Eric Berger

July 26, 2023 outlook: August is nigh

One-sentence summary

There are a couple of areas that we’re watching, but overall things are fairly quiet for July with no imminent threats to land; however we’re now just six days away from August and at some point the switch is going to flip.

Happening now: Not too much, thankfully

We’re watching a (very) poorly defined area of thunderstorms near the Bahamas that Matt mentioned yesterday. However the odds are still stacked against this becoming something to worry about. So I want to talk a little bit more about climatology today.

We’re still about three weeks away from when we typically would expect the Atlantic tropics to come alive. This often happens around mid-August, when sea surface temperatures near their summer peak, wind shear reaches a nadir across much of the Atlantic, Caribbean and Gulf of Mexico areas we’re concerned about, and tropical lows move off the Africa coast with some regularity. This period is easily visible when we look at historical activity in the Atlantic, typically running from August 10 to around October 20.

Historical activity in the Atlantic basin. (National Hurricane Center)

The past offers no guarantee for what will happen in the year 2023, of course. Already sea surface temperatures are absolutely sizzling in the Atlantic and Gulf of Mexico, and are plenty warm to support the development and strengthening of tropical systems. We are also (see next item below) starting to see tropical waves moving off the coast of Africa with a bit more frequency.

What’s been holding us back so far this year has been El Niño, and its tendency to keep wind shear levels in the Atlantic above normal. We’re going to really need that pattern to hold on this summer, or else the Atlantic basin is likely going to explode with activity in about two or three weeks.

The medium range (days 6 to 10): A new contender emerges

As expected, the National Hurricane Center has started to track a tropical wave that recently moved off of Africa into the Atlantic Ocean. The global models are somewhat bullish on this system as it moves westward across the Atlantic Ocean, and it may develop into a tropical storm in five to seven days, or so.

This probably will be a fish storm. We’ll see. (National Hurricane Center)

The most likely scenario for this system, however, is that it curves to the north before threatening the Caribbean Sea or continental United States, but we’ll continue watching it all the same.

Fantasyland (beyond day 10): Happily quiet

There’s not much else out there, even in the fevered minds of the global models 10 days or later from now. That will change, so for now we’re embracing the quietude.

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.