Eric Berger

July 20, 2023 Outlook: Dry air keeping a lid (mostly) on the tropics for now

One-sentence summary

As Tropical Storm Don swirls in the Atlantic, we’re watching another system that likely will not develop due to dry air.

Happening now: Don

Tropical Storm Don looks a little better this morning in its satellite appearance, and has a window to strengthen somewhat over the next day or two. During this time it probably will top out as a reasonably strong tropical storm, but northing more. Fortunately Don continues to follow a track that will keep it far out to sea.

Forecast track from the National Hurricane Center for Don.

By this weekend Don should lift far enough north that water temperatures will become too cold to sustain tropical storm characteristics. Once Don reaches waters below 70 degrees Fahrenheit this weekend, it is safe to say that Don will knotts be long for this world.

The medium range (days 6 to 10): Atlantic waves march west but have a lot of dry air to fight off

The National Hurricane Center continues to call attention to a tropical wave in the eastern Atlantic, forecasting a 20 percent chance of development over the next 5 to 7 days as it comes west. If I were buying stock in storms, I would give this one a “sell” rating due to a number of factors, including dry air to the system’s north and, eventually, probably in the Caribbean as well. Matt mentioned yesterday that the Saharan dust inhibiting this system is on its way toward the Gulf of Mexico eventually, so look for some reddish sunsets later next week along the U.S. Gulf Coast.

It looks like Don needed a friend in the Atlantic tropics. (National Hurricane Center)

As for this tropical system, there may be a brief window in about five days, before it reaches the Caribbean Sea, for a depression of tropical storm to develop. Therefore areas such as the Lesser Antilles should probably watch this system. But it’s not the kind of thing we need be too concerned about. Certainly, there will be bigger fish to dry the deeper we get into the season, in a few weeks’ time.

Fantasyland (beyond day 10): Biding our time

Overall, aside from Don, and potential shenanigans from the system mentioned above, things look fairly quiet for the rest of July.

But for those who know the Atlantic hurricane season, that’s to be expected. The real action often does not begin until the first or second week of August. At that point we’re going to have to see whether wind shear from El Niño is able to counteract historically warm sea surface temperatures in the tropical Atlantic. If not, well, we’re going to be busy here at The Eyewall.

July 12, 2023 Outlook: The Gulf of Mexico is blazing hot as we approach mid-July

One-sentence summary

The majority of the tropical Atlantic will remain fairly quiet, however it appears increasingly possible that a tropical system could form several hundred miles east of Bermuda during the next week.

Happening Now: No worries for most

In the Atlantic this week all eyes are, improbably, on an area of low pressure located about 500 miles to the east-northeast of Bermuda. As Matt pointed out on Tuesday, historically this is a very unlikely place for a tropical system to form in mid-July. But as we’ll discuss a bit more below, this is not a normal year. The seas in the Central Atlantic Ocean are fairly warm for this time of year.

All eyes, for now, are on the Central Atlantic Ocean. (NOAA)

The National Hurricane Center gives this system a 50 percent chance of becoming a tropical depression or storm over the next seven days before it would likely fizzle out, moving further north into waters less favorable for development. Given that this system almost certainly will remain out at sea, it should ultimately be of little concern to to us in terms of impacts. Unless you’re a fish. Or run a shipping company.

The medium range (days 6 to 10): Let’s talk about the Gulf of Mexico

Beyond the system in the Central Atlantic, there’s not much to say in terms of activity. But that’s perfectly normal for mid-July, when there’s often a lull in the tropics. However, I do think the warm water that’s allowing the Central Atlantic system to form offers us a cautionary tale.

If we turn our gaze to the Gulf of Mexico, we see very high sea surface temperatures. If you live anywhere along the coast, from Brownsville, Texas to Miami, Florida, you’ve probably noticed the very warm nights this summer. This is due, in part, to temperatures in the Gulf of Mexico that are running from 1 to 5 degrees Fahrenheit above normal. This onshore flow adds to the overall mugginess of the air.

Sea surface temperature anomaly in the Gulf of Mexico. (University of Miami)

This is not a concern now for tropical activity, as wind shear remains fairly robust across the Gulf, inhibiting storm formation. But it will become a significant concern as we get into August and September, when wind shear tends to relax a bit. I’m not making any concrete predictions here, but with sea surface temperatures this warm, if tropical systems do form they will have the potential to become very strong, very quickly.

Fantasyland (beyond day 10): Still quiet

Fortunately, there remains no sign of anything notable in the extended range right now. This is likely to change as we get toward the end of July and into August, but for now things are quiet.

July 5, 2023 Outlook: It’s all quiet on the Western front, and mostly so on the Eastern Front

One-sentence summary

As we went through the Fourth of July holiday all of the fireworks were in the sky, rather than in the tropics.

Happening now: Nothing in the Atlantic

The Atlantic remains quiet, and it should stay that way for at least the remainder of this week if not beyond.

The Eastern Pacific has also quieted down with the dissipation of two hurricanes, Adrian and Beatriz, in recent days. The potential remains for some additional development this week to the south of the Western coast of Mexico, but nothing that appears to be an imminent threat to land. This is something we’ll be tracking later this week, however.

Tropical Outlook for the Eastern Pacific Basin over the next seven days. (National Hurricane Center)

I also want to call attention to an excellent post published this week on Michael Lowry’s Substack that is tracking the influence of El Niño on Atlantic hurricane activity so far. This summer we’ve seen a strong El Niño develop in the tropical Pacific, where sea surface temperatures are much warmer than normal. Typically this pattern is associated with higher wind shear in the Atlantic. The bottom line is that wind shear does appear to be ramping up across the Atlantic basin as we get deeper into July, and this is likely to tamp down on tropical activity at least into the near term.

Current wind shear levels in the Atlantic. (CIMSS/The Eyewall)

I am hopeful that this wind shear will generally persist into August and September, when it would counteract the effect of extremely warm seas in the Atlantic that will otherwise be favorable to tropical storm activity.

The medium-range (days 6-10): Moisture but no swirls

Much of the immediate Gulf coast will see rain showers this week as tropical moisture surges inland, but this low pressure is unlikely to develop into anything of note. Another area to watch, potentially, is the southern extremity of the Caribbean Sea. But this is nothing to get too excited about, either.

Fantasyland (beyond day 10): All remains quiet

As of now, there doesn’t seem to be anything of note in the Atlantic basin for the day 10 or later period. July often sees a lull in activity, and that appears to be what is happening now. I’m happy to have it.

June 20, 2023 Outlook: Extreme sea temperatures are fueling Bret and a second Atlantic system

The National Hurricane Center began issuing advisories for Tropical Storm Bret on Monday, and we’re also tracking a second system not far behind that likely will also become a named storm. Both of these systems have formed in the “main development region” of the Atlantic where tropical systems often begin their lifetimes. However, the season for storm formation in the main development region typically does not kick off until August.

So what’s happening out there? Well, it’s blazing hot.

Graphic showing temperature anomalies in the main development region. (Ben Noll)

Ben Noll, a New Zealand meteorologist, noted on Monday that sea surface temperatures in the main development region are the warmest they’ve been on record for June. In fact, the seas are as warm now as they typically are in late August or September, when the Atlantic hurricane starts to peak. That’s one reason why we’re seeing a spate of early season activity.

A second chart from Ben is equally concerning, as it shows temperatures in this region presently exceeding those of the 2005 and 2010 Atlantic hurricane seasons, both of which produced frenetic activity. The 2005 season remains the most active year in my lifetime, and Gulf Coast residents will doubtlessly remember Katrina, Rita, and Wilma all reaching Category 5 status in the Gulf of Mexico.

Well, that’s concerning. (Ben Noll)

Warm seas are not the only factor in storm formation, of course. This year, with El Niño in the Pacific, we can have some hope that wind shear will counteract the formation of storms. But worryingly, so far, warm seas appear to be winning out against El Niño. I have to say that I am starting to get mildly concerned about what is to come this year, particularly in August and September.

One-sentence summary

We’re tracking Tropical Storm Brett as well as Invest 93L, which has been given an 80 percent chance of developing this week into a depression or named storms in the coming days.

Brett is being followed by a system that would be named Cindy, if it develops. (National Hurricane Center)

Happening now: The stage is set for Bret, with a possible encore

Here’s what we know about the two tropical systems out there.

Tropical Storm Bret

First of all, with apologies to fans of George Brett, this system has just one “t.” After forming on Monday the storm has changed little in intensity overnight, with sustained winds of 40 mph. This is likely due to some moderate wind shear nearby. Not enough to break the storm apart, but enough to keep its organization at bay.

The system has about three days to get its act together before shear is expected to increase, in which case Bret should start to weaken. At present the National Hurricane Center brings Bret to hurricane strength briefly, before winding it back down on Thursday night as it approaches the Lesser Antilles islands in the Caribbean Sea.

Bret is bound for the Caribbean Sea. (National Hurricane Center)

No one wants to see a tropical storm headed their way, and Bret is something that people in the Caribbean Islands, including Puerto Rico, the Dominican Republic, and Cuba will want to keep an eye on. Damaging winds and heavy rainfall are definitely possible with Bret later this week or weekend, although I don’t think we’re looking at a situation where this storm really blows up. My biggest concern is flooding, but it’s not really possible to say where the heaviest rain will occur. We should have a better handle on the overall threat tomorrow morning.

Invest 93L

Much like its predecessor, Bret, how well this tropical system gets organized is tied up with where it goes, with a better organized disturbance likely turning northwest before the Caribbean and a less organized one likely following 92L to the west and into the islands. For now the most likely outcome, I believe, is that this system turns north before reaching the Caribbean Sea. That would be best for all concerned, except maybe for the fish.

The medium range (days 6-10): And then there were three?

As Matt noted on Monday, there are some signs in the models that yet another disturbance will emerge off Africa soon, and that this may be something that could develop over the weekend or next week. However the models don’t appear too excited about this system becoming a big deal, likely due to a fairly uninviting environment overall for development. Certainly at The Eyewall we’re rooting for shear to have its day.

Fantasyland (beyond day 10): Possibly calmer to end June

After this present spate of activity, the overall tropics may turn a bit quieter to end the month and start July.

Hopefully?