The Eyewall

In brief: A tropical disturbance will move into the northeastern Gulf a little less than two days from now. Thereafter it should track westward. The most probable outcome is a moderate disturbance moving into Louisiana later this week, with the potential for heavy rainfall. But we will continue to watch things closely to see how the system evolves.

This weekend brought more flooding across parts of the United States. On Saturday evening the Davenport, Iowa area dealt with several inches of rain that flooded some homes and submerged vehicles. By Sunday the flood risk returned to Texas, where a large part of the Texas Hill Country saw a second round of heavy storms, including the previously hard hit Kerrville area. This produced flash flood warnings along and east of Interstate 35, but the strongest of the storms have now moved off to the southwest. Also this weekend there was a devastating fire on the North Rim of the Grand Canyon, which destroyed the historic Grand Canyon Lodge. So all in all, not ideal.

Gulf disturbance

After all of this, we are turning our attention to the tropics this morning. We have been mentioning the possibility of a tropical system developing this week in the Northern Gulf of Mexico for several days, and the National Hurricane Center has now begun highlighting the possibility. As of 8 am ET on Monday, forecasters there give the system a 30 percent chance of becoming a tropical depression or storm this week.

The remnants of a front, currently in the Atlantic Ocean off the coast of Georgia, should move across Florida over the next day or two, and into the northeastern Gulf. Once there, conditions could support the development of this area of low pressure into a depression or tropical storm that would continue moving generally to the west.

As to what happens after this, there is not great clarity in the model guidance. The background conditions, including sea surface temperatures and wind shear, are somewhat favorable for organization and intensification. But this is not an ideal situation, and the system is likely to remain fairly close to land. So we don’t expect this to explode over the deep and warm waters of the Gulf. Eventually it should move toward Louisiana.

One outlier model that appears to be most bullish on the system is the Germany based ICON, which brings a moderate tropical storm toward southern Louisiana by Thursday morning (shown below). Some people may remember that the ICON model is one of the outliers that correctly predicted Hurricane Beryl would impact Texas about a year ago, so we are not completely dismissing it. However, most of our other guidance does not develop a tropical storm, but rather keeps this at a disturbance or a depression level.

So in terms of intensification what we can say right now is that we don’t anticipate a significant wind storm. We cannot rule it out, but high winds and storm surge are not the main talking point. Rather, rainfall potential is.

Precipitation outlook

As this system tracks across the northern Gulf of Mexico, it is likely to bring increased rainfall chances to the Florida Panhandle, southern Alabama and Mississippi, and especially southern Louisiana. For now, NOAA’s Weather Prediction Center has that area, including New Orleans, under a “slight risk” of excessive rainfall next Thursday (shown below) and Friday.

That’s a good starting point, but depending on the evolution of this system that estimate may need to be bumped up in a day or two. The bottom line is that the second half of this week could bring a significant amount of rainfall into Louisiana. Right now we can only monitor the risk, rather than provide a definitive forecast. Hopefully that changes in a day or two.

As for areas further west, including Texas, we cannot rule out impacts at this time. However, none of our reliable guidance shows this system (or its heavy rainfall) tracking far enough to the west to bring heavy rains or winds to Texas. But it is something we will continue to watch.

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.