Changes
As of 5AM, Hurricane Matthew is a Category 3 storm with winds of 125 MPH moving N at 10. Its circulation was disrupted somewhat due to land interaction with Cuba but it is expected to restrengthen to a Category 4 storm as it moves through the Bahamas and approaches Florida. From there, it is expected to hug the Southeast coast and weaken under increasing wind shear.
There are a few key changes in the forecast as of the 5AM advisory:
- The track has shifted eastward and slowed down a few hours. This is positive for us in Charleston. The emerging guidance consensus is that the trough of low pressure moving through the Midwest, which is supposed to recurve the storm, may not be able to completely capture the storm and fully recurve it. What it will do is deflect it eastward more sharply. (This could set up a scenario where Matthew does a little loop-dee-loop in the ocean, but we will wait and see.) This new consensus is reflected in the official National Hurricane Center forecast.
- The storm should be weaker as it makes its closest pass. More wind shear is forecast as it approaches the GA/SC coast, which will weaken the storm. It’s now looking less likely that effects from a major hurricane will be felt here. That being said, intensity is still a notoriously tricky thing to forecast and we will need to watch this. The storm will still be a Category 2 hurricane and we must respect that. Storm surge and heavy rain continue to play into the forecast, and the risk for flooding will continue to be with us.
- Tropical storm force winds are still likely Friday into Saturday, but stronger winds are becoming more questionable. The risk for hurricane-force winds (74+ MPH) has decreased in Charleston. This is a positive trend, but we’re still a few days out and things can and very well will change.
What’s not changing
The basic scenario, a close pass from a tropical cyclone, is still very much with us. Wobbles to the west can still change the calculus, and it’s unfortunately still too far out to pin down the exact impacts we are going to have. This is why we in #chswx have been urging preparedness for the worst-case scenario while hoping for the best — the uncertainty demands it.
Remember that a hurricane is not a point on a map, but a fairly large area with a wide swath of impacts. Regardless of these wobbles, unless there is a drastic shift, Charleston will see issues from Matthew.
Continue to prepare for:
- Very high tides and storm surge, especially Saturday. While the guidance is starting to back off some of the crazier numbers I was seeing yesterday, there is still the potential for an 8'+ high tide early Saturday afternoon. This is on par with what we saw last year during our flooding event, and tides this high will certainly cause flooding in downtown Charleston. Parking garages open at 3PM today — if you live downtown, you will want to ensure you can move your car to a safer place.
- Heavy rain and flooding. Rain totals from Matthew may exceed 10" near the coast with 8–10" possible elsewhere. This combined with storm surge will almost certainly produce significant flooding impacts.
- Potential wind impacts, particularly near the coast. Sustained tropical storm force winds will be most likely near the coast, but everybody in the Charleston area should do their part to bring in loose items from around their home in preparation for the storm.
- Potential evacuation of the coastline. The Governor will be making the call at a press conference at 9AM. Many have already left; traffic was a nightmare last night. Schools are closed for the rest of the week in preparation for the evacuation. I expect shelter announcements to come soon for those who cannot get further inland.
My most important piece of advice is this: Please heed the advice of your local emergency management officials. They know what they are doing, and have your safety as their primary mission. If told to evacuate, do so, especially if you live somewhere that had serious problems with last October’s flooding.
The next full update from the Hurricane Center will come at 11am.
