June 7, 2023 Outlook: Europe names a windstorm, and Fantasyland comes alive

Good morning. Eric here, and I’m thrilled to extend my welcome to readers of The Eyewall. Matt has been doing a fantastic job so far, and the response we’ve received to the site has been great. Thank you for reading, and telling your friends and families in other states vulnerable to tropical weather. In today’s post we’ll talk about the lack of activity right now, and the GFS model’s propensity to develop spurious storms. Matt also continues his look at what to expect from the 2023 hurricane season, overall.

One-sentence summary

No meaningful tropical development is expected over the next week or so, though a system near the Azores Islands has a very low chance to briefly become something before the weekend.

“Oscar” is swirling off the coast of Africa and Spain. (EUMETSAT)

Happening now

Beyond the Azores system, nothing is happening now. Just a word on that storm, however, which is interesting to US readers in the sense that it allows us to talk about something relatively new. For the last eight years several European countries have started naming “windstorms,” and like we have a hurricane season they have a windstorm season. In this case, the Azores storm is named “Oscar,” and it could have impacts on the Canary Islands later this week. Some weather warnings are in place.

The medium range (days 6-10): Still quiet

If we look at the 10-day forecasts from the major global models, there is still really nothing to shake a stick at. This is perfectly normal for the early part of June.

Fantasyland (beyond day 10): No changes in thinking

There is life in fantasyland, however. In about 11 days from now, the GFS model develops a tropical low in the Caribbean Sea, and then drags a fairly potent looking storm into the Gulf of Mexico by about day 14 or 15. There are two reasons why this system is likely spurious. First of all, we commonly see these kinds of far-out tropical systems in the GFS model at this time of year. And secondly, when we look for support for this idea in the ensembles, it’s just not there.

Oh look, the GFS has manufactured a hurricane at <checks notes> day 15 of its current run. (Weather Bell)

Nevertheless, I would expect to see some chatter about this possibility over the next few days, as excitable observers look at the GFS model and say, “Oh look, a hurricane is going to hit Texas on June 23!” I mean, anything is possible, right? But it’s not something I’d lose any sleep over. We’re certain to face much more credible threats later this summer, so save your angst for something that’s more likely to be real.

The 2023 seasonal outlook Part 2: El Niño

When you hear the phrase “El Niño,” we would assume that most Gen X’ers, Xennials, and geriatric millennials think of Chris Farley and his 1997 take on the weather event on Saturday Night Live. Truthfully, that clip has aged pretty well. They got the gist of things correct.

What is El Niño? By definition, it is a periodic warming of the water around the Equator in the Pacific Ocean, west of Peru to the central Pacific, near the Dateline. In reality, it’s a pretty complicated phenomenon involving both the ocean and the atmosphere, and because of where it unfolds, it sends ripple effects around the world in the form of changes to weather patterns. You can read more about the “what” behind El Niño here, but we’re going to focus on how it impacts hurricane season.

How does El Niño impact the tropical Atlantic? What tends to happen during El Niño events is an uptick in tropical activity in the Pacific Ocean. With more warm water available in the tropics, with more thunderstorm activity spreading east from the Western Pacific, and with generally lower wind shear, the Pacific tends to be the action center during hurricane seasons with El Niño.

During El Niño events, there is usually more wind shear over the Atlantic basin due to the reshuffling of the upper level pattern as warm water expands east across the Pacific Ocean. Hurricanes do not like wind shear. (NOAA)

Because the structure of the upper atmospheric pattern changes when that happens, a situation develops where there is generally a mean ridge of high pressure (calm conditions) over the subtropical Pacific. With the jet stream, what goes up usually must come down, and that typically produces a mean trough (unsettled conditions) over the Caribbean and southwest Atlantic. Hurricanes like calm conditions in the upper atmosphere. That means reduced wind shear. So during an El Niño, the Pacific side usually has less wind shear than usual, while the Atlantic side usually has more of it, limiting the amount of hurricanes that form.

As a “for instance,” if we took the 10 strongest Oceanic Niño Index values (the statistically strongest summertime El Niño events) for the 3-month period of July through September going back to 1950, those hurricane seasons averaged 9 storms, 4 hurricanes, and 1 major hurricane, well shy of the 30 year average of 14, 7, and 3 respectively. Of course, within those 10 “quiet seasons” we had a handful of memorable storms: Betsy in 1965, Agnes in 1972, Joaquin in 2015, Audrey in 1957, Flora in 1963, Charlie in 1951, and Isidore and Lili in 2002. It only takes one! But the takeaway here is that El Niño does tend to favor less busy Atlantic seasons.

What’s El Niño doing right now? Well, we’re technically not yet in El Niño. There are certain criteria that need to be met over the course a few months. However, we’re all but officially there. The Australian Bureau of Meteorology this week declared an El Niño Alert, giving at least a 70 percent chance that it will happen. NOAA has us in an El Niño watch. A look at a sea surface temperature anomaly map clearly shows that the Pacific is warm.

If you look across the Equator at the Pacific Ocean west of South America you can see above normal water temperatures dominating the region, indicating development of an El Niño is likely underway. (NOAA)

Most of the global oceans are warm right now, but the El Niño certainly stands out. You can see this in an even more telling manner by looking under the surface of the ocean across the Equatorial Pacific.

Click to enlarge this animation from April through late last week, which is looking at water temperature anomalies in the Equatorial Pacific from 80°W longitude, across the Dateline to 120°E longitude, or basically from South America to Oceania. The surface is the top of the graph, and the bottom of the graph is 450 meters (~1,500 feet) below. That’s a lot of warm water. (NOAA)

There is nothing but warmer than normal water from the surface down about 700 feet across the Equatorial Pacific. Basically, El Niño is just about here, and it would be safe to assume that we will have one in place for the majority of hurricane season. Thus, when making the seasonal hurricane outlook, the first key point for 2023 is El Niño, so this should likely act against a busy season.

But these things are complicated, and while El Niño certainly gives us optimism that the season may be a bit more subdued than normal, that map of global water temperature anomalies above shows a big problem in the Atlantic. We’ll discuss that in more detail tomorrow.

June 6, 2023 Outlook: Azores low and the seasonal forecast

Happy Tuesday to all. It’s very early in hurricane season, but at the very least, we’re trying to make sure you have a reason to check us out each day with something interesting. Today we’ll have the first of four parts on the seasonal forecasting challenge for this particular hurricane season. We’ll discuss the forecast today, El Niño tomorrow, water temperatures in the Atlantic on Thursday, and then the risks regarding the season on Friday.

One-sentence summary

No meaningful tropical development is expected over the next week or so, though a system near the Azores Islands has a very low chance to briefly become something before the weekend.

Happening now: Strange system swirls near Azores

The fact that we’re even discussing the Azores in June is pretty ridiculous. Storms simply do not form here this early in the season. There’s an argument to be made that maybe 40 or 50 years ago, in this same scenario, we actually would not be talking about the Azores because the technology to monitor these things has improved so much. So in 2023, we can tag disturbances and even name lower-end systems that would not have had that done “back in the day.”

Regardless, it’s impressive and looking at satellite this morning, it’s evident that we have a system out there, however when you go “under the hood,” this is technically not a tropical or subtropical system at this point.

An area of non-tropical low pressure near the Azores Islands has a brief opportunity to acquire some subtropical characteristics before it moves toward and just offshore of Portugal. (Weathernerds.org)

In a future post, we’ll get into the technicalities of these things; what is subtropical versus tropical versus extratropical or cold core versus warm core and why all these things matter meteorologically. The bottom line on this particular disturbance is that it has about 24 to 36 hour window to develop some warm core (tropical) characteristics, as it is moving over an area with sea surface temperatures that are anywhere from 2°F to 5°F above normal.

The low pressure system near the Azores will be tracking over water that is much, much warmer than usual, though still a bit on the cool side for tropical development. (Weather Bell)

That said, the current 10 percent probability offered by the National Hurricane Center seems fair, as the water is still fairly cool for true tropical development here.

The medium range (days 6-10): Still quiet

There’s nothing new to add in this period today, so we’ll keep this simple. All’s quiet.

Fantasyland (beyond day 10): No changes in thinking

Yesterday’s post discussed why things may become more favorable for something later in the month. Nothing has changed today regarding that topic. The GFS operational model continues to spit out a somewhat spurious looking system around days 13-16. It continues to be mostly on its own bringing it northward toward the Gulf, lacking any real meaningful ensemble (multiple runs of the same model with tweaks) support for that at this time. We will get into the operational versus ensemble model differences sometime soon.

The 2023 seasonal outlook Part 1: The forecast

Alright, let’s talk the seasonal forecast. We will break this out into four parts over the coming days so as to not inundate you with too much stuff at once. Today, we’ll explore the forecasts. Tomorrow, we’ll discuss El Niño. On Thursday we’ll look at water temperatures across the Atlantic basin. We’ll wrap things up on Friday by putting this all together and discussing the risks.

The caveat I have to start with: Seasonal forecasts are mainly scientific research exercises. You should prepare each season as if it will be the one where a storm strikes. Below average seasons can be bad ones too. Last year was near average and produced Hurricane Ian. 1992? A pretty quiet season, but it produced a storm named Andrew. 1983? One of the quietest hurricane seasons on record. It produced a storm named Alicia for Houston. So whatever you see with respect to seasonal forecasts, it’s honestly not exactly useful information. Fun information? Sure. Useful? Not so much. Got it? Great.

Aggregated forecast from various government agencies, models, academic institutions, and private sector companies for the 2023 hurricane season. Click the image to enlarge, or click here to explore the forecasts yourself. (Barcelona Supercomputing Center)

The consensus for the upcoming season is “near average.” What does that mean? A consortium of AXA XL (a reinsurer), Colorado State University, and the Barcelona Supercomputing Center have been aggregating seasonal hurricane forecasts for a few years now. These forecasts come from the private sector, government agencies, seasonal models, and universities. They have a great site where we can get almost a consensus forecast for the upcoming season, as well as see the outliers (what we refer to as an “ensemble forecast” in meteorology). The consensus for this season (which is two storms deep as of today) is for roughly 16 named storms, 7 hurricanes, and 3 major hurricanes, which is near what an “average” season would produce.

I personally tend to put a bit more weight on Colorado State and NOAA’s outlooks because they’ve been at it for a long time, and they offer a good deal of insight into their processes. I will also speak highly of Weather Tiger, run by Dr. Ryan Truchelut. He also has a tropical newsletter, focused on Florida a lot but no less interesting that you may want to add to your repertoire. In my work in the energy industry, I have also crossed paths with CWG (Commodity Weather Group), Maxar, and Atmospheric G2 who all do good work in this space. You do this long enough, and you can find reasons to like or dislike any given forecast. Whatever the case, feel free to explore the individual forecasts there, but the consensus (16/7/3) is about as good as it gets right now.

That said, it’s complicated. Tomorrow, in part 2, we’ll talk about El Niño, and what it may mean for the season ahead.

June 5, 2023 Tropical Outlook: What is normal for June?

Good morning. Welcome to the first full week of The Eyewall, now a true tropical site since we had our first storm. A quick reminder, you can subscribe to our daily emails or reach our social media sites at the right on a desktop. If you’re on your phone, scroll down to the bottom of the page, and you’ll see the sign up form, as well as links to our social media sites just above the bottom. Facebook, Twitter, and the Gram are fully functional now. Still some work to do with TikTok. We’ll get there.

We’ll start this week by tying a closure ribbon around Arlene. It’s somewhat instructive to just look at how much rain has fallen over Florida for the last week.

Rainfall over the last week in Florida has been two to three times what is normal, with many locations seeing 5 to 7 inches of rainfall or more. (High Plains Regional Climate Center)

A nice reminder for hurricane season that impacts from storms are not always straightforward. While there has not been any real widespread flooding in Florida, there have been a few wild storms and certainly some localized flooding over the last week tangentially associated with Arlene. The highest June 1 through June 4 rain total I found in Florida as of yesterday morning’s CoCoRaHS reports was just shy of 8 inches of rain near Parrish, FL, which is just southeast of the Tampa Bay area in Manatee County. It should hopefully be a bit of a calmer week across Florida this week.

One-sentence summary

The tropics look fairly inactive over the course of this week, with little to watch.

Happening now: Not much

It’s quiet out there. Whatever is left of Arlene is getting funneled east and north toward a rather beastly upper level low that’s expected to pester coastal New England and Atlantic Canada through the week with rain chances and cooler than average temperatures. This is not a tropical feature, but it’s nonetheless interesting.

This map is looking up about 10,000 feet and shows low pressure off New England and some of Arlene’s remnants forecast to be well east of Florida later today. (Tropical Tidbits)

The National Hurricane Center has also tagged an area way, way out in the Atlantic south of the Azores for a 10 percent chance of development. That would be bizarre, but as of now it’s not a high probability risk. Aside from that, there’s nothing out there that’s a candidate for development this week.

The medium range (days 6-10): Still expected quiet

Not a lot to speak of for the next forecast period from the weekend into next week. The New England upper level storm exits, and another may try to follow suit for the Mid-Atlantic. The basin itself looks pretty quiet, which begs the question: Where should we be looking for development in June anyway?

Click to enlarge this map of historical storm origins from June 11-20 since 1851. (NOAA)

When we think about early to mid June, we think about two areas mostly: The Gulf and the northwest Caribbean. Though the map above cuts off in 2015, you get a pretty good idea of what history favors. In that sense, Arlene was not exactly abnormal. By far, the highest density of development in mid-June, however is the northwest Caribbean. So if you want to look for something, look there. Which brings us to…

Fantasyland (beyond day 10): Maybe watching the northwest Caribbean

So, if you are an avid model watcher, you may have noticed the last few runs of the GFS operational model picking up on what I derisively refer to as a “scareicane” on days 14-16 of the model run. The reason I call it that is because the GFS model in particular is notorious for taking relatively minor disturbances on day 10+ and inconsistently blowing them up into scary looking Gulf or Caribbean storms. In other words, if it looks crazy on day 15 or 16, it probably is.

The map here shows sea level pressure anomaly, or basically if surface pressures are expected to be above or below average. Per the GFS ensemble, on day 15, there is a slight signal for below average pressures but nothing too crazy. A stronger signal seems to exist in the Pacific. (Tropical Tidbits)

That said, if you dig a bit deeper, there is some reason to at least pencil in the June 20th (or later) period as one to perhaps watch for our next development window. As you can see above, there is support for lower than average surface pressure in the northwest Caribbean in about 2 weeks, but nothing that exactly stands out. However, we’re going to have a pattern more favorable for rising air, an ingredient tropical systems like, begin to move toward the eastern Pacific and perhaps far western Caribbean, or so it seems, around that time. Usually, when I see these signals in the modeling, it means that there may be something to come, but the GFS operational model is probably a solid 7 to 10 days too quick showing it out there. Judging by the potential for some of these better ingredients lagging the end of the run by a few days, that makes sense here. So that pushes us out closer to June 25th, give or take. A somewhat better signal appears to show up in the Pacific, so we’ll probably see something attempt development there before our next chance on the Atlantic side. That said, wind shear looks to remain quite strong, so as of now, all of this falls very much under “curiosity” more than concern.

In sum: Conditions may begin to get a bit more favorable for some sort of tropical system by late June, but it’s best to ignore any operational models showing rogue day 14+ hurricanes right now, as that is a very unlikely outcome. We’ll be back with more tomorrow.

In the meantime, please feel free to comment or drop us a feedback form to tell us what you like or dislike about these daily outlooks. You can expect this sort of update each weekday morning through October or November, with more frequent updates when there are storms threatening land. Feedback is always valued, but especially so right now as a new site. Thanks for your early support!

Arlene comes and Arlene goes

Tropical Depression 2 was upgraded to Tropical Storm Arlene yesterday afternoon, and as I am writing this, Arlene is on its way out. Here now, a quick recap of 2023’s first named storm.

No, but seriously, Arlene is on the way to dissipation later today or tomorrow. Looking at a satellite image today, Arlene is more curious looking than menacing.

Tropical Storm Arlene is a swirling area of clouds and isolated thunderstorms at this point, and should be downgraded to a depression or remnant low later today. (Tropical Tidbits)

There are some thunderstorms still on the far northeast side of Arlene, but that’s about all right now. The center is clearly visible, but without thunderstorms around that center, it’s clearly evident that shear and dry air are doing work. A forecast map from the GFS model that shows wind speed and direction (indicated by the little barbs on the map) and relative humidity in the upper atmosphere (brown = drier air and green = more moisture) shows that Arlene is in a very dry, very hostile (windy) environment aloft. This is a good recipe for disorganization, and as such, Arlene’s end game is clear.

Arlene is surrounded by dry air and under a high wind shear environment, which means it’s inevitably about to fall apart. (Tropical Tidbits)

So we’ll call that a wrap on Arlene for all intents and purposes.

Florida rainfall chances

For Florida, which on the map above is covered in higher moisture, there will continue to be rounds of thunderstorms today, and the National Weather Service in Miami continues the flood watch from Miami-Dade through Palm Beach Counties and around Lake Okeechobee. The heaviest rains on Friday fell north and west of the lake and between Tampa and Orlando.

Forecast rainfall through Monday morning in Florida, with isolated heavy rain likely between the Keys, Miami, and Tampa.

Rain totals as forecast above will be quite variable (and may be placed a bit differently than shown in the forecast). Some areas may see a quarter to half-inch or less, while others could easily see 2-4 inches of rain between now and Monday, so watch for ponding and areas of localized flash flooding, especially in spots that have seen a good bit of rainfall this week. Also, as is occasionally the case with tropical thunderstorms, we could see reports of waterspouts or even some isolated strong to severe storms today or tomorrow in South Florida.

Otherwise, that’s all to discuss. We’ll be back on Monday with our daily tropical update and a look at some seasonal forecasts for this year. Enjoy the weekend!