With Atlantic hurricane season officially starting on June 1, NOAA has predicted another above-normal storm season for 2021.
2021 Atlantic Hurricane Season Outlook
Although forecasters are predicting a 60% chance of an above-normal Atlantic hurricane season, storm activity is not expected to reach the historical level of activity that occurred in 2020. There is also a 30% chance of a near-normal season, and a 10% chance of a below-normal season. 2021 Atlantic hurricane season could extend the record for most consecutive seasons of above-normal activity to 6 seasons in a row.
El Niño Southern Oscillation (ENSO) conditions are neutral, with the chance of a La Niña return later this hurricane season. These conditions are associated with high storm activity, as the sea surface temperatures remain above-average. Neutral ENSO conditions and the possibility of La Niña also will cause weaker tropical Atlantic trade winds and enhanced west African monsoons.
The 2021 Atlantic Hurricane Season Outlook predicts a 70% chance of each of the following ranges of activity:
- 13-20 named storms with winds 39 mph or higher
- 6-10 hurricanes (winds 74 mph or greater)
- 3-5 major hurricanes, including category 3-5 (winds 111 mph or higher)
- Accumulated Cyclone Energy (ACE) range of 110-190% of the median
2021 Eastern Pacific Hurricane Season Outlook
This year’s outlook forecasts a near-normal or below-normal season to be most likely. There is a 45% chance of a near-normal season, and a 35% chance of a below-normal season. The probability for an above-normal season is 20%.
Two major climate factors play a role in the forecasted Eastern Pacific hurricane season. The below-average to near-average sea surface temperatures across the eastern Pacific hurricane region combined with the slightly above-average sea surface temperatures across the Atlantic hurricane region is associated with near or below normal hurricane activity. Additionally, the second major factor leading to near or below normal Eastern Pacific Storm activity is the redevelopment of La Niña.
The 2021 Eastern Pacific Hurricane Season Outlook predicts a 70% chance of each of the following ranges of activity:
- 12-18 named storms
- 5-10 hurricanes
- 2-5 major hurricanes
- Accumulated Cyclone Energy (ACE) range of 65-120% of the median