What’s up with the 2022 hurricane season forecast?


August was a quiet month for tropical storms. In fact, there hadn’t been a single named storm since early July, and it hadn’t happened in over 25 years. Yet, just hours into September, Hurricane Danielle developed and was quickly followed by Hurricane Earl. These two storms are a reminder that hurricane season is far from over and will likely remain active for several weeks. This season’s storm activity — or lack thereof — has many people wondering what’s going on in a hurricane season forecast and what has suppressed this year’s tropical activity so far. Having a better understanding of what it takes to create these seasonal forecasts can help businesses better understand potential risks and make informed decisions based on this information. Most hurricane season forecasts start by looking at the major environmental factors, such as water temperatures and upper-level winds, that influence tropical activity and how favorable those factors are to storm development. tropical. At a high level, hurricane season forecasts are relatively simple to predict. The task becomes more and more complicated when one tries to predict several months in advance the conditions impacting tropical development.

Although many factors influence tropical activity, the most important to consider is ocean temperature. Tropical convection, which powers hurricanes, is fueled by warm ocean water. To fuel tropical storms at lower latitudes, ocean water temperatures must be 80 degrees Fahrenheit or higher. Another important factor is where these warmer water temperatures are located as well as the overall extent of warm water. Generally, when warm water is more expansive than usual, there are more areas where storms can develop. Warmer than normal water also means that storm development could begin earlier in the year and, if it remains warm, support storm development later in the year. In short, warmer waters effectively lengthen the hurricane season and potentially increase the total number of storms.

Wind speed at different heights is another environmental factor that influences the development of tropical storms. Unlike tornadic thunderstorms which need highly variable winds with height to develop, ideal tropical development requires calmer, more uniform winds. While ocean temperatures vary slowly and are generally easier to predict, wind patterns change frequently and are more difficult to predict over the long term.

Forecasters also consider atmospheric humidity as another environmental factor in hurricanes. Although it is often assumed that air masses over the ocean will be moist, this is not always the case, especially above the lowest atmospheric levels. The source of the plumes of dry air that often settle over the tropical Atlantic actually comes from the Sahara Desert. When persistent high pressures are in place north and northwest of the Sahara – which has been the case this summer – dry air is channeled westward from the Sahara over the tropical Atlantic. The warm, moist air plumes rising from the Atlantic that would typically generate towering thunderstorms are instead robbed of their ability to do so by the dry Saharan air.

This summer’s hurricane activity was heavily influenced by this dry air and, to a lesser extent, wind shear, which limited storm development. The months of June, July and August show that with less favorable environmental conditions at the start of the hurricane season, the storms are slow to develop. However, since the first day of September, the dry airflow and wind shear have diminished considerably, allowing Atlantic storms to begin to develop. All indicators suggest that environmental conditions will continue to be more favorable through September and likely into October, so an active second half of the hurricane season still seems likely. Still, the slow start to the season means that most pre-season forecasts will end up being too high, even if the season ends with more than the average of 14 named storms and seven hurricanes.

With this overview of how the seasonal outlook for tropical storms is developed, it is truly helpful for governments and businesses to understand the environmental conditions involved in hurricane forecasting. This knowledge can help inform decision-making to protect people and assets from potential risks.

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