What to Expect in the 2021 Hurricane Season

Using predictive modelling, analog years, and lessons learned from 2020’s storms, we have created an overview of the forecast for the 2021 hurricane season.

Before getting into our findings, let’s look at the factors we consider when determining what the season will present. Water temperatures in the Tropical Pacific (whether we will be in an El Niño or La Niña pattern) and in the deep tropics is a key element in assessing if conditions will be favorable or inhibiting. Inhibiting means there is less likelihood of an active season, while favorable means a more active season.

What we know leading into the spring:

• Sea surface temperatures in the tropical Pacific have cooled (although a recent warming trend is something to keep an eye on). This results in favorable conditions in the Atlantic.
• The peak season looks neutral, with potential to shift toward favorable.
• There is only a 13% chance of being in an El Niño (which would create the least activity at peak season).
• Water temperatures across the Atlantic are currently above normal, and as we know, heat drives tropical activity.

Besides water temperatures, we also look at levels of atmospheric instability. More instability means more thunderstorms, which trigger larger storm formation. These triggers often occur off the coast of Africa, so we turn to the Main Development Region, the area spanning east of the Caribbean across the Atlantic, where the water temperatures are below normal.

What the ECMWF (the European model) is predicting:

• Below normal tropical activity in the MDR.
• A higher-than-normal ACE through September (110% of normal).
  - ACE is accumulated cyclone energy. It measures how energy exists in an area and accounts for the intensity and duration of storms, not just the amount.
• Using the ACE measurement, the MDR looks quiet, but there appears to be more energy than normal over the Atlantic.
• The prediction is 13.5 named storms in the upcoming season.

The ECMWF is close to normal when compared to the past three decades, however last year, this model was conservative in its predictions. Turning to the data in analog years, we have matched five previous years to this year’s predictions. For these, the ACE levels were all slightly above normal.

Given this information, StormGeo is forecasting the following:

• 19 named storms, 9 hurricanes and 5 intense hurricanes.
• The peaks for landfall include Texas, Louisiana, Mississippi, Alabama and Florida, with tracks forming in the Gulf of Mexico.
• There is potential for storm tracks to start closer to North and Central America.
• There will be high activity in the Gulf of Mexico, the passage of hurricane centers covering 50 miles.

In summary, we are anticipating an active hurricane season. For the developmental and associated risk areas, there be will less time to respond to storms due to their length of track and closeness of formation. Similar to 2020, there may be ‘short-track’ and ‘pop-up’ storms arising from the Gulf, and late track intensification of storms—storms getting much stronger very near landfall. We advise you to stay informed and continuously check back for our forecast updates.