Update - Tropical System Expected in the Gulf Late Saturday or Sunday

August 1, 2024

The situation with the tropical wave the NHC has been watching has changed quickly. About the only thing of any confidence at this point is that it is very likely that there will be some sort of tropical system in the southeastern Gulf of Mexico late Saturday or early Sunday. Development chances are still at 60% over 7 days and 20% over 2 days, so development is not certain. Unfortunately the forecast for this system is very complex with many possible outcomes. It has been designated an Invest (97L), so an additional suite of models have started to produce data. I think recon flights will start soon as well which feeds better data into the models. However, until a low level center of circulation forms, possibly by Saturday, uncertainty will remain high and might continue to remain high for some time after that. No need to get too excited at this point but folks along the Florida Panhandle, especially from the eastern to central Panhandle, need to start thinking about plans and preparations. I'll summarize some scenarios below.

Models are more or less all over the place both from run to run and between each other. I could share them with you, but I think they're going to keep changing for a while so they're not the most helpful yet other than to see the wide range of possibilities. The Euro dropped its idea of a run up the East Coast more or less which is somewhat the cause of the excitement. The future steering environment is complex and there are too many unknowns that are causing wildly different outcomes. The storm will be approaching an environment with a high pressure to the west, another high to the east, and a trough or front in between. The relative strengths and positions of these relative to the storm and its strength are unknown and causing the high model variability as things change slightly from run to run or as different models evolve each in slightly different ways.

In the following, "storm" could mean anything from a messy depression or tropical storm to potentially a strong hurricane. Here are the possibilities, not in any order: 1) Storm landfall in the Big Bend / eastern Panhandle area, with the storm potentially moving off to the northeast if it finds an exit, possibly stalling a bit along the East Coast. This has some trending model support but is by no means a lock. 2) Storm stalls either before or after landfall in scenario "1" and meanders around over land or over the water, possibly for days. 3) If "2" happens and the storm either stays over the Gulf or returns to the Gulf, which are possible scenarios, some solutions have it going west (Texas is technically in play...) before making another landfall, possibly strengthening, possibly skirting the coast or maybe offshore a bit. Some solutions keep this storm somewhere along the northern Gulf for nearly a week before it finally finds an exit to the north-northeast. It could also stall or meander inland for several days. This third scenario, or a few different versions of it, is probably a worse case as it is possible that a much stronger storm could develop than is likely in scenario "1" and/or a stalled/meandering storm could dump rain over an area for many days.

Other than maybe a short term trend for the 1st scenario, it's not really possible to say which is more likely at this point. Maybe something will change and confidence in one general solution will improve but I'm not expecting that for a few days. The next update will be Saturday or sooner if warranted.

Chris

Tropical Weather Update - 60% Chance of Development Over 7 Days

July 31, 2024

The National Hurricane Center is still watching a tropical wave as it moves west across the Atlantic. Currently located over the Leeward Islands, the NHC gives this wave a 60% chance of development over the next 7 days. Conditions have just been marginal enough for this wave to remain a player but the environment is expected to improve as it continues west-northwest.

You can get an idea of the possible future of this system by looking at the orange triangle shape and for now that is all you really need to know so you can stop reading here if you want. I'll tell you what the consensus is and then I'll tell you my thoughts. The current consensus is to favor the Euro (which shows development along the East Coast) because it has been very consistent and picked up on the chance of development earlier. You can see this in that most of the triangle stays to the right and out of the Gulf. I am a bit leary of trusting the Euro this early and I'll explain why after I give you a few more details on what the models are showing.

Throughout the history of this system the Euro (both the operational model and the ensembles) have been much more bullish on development than the GFS suite. The Euro picked up on development first, with the GFS only showing development many days later. The Euro, again both the operational model and a majority of the ensembles, has also been consistent at developing a storm near the Bahamas with varying tracks along the East Coast. The GFS operational model on the other hand, which again jumped on board a bit later than the Euro, has been favoring solutions that wait until the wave is in the Gulf before development occurs. The GFS ensembles typically have only had a minority of members showing development with forecast tracks waffling between the Gulf and East Coast and sometimes split between the two. For what it's worth, the Canadian model has favored Gulf development, but it has had some solutions similar to the Euro. But the overall consensus, weighted by the Euro and its 51 ensemble members, favors an East Coast solution. I will say also that the details behind why the different models are showing different solutions favors the Euro as well, people smarter than me see the Euro's solution as the more logical one, so it's not just that they're jumping on board because of a strong model consensus.

Now my thoughts. I think I have explained before that until a center of circulation has formed the models are just sort of guessing at when and where development may occur. When and where the storm actually forms can make a huge difference as to its eventual track and intensity. So there is that piece that is always in play. Also, the Euro (and its ensembles) were wrong with Beryl's track for a long time, it wasn't until just a few days beforehand that they started to show a landfall along the upper Texas coast. It was locked into a more southerly track with Beryl into Mexico and southern Texas. It is a bit counter intuitive, but the lack of a diverse set of outcomes from an ensemble suite (underdispersion) is a bad thing. We know forecasts are uncertain, and when a 51 member model fails to show uncertainty, especially when we know the forecast is uncertain as we did with Beryl and as we do now, that is indicating some kind of bias towards one particular solution. Biases can keep a model from showing a range of possible outcomes or cause a model to favor one influencing factor more so than it should. My concern is that we may be seeing a bias again in this case. It's not that I think the Euro is forecasting the future environment incorrectly, I have no basis for thinking that. I'm just a bit concerned with the overconfidence this early, especially with the Euro's history with Beryl. The Euro's forecast of East Coast development may very well be correct, as I mentioned many people are leaning this way, but I'm not going to feel comfortable about that until other models start jumping on board, until we have an overall consensus. We should have better data in a few days when this starts to tighten up and/or when it's designated an invest and the suite of hurricane models start to run.

So that's a long read and hopefully it's helpful. I think we'll start to have a better idea of where this system may go over the weekend. Hopefully this stays out of the Gulf but it's too early to write that off.

Have a good rest of the week.

Chris

Activity in the Tropics Expected to Increase Soon

July 24, 2024

A short update this morning to let you know that there are signs that we are getting close to an increase in activity in the tropics. First, there is no development expected in the Atlantic over the next 7 days so certainly no concerns. However, looking at the Global Tropical Hazards Outlook that was issued yesterday, you can see that there is a 20% chance of development indicated for weeks 2 and 3 (July 31 to August 13). This forecast is based on the expectation that environmental conditions for tropical cyclones will gradually improve in the coming days and because signals in the ensemble models, particularly the Euro, are showing an increasing probably of storm development in the areas indicated. Also, the Eastern Pacific is showing signs of possible activity in the coming week and that often portends activity in the Atlantic as you all know.

Atlantic 7-Day Outlook

Global Tropical Hazards Outlook

Once the current quiet period comes to an end we will likely not see much of a lull in activity until later in the fall. In fact, the signal is so strong that the long term precipitation outlook for August through October is for above average rainfall amounts in the Southeast driven by the expected high level of tropical cyclone activity.

Here in the southeast expect temps to get back to normal or a bit above normal as we end July and head into the first week of August. Rain chances are expected to stay a bit above normal as well.

Have a good rest of the week and a good weekend.

Chris

Nothing Doing in the Tropics - No Activity Expected Until August

July 18, 2024

It's been two weeks since my last tropical weather update when Beryl was still headed for Texas. After its landfall the tropics have been quiet. Low activity is not unusual this time of year as strong easterly winds blow dusty dry air off of the Sahara Desert creating a hostile environment for tropical cyclones across most of the Atlantic Basin. This is expected to continue for the foreseeable future (2-3 weeks, maybe a little longer) but once we get into August those winds calm and conditions improve. There's always a small chance of something popping up closer to the coast somewhere but right now no tropical cyclone activity is expected at least for a few more weeks. There's a small chance we may see a disturbance develop in the eastern Gulf next week from a weak tropical wave but I don't think it'll be anything more than a loosely organized group of storms and showers if even that.

To keep us all honest, I want to remind everyone that a high level of activity is still expected for the remainder of the season. In fact, on July 9th Colorado State University increased their forecast numbers for the remainder of the season. They are now forecasting 25 named storms, 12 hurricanes, and 6 major hurricanes (up from 23/11/5 respectively on June 11th). This includes the 3 named storms we've already had so they're expecting 22 more from here on out. In past hyperactive seasons their numbers have sometimes been conservative, so we may see even more than that. Don't let your guard down.

That's it for today. In the short term we should see some slightly cooler but wetter than normal weather followed by the return of near seasonally normal or slightly above normal temps from the last week of July into August. Rain chances look to stay slightly above normal for a while as well.

Once the development chance looks like it's starting to increase I'll send out another update.

Chris

Update on Beryl and Invest 96L, Quiet Period Coming Soon

July 3, 2024

Several pieces of good news today I think. First, confidence is fairly high that Beryl will not be a threat to the northern Gulf of Mexico but it is possible that there could be some impacts to the lower or central Texas coast. The official forecast is below. After peaking as a 165 mph category 5 storm yesterday, Beryl has finally weakened some but is still a 145 mph category 4 storm. It is expected to bring significant impacts to Jamaica within the next few hours and then to the Cayman Islands later today and overnight. The storm is expected to continue to weaken but will still be a category 2 hurricane when it makes landfall somewhere on the Yucatan Peninsula on Friday. The NHC has Beryl weakening to tropical storm strength after landfall but then restrengthening to a category 1 hurricane in the Gulf before making another landfall along the coast of Mexico or Texas Sunday or Monday.

There is still some uncertainty regarding the strength of the storm and track in the Gulf. The best resource for details on this is the Tropical Tidbits video I've linked below, but briefly if Beryl doesn't weaken as much as expected and/or traverses the narrow northern portion of the Yucatan there is the possibility of stronger storm that tracks farther north along the Texas coast whereas the opposite situation would lead to a weaker storm that stays more to the south. Again, if you missed it, the good news is that us along the northern Gulf are very likely in the clear. One impact we will see, however, is that large swells from Beryl are expected to cause dangerous rip currents along the beaches starting as soon as tomorrow and over the weekend. By the way, Beryl set a record not only by becoming the earliest category 5 hurricane but is also the strongest July hurricane on record and the earliest storm (by over a month...) with 165 mph winds!

Tropical Tidbits video from Tuesday

The second piece of good news is that Invest 96L behind Beryl is not expected to develop, at least not in the short term. Officially, it has a 20% chance of development over the next 7 days which is much lower than it was on Sunday. This makes sense because usually systems following another storm run into a hostile environment due to higher wind shear from the outflow of the leading storm. The leading storm usually causes the ocean to cool a bit in its wake so that helps as well. We shouldn't write it off altogether though. Several ensemble members show the system making another run at development once it reaches the western Caribbean or Gulf around Sunday or early next week, so that is something we need to watch. Right now it looks like anything that does develop will stay out of the northern Gulf, but it's possible that could change.

And now, the third piece of good news. It looks like once these two systems are out of the picture that the tropics will quiet down for several weeks as large scale conditions over the Atlantic basin become unfavorable for development. Right now this is only expected to last until the last week or week and a half of July but we'll see. Don't let the quiet period get your guard down as I'm concerned that the lull will just be priming the system for what could be a very busy August and September. So if you're keeping score, the good news is that we don't have a second Beryl roaring through the Caribbean and I think it's pretty likely that we will not see any impacts from tropical weather for the foreseeable future other than large waves and rip currents along the coast.

Here in the Southeast it is going to be typical July weather through the holiday weekend. In case you forgot, that means hot (ok, very hot) with a chance or rain on and off through the next week or so.

Happy Independence Day and stay safe.

Chris

Beryl Now a Major Hurricane, Likely Another Storm Forming Soon As Well

June 30, 2024

What I once thought would be just a squally weather system has now broken several records. As of 2 p.m. today Atlantic Standard Time (1 hour ahead of CDT), hurricane Beryl is a category 4 major hurricane. It was already one of the earliest named storms on record to form so far east for this time of year. When it became a major hurricane earlier today, it was only the third category 3 storm to achieve that strength in the month of June and the first to do so east of the Lesser Antilles. Now that it is a category 4 storm it stands alone in all categories. No category 4 storm has ever formed this early (in our known records). If this is a precursor to what the rest of the season may like it is not a good sign.

The official forecast from the NHC is below. Beryl is forecast to continue moving west-northwest for the foreseeable future. Beryl is expected to strengthen some more before it starts to slowly weaken (hopefully) in about 24 hours as it crosses the Caribbean over the next week. It's too early to rule it out, but right now a track into the northern/eastern Gulf looks less likely than other possibilities. A few ensemble members do show some curves to the north maybe 5-6 days from now but so far they stay mostly in the central to western Gulf. Most tracks currently continue to take the storm west-northwest towards the Yucatan Peninsula. If Beryl were to track on the northern side of the track envelope that curve could happen sooner, but again that looks like a low probability at this time. I think we'll have better confidence around midweek.

There are still a few other things going on in the tropics. The system behind Beryl (Invest 96L), will likely become a tropical depression sometime in the next several days if not a named storm. Models show a similar track as what we saw when Beryl was still forming, mostly west-northwest with a few curving to the north once it is in the Caribbean. It is possible that this will become a hurricane as well, but I haven't spent much time looking at the intensity forecasts. The system in the southwest Gulf is close to making a run at last minute development, but there is no change to the overall forecast and it remains no threat to the US.

That's it for today. I'm honestly still processing Beryl's rapid intensification and what that may mean about the rest of the season. In a video just the other day, Dr. Levi Cowan of Tropical Tidbits stated (I'm paraphrasing) that the thermodynamic environment wasn't supportive of rapid strengthening or a storm of this strength in this part of the Atlantic. He's a leading expert in this field of meteorology so clearly there's some lack of knowledge or understanding we still need to close the gap on.

Have a good week, I'll give you an update in a few days.

Chris

Tropical Development in the Atlantic Now Likely

June 27, 2024

A long one today, but you can stop after the first paragraph if you want. 

Well that changed fast... On Tuesday I mentioned that a few models were indicating the possible development of a tropical wave out in the Atlantic. For reasons I'll get into below, I was fairly confident that significant development was unlikely. This no longer looks to be the case. Now designated Invest 95L, the National Hurricane Center is forecasting a 70% chance of development over the next 7 days for a tropical wave now located a few hundred miles to the southwest of the Cape Verde Islands. It is very likely that the Windward Islands will be dealing with a tropical storm or low end hurricane on Monday. We'll have to watch it closely after that to see what happens in the Caribbean but we'll have a week or more to do so. I'll discuss a few more things below, but for now just know that we may be concerned about a storm coming into the Gulf in 7-10 days. A lot of things may change between now and then. The yellow area (Invest 94L) in the western Caribbean remains no concern.

A little history on this forecast. At the beginning of the week two tropical waves were being watched for development. The first wave had just emerged off the African coast over the weekend and the second was just moving over water. Initially the GFS was more interested in the first wave while the Euro was showing more development of the second wave, but neither were showing any strong signals for development and also no significant strengthening. That's not uncommon when models first start showing development, they typically don't go from showing nothing to high confidence of a strong storm. For this system, both models have now locked in on the first wave and are now very confident that a named storm will form over the next few days. There also may be some development from the second wave, but we need to be concerned about the lead system first.

Unofficially, there is a shorter period in the hurricane season in August and September called the "Cape Verde season." It is the time of year when conditions are right for long track storms to form near the coast of Africa and track all the way across the Atlantic. This is why I mentioned in my last update that it was a bit too early for the type of development we're seeing now, typically. While not exactly a Cape Verde storm, this system is developing farther east than we usually see this time of year, but we're really only a few weeks away from that starting to change. Below you'll see two "points of origin" maps showing the historical development locations of storms, one for late June and one for early July. We're right on the cusp of the transition when storms develop mostly in the Caribbean to the time when they develop in the main development region farther east in the Atlantic. This may be a 1-off, or maybe this transition is starting a little earlier this year, we'll see. Development this far east is still relatively rare. Also, the Caribbean, particularly the eastern Caribbean, is usually quite hostile to tropical cyclones this time of year due to high wind shear. These two factors are called climatology (or part of the many things that make up climatology), which is what we expect the weather to be normally for a given location and time of year. For both of these reasons, as well as the lack of strong model signals, I didn't expect a whole lot out of this system. It looks like I was wrong.

So what are the forecast possibilities? The good news is that the future of this system is a bit uncertain. The reason that is good is because the European ensemble has many of its 51 members forecasting a very strong storm and I really hope it is wrong. I'm hopeful because at least so far the 31 members of the GFS ensemble are not showing very many strong solutions. Weather models have biases where they tend to overdo or underdo certain features that influence the overall forecast, sometimes significantly. I don't know a lot about these, but my understanding from a trusted source is that is what we may be seeing here. The Euro has a bias that in this case may be showing more intensification and the GFS a bias that is leading to weaker solutions. That doesn't mean that these solutions should be thrown out, they represent the spectrum of possibilities with varying likelihood. Unfortunately a tropical cyclone development that will likely bring impacts to somewhere is very likely at this point. I'm hoping we'll see a middle of the road solution, with maybe (hopefully) a low end to moderate hurricane impacting the Caribbean and/or Mexico or Central America, but we need to watch for a curve to the north and perhaps a stronger storm.

There are a lot of possibilities for the track solution, but looking out a week from now it seems fairly certain that a track through the Caribbean is most likely over the next week. You can see this on the track density map below. After that the track possibilities are much broader. If one of the solutions from the Euro that shows more rapid strengthening is correct, that should cause the storm to be pulled more to the north, possibly out into the Atlantic before it can make it very far to the west. A weaker storm will stay on a more westerly track much longer. The average solution seems to be one that takes the storm mostly west for a while, with a lot of divergence after that. Right now, there aren't too many tracks that would bring the storm into the central or eastern portion of the northern Gulf, but the track is very uncertain after about 7 days.

At this point we just have to wait and see how the forecast evolves. This looks like the start of what is still expected to be a very busy year for storms forming close to this same location. I'll send out another update some time this weekend or early next week, hopefully we know more about the long term track by then.

Have a good rest of the week and a good weekend.

Chris