Idalia about to become a major hurricane and will deliver catastrophic storm surge to the Big Bend and portions of Apalachee Bay

One-sentence summary

Hurricane Idalia is expected to make landfall in the morning as a category 4 major hurricane, bringing catastrophic storm surge to the Florida Big Bend region and Apalachee Bay, an unprecedented storm in modern history for this region.

The forecast for Hurricane Idalia suggests at category 4 storm at landfall tomorrow morning in Apalachee Bay. (NOAA NHC)

Hurricane Idalia: 110 mph, moving North at 18 mph

As of the 11 PM ET advisory, Idalia is on the cusp of becoming a major category 3 hurricane. Idalia is beginning to take on “the look” when you look at satellite imagery. Unfortunately, if you’ve watched the Gulf since 2017, when a storm takes on “the look,” it usually means the forecast of a major storm with major impacts will verify. We’re in that boat tonight.

Hurricane Idalia is beginning to acquire “the look” we have come to know and dread in the Gulf of Mexico in recent years. (Tropical Tidbits)

What’s changed since late afternoon?

A few notable changes: First the storm track has shifted the landfall point even a little farther west, now in the middle of Apalachee Bay. This has implications on Tallahassee discussed below.

Second, storm surge heights have increased. They are now as high as 12 to 16 feet above ground level in the eastern portion of Apalachee Bay and the Big Bend. Basically St. Marks to Yankeetown is likely to be completely inundated with deep water. Surge heights are slowly being trimmed back on the southwest coast of Florida up through Tampa as Idalia accelerates north.

Surge forecasts have been added for North Carolina now, with perhaps as much as 2 to 4 feet in some of the mainland shores of Pamlico Sound, as well as near Cape Lookout.

Surge update

Catastrophic surge is expected in the Florida Big Bend. Not much else to say here. There’s been little change since earlier this evening in terms of this impact. The forecast has shuffled a bit with 12 to 16 feet of surge now as far west as the Wakulla/Jefferson County line, just east of St. Marks. We continue to believe this will come into an area with no real modern historic precedent of this level of hurricane hitting (best comp perhaps being in the late 1800s).

Storm surge is now expected to be as high as 12 to 16 feet above ground level in the eastern half of Apalachee Bay and the Big Bend, an absolutely catastrophic amount of water. (NOAA NHC)

This is the last warning folks in the relatively rural Big Bend have to get out. These smaller communities will need a lot of help in the days ahead.

Wind update

The core of strongest wind is expected to be just east of Tallahassee across much of the Big Bend into much of north-central Florida and far south Georgia. Live Oak, Lake City, Alachua, and Valdosta may all see significant hurricane-force winds. Considerable wind will also be possible as Idalia moves into Georgia, so communities like Waycross, Kingsland, or even Brunswick could see strong winds.

Purple, the area of worst wind potential may nudge a little left (west) depending on Idalia’s exact track. But much of the Big Bend and north-central Florida will see significant hurricane-force winds. (NOAA)

The exact location of these strong winds may maneuver a little west if Idalia’s track shifts any farther that direction.

Tallahassee

For the city of Tallahassee, the track of Idalia has not trended kindly today. The slight nudge west today has kept Tallahassee in play for the western eyewall of Idalia as it comes ashore. What does this mean? It means that most of the city will either see generic damaging winds (hurricane-force gusts, mostly) or sustained hurricane-force winds and widespread damage potential. There may even be a relatively noticeable east to west gradient of damage, with more of it on the east side and less to the west. We’ve gotten no real additional clarity tonight on exactly how close that will come, but suffice to say, it will be close.

Rainfall from Idalia

Idalia is expected to be a pretty healthy rainmaker as it comes north. Flood watches extend from Florida into North Carolina now. There will be corridor of 6 to 10 inches of rain up the coast, just inland, basically along and west of I-95, depending on exactly how Idalia tracks.

The rain forecast from Idalia is not significantly changed tonight, with 6 to 10 inches possible in interior south Georgia and South Carolina, as well as in portions of southeast North Carolina. (NOAA)

I think North Carolina bears some watching, as there is a sign in some modeling for an area of enhanced rainfall from about Cape Hatteras south and west onto the mainland near New Bern where amounts toward the higher end of the forecast range are possible. The Weather Prediction Center has a “moderate” risk (level 3/4) for this region for excessive rainfall and flooding for Wednesday.

The excessive rainfall outlook on Wednesday is at “moderate,” level 3 of 4, which means flash flooding is a good bet in some areas. I especially think SE North Carolina bears some watching tomorrow night. (Pivotal Weather)

Thankfully, Idalia should be moving offshore by Thursday morning, ending the rain threat in the Carolinas and Georgia.

As is always the case, isolated tornadoes do occur with landfalling tropical cyclones, and Idalia should be no different. The highest chances of a tornado would be in North Florida, coastal Georgia or coastal South Carolina.

Charleston, Savannah, and Jacksonville

We continue to monitor the risk of storm surge and coastal flooding in some of the larger metro areas on the Atlantic coast, in particular Charleston, Savannah, and Jacksonville.

For JAX, this should be hopefully mostly a nuisance event, with wind gusts to 50 mph and about 1 to 3 feet of surge. This would produce mostly minor to moderate flooding in the Jacksonville area.

In Savannah, winds could be stronger, as it will be closer to Idalia’s center when it comes by, so gusts of up to 70 mph are possible there. In addition, up to 4 feet of water above ground level is possible.

The Fort Pulaski tide gage, just downriver from Savannah is expected to peak with “moderate” tidal flooding levels. (NOAA)

The 10.3 foot forecast at the Fort Pulaski tide gage would be the highest since last November’s 10.41 foot level. This is associated with moderate coastal flooding.

In Charleston, the Harbor is still forecast to get to 8.3 feet, which qualifies as “major” tidal flooding. Of course, coastal flooding is a scourge in Charleston, and this level was achieved as recently as June of this summer.

Although tidal flooding is common in Charleston, with this forecast level being seen as recently as June, the heavy rain and wind may lead to slightly worse than usual impacts from this level of water. (NOAA)

Charleston should see wind gusts as high as 60 mph with Idalia as it passes by, which may in combination with heavy rain complicate drainage of water a bit, making this tidal level a little worse than what would normally be expected with 8.3 foot tides.

The second act

Once again, I just want to close out on this: Don’t worry about the second act of Idalia, as some models show it looping back toward Florida heading into next week. It’s simply not a relevant concern at the moment and the storm would likely be a shell of itself if it happened that way. We are not concerned right now about this coming to fruition in a serious manner. The focus should be on impacts tonight and tomorrow.

Our next post will aim to come at you around 7:30 AM ET Wednesday.

Idalia shifts a little west as forecast for major hurricane landfall continues in Florida’s Big Bend or Apalachee Bay

One-sentence summary

Idalia is steadily strengthening today and is expected to come ashore as a major hurricane tomorrow morning somewhere in the Big Bend of Florida or Apalachee Bay with catastrophic storm surge and damaging wind potential increasing for Tallahassee.

Idalia is forecast to blast into Apalachee Bay tomorrow morning as a major hurricane. (NOAA NHC)

Hurricane Idalia: 100 mph, moving N 16 mph

The bottom line on Idalia this evening: A catastrophic storm surge impact is expected in the Big Bend and Apalachee Bay from a major hurricane tomorrow morning. In addition, strong winds will buffet the west coast of Florida along with surge up through Tampa to the Big Bend as well. Tallahassee is now going to come close to getting into the western eyewall of Idalia as it moves inland, which could lead to wind damage and widespread power outages. Idalia will continue producing wind and rain impacts into south Georgia with coastal flooding up the Georgia and South Carolina coasts as well.

What’s changed since this morning?

A few things. First, the general forecast remains on track. The landfall point has nudged a bit farther to the west, which introduces the risk of catastrophic surge to a wider portion of Apalachee Bay. We are now looking at 3 to 7 feet on the west side of the bay and 10 to 15 feet on the east side into the Big Bend.

Storm surge will be catastrophic in the Big Bend area of Florida and on the east side of Apalachee Bay (NOAA NHC)

More on surge in a moment.

Tropical Storm Warnings extend up into North Carolina (Surf City) now with TS Watches posted north of there to the Virginia border. Hurricane Watches remain for the coast of Georgia and South Carolina up to Edisto Beach. Hurricane Watches were dropped on the west coast from Englwood to Longboat Key, and the Storm Surge Watch was dropped south of Bonita Beach, FL.

Another big change today has been the westward nudge likely putting Tallahassee in play for potential eyewall winds tomorrow morning as Idalia comes ashore. Using the GFS operational model as our guide, we can annotate roughly where the strongest winds *should* go at present.

A rough outline of where the strongest winds will be with Idalia: Not far from Tallahassee, perhaps stretching into Valdosta and much of South Georgia as well. This *could* shift around up to landfall. (Weather Bell)

Tallahassee is currently right on the edge of the stronger winds as Idalia comes ashore. This will probably be a close call between hurricane-force gusts and widespread hurricane-force winds with significant damage. Prepare accordingly. Anywhere that sees the strongest wind could see multi-day power outages.

Hurricane Idalia is slowly taking on much better definition as it intensifies and it should use tonight to turn itself into a classic looking major hurricane by morning. (Weathernerds.org)

Other notes on Idalia in Florida and South Georgia

We discussed Tallahassee above. Tampa Bay will likely see 4 to 7 feet of surge and at least tropical storm force winds. This will cause serious flooding around the bay and along the coast. Please heed the advice of local officials tonight and tomorrow.

For interior and eastern Florida, this actually looks a bit less impactful now. We are seeing bands with isolated tornadoes and gusty winds. But for places like Orlando and Miami, it should not get too much worse. For Jacksonville, that area will see winds pick up tonight and tomorrow as Idalia passes by to the north and west. Wind impacts will be most significant west toward Lake City and north toward Waycross, GA and Brunswick, GA. Minor surge impacts are possible on the First Coast, with slightly higher surge impacts in Georgia (2 to 4 feet).

For Savannah moderate flooding is expected, but for Charleston, SC major flooding is forecast.

Major flooding is expected in Charleston due to Idalia’s surge. Rainfall may exacerbate things during Wednesday evening’s high tide. (NOAA)

Along the Georgia and South Carolina coasts, as well as near where Idalia comes ashore in Florida, water levels could be locally higher than forecast due to heavy rainfall as Idalia comes in, preventing water from being able to drain.

More on surge

The amount of water that is expected to inundate portions of Citrus, Levy, Dixie, and Taylor Counties is catastrophic. The National Hurricane Center spends a lot of time deliberating when to use that word, but they chose it for this storm. Given that there is no modern history of a storm of this magnitude coming ashore in this area, there is no precedent for what is going to occur here. That’s a terrifying inundation map from this morning, which shows surge possibly going *well* inland from the coast in the Big Bend.

The inundation map for Idalia’s storm surge shows surge spreading well inland in the Big Bend. While the Big Bend is sparsely populated in Florida, for those communities, this will cause catastrophic damage. (NOAA)

The map above shows the scenario that has a 10% chance of being exceeded. This is somewhat of a worst-case scenario type map, but it gives you the right idea. You do not want to be on the coast or a few miles inland in the Big Bend. Surge impacts west of here will also be bad for Apalachee Bay, but less severe than this. Regardless, this is truly catastrophic surge coming to the Big Bend and east side of the bay.

Idalia’s exit

We still anticipate that Idalia will weaken to a tropical storm over Georgia and South Carolina, and it should exit the coast somewhere between Wilmington, NC and Savannah, GA depending on the exact track of the storm. From there, all bets are off in terms of track. We do expect wind shear to become a severe issue off the East Coast, so that should keep any reintensification of Idalia in check. I would not spend much time worrying over a second act of Idalia at this time. We’ll keep you posted. We’ll update once more later this evening and again in the morning. Look for a video update on our social channels this evening.

Editor’s Note:

I neglected to discuss rain before hitting publish. Here’s the latest rain forecast. Our late evening post will take a closer look at this.

Idalia’s Tuesday evening rainfall forecast (NOAA)

Idalia is now a hurricane and still on track to impact the Big Bend region of Florida as a major hurricane Wednesday morning

One-sentence summary

Hurricane Idalia is expected to rapidly intensify today and tonight and come ashore somewhere in the Big Bend area of Florida as a major hurricane tomorrow, producing extremely dangerous storm surge, in addition to strong winds and heavy rain well away from the center.

Hurricane Idalia is expected to come ashore on Wednesday morning near the Big Bend of Florida as a major hurricane. (NOAA NHC)

Hurricane Idalia

The bottom line on Idalia is that it is expected to come ashore near the Florida Big Bend as a major hurricane, without much modern precedent in this area. This will lead to severe wind and potentially catastrophic storm surge in many communities in this region. Preparations need to finished quickly today, and advice of local officials should be heeded.

What’s changed overnight?

The only notable change overnight (besides becoming a hurricane) may be that model forecasts have nudged the landfall point a little to the west. This further increases the odds of a historic surge event and hurricane impact in the Big Bend. There were no serious changes to watches or warnings, and you can see that Hurricane Warnings are posted from Manatee County north through coastal Franklin County in the Panhandle, as well as inland along and west of I-75. Tropical Storm Warnings are posted for the East Coast from Brevard County north past Jacksonville and into coastal Georgia just past St. Simons Island, extending inland across much of southeast Georgia.

The watch and warning situation as of 7 AM ET Tuesday. (Pivotal Weather)

Idalia’s track to Florida

Hurricane Idalia is expected to track steadily north/north-northeast today and tonight. The exact landfall point remains a bit fuzzy, but the overnight shift west is somewhat notable. There is a bit more risk in parts of Apalachee Bay than there perhaps seemed yesterday. But generally speaking, the Big Bend into Apalachee Bay seems most likely for landfall.

Idalia is getting its act together as it moves over exceptionally warm water southwest of Florida, and it will likely begin to look more like a classic hurricane through the day today. (weathernerds.org)

Idalia’s storm surge

With the track where it is, there have only been minor adjustments to the storm surge forecast from the National Hurricane Center.

Storm surge is still expected to be life-threatening and potential catastrophic for the Big Bend area in Florida. (NOAA NHC)

At this point, from Tampa south, most of the surge forecast is now baked in. North of Tampa, the bullseye of surge may shift a bit with landfall, closer to Aucilla River and in Apalachee Bay with a shift west in track, or just a bit down coast toward Homosassa with a little eastward shift. But in general, this morning is the time to finalize preparations for as much as 8 to 12 feet of water in the Big Bend and east side of Apalachee Bay.

The tidal forecast for Charleston, SC shows “major” flood levels being reached on Wednesday evening. (NOAA)

On the East Coast, we continue to see forecasts of about 2 to 4 feet of surge for Georgia and South Carolina south of the Santee River. For Charleston, there could be “major” flooding levels hit with this during Wednesday evening’s tide cycle.

Idalia’s wind

The wind forecast for Idalia brings it ashore as at least a 120 mph category 3 hurricane. There is some chance it could be stronger than that. Major hurricane force winds will be confined to a small area near the center as it comes ashore. Hurricane-force and tropical storm-force winds will extend out rather far from the center, especially to the east.

The current hurricane wind threat is highest in the Big Bend, with hurricane-force winds possible near Gainesville and as far inland as Valdosta, GA. Tallahassee should see at least hurricane-force gusts. (NOAA)

The primary wind damage risk will be in the purple shaded region above in the Big Bend. Tallahassee, Valdosta, and Gainesville into the extreme coastal northern fringes of the Tampa metro may see hurricane-force winds as well. Those winds may also occur on the immediate Georgia coast as well. Tropical storm-force winds will include much of Tampa and Jacksonville up toward Savannah and farther up coast into South Carolina. Power outages are likely for a chunk of north Florida, south Georgia, and coastal South Carolina.

Anywhere from 6 to 10 inches of rain will be possible in the hardest hit areas along Idalia’s track, leading to potential flash flooding. (NOAA NHC)

Idalia’s Rain

We continue to view rain as more of a secondary hazard from Idalia, as its forward speed *should* allow for some mitigation of outcomes there. Still, you could see as much as 6 to 10 inches of rain in spots, and in addition to causing localized flash flooding, this could exacerbate tidal flooding along the immediate coast or bays. Flood Watches are posted in many spots and may expand north through the day today. We’ll hone in some more on this later.

Idalia’s exit and distant future

What happens after Idalia exits the U.S. coast? That’s a great question that we just don’t have a great answer to right now.

Truly, we aren’t really sure what will happen to Idalia after it moves back offshore of the Southeast this weekend. We need some time to sort this out, but no one needs to worry at this time. (Weathernerds.org)

The pattern that will steer Idalia becomes more convoluted this weekend once it moves offshore of the Southeast. From there, models are, for lack of a better term, confused about where it will go or if it will even maintain identity at that point. The bottom line here is that no one needs to currently worry about a second act from Idalia, but we’ll keep tabs on this in the coming days to see what, if anything happens.

Hurricane Franklin

Franklin became a textbook category 4 hurricane yesterday, and it’s producing rough surf and dangerous rip currents in Bermuda and along the Eastern U.S.

Hurricane Franklin is expected to zip out to sea over the next 5 to 6 days, and it will probably eventually be absorbed into a storm over Greenland. (NOAA NHC)

Franklin is going to steadily head out to sea over the next 5 days, and it should eventually get drawn back north and west, absorbed into a high latitude storm over Greenland.

Elsewhere

Old Invest 92L has a shot at developing into a weak system east of Franklin’s track. A new wave emerging off Africa has about a 70 percent chance of development over the next week as it heads out to sea. No threats to land are seen beyond Idalia over the next 7 to 10 days.

Idalia on the verge of becoming a hurricane with its sights set on Florida’s Big Bend region

One-sentence summary

Final preparations in advance of expected major hurricane Idalia should be made by tomorrow morning on the Florida coast, as the storm’s impacts will begin spreading that way by Tuesday afternoon or evening.

Idalia is on the cusp of becoming a hurricane this evening as it begins to lift into the Gulf of Mexico. (NOAA NHC)

Idalia right now

Idalia has been battling some shear today that has held it back a bit in terms of significanr intensification and organization. To be clear, this was expected, and even in the face of this Idalia has held its own and added some lower pressure and stronger wind. As shear moves around a bit tonight and tomorrow and Idalia begins to advance northward, it should begin the process of rapid intensification, just in time for its arrival in Florida. The general rule of thumb in recent years has been that if anything can go wrong in the Gulf of Mexico, it will, and Idalia may add to that list. Let’s focus on impacts today.

Idalia has not moved a whole heck of a lot today, sitting generally just southwest of the western tip of Cuba.

A satellite loop shows some significant thunderstorms near and just south of the center of Idalia in the pink and purple hues. Idalia is expected to become a hurricane tonight. Florida is at the top-center of this loop. (Weathernerds.org)

Max winds are currently 70 mph, and Idalia should become a hurricane tonight. Hurricane warnings are in effect for western Cuba. As noted above, wind shear has inhibited Idalia a bit to this point, but we expect that to loosen up some tonight and tomorrow.

Forecast track & uncertainties

Idalia will broadly come north-northeast toward the Big Bend of Florida. There’s still a good deal of uncertainty on the exact landfall point. Because of the angle of approach from Idalia and the unique geography of Florida, a slight shift in track could yield a decent shift in surge impacts. As we’ll note below, the impacts beyond surge should be relatively baked in now for most spots, with a few exceptions.

You can see the ensemble spread here from the European model is still considerable, with a handful of ensemble members close to Tampa and many more spread across the Big Bend, as well as a couple as far west as Apalachicola. Recall, the Euro ensemble consists of 51 model runs “tweaked” at initialization slightly to produce some goal posts for outcomes. We need this in tropical situations.

In terms of wind and rain, the forecast will be fairly straightforward regardless of track. The exceptions to this will be the core maximum winds that extend out 10 to 20 miles from the center. We still need to fine tune that. But a broad swath of tropical storm or even hurricane force winds will be possible along much of the west coast of Florida and a bit inland from there.

The storm surge forecast for maximum potential water above ground level shows as much as 8 to 12 feet of surge possible from Chassahowitzka around the Big Bend to the Aucilla River. This is contingent on the exact track of Idalia, with these values shifting some based on the precise landfall point. (NOAA NHC)

In terms of storm surge, things get a lot trickier. As we saw with Ian last year, the track south of Tampa led to catastrophic surge in Fort Myers and an empty Tampa Bay. Initial forecasts were calling for significant surge flooding in Tampa. We will have to watch the exact track of Idalia closely to determine exactly where the worst surge occurs and where the inflection point between onshore and offshore winds occurs. But in general, significant, damaging, dangerous storm surge is likely in the Big Bend and along the Nature Coast south to near Tampa Bay. Surge impacts in Tampa should be considerable but not quite as serious as farther north. And surge impacts south of Tampa will be modest but notable. Moderate surge is possible on the South Carolina and Georgia coasts as well into Wednesday.

It cannot be overstated that everyone from Apalachee Bay to Sarasota needs to prepare for the reasonable worst case scenario surge, understanding that if the track shifts, conditions could get worse or better depending on that exact track. There will be some element of overpreparation in some communities, which is an outcome you need to accept. Wind is a concern with this storm, rainfall a secondary concern. Surge? The biggest concern I have with this thing. Please take it very, very seriously. There is no modern analog to this storm in the Big Bend, and the surge impacts are likely to be dire.

Intensity

The current National Hurricane Center forecast brings Idalia ashore as a major, category 3 hurricane with maximum winds of 120 mph. We could see a slightly stronger storm (or even a weaker storm!) depending on the track and how efficiently Idalia can undergo its expected rapid intensification.

The probability of hurricane-force winds along the path of Idalia show potential as far inland as Orlando and Ocala and as far west as Tallahassee still. Tropical storm winds are likely in these areas and capable of causing damage and knocking out power. (NOAA NHC)

For folks along the coast from Sarasota north, expect hurricane force gusts possible and sustained tropical storm force winds. Inland, including the west side of Orlando will see tropical storm force wind gusts. The core hurricane conditions will follow near and east of Idalia’s center, likely impacting the Big Bend, Nature Coast counties north of Tampa and perhaps grazing Ocala. Inland hurricane conditions are likely for Gainesville, Lake City, and perhaps the western side of Jacksonville, as well as in extreme southeast Georgia. As long as the storm stays on its current forecast track, Tallahassee should be spared significant impacts.

Click to enlarge the image of wind risk in Florida, with Orlando possibly seeing tropical storm force winds, Tampa seeing tropical storm to hurricane-force winds, and the strongest winds in purple west of Ocala and Gainesville (NOAA)

For the east coast, tropical storm watches are in effect from Sebastian Inlet, FL north past Savannah and Charleston to the South Santee River in South Carolina. Storm surge watches cover the area north of the Florida/Georgia line to the South Santee River.

Rainfall

In terms of rain, anywhere from 4 to 8 inches will be possible along the track of Idalia across North Florida, into southeast Georgia and South Carolina as well as southeast North Carolina. Flooding is possible in any of these locations, but the increasing forward speed of Idalia will hopefully help mitigate severe freshwater flooding concerns.

Places like Jacksonville, Savannah, and Charleston will want to prepare for a combination of surge flooding, worsened by rainfall, which will prevent water from draining as quickly as usual. In those areas, flooding could be a little more noteworthy. We’ll touch on that some more tomorrow.

As is always the case with landfalling tropical systems, isolated tornadoes are possible across Florida and into southeast Georgia and the southeast Carolinas.

So, to summarize:

  • Idalia is likely to lead to dire storm surge impacts in the Big Bend of Florida with no real good modern analog.
  • Surge is highly likely south and east of where Idalia comes ashore, far from the center, but the landfall point matters significantly in determining who sees the worst surge. All of Gulf Coast Florida between Apalachicola and Sarasota should prepare for surge impacts.
  • Idalia’s strongest winds will impact the Big Bend and just inland, but gusts to hurricane-force are possible for Tampa and Ocala, and sustained hurricane-force winds may impact Gainesville and the western side of Jacksonville. Idalia’s wind field will extend well east of where it comes ashore.
  • Rainfall is a secondary impact in most spots in this particular storm, but still 4 to 8 inches of rainfall could cause flooding in Florida, southeast Georgia, coastal SC and southeast NC.
  • Places on the East Coast like Charleston, Savannah, and JAX could be dealing with some moderate surge flooding exacerbated by rainfall that limits drainage.

Our next full update will be on Tuesday morning. Look for a video update this evening on our social channels and follow our Twitter feed and Instagram stories for some other notes this evening.

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