Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 1:04 PM GMT on August 19, 2008
Tropical Storm Fay plowed ashore just south of Naples, Florida at 5 am EDT, as a tropical storm with 60 mph winds. The radar image of Fay at landfall (Figure 1) shows that the storm was never able to form a complete eyewall, which limited it's ability to intensify. Wind shear was the primary reason Fay never got its act together.
Fay is headed north-northeast along the Florida Peninsula, but was still generating sustained winds of 42 mph at the coast at Naples 7 am EDT. The highest winds observed at Naples during landfall were sustained at 46 mph. Key West got Fay's brunt yesterday--winds reached 60 mph shortly before the center passed over around 5 pm.
Figure 1. Radar image of Fay at landfall.
Figure 2. Latest radar-estimated precipitation for Fay.
Impact on Florida
The main concern in Florida will be Fay's rains. Radar precipitation estimates (Figure 2) show that Fay has dumped 8-10 inches of rain over a large swath of Palm Beach County. Four to eight inches were common over the rest of South Florida. These heavy rains will spread northward into Central Florida today, and into northern Florida on Wednesday. One concern I have is that Fay may stall out over northern Florida with its center just offshore Wednesday through Friday, potentially dumping large amounts of flooding rains. However, Fay's rains should be beneficial for Central Florida, where Lake Okeechobee is three feet below normal, and water shortages are a problem.
Where will Fay go next?
The computer models continue to disagree on the long-term path of Fay. Most of the models now agree that the trough of low pressure pulling the storm to the north will not be strong enough to finish the job. Fay will probably be left behind by the trough, and forced westward by a ridge of high pressure expected to build in. The official NHC forecast keeps Fay over Florida and turns the storm to the west over southern Georgia. However, most of the models expect this turn to occur further south, and have been trending further south in recent runs. I give Fay a 60% chance surviving its traverse over Florida, then turning back to the west over the northern Gulf of Mexico by Saturday. This would allow the storm to regenerate, before potentially making landfall again along the northern Gulf Coast between New Orleans and the Florida Panhandle early next week. The GFDL has the rather unnerving solution of pushing Fay out into the Atlantic Wednesday, intensifying it to a strong Category 2 hurricane that then hits the Georgia/Florida border region Friday night. The HWRF is similar, but foresees that Fay will only be a 50-55 mph tropical storm when it hits Georgia. Given the rather high levels of wind shear (15-20 knots) predicted to be over Fay late this week, plus Fay's recent inability to build an eyewall in the 24 hours it had over the Florida Straits, I am discounting the GFDL model's solution of a hurricane hitting Georgia. However, Fay may push out to into the Atlantic far enough to regenerate some on Thursday or Friday, before it is forced back west again over northern Florida or southern Georgia.
Links to follow
Wundermap for Central Florida
Naples, FL weather
Melbourne, FL radar
Elsewhere in the tropics
A tropical wave near 13N 38W, about 900 miles west-southwest of the Cape Verde Islands, has lost most of its heavy thunderstorm activity this morning. This system (94L) shows signs of rotation on visible satellite imagery. Wind shear is a modest 10 knots over this disturbance, and is expected to remain about 10 knots through Wednesday. The storm is over warm 28°C waters. Given these moderately favorable conditions, NHC is giving this system a medium (20%-50% chance) of developing into a tropical depression by Thursday morning. The storm is expected to track west-northwest and be near the northern Lesser Antilles Islands by Friday night. Wind shear is forecast to increase to 20-30 knots over the storm Thursday-Saturday, which should halt any development. There is a large area of dry air and Saharan dust to the northwest of the storm, as seen on water vapor satellite imagery. This dry air is already interfering with development, and likely will continue to do so over the next three days. The GFDL and HWRF develop 94L into a weak tropical storm, but none to the other models develop it. I don't expect this storm will be a problem for the Lesser Antilles.
The next blog will be Wednesday, and may not be until the afternoon. I'm probably going to take the day off and let one of the other wunderground meteorologists fill in for me. It's time to take a break from "The Joker"!
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