Tropical Storm Debby: Expect More Rain

Tropical Storm Debby formed on June 23rd, making it the earliest date in the Atlantic for the 4th named storm, breaking the previous record set by Dennis on July 5th during the infamous 2005 season. It was slow to get organized and was an area of interest since about June 18 in the western Caribbean Sea, before drifting across the Yucatan Pensinsula, and finally reaching tropical storm status in the central Gulf of Mexico. Since then, its motion has been slow and unpredictable owing to weak steering currents, and is now located just 80 miles from the northwest Florida coast.

Tropical Storm Debby remains disorganized with very little deep convection near the center, but as history has taught us, even a weak tropical storm is capable of being destructive.

By far, the biggest issue associated with Debby is the rainfall, as expected. Parts of the Florida panhandle have received nearly 25″ of rain in the past few days (much of that came in the past day), but the bulk of Florida has been hit with 6″ or more. To add to that, an additional 3-6″ is expected over northeastern Florida in the coming few days.

As of 8am EDT today, Tropical Storm Debby has peak sustained winds of 40kts and a 991mb central pressure. It’s centered about 85 miles west of Cedar Key, FL and drifting east at 3kts. It is expected to come ashore on Wednesday morning between Apalachicola and Tampa as a tropical storm.

Tropical Storm Debby’s pre-storm path is indicated in dashes, while the forecast path is dotted.

Again, the biggest threat will be additional heavy rain, and the exact timing and location of landfall makes little difference. As far as storm surge goes, some areas in western Florida could see up to 6′ above normal tidal levels, particularly in Waccasassa Bay, Withlacoochee Bay, Crystal Bay, and Homosassa Bay. You can find additional details and maps of storm surge products at the National Hurricane Center website.

Have questions about Tropical Storm Debby or other Hurricane related topics? Leave them in the comments section below.

Brian McNoldy
Senior Research Associate
& Author of Tropical Atlantic Update
Follow Brian on Twitter: http://twitter.com/BMcNoldy

How Will Climate Change Affect Hurricanes?

Before Tropical Storm Fay (2008)

One area of hot debate is how climate change will affect hurricanes. Some people have the image that things will only get worse with hurricanes becoming stronger, more frequent and making landfall on the US coast more often. However, current scientific research is working to obtain a better estimate on what exactly the impact of climate change will be on hurricanes. The latest scientific consensus has emerged to show that there is a projected decrease in hurricane frequency for the Atlantic and that the strongest (Category 4 and 5) hurricanes will have increased wind speeds by 5-10 mph and will occur slightly more frequently (Knutson et al. 2010). Thus, for a given season there will be fewer storms, but the ones that do form have potential to be ever so slightly stronger.

During Tropical Storm Fay (2008)

While all this information is important, what about where they will go? Will climate change have a large impact on where hurricanes make landfall? To answer this question, I am looking at changes in tracks from differences in the atmospheric circulation and genesis location (where a storm forms) in a future climate. As with the other hurricane-related impacts, results suggest minor changes in tracks to occur for the Atlantic. There is a projected decrease of ~2-3 storms per decade over the Western Caribbean and Southern Gulf of Mexico and a slight increase in tracks that stay over the open ocean. So, what does that mean for the US East and Gulf coasts? It tells us that for June through November, the coasts will still be vulnerable to the threat from hurricanes.

-Angela Colbert
Graduate Student
Meteorology and Physical Oceanography
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