After a somewhat wild day at times with Idalia, Thursday will provide much, much better weather. Lingering breezy conditions and cloud cover will give way to mostly sunny skies by afternoon, with highs topping out in the low 80s as northwest winds bring some drier air into the area. This will kick off a nice Friday and long weekend, too. We’ve earned it, methinks.
Thanks for following along, as always, throughout Idalia. Your reports were invaluable to NWS warning operations and helped your neighbors stay in the know about what was happening. Social media, for all its problems, can still be super cool in times like these.
Hurricane Idalia, which as of this writing was a strong Category 2 hurricane with 100 MPH maximum winds, will make landfall as a major hurricane in Florida later Tuesday or early Wednesday. From there, Idalia will turn more northeast, bringing heavy rain, gusty winds, coastal and freshwater flooding, and the risk for a tornado or two within rain bands to the area later Wednesday into early Thursday morning. Trends have been for the storm to track a little more inland of the coast than we’ve seen forecasted in the past day or so, and there is pretty good agreement that this will be the case, expanding the heavy rain threat further inland along with the tornado threat in the evening. Here’s a full rundown of what to expect.
Tuesday will be another warm and muggy day as we prepare for Idalia’s arrival in the Lowcountry. We start the day in the mid-70s and warm to around 90° with heat indices approaching 100° within the increasingly tropical airmass. Showers and thunderstorms should begin to fire along the seabreeze in the afternoon and become somewhat numerous at times. Heavy rain capable of minor flooding will be possible. We’ll also need to watch the risk for coastal flooding in the evening, with minor to moderate flooding possible as water levels approaching 7.5′ with the 7:31 PM high tide. Due to the Storm Surge Watch in effect, there will be no Coastal Flood Advisory, so keep that in mind.
Sunday will be yet another warm and muggy late-August day across the Lowcountry. We’ll start the day in the mid-to-upper 70s before highs head to the low 90s in the afternoon. Heat indices should peak in the low 100s. From there, we should see a scattering of showers and thunderstorms along and ahead of the seabreeze. We may also see some activity from the north near a stalling cold front trying to infiltrate the area as well. The strongest storms will be capable of heavy rain and gusty winds, though widespread severe weather is far from in the cards. Overall, no washout of a day, just be ready to move outdoor activities inside if storms approach.
The air on Wednesday evening is fairly glorious — dewpoints in the mid-60s behind the seabreeze, with even some 50s dewpoints ahead of it — thanks to a cold front that pushed through earlier in the day. We’ll keep some of this dry air around for Thursday, which will keep the high of 92° feeling closer to 93-94°. We’ll see a few clouds across the area, but otherwise, it’ll be another reasonably pleasant late-August day.
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.
Sunday’s forecast looks fairly similar to Saturday’s: We’ll start the day in the mid-70s and head toward around 90° in the afternoon under partly cloudy skies. Heat indices will top out around 100-101°, with perhaps locally higher values closer to the coast. A scattering of showers and thunderstorms will once again be possible as the seabreeze presses inland, with heavy rain a continued concern with decent low-level moisture still in place. Ridging developing aloft will keep a lid on widespread coverage of showers and storms.
On and off showers and thunderstorms will continue for Thursday as a front remains stalled to our west and deep moisture resides over the area. We start the day in the mid-70s before highs top out around 90° before showers and thunderstorms fire. Once again, storms could pack heavy downpours that could lead to some flooding in a few spots, so be alert to quickly-changing conditions.
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’re back to heat and humidity for Thursday as the brief respite of drier air comes to a close. Lows will be rather balmy — upper 70s away from the coast, likely at 80° or above closer to the coast and in Downtown Charleston — as the high temperature heads to the mid-to-upper 90s in the afternoon. Expect heat indices 105-110°, with the warmer heat indices near the coast where the higher dewpoints will be found. NWS notes a heat advisory might be needed; will keep an eye on that.
A few thunderstorms will be possible during the day Thursday as a disturbance moves by to the north. A couple storms could be on the strong side with damaging wind gusts the main concern. Not everyone will see storms, though.