Matt Lanza

Hurricane season appears to be unofficially over, so let’s do a quick review and talk about bomb cyclones in the West

Headlines

  • Hurricane season is unofficially over, as no activity is seen over the next 10 days, taking us through to about December.
  • 2024 will end up as a “hyperactive” season but barely.
  • Meanwhile, the West is seeing a storm almost as strong as a major hurricane spinning offshore.
  • Significant, damaging wind is possible in the Seattle area tonight.
  • A prolonged atmospheric river in California and southern Oregon will produce over 10 inches of rain in spots, and a rare day 3 high risk (level 4/4) of flooding exists in northern California for Thursday.

2024 Atlantic hurricane season ends — we think

With the degeneration of Sara’s remnants yesterday, it would appear that we’re basically done with the 2024 Atlantic hurricane season.

Exhale. (NOAA/NHC)

Unfortunately, Tropical Storm Sara was deadly in Honduras while dumping upwards of 20″ or more of rainfall. As much as 1,000 mm (40 inches) was analyzed in northern, coastal Honduras. Though deadly, it appears that the number of fatalities will remain well under some other notable rainstorms of the past in Central America. Good warnings likely helped.

With that, the season seems to be over now, as we see nothing over the next 7 days, and the models are pretty quiet beyond that. So where will we finish? It appears 2024’s accumulated cyclone energy (ACE) will finish at the bottom of the list of hyperactive seasons. We had 18 storms, 11 hurricanes, and 5 major hurricanes. The 11 hurricanes tie for fifth most in a season.

This season’s accumulated cyclone energy (ACE) was driven by a late season surge, just pushing us to the edge of “hyperactive” status for the year, impressive but perhaps less so given the seasonal expectations. (Colorado State)

Did the season live up to the preseason hype? Probably not. But with over $190 billion in unofficial damages, it ranks near the top of the list of worst seasons on record. So you can find a metric that says this year was as bad as feared or was a total bust. The world is your oyster. But for parts of the Caribbean, Florida, and Appalachia, this season will be for the history books. And that’s really all that matters.

We can take a more in depth look at the season later. I want to transition us into post-season mode now at The Eyewall. We’re still experimenting with what works because we want to continue to grow our audience, but we also want to stay in our lane to an extent. Ultimately though, weather is our lane. And we should be chiming in when significant weather is a big story. And today, it’s a big story on the West Coast.

Western U.S. and Canada drenched and pummeled

There are two major stories developing on the West Coast. The first is occurring as I type this. A massive storm is rapidly deepening off the Northwest coast.

A massive, potentially historic storm has developed off the coast of Washington and Oregon. (Weathernerds.org)

Yes, this is a bomb cyclone. That term gets tossed around often, and some people consider it hype. But it’s a legitimate meteorological term with a very specific definition. The lowest pressure of the storm must drop at least 24 millibars in 24 hours or less to attain “bomb cyclone” classification. While it may seem like bomb cyclones are rare, they really aren’t, happening multiple times a year on average near North America. What makes this particular storm stand out is the amplitude and rate of deepening that it is undergoing. Basically, the storm has dropped over 25 millibars just this afternoon, achieving “bomb” status incredibly quickly.

There will be multiple impacts associated with this storm, including a major downslope wind event east of Seattle tonight, where gusts in excess of 50 to 60 mph could occur in some of the heavily populated suburbs near the Cascade foothills. This will be worse than a typical wind event for this region, likely causing some localized damage and numerous power outages.

Very strong downslope winds in the Cascade foothills tonight could cause damage and knock out power on the eastern side of the Seattle metro. (NWS Seattle)

In addition, strong winds will occur at the coast, though thankfully the worst winds will remain well offshore due to the storm not making landfall. Heavy mountain snow and lower elevation rain will occur as well, and blizzard warnings are posted for the Cascades.

Meanwhile, a long duration atmospheric river event is going to take aim at California and southern Oregon in the coming several days, dumping copious amounts of rain and mountain snow, and some rain-on-snow potentially as well.

Over the next 3 days, the strongest portion of the atmospheric river will aim at northern California. (Scripps Center for Western Weather and Water Extremes)

This will peak as a category 5 atmospheric river, which means significant impacts are likely, and the NWS Weather Prediction Center already issued a high risk of flooding (level 4/4) for northern California on Thursday, which I believe is the first time this has occurred for a non-tropical storm.

A high risk (level 4/4) is posted for northern California , north of Mendocino for Thursday for flooding rain. (NWS WPC)

High risks don’t seem to be as rare as they used to be, but obviously for a day 3, confidence has to be exceptionally high or the risk has to be exceptionally high. I think a confluence of factors is impacting that. In terms of rainfall over the next week, it’s going to get messy. Over 10 inches of rain should fall in some of the mountains in northern California. Snow will also occur, but as the atmosphere warms a bit, the snow levels will increase. So this could be a damaging event in addition to a possibly beneficial one. Extremes rule the day in California. More to come.

Tropical Storm Sara near the Honduras coast, a Central America flood maker

Headlines

  • Catastrophic flooding from Sara is possible in northwest Honduras.
  • Significant flooding and mudslide risk exists elsewhere, from the southeastern Yucatan into Belize and in portions of Nicaragua.
  • Sara is very close to the coast of Honduras now and should generally maintain intensity with just a little strengthening once back out over water en route to Belize Sunday.
  • Sara’s remnants will be absorbed into a Gulf of Mexico cold front next week with no direct impacts to the U.S. expected.
Tropical Storm Sara made landfall in Honduras and will drift toward Belize this weekend. (NOAA NHC)

Tropical Storm Sara dumping rainfall on Honduras

We’ve been discussing Sara all week, and the one element we keep trying to hammer home is the flooding threat this storm provides for Honduras in particular but now also Belize.

Catastrophic flooding is possible in northwest Honduras with severe flooding elsewhere into Belize and perhaps even the Yucatan as Sara drifts that way. (NOAA WPC)

The mountainous portions of northwest Honduras are likely to see the worst of the flooding. Rain totals may exceed 20 to 25 inches in this area (500 to 600 mm). Outside of that, rain totals north of 10 inches are likely from Quintana Roo into Belize, the central coast of Honduras, and perhaps into portions of Nicaragua. These types of storms typically end poorly in these areas, so all we can do at this point is hope for the best.

In terms of the tropical element of things, the National Hurricane Center noted this morning that there is a distinct lack of observations available from Honduras, so trying to pin down the center of the storm has been challenging. But using satellite, we can see where the heaviest thunderstorms are at least.

Tropical Storm Sara is somewhere near the coast or just inland in Honduras with very heavy thunderstorms occurring in western Honduras and just off the coast of Mexico and Belize. (Weathernerds.org)

And indeed those heavy storms are hammering portions of western Honduras. Sara will likely hold steady or weaken just a bit depending on if it’s over land or over water. All in all, we don’t expect a whole lot of major change in Sara’s intensity over the next couple days. Sara will have a little runway to perhaps work with on the way from Honduras into Belize as it passes over the Caribbean again. But the ceiling for intensity should remain fairly low, as it will quickly move back over land in Belize and the Yucatan. Its time over land there should essentially kill it off before it gets absorbed into a cold front over the Gulf of Mexico next week.

Beyond Central America, no direct impacts are expected in the U.S. There is some chance that as Sara is absorbed into next week’s cold front it could help enhance rainfall or introduce a severe weather risk to Florida, Georgia, or the Carolinas. But that should be all.

Never say never, of course, but beyond Sara, we think that’s probably it for the 2024 Atlantic hurricane season. We’ll have more to come on Sara this weekend.

Tropical Depression 19 will be a deeply serious flooding threat for Honduras

Headlines

  • Tropical Depression 19 should become Sara later today.
  • Sara will be a deeply serious flooding threat to coastal Honduras.
  • The odds of a major hurricane, in particular a major hurricane tracking toward Florida have dropped off since yesterday.
  • There is still substantial uncertainty surrounding the details of Sara’s development and peak intensity, but broadly a drift/stall near the coast of Honduras through the weekend, followed by a track toward Belize and the Yucatan and then a hook northeast toward Florida is favored.
  • Also, our parent site, Space City Weather is doing our annual fundraiser if you are interested in also directly support the work of The Eyewall!

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On with the show…

TD 19 is going to hug the coast of Honduras over the next few days, but exactly where that stall happens is critical in determining if it becomes a hurricane or not. Either way, it’s going to deliver a massive flooding threat to Honduras. (NOAA NHC)

Tropical Depression 19: A major Honduras flood threat, less of a Florida hurricane threat

Invest 99L was given the potential tropical cyclone treatment yesterday. It’s now officially Tropical Depression 19, and it is expected to become Sara by later today. The track of 19 is pretty straightforward — but also immensely important and sensitive to exactly where it sets up. If we look at the forecast for hour 60, which is for Saturday morning, notice that the models are in pretty solid agreement. Each dot below shows where one of the 51 ensemble members is placing Sara’s center at that time.

There is good model agreement on roughly where Sara will be over the next 3 to 4 days. But the proximity to land is going to throw an enormous wrench into determining the exact intensity. (Tomer Burg)

For Honduras, unfortunately this only means the difference between a really bad situation and a really, really bad situation. Significant flash flooding and mudslides courtesy of torrential rain will be likely heading into the next several days as 19/Sara crawls along the coast of Honduras.

Rain totals could exceed 20 inches (500 mm) in parts of coastal Honduras over the next 5 to 6 days, leading to severe flooding. (NOAA WPC)

If the center of Sara stays offshore, it could become a hurricane, which would yield an even worse outcome. But even if that does not happen and Sara stays along the coast or just inland, the rain issues will be just as bad.

But that position of Sara over the next 3 or 4 days will have implications on what happens next for Belize, the Yucatan, and Florida. Sara should eventually get dislodged from its stall and start tracking toward Belize and the Yucatan by Monday. Obviously if it’s still over water and a hurricane, that could produce a pretty rough impact on Belize or Mexico. If it emerges from over the physical coast of Honduras, it will be less of a threat to be a hurricane.

Models have increased agreement on land interaction with Honduras keeping the storm weaker and more over land the next 5 days, but there is still uncertainty. (Tomer Burg)

If anything, trends since yesterday have drastically lowered the potential for a hurricane or major hurricane. There is simply too much land interaction with Honduras and the Yucatan or Belize. But there is a heaping amount of uncertainty still.

For Florida, this means that the threat of a significant hurricane on the west coast seems to have fallen off a good bit since yesterday. That’s good. I would continue to monitor this closely, but the trends have been friendly to you. There could still be some heavy rain and strong thunderstorms as a powerful cold front sweeps across the state next Wednesday. We’ll assess this in the coming days.

In the meantime, any interests in Honduras in particular, but also perhaps Belize or the Yucatan should monitor Sara closely. Even if it never becomes a hurricane, the flooding threat is dire for coastal Honduras. We’ll keep following this aspect of things.

Sara should soon form, a significant late season threat to Honduras in particular and something for Florida to monitor closely

Headlines

  • The Caribbean tropical wave is now Invest 99L and is likely to develop into a depression or Tropical Storm Sara in the next day or two.
  • The system will come west and then slam on the brakes near Honduras. Much of what happens next depends on how close to the coast that stall occurs.
  • A stall over or near the coast would likely lead to a weaker storm that turns north and northeast next week toward the Panhandle or Big Bend of Florida.
  • A stall offshore of Honduras would likely lead to a stronger storm or potential major hurricane risk to the west coast of Florida next week.
  • Both scenarios are likely to produce significant to potential devastating rain for portions of Honduras.
  • Interests in Florida, the Yucatan, Belize, Honduras, and Nicaragua should monitor 99L’s progress closely.

Sara likely to stir up problems

Sara (spelled without an H) is likely to develop within the next 48 hours or so from Invest 99L in the Caribbean. This morning’s satellite view shows a disorganized but otherwise pretty potent little area of thunderstorms over the Caribbean. It’s at least showing nascent signs of organization, but it appears relatively lopsided. In other words, if there is a center, it’s on the northern edge of all the thunderstorms.

Thunderstorms associated with Invest 99L lie primarily to the south of where the center would likely form, so while robust it’s still fairly disorganized. (Weathernerds.org)

Over the next 48 hours, models are in good agreement that this will be slow to develop initially while moving west at a pretty steady clip. Once it gets near the coast of Honduras, the steering currents will force 99L or Sara to slam on the brakes.

Sara/99L likely to be forced to slow to a crawl or stall near the northeast coast of Honduras on Friday. (Tropical Tidbits)

This means one of two things. Either the storm will stall near land enough to not become a significant tropical system (though still a potentially major rainmaker) or the storm will stall over the Caribbean’s deep, warm water and rapidly intensify. Truthfully, neither scenario is particularly great. And in fact, modeling is in decent agreement on a major rain and flooding event potentially for Honduras. Current forecasts suggest 10 to 20 inches or more (400 to 600 mm) are possible over the next 5 days for the northern third of Honduras.

A significant rain or flooding event is becoming increasingly likely in Honduras. (Pivotal Weather)

So, regardless of how much 99L or Sara develops through the weekend, this is going to deliver abundant rainfall to at least Honduras. Belize and Nicaragua should also monitor this closely in case things should change.

Models are in great agreement on this unfortunately with almost all the European ensemble’s 51 individual members showing low pressure stuck near the coast of Honduras through 96 hours. Again, in terms of how strong this gets, where that “stuck” point happens is critical, and that’s where the bulk of the uncertainty lies right now.

Among the 51 European ensemble members, there are virtually no outliers right now in terms of getting 99L or Sara stuck near Honduras late this week and weekend. (Weathernerds.org)

From here, almost everything will depend on where that stall occurs. At a high level, we know that Sara/99L is going to get picked up and carried north and then northeast by an autumn cold front that sweeps across the Gulf next week. So for folks in Texas and Louisiana, no worries with this. But for folks in Florida, this is very important. A storm that stalls offshore to the east and north of the Honduras coast and is allowed to intensify will likely turn north and northeast farther north and east, posing a potential major hurricane risk to the west coast of Florida. A storm that stalls near or on the coast of Honduras would not be as intense and would likely either get absorbed into the front next week or come north as a tropical storm into the Panhandle or Big Bend region of Florida. Much more manageable.

Two general scenarios exist for 99L/Sara, one which is stronger and farther south, bringing a major hurricane risk to Florida next week or a much weaker farther north one. (Weathernerds.org)

Unfortunately, it’s too soon to say which scenario is more likely. The timing is a little sketchy as well, but we’re probably looking at impacts to Florida, in whatever form Sara will be in around Tuesday or Wednesday next week.

Bottom line: Folks on the west coast of Florida must again remain vigilant for another storm unfortunately. Despite the calendar saying that it’s mid-November, the weather pattern thinks that it’s mid-October. You should also be viewing this way and start considering some preparations in Florida. If you have friends or family in Honduras, ensure that they’re aware of what’s coming. Central America flooding events can be utterly disastrous. This has that potential unfortunately.