High pressure wedging in from the northeast made for a much cooler day on Wednesday — the high only reached 77°, the coolest high since 76° on May 31 — and we’ll keep that going into Thursday. Winds kick up a bit more Thursday as low pressure begins to spin up offshore, tightening the pressure gradient across the area. There could be some showers within the wedge at any point during the day, but nothing too out of control by any stretch. The main hazards will be a risk for coastal flooding at times of high tide. The 6:40am high tide could touch 7′ MLLW, producing some minor flooding in the most vulnerable locations. The evening high tide, which peaks around 7:10 PM, will run more than a half-foot higher, with moderate coastal flooding expected. Be ready for road closures downtown during the second half of the commute.
Low pressure aloft will drift northward into our neck of the woods on Tuesday, which should help kick up a little more in the way of showers and thunderstorms, especially in the afternoon and evening. It’ll be another warm and muggy start, with lows in the low to mid-70s across the area to start the day. Some guidance suggests storms appear possible near the coast to start the day, moving inland with time as the seabreeze pushes inland. The main concerns will be the potential for isolated flooding due to heavy rain from slow-moving storms and the risk for storms to produce strong wind gusts.
Another warm mid-September day lies ahead for Thursday as high pressure remains the dominant weather feature at the surface and aloft. We’ll get off to another pleasant start with lows in the upper 60s warming to the upper 80s in the afternoon with dewpoints in the mid-to-upper 60s away from the coast, where dewpoints will settle in the 70-72° range. Dry air in the atmospheric column will make for mostly sunny skies, with just a few passing clouds expected.
A front coming through on Tuesday will knock temperatures back from the record levels of the past two days, bringing some breezy conditions and maybe some coastal flooding in the process. We start the day in similar fashion to the past couple days, with lows in the mid-70s expected. High pressure building south will swing winds around to the east and northeast in the morning, turning things gusty in the process (especially at the coast). This wind may also help drive tidal departures higher, perhaps causing some minor coastal flooding with the midday high tide. Widespread flooding issues are not expected, though. We will see dewpoints begin to drop during the afternoon with highs peaking just in the upper 80s, right around mid-September normals.
Late-summer heat and humidity continues to build as temperatures look to return to the 90s for Thursday after a balmy start in the mid-70s. We should see a bit more in the way of afternoon showers and thunderstorms on the seabreeze with high pressure beginning to weaken, though not everyone will see rain, either. A few pockets of heavy rain will be possible with moderate instability and precipitable water values (generally the amount of water you could wring out of a column of air) a little over 2″.
There may be one more round of salt water flooding with Thursday evening’s high tide around 8:18 PM, but it’ll be on the minor side with water levels peaking in the 7-7.2′ range. Rain shouldn’t be an issue as the seabreeze will be well inland by that point, though. From here, we should see diminishing astronomical influences and less of a chance for coastal flooding, though there remains an outside shot on Friday coincident with the full moon.
Thursday looks to generally be a repeat of Wednesday (weather-wise, anyway). We’ll start the day in the mid-70s once again, warming to the low 90s in the afternoon. Mid-70s dewpoints will help drive the heat index into the upper 90s to around 100° — not quite August, but getting long in the tooth. The day should be primarily quiet with partly cloudy skies expected, though like we saw roll through Moncks Corner on Wednesday, a stray shower can’t be totally ruled out.
The first day of September marks the beginning of climatological fall, but it certainly won’t feel that way with a stretch of 90s coming up. Tuesday starts this streak, with highs expected in the low 90s after a low-to-mid-70s start. Ridging aloft will continue to build over the area, and that should suppress much in the way of shower and thunderstorm development in the afternoon, though a stray popup isn’t out of the question.
Thursday’s weather setup will be similar to what we saw on Wednesday with scattered to numerous thunderstorms affecting some spots while the sun peeks out elsewhere. Temperatures will start in the low to mid-70s once again, warming to around 90° in the afternoon — just a smidge above normal for late August. The severe weather risk is low, but once again, a storm or two could produce gusty winds. There is also the risk for flooding given slow storm motions and potential training of rain across the same spots, so stay alert as you get out and about tomorrow.
Tuesday will be a lot like Monday was, it looks like, with lows in the mid-70s yielding to highs in the low 90s in the afternoon. With the persisting stationary front to our west and the afternoon seabreeze, we can expect generally scattered thunderstorms to develop once again in the afternoon. Not everyone will see a storm, but those that do could see heavy downpours and even some severe weather, with damaging wind gusts the main concern.
Another hot day lies ahead on Thursday, but we do have some changes coming that will turn conditions a little more unsettled, which in turn will start to take the edge off this heat some.
That being said, Thursday will mark the ninth consecutive day of heat headlines of some sort, whether it be a Heat Advisory or an Extreme Heat Warning, and it’s getting very difficult to find new ways to tell you it’s going to be hot. We start Thursday in the upper 70s to low 80s once again, with air temperatures in the afternoon peaking in the mid-90s. Heat indices will once again peak between 108-112° — not as bad as it has been, but still pretty gnarly — and that’s prompted the aforementioned heat advisory for Charleston and Berkeley counties. (Looks like we’ll fall short of heat advisory criteria in Dorchester County, but it will still be quite hot to the point where you’ll want to monitor for heat illness if outdoors for an extended period.) A few of us should see some isolated to scattered thunderstorms in the afternoon along and ahead of the seabreeze. There’s not much shear and storm motions will be slow, so heavy rain will continue to be a concern, and with plenty of instability available, storms could produce frequent lightning and gusty winds in downbursts. Be ready for conditions to change on a dime if out and about.
