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Isaias @ 11am: Tropical storm force wind probabilities increase

/ August 3, 2020 at 1:32 PM

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.

Tropical storm force winds more likely in the metro area

Maximum sustained wind speed forecast from 6PM Monday to 6AM Tuesday. Source: National Weather Service

The westward shift in track at 11am was subtle, but will do a couple things if it verifies:

Timing for the strongest winds in the metro area appears to be between 5 and 8 PM based on the latest gridded forecast from the National Weather Service.

While another wobble back east is not out of the question at all, we will need to monitor this potential for stronger winds in the metro area, producing power outages and tree damage.

Worst-case tide scenario appears unlikely, but flooding remains probable downtown

Isaias’s faster forward motion will significantly reduce the likelihood that peak storm surge will combine with high tide. The center looks to travel north of our latitude by 7PM or so, which will subsequently shift winds around to the north and northwest. This is very good news for avoiding an absolute worst-case flooding scenario. However, heavy rainfall ahead of an increasing tide will still likely produce flooding in downtown Charleston this afternoon and evening, which may prove to still be significant. Flood precautions should be just about complete as heavier rain looms off the coast, looking to begin to have impacts closer to 3-4 PM.

More here as needed throughout the evening!


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