Charleston Weather Blog

Forecast explanations, atmospheric science, and other cool weather-related stuff for Charleston, SC

Rest of the work week: A little lull, then turning soggy again

/ September 5, 2022 at 9:03 PM

We’ll get a break in the more widespread rain as we head back to work and school on Tuesday as the surface configuration briefly turns a little more summer-like. We won’t stay completely rain-free — isolated to widely scattered showers and thunderstorms will be possible in the afternoon — but it certainly will be a bit of a shift from where we’ve been. The lower shower and storm coverage means temperatures will head to the low 90s in the afternoon; mix in the humidity and it’ll feel closer to 101-102°. We’ll repeat this on Wednesday before another front moves into the area by Thursday. Said front will once again stall out nearby — just not enough oomph yet to get these through at this point in the season — and keep us very unsettled from Thursday through Friday and into the weekend. This will send temperatures down to the upper 80s on Thursday to the low 80s on Friday with numerous showers and thunderstorms expected each afternoon. Heavy rain will be possible, and we may not get out of this week without another bout with flooding somewhere in the metro. Stay tuned to forecast updates.

Labor Day: Dodging showers and storms from time to time

/ September 4, 2022 at 10:28 PM

Labor Day looks to feature an uptick in shower and storm coverage when compared to Sunday’s relatively quiet weather, but it still doesn’t look like a situation where outdoor plans will be totally washed out. After a little drier air worked its way into the area for Sunday, more moisture will move back in from the southwest for Monday. We could start the day with some showers and storms advancing northeastward across the area with some brief downpours embedded. Then, the seabreeze should kick in during the afternoon and help develop more showers and thunderstorms, which will progress inland with time. Heavy rain is the main concern from any thunderstorms; with precipitable water values over 2″, there will be a risk for flooding in a few spots where heavy rain repeats on itself. Of course, lightning will be a concern as well — as always, remember that if you’re hearing thunder, you’re in the strike zone. When thunder roars, go indoors!

Like the last few mornings, we’ll start in the low-to-mid 70s (warmer near the coast) and head toward the mid-80s in the afternoon outside of any showers and thunderstorms that develop. Mix in the humidity and it’ll feel closer to some very muggy mid-90s.

Bottom line: It won’t rain all day, but you’ll want to keep an eye to the sky in case conditions begin to head downhill. Be flexible with your outdoor plans and have a solid plan B in your back pocket.

Sunday: Still dodging scattered showers and storms

/ September 3, 2022 at 8:20 PM

Sunday’s forecast is essentially a matter of highlighting today’s weather, hitting Cmd+C, then Cmd+V (or Ctrl if you’re on Windows or Linux). Onshore flow will continue with the risk for scattered showers and storms throughout the day. Better rain chances will be found at the coast in the morning before transitioning inland with the seabreeze in the afternoon. Precipitable water values will remain at or above 2″, which will promote the risk for isolated downpours and perhaps flooding concerns if heavy rain ends up repeating over the same area. The diffuse stationary front which has been plaguing our surface pattern for the better part of a week now will wobble a little further southwest for Sunday, which should keep the more widespread rainfall in Georgia. Even still, though, stay flexible with your outdoor plans and be ready to move them inside quickly if storms approach.

Temperatures will once again follow today’s trend: lows in the low-to-mid-70s to start the day, with highs topping out in the mid-to-upper 80s before showers and thunderstorms set in. Heat indices will run in the mid-90s with the continued summer-esque humidity in place.

This pattern looks to continue into Labor Day and beyond. Aloft, ridging remains firmly in place over the next several days as an upper low cuts off over the Midwest. In the tropics, Tropical Storm Earl, which was named last night, will recurve well away from the US before it becomes a threat to land, while Danielle remains very far out in the Atlantic, an issue for shipping traffic and fish.

Saturday: Scattered storms as a stalled front lingers

/ September 2, 2022 at 9:21 PM

Saturday looks to bring another round of scattered showers and storms to the area, possibly as soon as sun-up as storms develop offshore and drift inland within onshore flow. During the day Saturday, a stationary front could wobble back north into the area, which may help focus additional shower and storm development in the afternoon. Unfortunately, the models are still varying quite widely on precipitation coverage during the afternoon and evening hours, so it’s going to be difficult to pinpoint exactly when and where it will rain until trends become apparent tomorrow. With that in mind, I don’t think it is wise to totally shelve outdoor plans, but I would recommend having a strong backup plan in your back pocket ready to go.

Thanks to onshore flow, lows on Saturday will run a couple clicks above normal (low to mid-70s) and highs will run a couple clicks below normal, generally running in the mid-80s in the afternoon ahead of any showers or thunderstorms that may develop. Mix in humidity and it’ll feel like the mid-90s.

We look to stay in this pattern through the Labor Day holiday, with variable rain chances each day driven largely by the positioning of the stalled front and the state of the atmosphere after any convection on the previous day. My advice remains the same: Don’t cancel plans, but be ready to change them.

Friday & the (Labor Day) weekend: Remaining unsettled

/ September 1, 2022 at 6:47 PM

Well, today was supposed to feature a lull in the shower and storm action, with more isolated coverage…and then it rained for five hours, flooding downtown Charleston again while 3-5″ of rain dumped on Johns Island and West Ashley. This was due to the combination of a stalled front and outflow from a thunderstorm cluster that developed to our northwest. Add in a little upper-level energy and you have a very, very soggy Thursday afternoon. Thankfully, the bulk of today’s rain is over and we should largely dry out overnight (though with fog a distinct possibility).

As we head into Friday, scattered storms remain in the forecast as the ever-present front remains close by. The impact on our weather will largely be driven by how far south it slips tonight into tomorrow. Right now, the expectation is that the greatest concentration of storms will be to our south and west, but I do anticipate that we’ll see a few more downpours tomorrow across the metro area, perhaps again having impacts on the evening commute.

Shower and storm coverage is expected to tick up a little bit more Saturday as onshore flow becomes a little more convergent at the surface. That’ll be the day with the greatest potential for persistent rainfall (at least as currently forecast). There is a little model disagreement with where the surface front will be, though, and so that’ll drive a little uncertainty. Heading into Sunday and Labor Day, rain chances continue to persist, with scattered coverage expected as a coastal trough develops and hangs around. This doesn’t look to be a full-day washout for Labor Day, but be ready to move outdoor activities inside.

With the persistent risk of scattered storms and the ensuing cloud cover, highs should stay in the mid-80s each day after starting in the lower 70s. This is around, if not a touch below, early September normals.

Rest of the work week: A lull in the action brings warm temperatures back

/ August 30, 2022 at 7:55 PM

As we head into mid-week and look to round the corner toward Labor Day weekend, we’re going to see a reduction in shower and thunderstorm coverage for a few days as some drier air aloft works in from the north and west. We’ll keep isolated to scattered shower and thunderstorm chances in the forecast as those probabilities won’t be totally eliminated, particularly near the coast, but we shouldn’t see the sustained flooding rains that have been a concern the past couple days. Areas further inland could even see a rain-free couple days, especially on Thursday as a front clears the area and stalls to our south.

As rain chances diminish, temperatures turn back up to a little above normal as we close out August and enter September. Expect highs around 90° for Wednesday; mix in the plentiful humidity and it’ll feel closer to 100-102°. Thursday will run pretty warm, too, with highs around 90° and heat indices in the upper 90s once again expected. Rain chances begin to tick back up on Friday, and that’ll lead to high temperatures topping out a little lower than the previous couple days, generally in the mid-to-upper 80s.

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Tuesday: More scattered storms, possibly another wet commute

/ August 29, 2022 at 11:08 PM

After a torrential deluge that closed numerous streets both in downtown Charleston as well as North Charleston, we should see a little less coverage of showers and thunderstorms for Tuesday, but more heavy rainfall will be possible. We could once again see some wet weather for tomorrow morning’s commute as another round of showers and storms skirts up the coast. Then, a more typical afternoon round of scattered showers and storms should fire up along the seabreeze as temperatures are expected to climb to the mid-to-upper 80s. Given the drenched soils from Monday’s rains, it may not take much to cause additional flooding problems on Tuesday where heavier rain falls, so that’ll certainly be something worth watching. Flooding rain, though, should certainly not be as widespread as we saw today.

We’ll continue to see a decrease in coverage as the week goes on, though scattered showers and storms will remain possible each afternoon, with a few stronger storms not out of the question Wednesday into Thursday. An uptick in coverage is possible Friday into Saturday depending on where a cold front stalls out — stay tuned for refinements.

The week ahead: Wet pattern continues

/ August 28, 2022 at 11:13 PM

More wet weather is on the way as we remain in a rather unsettled pattern heading into the first days of September (and meteorological fall!)

We’ll likely start Monday with showers and maybe some thunderstorms in the metro area as offshore storms make a run to the coast. Be ready for a somewhat complicated commute due to rain. It’ll be worth watching downtown around high tide just before 10am, too, for the potential for heavy rain to combine with said tide to possibly produce some street flooding. Storms and their associated pockets of heavy rain will continue to spread inland throughout the day. Rain and cloud cover will keep temperatures suppressed to the low 80s.

We stay unsettled heading into Tuesday as a front moves toward the area. Thunderstorms will become likely once again in the afternoon, though temperatures will have a little more time to rebound into the upper 80s. Expect more scattered coverage Wednesday as a little drier air aloft moves in, which will allow temperatures to head into the low 90s in the afternoon ahead of the front. The front moves by Thursday and stalls out to the south, which will help keep moisture in place and the risk for showers and thunderstorms in the forecast as we head into the Labor Day weekend. As is customary for late summer, there will not be any day that’s a total washout — just have backup plans for any outdoorsy things you might have going on.

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Weekend forecast: Keep rain gear handy, but not a total loss

/ August 26, 2022 at 10:56 PM

Our weather looks to stay somewhat unsettled this weekend as we remain within a somewhat stormy pattern across the eastern US. If I’m picking a day for outdoor activities, I like Saturday; a little drier air will punch down into the area from the north and should help shunt the better rain chances southward. That being said, scattered showers and a few thunderstorms should still develop along and ahead of the seabreeze in the afternoon, so stay on guard if you do have outdoor plans. It’ll be a bit warmer than it’s been the past few days, with highs reaching into the upper 80s courtesy of a little bit more sunshine than we’ve seen recently.

Sunday should see a little greater shower and storm coverage as more moisture spreads back into the area. The best chance for showers and storms will be in the afternoon, but guidance suggests the potential for rain as early as mid-morning. Don’t write off any outdoor plans just yet, though — trends will become more established tomorrow. Highs will run a touch cooler with more cloud cover and storms expected — generally expect mid-80s in the afternoon.

Friday & the weekend: More showers & storms, but no washout

/ August 25, 2022 at 9:28 PM

The pattern looks to stay generally unsettled heading into the last weekend of August, though some subtle changes will help reduce coverage at least a little on Saturday and Sunday.

Showers and thunderstorms remain likely particularly Friday afternoon and evening as a front remains stalled just offshore and energy aloft pivots into the area. We continue the risk for heavy rain with precipitable water values well in excess of 2″ expected to persist — plenty of moisture for deep convection to wring out. Watch for ponding of water on roads or even isolated bouts of flooding.

Slightly drier air will then poke in from the north on Saturday into Sunday. This should have the effect of scattering out shower coverage a little bit more, particularly on Saturday. However, the area won’t totally get off scot-free when it comes to rain this weekend, so be sure your outdoor plans have an indoor backup just in case.

Temperatures will remain a few clicks below normal for late August as cloud cover and rainfall stick around. Generally, we should expect lows in the low 70s each morning (running a little warmer near the coast thanks to warm sea-surface temperatures) followed by highs in the mid-80s in the afternoons.