After what was an uncharacteristically wet and cloudy weekend across the Lowcountry, we will gradually move back into a more typical late-summer regime of afternoon thunderstorms and temperatures reaching the low 90s for the upcoming work week. But first, we’ll need to deal with a higher-than-normal risk for additional showers and thunderstorms on Monday, with potentially heavy rain having impacts starting early in the morning.
We continue to watch Hurricane Marco and Tropical Storm Laura as they continue on an unfortunate course to delivering a 1-2 tropical punch to parts of the Gulf Coast next week. Aside from some enhanced moisture funneling into the area from the storms around the western side of the Atlantic ridge through Monday, it does not appear that Marco or Laura will have any impacts in our area. We are now in the peak of the season, though, and we’ll want to keep a close eye on any waves that meander into the Atlantic from Africa for development over the next few weeks. Stay tuned…
After a brief respite from suffocating humidity today — the overnight temperature dropped to 69°, according to NWS, the coolest since June 20’s low of 67° — we will see rain chances return to the forecast as the upper trough which has kept things quite unsettled remains in place for the next few days. Brief bouts of heavy rain will be possible once again, but it won’t rain all the time or even every day at one particular spot. As we get into the weekend, Atlantic high pressure looks to build back into the area, which will help tamp down the overall coverage of storms (and begin sending temperatures back upwards a bit).
High pressure in the Atlantic and low pressure inland will keep the squeeze on for showers and thunderstorms each afternoon this week. Temperatures will top out in the upper 80s to around 90° each day before the onset of thunderstorms cools some of us down.
Thunderstorms will move slowly and thus have the potential to put down some pretty good rainfall, especially as we start the week, so be ready for localized flooding where storms set up. Lightning will certainly be a hazard as well, but the threat for severe weather otherwise remains low (though a wet microburst can never be ruled out).
After Isaias, we find ourselves back in a wetter-than-normal summertime regime, with scattered thunderstorms possible each day as we remain under a trough of low pressure aloft. Plenty of atmospheric moisture will remain in place, allowing for heavy rain in any thunderstorms that develop. Be on the lookout for plentiful lightning, too, with the occasional storm turning severe with strong downburst winds.
Temperatures will remain generally around where they should be in early August: Upper 80s to low 90s. Mix in the humidity and heat indices in the 100s will be routine, with dangerous heat indices around 105° possible for Thursday and Friday.
Much quieter weather today as Isaias has long since departed the Charleston area. Temperatures top out in the low 90s, but the humidity will feel closer to the low 100s. There is a slight chance of an isolated PM shower or thunderstorm on the seabreeze as it advances inland this afternoon. A trough of low pressure aloft will keep things a little stormy each afternoon as we go into the rest of the week.
The 11am advisory from the National Hurricane Center tweaked the forecast track for Isaias a little westward and faster. Maximum sustained winds remained around 70 MPH despite some signs of dry air intrusion. It is forecast to make landfall as a Category 1 hurricane somewhere around Georgetown or the Grand Strand.
The westward shift has some small implications for wind and tide forecasts for this evening. Overall expectations for impacts remain on track, though.
Well, Isaias is here and is already raining on us a little bit; I’ve already picked up .72″ from the first round of rain this morning. There’s more where this comes from as Isaias makes its closest pass to Charleston tonight on its way to an expected landfall somewhere between Myrtle Beach and Wilmington.
Impacts from Tropical Storm Isaias are becoming more likely in the Charleston metro area starting tomorrow morning, and additional watches and warnings are now in effect.
Early this morning, the National Hurricane Center upgraded the Tropical Storm Watch to a Tropical Storm Warning across the Tri-County area. A Storm Surge Watch is now in effect for coastal Charleston County, as well. The National Weather Service in Charleston hoisted a Flash Flood Watch for the Tri-County, which goes into effect tomorrow at 8am.
As of 5 PM, a Tropical Storm Watch is now in effect for the Charleston Tri-County area. This means that tropical storm conditions — winds 39-73 MPH, heavy, flooding rainfall, storm surge, and isolated tornadoes — will be possible within the watch area within the next 48 hours. This is your signal that preparation should be underway for the potential for wind damage, power outages, and flooding from Isaias as we head into Monday and Monday night.
At 8am, Isaias — not the most picturesque hurricane one has ever seen, but a hurricane nonetheless — was making its move on Andros Island in the Bahamas. The storm has been struggling with westerly shear and dry air intrusion, which will keep its intensity capped for now. Today is a pivotal day in the evolution of the storm’s track for the next few days, and we’ll all want to keep an eye on it as we begin to prepare for its arrival Monday.