Catastrophe modeling firm Risk Management Solutions (RMS) issued the following advisory on Tropical Storm Debby this morning:
Tropical storm winds and heavy rain are affecting the northeast Gulf States as Tropical Storm Debby lingers off the northwest coast of Florida. As of Monday morning, Tropical storm Debby was located in the northeast Gulf of Mexico approximately 90 miles south-southwest of Apalachicola, Florida with maximum sustained winds of 60 m.p.h.
Debby is a large storm with tropical storm force winds extending outward up to 200 miles, mainly from the north and east of the center (affected the coast of Florida). Debby is almost stationary and rainfall associated with the storm is already starting to affect the mid-west coast of Florida in the Tampa region and areas just to the northeast of Tallahassee.
There is still considerable uncertainty in the track and intensity guidance associated with Debby. Most forecast track models take Debby in a northeasterly direction over the course of the next few days, making landfall in Florida between 48-96 hours. The National Hurricane Center has opted for a more northerly track that brings Debby over northwest Florida sometime on Wednesday or Thursday.
As Debby is already fairly close to land and as the storm moves progressively closer, the land will have an impact on storm intensity. Although some further intensification is forecast by the NHC and a couple of the global models, there is good consensus that Debby will not reach hurricane status due to the expected interaction with land. However as Debby is located over sea surface temperatures around 27C-28C and upper level air conditions are likely to become more conducive to intensification, the longer Debby stays over these warm waters, the higher the chance there is of further intensification.
“The main risks associated with Debby are tropical storm strength winds that will continue to affect portions of the northeast Gulf Coast over the next few days, coastal flooding related to storm surge, flooding as a result of heavy rainfall, and the risk of a few tornadoes across the eastern Florida Panhandle,” said Neena Saith, director of catastrophe response at RMS.
The rainfall may prove to be Debby’s greatest hazard, particularly as the storm is very slow moving and the regions due to be impacted already have saturated soils from previous rain events. Rainfall accumulations of 10 to 15 inches are forecast over the Florida Panhandle and the northern part of the state, with isolated maximum amounts of 25 inches possible.
Debby formed on Saturday, becoming the earliest fourth named storm on record and two months earlier than when the average fourth named storm is expected to form (i.e. on August 23). The previous record for the earliest fourth named storm was set by Dennis in 2005 which formed on July 5.
RMS will continue to closely monitor Debby and the associated impacts.