Our recent dry respite is about to come to an end as disturbances aloft interact with a surface front to keep things unsettled for a few days. The greatest coverage of storms will be on Friday as the most vigorous disturbance moves on by with the front sinking into the area. Numerous showers and thunderstorms are expected, and this will have the effect of suppressing highs into the mid-80s. Instability should be fairly weak, and the severe weather threat is low, but some heavy downpours will be possible which could lead to some areas of flooding.
Thursday should be generally quiet across the metro area for the vast majority of the day as dry air characterized by dewpoints in the mid-60s — about as good as it gets at this point in the year — hang around for one more day. Expect the day to start in the low 70s once again with highs warming to the upper 80s in the afternoon. Clouds will be on the increase throughout the day as a disturbance approaches, with a slight chance of showers after sunset, but again, the vast majority if not all of us get Thursday in rain-free.
Heat indices head back into the danger zone for Friday and the weekend as an uptick in moisture within onshore flow sends dewpoints up into the mid-to-upper 70s. This will also help in bringing scattered to numerous showers and thunderstorms ashore across the area, perhaps as early as the morning, pressing inland with time with the seabreeze as the day goes on, much like Thursday. We’ll see a similar setup on Saturday, while Sunday should feature a more standard afternoon/evening thunderstorm configuration. The good news is that rain will not hang out terribly long in any one location, and should represent nothing more than a brief inconvenience.
Highs on Friday top out around 90° and in the low 90s on Saturday, while air temperatures warm into the mid-90s on Sunday. Heat indices will head above 105° each afternoon thanks to the aforementioned tropical air. Sunday could feature heat indices approaching 110°, which could lead to a heat advisory. Be cautious if you are out and about during the heat of the afternoons over the next few days!
Standard late-July weather continues for Thursday. We’ll see primarily partly cloudy skies across the area with highs topping out in the low 90s ahead of the seabreeze. Heat indices should top out around 103° or so, with some locally higher values closer to the coast possible for a brief time as the seabreeze moves inland. Said seabreeze should be responsible for a few showers and thunderstorms during the afternoon hours, moving inland with time. Some locally heavy rainfall and gusty winds will be possible in the strongest storms, but they shouldn’t last terribly long at any one location.
We have one more really hot day on Friday, with heat indices well in excess of 105° expected one more time in the afternoon. A few 110° readings won’t be ruled out, either, and it’s possible another Heat Advisory will be needed as air temperatures head into the upper 90s.
Scattered afternoon thunderstorms will again figure into the forecast, and one or two of them could produce damaging downburst winds. There is a risk for more organized severe weather moving down the Savannah River Friday night. The degree to which we experience this will be largely determined by the position of the subtropical ridge, which should retrograde a little more westward by tomorrow evening, keeping the main threat to our southwest. We’ll watch it, though.
Heading into Saturday and Sunday, troughing combined with a weak front stalling out nearby will keep afternoon shower and thunderstorm chances in vogue. Temperatures won’t be quite as scorching as we’ve seen, though, with highs topping out only in the low 90s thanks to the lower heights aloft. This is closer to normal for this point in the year. Heat indices, however, will still run above 100° each afternoon, and could make a run for 105° on Saturday. Stay cool if you’re spending time outdoors, and be ready to bring outdoor activities inside in case thunderstorms threaten.
Thursday is going to be another hot day across the area. Expect to start the day just barely below 80° inland and likely a couple degrees above it closer to the coast. We’ll warm back into the mid-90s during the day, and with dewpoints not mixing out quite as much — expect them to hang around in the mid-70s — we should see heat indices peak around 110° or so in the afternoon. This is certainly well into the danger zone for heat illness, so please do take it easy if you must be outside. There’s no Heat Advisory as of this writing, but don’t be surprised if one is issued by morning.
Attention then turns to the potential for showers and thunderstorms to move into the area in the afternoon and evening courtesy of a disturbance rounding a retreating ridge of high pressure. Most of these storms should be efficient rainfall and lightning producers, and a few of these storms could be on the strong side with damaging wind gusts the main concern. Hail can’t be ruled out, either. Stay alert to rapidly changing conditions as we get into tomorrow afternoon and evening, and don’t be surprised if there are evening commute impacts.
Fortunately, wildfire smoke will play much less of a role in Thursday’s weather as it continues to disperse southward.
Friday and the weekend will feature another round of warm temperatures, with heat indices running 105-110° by the weekend, and a solid chance of thunderstorms each afternoon and evening. We’ll start each day in the upper 70s — perhaps not getting below 80° downtown and at the beaches — before warming to the mid-90s each afternoon. Surface dewpoints running solidly in the mid-70s will yield heat indices approaching 105° on Friday. The weekend should peak even hotter, with heat indices approaching 105-110° each afternoon. Stay tuned for the potential for Heat Advisories from the National Weather Service.
From there, showers and thunderstorms will fire each afternoon along and ahead of the seabreeze. Heavy rain and frequent lightning will be the main concerns, though the stronger updrafts found where outflow boundaries collide could be capable of producing a marginally severe storm or two with damaging wind gusts the main concern. As is often the case in July, it will not rain all day, and some of you may not see rain every day. Just be ready to bring outdoor activities inside in case thunderstorms approach. Severe or not, lightning makes every thunderstorm dangerous. “When thunder roars, go indoors!”
Expect one more generally quiet weather day on Thursday (though a shower or storm can’t be ruled out in the afternoon, especially further inland) before things turn more unsettled as a trough digs in for Friday and the weekend.
Afternoon showers and thunderstorms remain in the forecast for Friday and the weekend with an active seabreeze and plenty of heat and humidity. Highs each day will top out in the low to mid-90s, with heat indices over 105° expected. Sunday’s heat index could approach 110°, in fact. Airmass showers and thunderstorms will be possible in the early afternoon, with more activity kicking up along the inland-moving seabreeze as we head into the evenings. As always, keep up to date with forecast changes as small tweaks — such as the pocket of drier air aloft that enveloped the area Thursday, which kept thunderstorms to a dull roar — could mean a better (and vice versa) day of weather.
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.
