Overall, the weekend forecast is looking solid for doing stuff outside. Expect comfortable starts in the mid-60s (warmer at the beaches), more than ample sunshine (especially Sunday), and warm afternoons with high pressure in control. Saturday looks to be the warmest day of the set with highs topping out around 85° in the afternoon. A reinforcing round of slightly cooler air moves in for Sunday, and that will help cap highs in the low 80s.
After a fairly cool and cloudy day on Thursday, cloud cover breaks up a bit for Friday into the weekend, and this will allow temperatures to return to the low to mid-80s each afternoon. Temperatures will peak Saturday before a little cooler air works into the area Sunday. Overall, it looks pretty good to get out and do stuff, especially with the northeasterly winds backing off a bit more as the pressure gradient relaxes.
Rain will generally be a non-factor in our weather starting Thursday (except for maybe some brushes near the coast) heading into Friday and the rest of the weekend. We start the day around 65° with some cloud cover in the area. A northeasterly breeze courtesy of high pressure wedging into the area from the northeast will continue to keep temperatures down to about 80° at warmest in the afternoon with cloud cover hanging around. We should see some sun break through at times as well, though.
The main weather concern will be coastal flooding at times of high tide, and it could be somewhat disruptive to the morning commute in particular. High tide around 7:30am will top out around 7.9′, which is the high end of moderate flood stage in Charleston Harbor. The evening high tide should reach even higher, with water levels around 8.1′ expected around 8pm. Watch for road closures as you commute Thursday morning and then again a little later Thursday evening, particularly if downtown is in your plans.
High pressure wedging into the area will keep us on the somewhat cool and cloudy side for the next few days, with shower chances peaking Wednesday before tapering off for Thursday and Friday (though cloud cover and the occasional shower or storm will linger). Highs on Wednesday and Thursday shouldn’t get out of the upper 70s, while we may trend a little warmer Friday as some drier air begins to work in and a little more sunshine becomes possible.
We have one more day of the upper 80s in store before changes arrive in the form of a wedge of high pressure building in from the northeast for the rest of the week. Tuesday starts in the upper 60s inland to perhaps mid-to-upper 70s closer to the coast. Highs then head into the upper 80s once more, and with dewpoints edging up into the upper 60s, it’ll feel closer to 90° or so. From there, clouds will increase and a few showers should break out in the afternoon, though nothing over-the-top is really expected. There may be a rumble of thunder late, but overall, not expecting much in the way of lightning. Shower chances continue into the evening, and really for much of the rest of the work week from there.
More showers and thunderstorms are forecast for Thursday afternoon as a warm and humid atmosphere remains firmly in place across the area. Temperatures will warm to the low-to-mid-90s before storms start to kick up after convective temperatures are met. Shear is weak and instability is about average, but there will still be plenty of moisture to wring out of the atmosphere, so expect frequent lightning and heavy rain with the stronger of Thursday’s thunderstorms. There will be the risk for storms to anchor a bit and rain a lot in one spot as westerly flow aloft fights against an inland-moving seabreeze. (Daniel Island knows all about this, with several stations on the island recording 2-3″ of rain in a couple hours’ time.) A damaging wet microburst or two can’t be discounted either especially near where outflow boundaries collide. Once again, keep an ear out for warnings and take it easy on the commute.
One more round of coastal flooding is possible with the Thursday night high tide at 11:43 PM. Expect water levels between 7.1-7.3′ to produce some minor flooding generally between 9 PM-1 AM. A Coastal Flood Advisory will likely be issued. From there, the astronomical influences of the full moon will wane further, and while water levels may get close on Friday night, we should be done with this round of king tides.
Hot weather continues to start the week before yielding to more numerous showers and thunderstorms starting mid-week. (It’ll still be hot and humid, though.)
The weather story of this Fourth of July holiday looks to be the first big heat episode of the season across the Lowcountry. After highs in the low 90s on Saturday, air temperatures should top out in the mid-90s on Sunday, with heat indices running above 105° in the afternoon thanks to dewpoints in the low 70s. There will be a chance for an isolated shower or thunderstorm or two on the inland-advancing seabreeze in the afternoon, but the vast majority of us will stay rain-free — and hot.
The weekend forecast basically screams “first weekend of July in Charleston.” Morning lows bottom out in the mid-70s, while highs reach the mid-90s each afternoon with a few showers and storms possible along and ahead of the seabreeze. Humidity will be on the increase throughout the weekend. Heat indices on Saturday top out around 100-101°. On Sunday, the dewpoints head into the mid-70s and sends the heat index to around 106° in the afternoon. By virtue of it being July 2nd, there will not be a heat advisory as the criteria heads up to 110° on July 1, but anything past 105° is dangerous heat, and you should take the appropriate precautions.
The only potential fly in the ointment could arrive late Saturday/early Sunday as a thunderstorm complex rounding a ridge of high pressure approaches the area. It should be weakening, but a couple models suggest that it could hang on to bring some overnight/early morning rain. These are hard to pin down beyond a day or so, so stay tuned to forecast updates. For now, though, the going forecast for isolated PM thunderstorms looks solid.
A cold front will move through the area early Sunday, which will cap highs in the low 80s — well below normal for early June in the Lowcountry. We’ll see a mix of sun and clouds as high pressure wedges in from the northeast, but rain is not expected with the drier airmass filtering in. It’ll be a little breezy — gusts 20-30 MPH will be possible out of the northeast, especially at the beaches and on elevated surfaces such as the bridges.
The main weather concern for Sunday revolves around coastal flooding. A water level over 8′ is expected once again with Sunday evening’s high tide, which peaks around 9:10 PM. This will produce major coastal flooding once again, closing numerous roads in downtown Charleston and potentially causing disruptions on barrier islands as well. This degree of flooding is extraordinarily rare for June, with only three major flooding events on record — once in 1982 and twice in 2009. Be ready to use alternate routes if you are out and about Sunday evening.
