Here’s what to expect in the tropics during July

Colorado State University releases 2025 Atlantic hurricane season outlook_copy

FOX Weather Hurricane Specialist Bryan Norcross discusses the first outlook issued for the 2025 Atlantic hurricane season, which was released Thursday morning by forecasters at Colorado State University. The CSU team is calling for 17 named storms, nine of which are expected to become hurricanes. Four of those hurricanes could reach major status, with winds of at least 111 mph (Category 3 or higher).

Depending on how you measure tropical activity in the Atlantic, the basin is either busier than a normal hurricane season or far behind how powerful a typical season usually is.

How can both be true?

Despite two tropical cyclones already having formed, their impacts have been minimal, their lifespans short, and their energy contribution to the season fairly minuscule.

Meteorologists use a measure known as Accumulated Cyclone Energy, or ACE, to quantify the strength and duration of tropical storms and hurricanes.

So far this season, ACE is far below average - a sign that the cyclones, while above average in number, have lacked both staying power and punch.

Through the first month of the season, the combined ACE value for all tropical activity in the Atlantic basin is under 0.5 units, a value meteorologists consider extremely low.

For context, through the first month of the tropical season, the ACE value is usually north of 2.0, which puts the year roughly 90% behind in terms of ACE.

The act of identifying or naming cyclones for only a few hours is nothing new, but with increased observations from satellites and aircraft, features that weren’t named years ago now are checking off names on season lists.

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Why July may be a repeat of June

Several signals suggest that the second month of the 2025 hurricane season will continue what the first started - brief spouts of activity without substantial development.

Although sea surface temperatures are well above normal across parts of the Gulf and Caribbean, other factors are working against storm formation.

Atmospheric pressures across much of the basin remain higher than normal, which tends to suppress storm development.

Expected rainfall across tropical breeding grounds in the Atlantic and Caribbean is also expected to be below average, a sign of a dry and stable atmosphere.

Another signal forecasters watch is the Madden-Julian Oscillation (MJO), an upward pulse of tropical moisture that moves around the globe.

When the MJO is in an active phase over a basin, it can provide favorable conditions for cyclone formation.

For a large portion of July, the MJO is expected to be in an inactive phase across the Atlantic, limiting the likelihood of storm organization.

Forecast models suggest that, throughout July, the primary opportunities for storm formation will come from features such as frontal boundaries and thunderstorm complexes that drift over warm waters and find a limited pocket for development.

The waters off the southeastern U.S. coastline, as well as parts of the Gulf of Mexico, may be the only zones "in play" for brief development.

Even with development, a cyclone’s rainfall and coastal erosion will likely be more memorable than the storm’s name.

Stalled frontal boundary along the Southeast.

(FOX Weather)

2025 ATLANTIC HURRICANE SEASON GUIDE

On average, a typical July only produces one named storm and zero hurricanes, so if current trends persist, July 2025 will likely fall around average in terms of overall count.

Still, experts caution that the unimpactful start to the season for the U.S. is not a guarantee it’ll remain that way in the coming months.

Hurricane activity across the basin usually doesn't begin to pick up until around August 20, when Colorado State University holds the annual tradition of ringing the hurricane bell, warning of the heart of the season.

The official hurricane season for the Atlantic Basin (the Atlantic Ocean, Caribbean Sea and Gulf of Mexico) is from June 1 to Nov. 30. As seen in the graph above, the peak of the season is Sept. 10. However, deadly hurricanes can occur anytime in the hurricane season.

(NOAA/NHC / FOX Weather)