The National Oceanic and Atmospheric Administration (NOAA) is predicting another above-normal Atlantic hurricane season for 2021.
Forecasters predict a 60% chance of an above-normal season, a 30% chance of a near-normal season and only a 10% chance of a below-normal season. However, experts don’t anticipate a historic level of activity like that in 2020, when a record-tying 31 tropical cyclones formed (2005), with a record-breaking 30 of them becoming named storms.
2021 Atlantic hurricane season forecast. (Sources: NOAA, Colorado State University)
For 2021, a range of 13 to 20 named storms is likely. An Atlantic cyclone becomes a named tropical storm once its sustained winds reach 39 mph. NOAA is expecting six to 10 of the tropical storms to turn into hurricanes. This happens when sustained winds reach 74 mph. The forecast calls for three to five hurricanes to intensify into major hurricanes of Category 3 or higher, with sustained winds of at least 111 mph. NOAA is predicting these ranges with 70% confidence.
“Now is the time for communities along the coastline as well as inland to get prepared for the dangers that hurricanes can bring,” Secretary of Commerce Gina Raimondo said in a Thursday news release. “The experts at NOAA are poised to deliver lifesaving early warnings and forecasts to communities, which will also help minimize the economic impacts of storms.”
Last month, NOAA updated the statistics used to determine when hurricane seasons are above, near or below average relative to the latest climate record. Based on this update, an average hurricane season produces 14 named storms, seven hurricanes and three major hurricanes.
El Niño Southern Oscillation (ENSO) conditions are currently in the neutral phase, with the possibility of La Niña returning later in the hurricane season.
“ENSO-neutral and La Niña support the conditions associated with the ongoing high-activity era,” Matthew Rosencrans, lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center, said. “Predicted warmer-than-average sea surface temperatures in the tropical Atlantic Ocean and Caribbean Sea, weaker tropical Atlantic trade winds and an enhanced west African monsoon will likely be factors in this year’s overall activity.”
Scientists at NOAA also continue to study how climate change is impacting the strength and frequency of tropical cyclones.
“Although NOAA scientists don’t expect this season to be as busy as last year, it only takes one storm to devastate a community,” Ben Friedman, acting NOAA administrator, stated. “The forecasters at the National Hurricane Center (NHC) are well-prepared with significant upgrades to our computer models, emerging observation techniques and the expertise to deliver the lifesaving forecasts that we all depend on during this, and every, hurricane season.”
NOAA has updated several of its products and services, hoping to improve hurricane forecasting during the 2021 season.
- In March, NOAA upgraded the flagship Global Forecast System (GFS) to improve hurricane genesis forecasting and coupled GFS with a wave model extending ocean wave forecasts from 10 days to 16. Additionally, Global Positioning Satellite Radio Occultation (GPS-RO) data are now included in the GFS model, providing an additional source of observations to strengthen overall model performance.
- Forecasters at the NHC are now using an upgraded probabilistic storm surge model — known as P-Surge — which includes improved tropical cyclone wind structure and storm size information that offers better predictability and accuracy. This upgrade extends the lead time of P-Surge forecast guidance from 48 to 60 hours in situations in which there is high confidence.
- NOAA’s Atlantic Oceanographic and Meteorological Laboratory will deploy its largest array of air and water uncrewed systems to gather data designed to help improve hurricane intensity forecasts and forecast models. New drones will be launched from NOAA Hurricane Hunter aircraft that will fly into the lower part of hurricanes. Across the ocean, sail drones, hurricane gliders, global drifters and air-deployable technology will track various parts of the life cycle of tropical storms.
Last year’s record-breaking season serves as a reminder to everyone in coastal regions or areas prone to inland flooding to prepare for 2021.
2021 Atlantic tropical cyclone names. (Source: NOAA)
“With hurricane season starting on June 1, now is the time to get ready and advance disaster resilience in our communities,” FEMA Administrator Deanne Criswell said.
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