Matt Lanza

One-sentence summary

Hurricane and storm surge watches are now posted along much of Florida’s west coast and parts of the Panhandle as Idalia is expected to bring impacts by Tuesday.

Tropical Storm Idalia

Tropical Storm Idalia (pronounced “ee-DAL-ya” for those that were not sure) formed this morning, and quite frankly it looks no better organized now than it did then. So in essence, not a whole lot has changed from our morning post.

This was mostly expected. Idalia is unlikely to really get moving in terms of intensity until it start getting a lift north, meaning a lot of the intensification we see from this storm may not occur until it’s rather close to land. Idalia is not exactly a small system, with thunderstorms extending from the Yucatan to east of the Isle of Youth in Cuba, which is about 400 to 500 mile wide swath of unsettled weather. To underscore, while the track of Idalia does matter, one need not be close to the center to feel the impacts of this storm as it comes north.

The track forecast today has not seen any dramatic changes, so, broadly we still expect a hurricane approaching the eastern Panhandle, Big Bend, Nature Coast, or Tampa area by Tuesday night. Again, given the size of Idalia and the geography of Florida, hurricane impacts may touch the coast well south of wherever Idalia comes ashore. So, it’s entirely conceivable that (hypothetically) Idalia makes landfall, say, near Cedar Key, while producing hurricane impacts as far south as Sarasota.

Indeed, the biggest change this evening is that we now have a broad swath of the Florida coast under Hurricane Watches and Storm Surge Watches.

Storm Surge Watch: Indian Pass on the Panhandle south to Chokoloskee on the southwest coast.
Hurricane Watch: Indian Pass south to Englewood, between Sarasota and Fort Myers
Tropical Storm Watch: Englewood south to Chokoloskee and for the Dry Tortugas.

On the map below I have overlaid the watches for Florida, in addition to the probability of 60 mph winds and the most likely arrival time of those tropical storm force winds. You can see how wide the berth is for potential strong wind.

The storm surge forecast from the NHC is somewhat aggressive, and it seems warranted given Idalia’s current forecast intensity. The map below shows the reasonable maximum surge above ground level in the impacted areas.

One important note: During Irma and last year during Ian, because of the wind direction, surge was directed out of Tampa Bay. With Idalia currently forecast to pass west and north of Tampa, this would direct surge *into* Tampa Bay. So please don’t go storm chasing this to see a dry Tampa Bay. Another important note: As Idalia’s forecast is revised, this forecast will be revised too, and you should be following forecast progress closely. Florida’s geography and the unique interaction with storms coming from this direction can lead to some substantial forecast impact changes with surge in particular.

So, for folks along Florida’s west coast, the Big Bend, and parts of the eastern Panhandle: You will need to be ready for potential hurricane impacts, regardless of exactly where Idalia comes ashore.

The rainfall forecast has not changed a ton. Idalia keeps moving at a good clip once it gets north of Florida. While this will by no means prevent flooding in spots, it does help to probably limit flooding concerns a bit. We’ll watch the situation in Carolinas a bit closely, as some heavy rain will front run Idalia today and tomorrow, and flood watches are already posted in eastern North Carolina. If I were watching some place closely for flooding risk, it would be there right now.

So, to summarize:

• Idalia is still forecast to become a hurricane as it comes north into Florida Tuesday night.
• Storm surge and hurricane watches are posted along much of Florida’s west coast indicating that surge and hurricane conditions are possible.
• The forecast storm surge will be contingent on exactly where Idalia comes in but a substantial surge event is possible for the Nature Coast and Big Bend. Folks in Tampa Bay should watch this closely as well.
• While portions of SW Florida impacted so badly by Ian last year are unlikely to take a direct hit from Idalia, there will likely be impacts there from high water, rough surf, and some gusty winds and some vulnerable portions of the waterfront still not fully recovered may see some issues.
• Heavy rain will follow Idalia inland and North Carolina may be in line for the greatest inland flooding risk as it stands right now.
• The forecast IS going to change in the coming days so check back for more.

We will have our next update for you as usual on Monday morning.

One-sentence summary

Tropical Depression 10 continues to slowly organize off the Yucatan, and it continues to look to come north as a hurricane, impacting somewhere in Florida by Tuesday night.

Tropical Depression 10 Tropical Storm Idalia

Editor’s Note: Tropical Depression 10 was upgraded to Tropical Storm Idalia immediately after pressing “Publish.” While the content is unchanged, “TD 10” should now be referred to as Idalia.

One look at TD 10 this morning on satellite allows for two thoughts for me as a meteorologist. First, where is the center? Second, that’s a *lot* of thunderstorms.

In terms of the first point, the center seems to be located near Cozumel. The NHC just placed the center about 75 miles ESE of Cozumel. It’s been doing a bit of a loop, but it remains in tact at least. TD 10 is expected to drift north over the next 24 hours, slowly organizing as it does so. We could have a tropical storm by later today or tomorrow.

Thereafter, steering currents should direct this north/north-northeast toward the Florida coast. There are two important changes today in terms of track outlook that may not be obvious from the NHC outlook. First, the organization of TD 10 is still an issue. Until this thing can really wrap up and get going, there is some risk that the center tries to “reach” for the thunderstorms, which is to say, it’s entirely possible the center relocates at some point today. Second, model consensus on TD 10’s future track has shifted a little to the right (or east) since yesterday. This keeps the west coast, especially north of Tampa along the Nature Coast in play, as well as the Big Bend and Panhandle. Basically, everyone from about Destin to Sarasota should continue monitoring TD 10’s progress closely.

The reason you may be hearing a lot about TD 10 and its future is because of where it’s located. It’s over deep, rich warm water, an untapped resource it can probably tap into as it organizes. If and when that happens, TD 10 could quickly go from funky to formidable. And it remains likely that portions of the Florida coast will be dealing with hurricane impacts by Tuesday night. The NHC forecast brings maximum winds to 90 mph as TD 10 (then Idalia) comes ashore. It’s possible it could be stronger than that. In addition to wind, storm surge will probably be an issue as well as this storm comes ashore. The West Coast of Florida will need to watch this, as well as the Big Bend area, where surge could be maximized depending on the exact track of the storm.

In addition to wind and surge, there is always the rainfall. A general 3 to 6 inches is likely along TD 10’s track as it comes north. Areas to the east of the track may also see some enhanced rain. Higher amounts are likely in spots and the potential for inland freshwater flooding is possible for Florida into Georgia and the Carolinas.

Bottom line on TD 10:

• Gradual organization is expected today and tomorrow, leading to a hurricane impact by Tuesday night somewhere on the west coast or Panhandle of Florida.
• Rapid intensification is possible as TD 10 enters the Yucatan Channel or Gulf.
• Storm surge flooding will likely be an issue on Florida’s west coast or in the Big Bend area.
• Specific track details still need to be ironed out.
• Heavy rainfall from TD 10 will lead to localized flooding concerns from Florida and Georgia through the Carolinas.

Our next update on TD 10 will be Monday morning, unless things change or become sharply clearer later today.

Hurricane Franklin

Meanwhile, in the Atlantic, Franklin had become a bit of a curiosity and afterthought yesterday as it looked to pass west of Bermuda as a hurricane. That has since changed some.

While Franklin should still miss Bermuda comfortably to the northwest, it may be large enough to produce fringe impacts on the island, including gusty winds and heavy rain, in addition to rough surf, rip tides, and beach erosion (something we may also see on the U.S. East Coast later this week). Franklin is forecast to peak in intensity before passing Bermuda, but still a decent, large-sized hurricane passing 100 to 150 miles away is capable of producing some impacts. Folks in Bermuda will want to monitor Franklin’s progress closely. For Newfoundland, this should mean fewer impacts ultimately.

One-sentence summary

Invest 93L was upgraded to Tropical Depression 10 this afternoon, and it is likely to impact the west coast or Panhandle of Florida as a hurricane on Tuesday or Wednesday.

Tropical Depression 10

As of Saturday evening, Tropical Depression 10 was spinning in or just south of the Yucatan Channel and off the coast of the Yucatan.

TD 10 has a well defined center it appears and a pretty healthy circulation about it as it spins, mostly in place due to the absence of any real steering currents in this area. Heavy thunderstorms are displaced well east of the center over western Cuba and the Isle of Youth.

At present, we have tropical storm warnings from Rio Lagartos through Cancun and Cozumel south to Tulum on the Yucatan, and there are tropical storm watches in effect for the Isle of Youth and Pinar del Rio in Cuba. Warnings mean tropical storm conditions are likely, while watches mean they are possible. We are still a day or so away from watches being issued in Florida I believe.

Tropical Depression 10 will stay in place much of tomorrow before drifting northward on Monday and then picking up the pace Tuesday. Broadly, it still is expected to track toward Florida, be it the Panhandle or the west coast. Modeling is focused on this tracking close to the NHC map above, near the Big Bend of Florida. However, given that there is a bit of uncertainty in terms of how the center behaves in the next day or two, everyone from the Alabama coast through the Keys and Cuba should be monitoring Tropical Depression 10’s progress. The next name on the list is Idalia.

In terms of intensity, the NHC forecast above explicitly shows a 75 mph category 1 storm heading into the Panhandle or Big Bend. However, there is reason to believe that modeling and forecasts may be somewhat underdone. Water temperatures along the path of TD 10 will be very, very warm and that warm water is very deep as well, so this will have much fuel to feed off of. If wind shear or dry air get involved, this could limit the storm’s intensity some, but probably not entirely. Land interaction is also a wild card over the next day or so near the Yucatan, so the intensity forecast is a bit uncertain. I would anticipate at least a low-end hurricane, however, on the Florida coast by Tuesday night or Wednesday morning.

In addition to tropical impacts on the Florida coast, this is looking like a healthy rainmaker for Florida and the Southeast. Anywhere from 4 to 6 inches of rain are possible along and to the east of the path of TD 10 in Florida, and higher amounts are likely in some places depending on exactly how things play out. The rainfall distribution may change some once the storm ends up in the Southeast, with a widespread heavy rain possible, if not likely for parts of Georgia and the Carolinas. Details on this will get ironed out in the coming days.

Again, like much of everything regarding TD 10, you can anticipate forecast changes to the above map.

The bottom line:

• Tropical Depression 10 is forecast to impact the Florida Panhandle, Big Bend, or west coast as a hurricane this coming week.
• The intensity of TD 10 at landfall is highly uncertain, but folks in Florida in the cone should be preparing for at least category 1 type hurricane impacts.
• The exact landfall and track remain uncertain.
• Heavy rain will likely follow TD 10 northward, potentially leading to some flooding issues in parts of the Southeast from Florida into Georgia and the Carolinas.

We will have another update on Tropical Depression 10 and the rest of the tropics by about midday Eastern time on Sunday.