Matt Lanza

Hurricane Erin growing in size, likely to cause dangerous rip currents and rough surf on the East Coast

In brief: Erin is weaker but larger today. As the wind field continues to expand and Erin reintensifies, look for significant impacts on the East Coast from rip currents and rough surf. Near term tropical storm impacts will affect the southeast Bahamas and Turks and Caicos Islands. Fringe impacts remain possible later this week for the Outer Banks, Bermuda, and Newfoundland.

(NOAA NHC)

Erin underwent an eyewall replacement cycle (ERC) overnight. An ERC is essentially a way for a storm to press the reset button while it’s at a powerful intensity. A new eyewall forms on the outside of the original eyewall, allowing the storm to expand in size. The trade-off is that when an ERC occurs, the storm loses intensity. Then, typically it will begin to reintensify. In Erin’s case, it weakened from a category 5 to a category 3 storm this morning, and now it should undergo another round of intensification.

24 hour change in satellite presentation of Erin from Friday to Saturday to Sunday. (College of DuPage)

If you look at the satellite imagery above, you’ll see Erin pretty clearly near the Caribbean islands. You can see how ragged it looked on Friday morning, how potent it looked on Saturday morning, with a very, very clear eye. But if you look close enough, you can see how it expanded in size today. Erin’s tropical storm-force wind field has expanded markedly since yesterday. It went from a 125 mile radius yesterday to 205 miles today. Hurricane-force winds remain relatively tightly wound to the center, only extending out 25 miles. The ERC will most often expand the tropical storm wind field, making the storm a bigger surge and wave maker than anything else. Whatever the case, expect Erin to remain a major hurricane the next 2 to 3 days with winds fluctuating between category 3 and 4 intensities. More importantly, Erin could continue to slowly grow in size.

Track is becoming a little more important to potential outcomes for various locations. Starting in the near-term, the Bahamas and Turks and Caicos Islands are likely to experience tropical storm conditions today and tonight. Tropical Storm Warnings are posted for the Turks and Caicos, and a Watch is posted in the southeast Bahamas. That could get upgraded to a warning before too long. Heavy rain and gusty winds in those outer bands, much like we’ve seen in Puerto Rico since yesterday will be possible.

Erin’s track has slowly migrated a bit to the south and west. Coupled with size expansion, this may mean some additional impacts in the Outer Banks or Atlantic Canada, as well as Bermuda. (Brian Tang/UAlbany)

The consensus track from the top performing models has been correcting south and west really since Erin formed, but also over the last day and a half or so too. This adjustment is leading to some slightly increased concerns for the Outer Banks of North Carolina in particular but also perhaps Atlantic Canada, particularly Newfoundland. First off, you can see how the wave forecast will go this week. Large waves begin pounding the East Coast Tuesday, peaking on Wednesday and Thursday, and then diminishing next weekend.

Large waves will propagate outward from Erin, beginning to reach the U.S. East Coast by Tuesday. (Weathernerds.org)

Suffice to say, this will make for very poor conditions at the beach. Anyone planning to visit the beach or go swimming this week from Florida into New England should give second thought to doing much in the ocean through at least Friday. If you do go swimming, please head all flags and posted signs and only swim where lifeguards are present. Between the rough surf and very dangerous rip currents, it will become straight up unsafe at times, even for stronger swimmers.

In terms of whether or not we see any direct impacts, or at least fringe bands make it to the Outer Banks, it’s very much a wait and see situation. If the current forecast holds unchanged, maybe not much more than gusty winds at times. If the trend west continues further, we will begin to say that gusty winds, possibly tropical storm force gusts, and locally squally conditions will become more likely. We’d encourage folks in eastern North Carolina, particularly on the Outer Banks to continue to watch Erin closely. This area is pretty used to hurricane impacts, but as always, keep an eye on things to be safe.

Down the road for Nantucket and Cape Cod, it seems likely that Erin will pass far enough offshore to avoid impacts. Probably still right to keep tabs on any changes. And then heading toward Newfoundland, if Erin impacts that area, it would not be until next weekend. Plenty of time to watch and still most likely just a brush by. For Bermuda, Erin may also cause a brush-by of impacts as it comes north.

Bottom line: The most serious impacts in Erin’s future will likely be rough surf and rip currents on the East Coast, but there is growing consensus that some fringe impacts will affect the Outer Banks, Bermuda, and possibly Newfoundland before all is said and done.

Behind Erin

I’ve already seen the “usual suspects” on social media move on from Erin “fear porn” to the next system. The NHC has assigned this one a 20 percent chance of development over the next week in the eastern Atlantic.

Development odds sit at 20 percent today for the next system that will follow Erin across the Atlantic this week. (NOAA NHC)

Admittedly, I think the odds of development are truthfully higher than this. I would expect we see an attempt at a tropical depression by Wednesday or Thursday. This system is likely to come west across the Atlantic at a slightly farther south latitude than Erin did. So in some ways, this should be a little sneakier. If we look at the upper map that this disturbance will be working around, we can see a couple key things. First, Erin is going to erode high pressure in the subtropical Atlantic. This will keep a pretty stout weakness in place there. If this next wave is quick to develop, it would almost certainly follow Erin to the north in the open Atlantic. However, there is another pretty strong trough of low pressure in the upper atmosphere expected to dive southeast into the Eastern U.S. after next weekend. If and when this occurs, it would also be likely to “capture” this next wave.

The next wave has a couple opportunities to be picked up and pulled northward. Questions remain as to what shape it will be in if that happens, or if it will even develop at all. (Tropical Tidbits)

Of course, this all matters. But it’s too soon to speculate on how it matters. Generally speaking, the quicker this is to form, the quicker it would be to exit. The slower it is to develop, the higher chance it may become a disturbance of land impact eventually. But there remain questions on if this will be able to develop a whole lot at all. AI modeling strongly supports the “follow Erin out to sea” outcome. European modeling is less sure but also less bullish on development. The GFS is literally all over the map, ranging from the Gulf to east of Bermuda. So, we have a couple thoughts here, but we’ll need to watch things over the next few days before we can begin to say anything with any degree of confidence. Stay tuned.

Hurricane Erin, still unlikely to directly threaten land, undergoes a historic round of intensification, now flirting with category 5 intensity

In brief: Erin enters the record books as one of the quickest intensifying Atlantic hurricanes on record, now flirting with category 5 intensity. It remains unlikely to directly threaten any land, but fringe impacts will continue to impact the northeast Caribbean, possibly the Bahamas, and perhaps Bermuda. No threat to the U.S. or Canada.

Erin exploded overnight into a category 4 hurricane. As of the 11 AM AST advisory it has 155 mph maximum sustained winds, just a sneeze away from category 5 intensity.

Erin’s forecast track. (NOAA/NHC)

Why? Well, it always was expected to strengthen quickly. But Erin was able to close itself off from external dry air and shear and basically insulate itself, contract in size, and explode.

Hurricane Erin’s satellite appearance in the last 24 hours has evolved dramatically. (Tropical Tidbits)

Erin’s small size works to its benefit, as hurricane-force winds extend out a mere 30 miles from the center. This is good news for the islands, as they’ll be a comfortable distance from the powerful winds. Erin should intensify a little further today. After today, the storm will likely become prone to fluctuations and internal processes that impact intensity (things like eyewall replacement cycles, etc.). So it may wax and wane a bit after today or tonight.

Calm seas in the eye vs. rough seas in the eyewall of Erin from the hurricane hunter mission this morning. (NOAA)

Let’s talk real quick about Erin’s intensification rate. Erin is the quickest intensifying Atlantic hurricane by a significant margin (before Sept 1) that we have data on, according to Sam Lillo. A 70 mb drop in 24 hours is incredible. The warming oceans are certainly one factor playing a role in this. By every metric, Erin will go down as a historic Atlantic hurricane.

Heading into next week, Erin will begin to feel some wind shear and start advancing toward cooler water, so we’ll see a slow decline in intensity for Erin, with most modeling bringing it back below major hurricane intensity by Tuesday or Wednesday.

How about track? Well, we’ve got good agreement today. At present, we’re seeing some wobbles and subtle shifts southward, so there could be some additional adjustments to the track forecast above, but in general, modeling agrees that this will slow down and turn northward by early next week, pass well off the East Coast and west of Bermuda and south of Atlantic Canada while heading out to sea.

Various ensemble modeling is in pretty good agreement on track with Erin, with Bermuda still perhaps at some degree of risk as Erin exits. (Tomer Burg)

Erin is going to grow in size, so for folks in Bermuda, it will be important to recognize that even though Erin is likely to weaken on its way out, it will be larger in size, which means a close pass, even west of Bermuda could bring some direct or fringe impacts. The biggest questions right now are on the exact timing of various turns.

I don’t want folks to pay too much attention to the wobbling or even track shifting we see north of the islands right now. I see this with every strong storm that occurs. While that stuff does matter in the near term, it should not have a major impact on things in the long term. Powerful storms like Erin tend to wobble and meander a little on the general heading they’re moving in, and it’s not at all uncommon for a storm to deviate from the forecast track by a good bit in the short term before correcting back in time.

For folks in the islands right now, experiencing heavy rain and gusty winds, yes, continue to monitor Erin, but again, the worst of this will stay north of those islands.

Hurricane Erin passing northeast of the Virgin Islands and Puerto Rico. (RadarScope)

On the East Coast of the U.S. and in Atlantic Canada, get ready for rough surf and strong rip currents. That will be increasing in the days ahead. Folks planning a late summer vacation next week to the Jersey Shore or Outer Banks or wherever just want to keep in mind that swimming conditions may be suboptimal or even unsafe at times.

So, bottom line on Erin:

  • Should become a category 5 storm, as it is one of the fastest intensifying Atlantic storms known in the historical record.
  • Track will wobble and meander off course at times; this is normal for elite hurricanes and it doesn’t portend a significant forecast track change.
  • Currently not expected to directly impact any land.
  • Locally heavy rain and gusty winds in the northeast Caribbean today and tomorrow from outer bands and squalls.
  • Rough surf and rip currents likely to become an issue on the East Coast next week.
  • Bermuda should continue to monitor Erin’s progress closely.

Erin now a hurricane but still not a serious land threat, while we watch Upper Midwest flooding risks this weekend

In brief: Invest 98L is about to move ashore in Texas, ending development risks. Erin has finally become a hurricane, and it is expected to intensify in the coming days as it avoids land. An additional tropical wave may or may not develop next week behind Erin. Flooding risks are noteworthy this weekend in the Upper Midwest and in the Grand Canyon.

Invest 98L in the Gulf

First off, let’s get the elephant in the room taken care of: Invest 98L, the tropical disturbance approaching the South Texas coast is becoming less likely to develop now, particularly because it’s quickly running out of runway to work with. Odds remain 50% per the NHC, though if it does develop, it would be a tropical depression for about 3 to 6 hours or less before reaching land in South Texas.

That being said, it looks somewhat interesting on satellite this morning, conversationally at least.

Invest 98L is basically a gnarly looking blob of thunderstorms. (Tropical Tidbits)

This may look a little scary, but in reality, there is no low-level circulation so while there are some heavy thunderstorms and heavy rain underneath this blob of clouds, the system is not organizing much. So you can disregard any meaningful tropical development (wind, coastal flooding) elements of this for the most part.

What we will watch for at least is rain.

A marginal risk (1/4) for flash flooding exists across the Houston area today, with slightly higher risks closer to the thunderstorms in the Valley. (NOAA WPC)

That heavy rain offshore is going to move ashore between Corpus Christi and Brownsville this morning. For the most part, these areas remain in abnormal dryness of lower-end drought, so this rain would be mostly beneficial in nature. Some additional heavier thunderstorms may fire off on the periphery of things late this morning and afternoon, spreading north toward Houston and Victoria and perhaps even as far inland as San Antonio. But by and large the heaviest rainfall will probably be where this stuff comes ashore this morning.

Invest 98L’s blob of rain will come ashore in South Texas later today. (College of DuPage)

We should then be able to close the books on Invest 98L.

The 11AM AST advisory from the NHC. (NOAA NHC)

Hurricane Erin

Erin has finally crossed the threshold into hurricane status this morning. While it certainly still has a number of structural issues, it’s got the underlying parts necessary to make hurricane status.

Erin is trying. Still. But it is now a hurricane. (Tropical Tidbits)

Erin is moving off to the west northwest now at about 15 to 20 mph, a little slower than in recent days. This heading and speed should ensure it stays north of the Caribbean islands. Still, some fringe impacts will bring outer bands with locally heavy rain and gusty winds to the Virgin Islands and Puerto Rico. In addition, strong rip currents and rough seas should batter the islands this weekend. I love the graphic below from the NWS in San Juan.

(NWS San Juan)

Erin pulls away late this weekend. Looking down the road, this should pass similarly north and east of the Bahamas and Turks and Caicos Islands in particular. Again, some fringy type impacts are possible there, particularly with respect to rough seas and rip currents.

From there, the song pretty much remains the same. Erin is expected to turn northwest and north and eventually turn out to sea. Erin should be pretty straightforward track-wise in terms of how it maneuvers around the gap in high pressure over the western Atlantic. I would expect some farther west adjustment of the track forecast from the National Hurricane Center, but in general, look for this to turn north just west of 70°W longitude.

Erin’s tropical modeling is in pretty good agreement overall with minimal outliers at this time. (Tropical Tidbits)

This should keep Erin comfortably east of the U.S. East Coast. This current forecast track also shoots the gap between Bermuda and the East Coast, which would be good for the island. Still, folks on the East Coast and near Bermuda should continue to monitor Erin’s progress in the coming days.

Erin is likely to gradually strengthen over the next couple days. I would not be shocked if we see a burst of intensification as Erin turns northwest on Sunday. It’s going to have to battle a little shear, but the environment may become much more favorable overall, especially with such warm water in the southwest Atlantic. We will almost certainly get our first major of 2025, and it may put on a show for a short while. But as with anything tropical, we’ll see.

Bottom line today: Erin does not appear to be a serious threat to any land mass at this time, but it will be good for folks in the Turks & Caicos, Bahamas, East Coast, and Bermuda to continue monitoring Erin’s progress through the weekend.

Elsewhere

We’ve got a tropical wave likely to follow Erin next week that has the potential to develop, but….uhhh…yeah. Good luck resolving anything today.

A wide dispersion of possible locations of a tropical wave next Tuesday in the Atlantic. (Google Weather Lab)

I won’t bother to try to resolve any of that for you. Just know that we will probably be tracking another tropical wave next week, though at this time it looks to be less organized than Erin.

Beyond the tropics, heads up in Minnesota and Wisconsin. A multi-day rain and thunderstorm event is likely to pile up some healthy rainfall and it stands out as being in a slight risk (level 2/4) the next 3 days for flash flooding.

Heavy rainfall will add up to as much as 2 to 4 inches from central Wisconsin back into Minnesota, including the Twin Cities. (Pivotal Weather)

Repetitive rounds of thunderstorms will move through this area, including a slight risk (2/5) for severe weather today. Hopefully the heaviest rains stay north of the Milwaukee area that was severely impacted by flooding last weekend. Right now it appears that will be the case, but this will merit some monitoring through the weekend.

Slight flash flooding risk (level 2/4) is posted today, tomorrow, and Sunday in the Upper Midwest. (NOAA WPC)

Additional flooding risk as a result of the large burn scar from the Dragon Bravo fire complex in Arizona exists the next couple days as well.

Flooding risks in the Dragon Bravo fire burn scar will be significant with any locally heavy rainfall. (NWS Flagstaff)

The fire itself is 56 percent contained as of yesterday evening, but any heavy rainfall from monsoon thunderstorms will ramp up flooding and debris flow risks in the Grand Canyon region. Anyone hiking or camping near the perimeter of the fire’s burn scar or in the Grand Canyon and along the Colorado River, particularly around Bright Angel Creek should be aware of these risks.

Erin putting itself together Thursday and should pass north of the islands this weekend

In brief: Tropical Storm Erin will pass north of the islands this weekend before likely beginning to turn north off the East Coast. Questions on the exact track remain that could influence impacts in various spots, so continued monitoring is recommended for the East Coast, Atlantic Canada, Bermuda, the Bahamas, and the northeast Caribbean. Invest 98L in the Gulf will probably produce mostly positive rainfall over South Texas tomorrow and Saturday.

Tropical Storm Erin

If we look at satellite this morning, it’s certainly the healthiest look Erin has had this week.

Erin looks like an actual tropical storm this morning. (Tropical Tidbits)

It’s clearly not the healthiest storm we’ve ever seen, but it’s doing enough to give the impression of slow intensification. As a result, Erin’s intensity is nudged up to 60 mph as of the 11 AM AST advisory. Using the latest map from Tomer Burg’s excellent site, it’s actually instructive to see what Erin has ahead of itself.

(Tomer Burg)

Erin is moving into an environment with very warm water temperatures, and it’s not going to exit that environment for at least 5 or 6 days. Erin should begin to tap into this environment over the next couple days, and it’s possible that we see a burst of rapid intensification at some point. Erin has not completely rid itself of dry air yet, so that may limit just how out of hand intensification can get. Whatever the case, given a favorable upper environment and warm water temps, one would expect Erin to start tapping the accelerator a bit today and tomorrow. After Friday and into this weekend, the storm may begin to “feel” some added wind shear to the west. This could slow the intensification rate a good bit. The models love this storm, and they’re quite aggressive with intensification over the next 3 to 4 days, with most pinning Erin at Cat 3 or above.

In terms of how close it gets to the islands, which is the first hurdle in terms of Erin’s track, there is strong agreement that it will pass comfortably north to avoid serious direct impacts. The Euro ensemble below shows this well.

The Euro ensemble’s 50+ members show Erin staying comfortably north of the islands, keeping serious direct impacts out of those areas. (Weathernerds.org)

What can we expect? Probably just a graze. As Erin passes north, it’s likely that some outer bands will graze Puerto Rico, the Virgin Islands, and the northeast Leeward Islands. Below is a forecast map for Saturday morning from the European operational model. Often, we tell you to ignore operational model guidance, but 2 to 3 days out, these deterministic models have value, particularly with established storms like Erin.

Erin’s Saturday morning forecast north of the Caribbean islands. (Pivotal Weather)

Mostly, however, the impacts will be marine-driven: Rough seas, high tides, rip currents.

(NWS San Juan)

Certainly something to monitor and keep track of, particularly if you have any marine interests or will be visiting the area this weekend. But this is mostly from a safety and awareness standpoint. No direct or major impacts are expected.

Beyond the Caribbean islands, what happens next? Well, there’s always some inherent uncertainty in tropical systems, but it’s not always equal. In other words, some 5 to 7 days forecasts have higher confidence than others. In this one, there is fairly high confidence that Erin is what we thought it was. Erin will turn northwest, then likely north and northeast rather quickly off the East Coast.

Erin’s forecast track has inherent uncertainty, but it is still expected to remain offshore of the East Coast. (Tropical Tidbits)

The questions I still have involve how close to the Bahamas and eventually Bermuda Erin gets. Additionally, how far offshore the storm will pass from the East Coast and Atlantic Canada. There has certainly been some “creep” to the west in the last couple days, which has undoubtedly made some folks on the East Coast a little uneasy. But at this point, all we can say is to keep an eye on things. We do not expect a track, plowing Erin into the Carolinas or New England. But it could always pass close enough for some impacts. We’ll keep you posted. Bermuda needs to watch Erin very closely. Hopefully we see some clarity on that in the next couple days.

One thing we can say for sure? Rough surf and rip currents will begin to increase by later this weekend or early next week on the East Coast. Please use caution in the water, particularly if you’re taking a late summer vacation next week.

We’ll keep you posted through the weekend.

Invest 98L

Meanwhile, in the Bay of Campeche, the tropical wave that we started watching a little more closely on Tuesday evening has now been designated Invest 98L. It actually looks okay this morning, though it lacks any sort of defined circulation center. So at this point, it’s just a coherent area of thunderstorms.

Invest 98L is well defined with thunderstorms, but it lacks any formal tropical organization. (Tropical Tidbits)

Invest 98L is going to track almost straight northwest over the next 24 to 30 hours. This should come ashore in Texas by Friday evening. Any development will be lower-end and rather disjointed. In other words, we could see a sloppy tropical depression come out of this, but we probably won’t see a named storm.

Invest 98L will move into Texas tomorrow evening. (Tropical Tidbits)

That said, given the thunderstorm organization here, we could see some locally heavy rainfall in South Texas as this comes in. I think as we saw last month, it does not take a well organized tropical system to cause problems in Texas. As this moves from the coastal bend into interior Texas, we will keep an eye on flooding risks that may emerge from this, although right now those risks are on the low to very low side.

5-day rainfall forecast focused over Texas shows generally 0.5 to 1 inch of rain on the coast, with lower amounts inland.

Overall, the thinking is that this will be more beneficial with increased rain chances over drier South Texas than anything else.

Elsewhere, no other specific waves are of serious concern right now, but we’ll keep an eye on that over the next few days and see if new areas of interest are introduced. We’ll stop there for now. Keep tabs on our Notes for any intermittent updates.