The 2024 tropical storm and hurricane season could be another active one

The official start of the tropical storm and hurricane season in the Atlantic and Caribbean waters is a little more than three months away. With the strong El Niño starting to weaken along the equatorial regions, many forecasters that specialize in sea-surface temperatures are indicating the increasing chances of another active season.

Based on the 30-year average from 1991 to 2020, there is a new average of about 14 named storms. Seven of 14 storms, on average, will form as hurricanes with three of them becoming major hurricanes. Sept. 10 is the approximate peak of the tropical storm and hurricane season which officially begins June 1 and ends Nov. 30.

During El Niño years, especially strong ones, the formation of tropical storms and hurricanes in the Atlantic and Caribbean waters are often limited due to the wind shear. However, the record warmth of the Atlantic sea-surface temperatures in 2023 helped to create an above-average 20 named storms, which was the fourth highest since 1950. Out of the 20 systems, seven of them became hurricanes and three of those big storms intensified into major hurricanes.

During the 2022 season, there were 14 named storms that included eight hurricanes. Two of those hurricanes were major, including Hurricane Ian. This hurricane brought significant damage to western Cuba, the southwestern and central portions of Florida and the Carolinas. When Ian was finished, the total damage was estimated at a whopping $113.1 billion. That season, as well as 2021, was influenced by the cooler La Niña sea-surface temperature pattern.

The 2021 season was the third-most active on record as it produced 21 named storms. It was also the second season in a row, and third overall, in which all storm names were used. However, starting with the 2021 season, the Greek alphabet is no longer used when named storms exceed 21. Instead, they will use a “supplemental list” of names based on the modern English alphabet. There have been 21 names per list and those beginning with Q, U, X, Y and Z are not on the list because the WMO said those letters are “not common enough or easily understood in local languages to be slotted into the rotating lists.”

The upcoming season may be similar to years when moderate to strong El Niño events were fading toward the formation of a new La Niña. As I’ve mentioned earlier, many forecast computer models are predicting that we’ll be in a “La Nada,” the in-between warm El Niño and cooler La Niña sea-surface temperature pattern as soon as the spring season. There is also the potential of a new La Niña along the equatorial regions by the end of this year. Also, a few of the long-range forecast models for sea-surface temperatures indicate that we could see at least a moderate La Niña event late in the year.

Since 1995, the average number of named storms after a major El Niño event was nearly 17 named storms. The highest number occurred in 1995 and 2010 with 19 systems forming.

For 2024, it’s very possible that we could rival last year’s total of 20 named storms. With ocean temperatures still above average in the Atlantic Ocean, we could see a total of named storms in the low to mid-20s if sea-surface temperatures cool down as quickly as many are projecting.

For tropical storms and hurricanes to form in the Atlantic and Caribbean waters, as well as the Gulf of Mexico, ocean temperatures need to be at least 80 degrees Fahrenheit. During the summer season in 2023, average sea-surface temperatures across these regions have been at record levels. Around the peak of tropical storm formation in early September 2023, readings in some areas were reported to be in the mid-to-upper 80s.

In terms of our local weather, it’s looking like an unsettled week across the Inland Northwest as a series of storms are expected to bring rain or snow to the lower elevations with plenty of fresh snow in the higher mountains.

In Coeur d’Alene and surrounding areas, it’s always a “temperature thing” depending on whether we get snow or rain. Many locations will be “on the line” between rain and snow, but we expect there will be periods of measurable snowfall this week, especially during the overnight hours. The long-range forecast models are also pointing to the potential for snow in early March across the lower elevations of North Idaho. Then, conditions are looking warmer and a bit drier toward the middle of next month.

As of the weekend, Coeur d’Alene still sits at a seasonal snowfall total of 33.2 inches. Between now and the end of March, we’re forecasting that the final snowfall total for the 2023-24 season will probably be around the mid-40s. However, with the expected formation of a cooler La Niña late this year, the 2024-25 snowfall season is expected to be much higher with a better chance of a White Christmas across North Idaho and parts of eastern Washington.

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Contact Randy Mann at randy@longrangeweather.com.