Tropical Atlantic Off To Slow Start, But Meteorologists Still Expect Active Season!
It’s been a quiet start to the 2023 Atlantic Hurricane season with only 5 storms so far; an unnamed Subtropical Storm, Tropical Storm Arlene, Tropical Storm Bret, Tropical Storm Cindy, and Hurricane Don, all of which remained over the ocean and had little to no impacts on the U.S Coastline. However, the Pacific has been a bit more impressive producing 3 hurricanes with Calvin becoming a major hurricane. This time last year we had only had 3 systems in the Atlantic: Tropical Storm Alex, Major Hurricane Bonnie, and Tropical Storm Colin so we aren’t falling far behind just yet, as the peak hurricane season lies ahead!
In the past couple of months, tropical activity in the Atlantic has remained low with little tropical formation, thanks to a couple of factors. The first being the persistent troughing across the eastern United States allowing more wind shear into portions of the Gulf of Mexico and Atlantic. However, we also continue to see a lot of dry, dusty Saharan air at the mid-levels. This keeps storms from forming, as they need moist air to do so.
Looking ahead, the National Hurricane Center (NHC) released an updated forecast for the Tropical Atlantic last week. The update increases the probability of an above-normal Atlantic Hurricane season from a 30% chance in May to now a 60% chance in August. For the entire season, the NHC is forecasting 14-21 named storms, 6-11 of those will become hurricanes, with 2-5 becoming major hurricanes. It is important to remember, this forecast does not predict landfalling storms, just development.
After a slow start to the Atlantic season, why are we seeing greater confidence in more tropical systems now? While El Nino tends to lead to a below average Atlantic hurricane season, temperatures in the Atlantic and especially the Gulf of Mexico are extremely warm. In fact, record warmth has been observed. Current ocean temperatures are running around 30-33° C (86-91° F) in the Gulf and Caribbean! This is a lot of energy to work with if tropical systems can develop as water temperatures for tropical systems to develop only need to be 79°F +.
That being said, we still need less wind shear and more moisture in order for the tropical Atlantic to come alive. As of today (8/15/23) conditions are still unfavorable in the short-term. However, the NHC is watching a couple of tropical waves coming off the coast of Africa mid to late week. These could slowly organize into tropical systems with time. Some ensemble data shows the possibility of an increase potential for tropical development as we head into the latter portions of August.
Overall, there is still a lot of time for the tropical season to become active, as 11 of 14 named storms last year occurred between September 1 and November 11. The climatological peak for hurricanes in the Atlantic occurs September 10th, with hurricane season lasting through November 30th.