A rare event took place today over the Atlantic – three simultaneous hurricanes are active over the basin for the first time since 2010. Hurricane Irma continues to be a very dangerous category 5 hurricane, while Tropical Storms Jose and Katia both strengthened into category 1 hurricanes today. Irma continues to pose a very serious hurricane threat to the Southeastern United States, while Jose and Katia are expected to continue strengthening and could become major hurricanes. It is possible that the Atlantic could see an extremely rare event later this week: three simultaneous major (category 3 or stronger) hurricanes. I will focus mainly on Irma tonight and will discuss Jose and Katia more tomorrow.

Irma likely to begin to weaken soon, but still expected to remain a very strong hurricane for several days

As of 11:00 p.m. EDT, Hurricane Irma was centered near 19.4°N 66.8°W, and was moving west-northwestward at about 16 mph. Maximum sustained winds were 160 knots (185 mph), with an estimated minimum pressure of 916 mb based on the reconnaissance aircraft data. Irma passed through the Leeward Islands early this morning, and is currently located just north of Puerto Rico. The appearance of Irma has remained impressive today, although the eye has contracted somewhat compared to yesterday. Irma is very likely peaking in intensity and a weakening trend is likely to begin tomorrow. However, the intensity forecast remains challenging due to the possibility of eyewall replacement cycles. Irma should pass north of Hispaniola tomorrow as it begins to move west-northwestward towards the southeastern Bahamas. Irma is then expected to begin to turn to the north on Saturday, and the latest official National Hurricane Center (NHC) forecast keeps Irma just offshore the Florida coast. This is in agreement with much of the latest model guidance, which generally keep Irma offshore, although a direct landfall on Florida is still a strong possibility.  Although Irma may not make landfall in Florida, it will likely be just offshore, and major hurricane conditions are still possible. There is an increasing chance that Irma makes landfall in Georgia or South Carolina as a category 2 or 3 hurricane, while taking a northward path inland. Residents of the Southeastern United States should be prepared as Irma is likely to impact a large portion of the area.

I will be back tomorrow with another post on Irma, Jose and Katia.