quality forecast is on the lower side of code yellow for Wednesday, but that seems to be primarily due to ozone. As always, we’ll keep an eye on this in case smoke mixes down a little more than expected.
Troughing digs back in across the area over the weekend, which will send temperatures downward and bring rain chances upward, breaking this mini-heat wave. (You either get the heat or storms this time of year — not really a third option!)
We begin a rather hot stretch of weather — yes, even warmer than we’ve been — starting Tuesday as ridging builds aloft. Downslope flow from the northwest will act to warm the air as it sinks as well as help to keep the seabreeze pinned closer to the coast, which will help drive air temperatures well into the mid-to-upper 90s across the area after an already warm start in the upper 70s to around 80° at the coast. Mix in humidity and you’ll find heat indices across the area ranging from about 105-110° during the height of the afternoon. We’ll be in this heat index “danger zone” for a few days, so be sure to take it easy if you have to be outdoors during this time, and get lots and lots of water.
As the ridge builds aloft, this will also help to put a lid on afternoon thunderstorms for the most part; a shower or storm can’t be totally ruled out, but don’t count on one for any sort of heat relief.
Finally, Canadian wildfire smoke will add a milky haze to the overall sky composition. Upstream observations suggest that there could be some minor air quality impacts, but so far no major issues are anticipated. Stay tuned, though.