Eric Berger

One-sentence summary

Hurricane Lee is slowly starting to weaken, but remains a large and powerful hurricane as it turns northward on Wednesday morning and it will eventually bring significant impacts to parts of eastern New England and Atlantic Canada this weekend.

Current status of Lee

As of 8 am ET on Wednesday morning, Lee has sustained winds of 115 mph and is moving to the northwest at 6 mph. In terms of timing, it will bring impacts to Bermuda starting late tonight through Friday, and then into New England and Atlantic Canada by later on Friday and Saturday. By that time Lee will be weakening, but should still pack a punch given its large size.

Lee track forecast

Our confidence in where Lee will go over the next couple of days is high. After turning today it should move more or less north, passing to the west of Bermuda. A tropical storm warning is in effect for the island due to the threat of heavy rainfall and strong waves. However, Bermuda thankfully should be spared the worst effects of Lee along this track.

After days of uncertainty, we should finally start to get some clarity today on Lee’s track at the end of this week, and its implications for residents of New England and Atlantic Canada. At this point I’m leaning toward a northward track until Friday, at which point the storm should make a dogleg to the left. Our main forecast question, in regard to track, is how significant will this westward bend be? It depends on the strength of a trough of low pressure over the Pennsylvania and New York region.

Our best hurricane and global models indicate that this turn will bring the center of Lee fairly close to the Cape Cod region of Massachusetts early on Saturday morning, although the storm is still expected to remain largely offshore. The center would then move into coastal Maine by Saturday night or Sunday morning. The center would subsequently move through Atlantic Canada and make its exit to the northeast. Again, we should get a better handle on the details of this dogleg over the next 24 hours, and we’ll have an update for you late this afternoon.

Lee intensity forecast and impacts

Lee now faces a number of factors that should lead to a gradual diminishment in strength, including increasing wind shear and a track that will bring it over cooler seas. However, this process should be slow, and it is likely that Lee will approach Cape Cod and Maine this weekend as a broad, Category 1 hurricane. As it likely will be starting to transition into an extratropical storm, you can probably expect the storm to behave more or less like a very large nor’easter.

After bringing tropical storm impacts to Bermuda, Lee could start to bring Tropical Storm-force winds to the Cape Cod area of Massachusetts by Friday night, and into Maine and Nova Scotia by Saturday morning. How strong will these winds be? That will depend ultimately on the storm’s track and how much its intensity wanes, but the following wind gust forecast from the European model offers a decent representation of risk. Note that wind gusts are short bursts of wind, and that sustained winds will be lower.

Rainfall totals are likely even less predictable than winds, because they’re not only dependent on track but also more localized conditions that will determine where thunderstorms train. The heaviest totals are likely accumulate in Maine and Nova Scotia, where some areas may see 3 to 6 inches of rainfall in a fairly short period from Lee.

There will, of course, be myriad other effects from this storm. One of them is storm surge. We have seen in the past the larger hurricanes tend to produce a more significant surge of water, and it appears as though Lee could bring a pretty significant coastal surge event into Maine and parts of Canada. The details of this will be worked out in the next day or two as we fine-tune the track forecast. Accordingly, Beach erosion, rough surf, and rip currents are a lock for the East Coast and Atlantic Canada. Not a good beach weekend, to be sure. Areas that see stronger winds and rainfall will likely see downed trees, which could in turn knock down power lines. So be prepared for some disruptions of that kind, as well.

Hurricane Margot and the rest of the gang

Margot is a hurricane at sea. Fortunately there is nothing to see. After spinning and going whee. In a few days, it should cease to be.

Beyond Margot there is another system that is very likely to develop into hurricane over the next several days. This system is probably not a concern for the continental United States or Caribbean islands, but could definitely be something for Bermuda to watch. If so, impacts would occur about a week from now, or maybe a bit longer. But we have a lot of questions to answer before getting into a specific forecast for a storm that would be called Nigel, should it form.

Look for our next update on Lee late this afternoon.

One-sentence summary

Idalia make landfall near Keaton Beach, Florida, at 7:45 am ET this morning as a Category 3 hurricane with sustained 125-mph winds. The hurricane will continue to produce significant impacts on Florida and other southern states for about the next 24 to 36 hours before it exits into the Atlantic Ocean.

Storm surge

Let’s start with storm surge, which has been considerable in Florida’s Big Bend area. This part of the state has a relatively low population, but Idalia has still been flooding villages and knocking down trees in northern Florida. Peak storm surge levels were about 10 feet, or higher, in the Keaton Beach areas and further south down the coast, toward Yankeetown. As expected, Idalia came in far enough north of the Tampa region on Florida’s Gulf coast to spare that large metro area from its worst effects.

The other area of concern, in terms of surge, is along the coast of South Carolina, particularly near Charleston. Moderate to major flooding is expected in coastal South Carolina later this afternoon when Idalia’s storm surge combines with high tide.

Damaging winds

Idalia briefly reached Category 4 status this morning, but started weakening just before landfall early on Wednesday. This weakening was due to the storm undergoing an eyewall replacement cycle, a process by which an older eyewall weakens and a new one forms. After coming ashore, as storms typically do, this interaction with land has rapidly reduced Idalia’s maximum sustained winds. As of 11 am ET, the National Hurricane Center says they have fallen to 90 mph.

This is still strong enough to uproot trees and down power lines, however. This will be a significant problem in northern Florida, and southern Georgia and South Carolina. Idalia is expected to weaken to just below hurricane strength before moving into the Atlantic Ocean on Thursday morning.

Inland rainfall

Despite Idalia’s relatively rapid forward movement, it is still expected to produce a significant amount of rainfall along its track across the Southeastern United States, including North and South Carolina. Some areas may see as much as 6 to 10 inches of rainfall in total, and a major concern is rainfall rates.

Tropical storms can produce some of the most explosive rainfall rates, which quickly back up drainage systems. Already, this morning, there have been reports of 5 inch-per-hour rainfall rates in Southern Georgia, which will cause significant inland flooding.

A rare location for such a storm

Meteorologist Steve Bowen has plotted the 21 known hurricanes, since 1851, to strike the Florida peninsula. Many of these storms were clustered in Southern Florida, with only a small handful in the Big Bend region of Florida. The strongest of these, Hurricane Michael, made landfall in 2018 with 160 mph winds.

Our next update will be today by around 5 pm Eastern.

One sentence summary

Franklin has intensified into a major hurricane, with 130 mph sustained winds, overnight; but the bigger threat to land is Tropical Storm Idalia, which could become a major hurricane before striking Florida’s Gulf coast later this week.

Tropical Storm Idalia

We’re going to start with Idalia, because that poses by far the biggest threat. As of this morning, Idalia is nearing hurricane status with 65 mph winds, and it will probably reach that milestone later today. Unfortunately, it is likely to strengthen further over the next two days as it crosses over Gulf of Mexico waters that are extremely warm and, critically, moves into an upper atmosphere that should not significantly hamper intensification. For now, the National Hurricane Center forecasts that Idalia will become a Category 3 hurricane prior to landfall, but the storm could easily be a category stronger or weaker by Tuesday night as it nears the Florida coast. The one saving grace here is that Idalia will only have a little more than 24 hours over the open Gulf of Mexico waters to strengthen, and some modest wind shear may limit its ceiling.

So where will Idalia go?

Later today the storm will cross the far Western edge of Cuba, and then move into the Southeastern Gulf of Mexico. After that it will move north-northeast, toward Florida. Our best forecast models are increasing in confidence, but there’s still some uncertainty in where Idalia’s most devastating winds and storm surge will go. The most likely area for landfall is the Big Bend area of the Florida coast, but a landfall from Panama City down to Tampa remains possible. The populated area of Tampa is on the right side of the storm, susceptible to the strongest winds and storm surge. However, based upon our best forecasts right now, the Tampa region would miss out on Idalia’s worst. But it’s going to be close.

Hurricanes produce three major threats: inland rainfall, storm surge, and damaging winds. In Idalia’s case, inland rainfall is slightly less of a concern because the storm is expected to maintain a reasonably high forward motion on Tuesday and Wednesday, as it crosses Florida and Georgia. That is not to say there will not be inland flooding from Idalia, particularly in areas such as Georgia and the Carolinas, but it should be mitigated by forward speed.

So the bigger issues are likely to be storm surge and damaging winds. Both of these effects will be most intense along the line of the storm’s track, and to its right-hand side. We can see this in the forecast “wind gust swath” from the European model. Now this is just one model run, and most definitely subject to change, but it gives you a sense of how the worst of the winds will be relatively localized, near the core of of the storm. Wind gusts of up to 130 mph are possible, based on this forecast.

As for storm surge, this again will depend on the track’s location. For now the worst of it looks to occur in the Big Bend area of the Florida coast.

We will have an update on Idalia later today. The bottom line is that if you live in Florida, including the Tampa area, today is the last full day to make preparations for the impending storm. This is a storm to be taken seriously. Tropical Storm-force winds could arrive in parts of the state as early as the middle of the day on Tuesday.

Major Hurricane Franklin

Franklin has continued to strengthen overnight, and as of 7:35 am ET this morning the National Hurricane Center reported that the storm had reached sustained winds of 130 mph. Some further strengthening is likely later today as Franklin continues passing over warm waters and enjoys low wind shear.

Fortunately—very fortunately—Franklin is behaving for a storm in the Western Atlantic Ocean. Its projected track will follow a course far enough off the Atlantic seaboard of the United States to spare the coast of any significant effects. Moreover, Franklin should remain just far enough west and north of Bermuda to also spare the small island of its worst effects. Some tropical storm warnings may still be necessary for Bermuda, but it should be miss out on anything close to the worst of what the Atlantic season’s first major hurricane could dish out.

So go on Franklin, get on with your bad self.

What else is out there?

After Franklin and Idalia there is another system likely to develop from a tropical wave that will move off Africa on Tuesday. However, we don’t anticipate that this system will track toward the Caribbean Sea or the United States. It likely is not a concern as we head into early September.