Eric Berger

In brief: Today’s update provides an overview of the dusty tropics and a look at a new seasonal forecast from Colorado State University. We also dig a little deeper into storms today in the Midwest, and the potential for excessive heat in the West.

Hi everyone, Eric Berger here. As you probably know Matt does the majority of forecasting on The Eyewall but I’m here to back him up, and so I pinch hit occasionally. This is the first time I’ve written for the site since we have moved our newsletter over to Substack, and I just wanted to thank everyone who has signed up. The response so far has been tremendous, and we are already making plans to improve The Eyewall as a result. But for now we are going to focus on hurricane season, heavy rains, and heat in today’s outlook.

The tropics

Let’s start in the tropics where, happily, everything is quiet all the way from the Central Pacific Ocean to the Eastern Atlantic. This is not all that abnormal for the first half of July, but it is nonetheless welcome. Looking ahead, due to a variety of factors including a new and fairly large plume of dust moving off the Sahara into the Atlantic, we think things will remain fairly quiet for at least a few more days—and hopefully more!

In this interim period of quiescence I wanted to take a peek at the updated seasonal hurricane forecast from Phil Klotzbach and his team at Colorado State University. As you can see in the chart below, the team has slightly lowered their outlook in terms of named storms and hurricanes, and reduced the overall forecast for Accumulated Cyclone Energy by 10 percent. This is only a slight modification, and given the inherent error within seasonal forecasts such a change does not mean a whole lot. But in the main, you’d rather be trending downward in seasonal activity than upward, no?

As for why the Klotzbach team made the change, here’s what they wrote in their abstract: “We have decreased our forecast slightly and now call for a slightly above-normal 2025 Atlantic basin hurricane season. The primary reason for the slight decrease in the outlook is both observed and predicted high levels of Caribbean shear. High levels of Caribbean shear in June/July are typically associated with less active hurricane seasons.”

Midwest rains

Areas of the upper Midwest, including parts of Iowa, Missouri, Wisconsin, and Illinois will be subject to heavy rainfall on Friday and Friday night. In the big picture we see a large trough over the Central Plains that will be supportive of storms. Such complexes of thunderstorms, known as mesoscale convective systems, will be possible from late morning through the early evening hours. Most likely we will see a line of storms develop over Iowa and Wisconsin before moving southward into Missouri and Illinois.

From an impact standpoint I don’t believe these will be too serious. However, given the setup, some modest flooding is possible later today where the stronger storms set up. This forecast from the Weather Prediction Center provides an idea of where the greatest risk of heavy rainfall will come later today. By late evening the flood risk should be diminishing for the Midwest.

Sizzling in the west

Much of the Western United States will see high temperatures this weekend above 100 degrees. For some areas in Arizona and Southern California, this is nothing new. But the highs for a broad swath of northern California, Oregon, Washington state, and elsewhere in the west will be 5 to 15 degrees above normal. This heat is due to a building dome of high pressure that will affect much of the West through Sunday. The heat should break by Monday for much of the region.

However, the forecast for the Northwest turns even more extreme next week. Areas near Portland and Seattle could see highs in the mid- to upper-90s on Tuesday and Wednesday as high pressure rebounds. There is still some uncertainty in the upper-level pattern that may moderate temperatures slightly. But for these areas this is very high heat, and an Extreme Heat Watch is in place for Tuesday afternoon through Wednesday evening.

That’s all for us today. We hope everyone has a great weekend.

Headlines

• 94L in the Central Atlantic Ocean continues to putter along
• Significant development is less likely as the system nears the Caribbean Sea
• Parts of Central America could see heavy rainfall over the next week from tropical moisture
• Overall there appear to be no threats to the United States over the forecast period

Invest 94L

We’re continuing to track an area of low pressure that is moving across the central Atlantic Ocean. Overall, this system is expected to continue moving more or less westward, or just north of due west, this week. This would put it in the vicinity of Puerto Rico or Hispaniola by this weekend. We can be fairly confident in this general track. What I’m less certain of this morning is whether anything actually develops.

The National Hurricane Center gives Invest 94L a 40 percent chance of becoming a tropical depression or storm during the next seven days, and frankly this feels a little generous. Most of the major models that we look at no longer develop 94L into a tropical system (a few still do). In any case, this is something for the Caribbean islands and possibly the Bahamas to continue to watch, but our overall concerns for significant impacts from 94L remain fairly low. If our thinking on this changes, we’ll of course provide a timely update.

Caribbean Sea blob

The National Hurricane Center has also begun highlighting an area that Matt has been talking about for awhile in the western Caribbean Sea. This mass of showers and thunderstorms is not particularly organized, nor do I think it probably will become a depression or named storm. However, this part of the Caribbean Sea remains very warm, so there is at least the potential for something.

Regardless of development, however, this system could prove a rainmaker for southern Belize, Guatemala, and Honduras over the next week or 10 days. Depending on whether the heaviest rains remain offshore or push further inland, rainfall from this tropical blob could potentially lead to some mudslides in the region.

Elsewhere

As we get deeper into October, the tropics are starting to wind down. The Atlantic season doesn’t officially end until November 30, of course, but at this point we don’t see any near-term threats to the United States. That’s a good thing as areas hard hit by hurricanes Helene and Milton continue to recover, and start to rebuild.

Headlines

• Milton is nearing hurricane strength as it begins to move eastward toward Florida
• The storm is forecast to rapidly intensify today and Monday as it encounters very warm seas
• The intensity forecast becomes more complicated as Milton nears Florida, and faces more hostile atmospheric conditions
• Residents along the western coast of Florida should make preparations today and Monday in advance of the storm’s arrival

Milton on Sunday morning

As of 11 am ET on Sunday morning, Milton has strengthened to a 65-mph tropical storm, which is just 10 mph below hurricane strength. Given that an eyewall has formed, it is likely that Milton will become a hurricane later today, and possibly strengthen into a major hurricane by Monday. The storm has started to move a little bit more, toward the east-southeast, at about 6 mph. Its motion will continue to accelerate over the next couple of days as steering currents become more pronounced.

Major sources of uncertainty

In this section I want to talk about what is known, and what is not, in regard to Milton. Let’s start with the track of the storm. Overnight, there has been a modest southern shift in several of the most important models we look at. Although there remains some uncertainty, at this time the most likely outcome for a Florida landfall on Wednesday is somewhere just north of Tampa Bay to just south of Fort Myers. I would anticipate that the track forecast will really tighten up during the next 24 hours. However, time is running out for preparations, with tropical storm-force winds possibly reaching the west coast of Florida by as early as Tuesday evening.

Next, we’ll move to intensity. This is really where there is the largest amount of uncertainty. We expect Milton to intensify rapidly over the next couple of days because it will be traversing very warm waters and face only modest levels of wind shear. The National Hurricane Center predicts that Milton will peak as a strong Category 3 hurricane on Tuesday evening, with 125 mph sustained winds, as it nears Florida. It might be even stronger.

Around that time, however, Milton will be encountering increasing levels of wind shear, which disrupts the circulation of a hurricane much like trying to skate on uneven ice. Another potentially significant factor is the intrusion of dry air from the north and west of Milton, which will be wrapped into the circulation of the hurricane. This dry air results from the front the northern Gulf of Mexico that is helping to steer Milton toward Florida. The image below shows how dry air might become entrained into Milton by Tuesday evening and Wednesday.

How all of this plays out is difficult to predict, even though we are only about four days from Milton making landfall. A weaker storm is unquestionably better in terms of wind damage. However, a weakening storm could also become larger (Milton is fairly small right now), and a larger storm often produces a more powerful storm surge, and has more far-reaching effects. This is why we cannot say too much about impacts from Milton for specific areas of Florida yet. Too much depends on track, size, and intensity of the hurricane, which all remain a bit fuzzy.

The bottom line remains pretty simple, however. A powerful and potentially destructive hurricane is headed toward the west coast of Florida, and will strike the state in the middle of the week. Milton will bring strong winds, heavy rains, and a significant surge to parts of the state. People who live along the west coast, especially from Fort Myers to the Tampa Bay metro area, should prepare for the worst in terms of wind, surge, and rainfall now. Much of the rest of Florida, aside from the Panhandle, should prepare for the possibility of heavy rainfall.

Tampa hurricane history

The Tampa Bay metro area, with a population of more than 3 million people, is the most developed region on the west coast of Florida. Among hurricane forecasters, the region is famous for dodging major hurricanes. A major hurricane, defined as Category 3 or larger, has not made a direct impact on Tampa Bay since 1921, more than a century ago. This was the Tampa Bay Hurricane, and was so-called because back then there was no formal naming convention for tropical storms and hurricanes.

A century ago the region had less than one-twentieth the population is does now, about 125,000 people. The Tampa Bay area has had some close calls of late, including Hurricane Charley, in 2004; Hurricane Irma, 2017; Hurricane Ian, 2022; and of course Hurricane Helene this year. Will the region’s luck hold out with Milton? It’s way too early to make any kind of prediction.

Elsewhere in the tropics

There is plenty of other activity in the Atlantic tropics. Hurricane Kirk is rampaging across the mid-Atlantic Ocean, and although it is thousands of miles distant, producing some modest swells along the US East Coast. Eventually, as an extra-tropical storm Kirk could bring some disturbed weather to northern Spain or France. Hurricane Leslie has also formed in the open Atlantic, but this storm is not going to bother anyone, anywhere. For now, the focus is going to be all about Milton.

Matt will have an update by or before 6 pm ET today discussing the latest on Milton, and our thinking on its most severe impacts.