Here’s what you need to know about the approaching tropical storm

Jonathan Rizzo, Warning Coordination Meteorologist with the National Weather Service in the Florida Keys, joined Good Morning Keys on KeysTalk 96.9/102.5FM this morning to talk about the potential incoming weather.

Tropical storm Idalia looks to be headed toward Florida.

Rizzo said, “Idalia is actually a strong tropical storm. It’s moving slowly northward. So it’s going to be near the western tip of Cuba by this evening, and then move into the southeastern Gulf of Mexico during the early morning hours Tuesday.”

There is a tropical storm watch in effect for the Lower Keys from the west end of the Seven Mile Bridge to Key West.

Rizzo said, “It means that we have a potential of tropical storm force winds and we’ve just got to remain vigilant because we’re pretty much right up at the line here. We have a tropical storm warning already in effect for the Dry Tortugas. It’s going to be really rough out in the waters west of us. Any nudge of the track slightly eastward or if the hurricane center, which is of course watching the future track intensity and size of the storm, if that nudges anywhere closer, we could have that watch upgraded to a warning which means we would expect tropical storm force sustained winds in the Lower Keys.”

Further north it doesn’t look like there’s any potential at the moment for a watch or warning.

Rizzo reminded, “But we’re going to feel it as it goes by all through the Keys. It’s going to get windy, there’ll be a south wind, the waves are going to kick up on the ocean side and because of the long duration as Idalia moves up into the eastern Gulf, we’re expecting some rises on the ocean side. It could get the water one to two feet above normal high tide. So that’s going to cause some extensive street flooding and build in the low lying ocean side neighborhoods. There will be heavy wave action, which means sea seaweed sponges and other matter gets tossed up over the sea walls and docks. So, anywhere along the ocean side, facing beaches, we expect definitely some over-wash and some flooding there.”

The storm likely won’t be all rain. There could be hours where it’s just windy and then suddenly there will be a fast-moving squall.

Rizzo said, “These conditions will go all the way into Wednesday. But by Wednesday evening, Idalia will be far enough north, unfortunately probably a major hurricane up in the Northeast Gulf of Mexico and approaching this Florida coast up there. But down here, we think our conditions will start to gradually improve. By Thursday, hopefully we can have most, if not all of our marine hazards, taken down by that point.”

It’s important not to get a false sense of comfort.

Rizzo said, “When folks are looking at those cones on the map, that only represents the two thirds chance that the center of the storm actually passes within that cone. So naturally, it gets narrower as you get closer in time to the closest approach or a landfall. So that does not tell you where the hazards are. That’s where watches and warnings come into effect. They’re very simple pieces of communication that can tell you whether you have an increased potential of seeing something or whether or not we’re actually expecting it in the area. So tropical storm watches and warnings refer to the winds. Thankfully, we’re not expecting the type of surge that would warrant a storm surge warning, but we’ll probably have to issue coastal flood advisories and coastal flood warnings because of the potential threat to property such as vehicles in low lying areas or near the ocean front. We want to make sure we take this time today, it’s getting a little bit breezy, but we’re not expecting heavy weather for much of the daytime here.”

Today would be a great time to secure loose objects in the yard.

Rizzo said, “For those who do live in low lying areas and especially if you live on a street where you see the king tides come up this time of year, unfortunately with the king tide coming up, we have a full moon coming up on Wednesday, this is all going to lead to a potentially higher water level without having hurricane force winds or things like that, we can see definitely some coastal flooding. So folks who in those areas might want to consider moving their cars to a different location.”

It looks like the storm may roll in late tonight.

Rizzo said, “It will start out with an occasional squall, probably late tonight, perhaps after midnight, but we’re expecting the heaviest weather to kind of set in during the morning hours tomorrow after sunrise. It’ll be worse towards the western end, towards the Key West area and the waters west. That will continue all the way through into Tuesday night. But we expect some gradual improvement to set in starting Wednesday. Hopefully by Thursday, the winds will be low enough that folks can get around and make sure they take care of anything that might have been blown about.”

How accurate is the modeling at this point?

Rizzo said, “You’re referring to something that folks like to call the spaghetti plot. They are basically numerical trackers of where the lowest pressure is on every member. Ensemble MOM modeling, for instance, is the single model that has slightly perturbed conditions at the start and that’s due to we have uncertainty about the exact location of the storm, how strong is the maximum winds and structure and size and those can cause deviations down in time where it goes. What’s interesting about this one is even after meandering about in the Northwest Caribbean, and kind of wandering around, now that it has established that north track we see tightly clustered, in other words, the spaghetti looks like it’s all still bundled up in the box. When you see them close together, that gives higher confidence on where the storm may go in the official hurricane center forecast. So things we look for, we don’t see strands of spaghetti, in many cases, making a turn right for the Keys. Those outliers that we noticed, don’t appear as strong as those that are following that tightly clustered track. So confidence is increasing.”

The uncertainty lies in the exact size of the storm.

Rizzo explained, “So imagine a bull in the china shop, well the bull is quite large and if we don’t get that size correct it’s going to bang into the Key West dish as it walks down the aisle. Right now, because of that potential, we do have the tropical storm watch. If anything, appears to make those tropical storm force winds in the forecast move further east, then we would have to upgrade to a warning later today. That’s going to be the big dilemma today that we’re going to try to solve.”

How much of a factor was the recent extreme heat in the formation of this particular storm, as well as potential other storms throughout our hurricane season?

Rizzo said, “The water temperatures out in the deep ocean are, they’re just a little bit more than normal compared to what we had in the shallows recently, a few weeks ago for Florida Bay. This is late August. This is when the waters are pretty much the warmest all throughout the Caribbean. What is important in the track with Idalia is that as it moves north into the Gulf of Mexico, it’s going across the loop current. What makes that even more of a source of energy than the Caribbean itself is that the warm water is not just warmer than the surrounding parts of the Gulf, but it’s sufficiently deep, which means hurricane force winds and the large waves that it churns up in the Gulf of Mexico don’t cause cold water to up well, from underneath. It’s just more warm water. So what that means is you can bring an intensifying hurricane through there without chilling the waters and that’s why this is going into the factors of the fact that Idalia may intensify rapidly in the eastern Gulf and right now is forecast to be a major hurricane as it approaches the Gulf Coast by midweek.”

What’s the most important part of this storm that the public should know?

Rizzo said, “Don’t get hung up on the center tracks and the cone because the cone does not represent the impacts. Follow the messages that relate to watches and warnings. If that tropical storm watch is upgraded to a warning for the Lower Keys, that means we go from a strong possibility to an expectation. So tropical storm force winds as we learned, even as Ian passed by, of course Ian was at the time stronger and was closer moving over the Dry Tortugas. You can see what tropical storm force winds do when the winds blow 50, 60 miles an hour and your wind gusts can get up above 70 miles an hour. That’s when the trees really start to come down, even in a hearty area such as the Florida Keys. Once you get into that upper range of winds, that’s when you start seeing the big serious power outages and things. So hopefully, we’re going to cross our fingers and hope that’s not the case with us, but that we’re dealing with more lower end tropical storm force conditions. But as we as you know, it can take just one squall to blow something around. So again, the message goes back to please don’t look at the cones to decide whether to secure your loose objects outdoors and of course if you have a small vessel outside that you want to secure. The weather is good right now to do that.”

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