Wilma smashes ashore near Marco Island

Wilma smashed ashore near Marco, Florida at 6:30 am EDT this morning as a Category 3 hurricane with sustained winds of 125 mph. The Hurricane Season of 2005 continues to rewrite the rules, as Wilma maintained an impressive intensification phase right up until landfall in the face of very significant wind shear--up to 30 knots. Current Miami radar shows that the southwest side of Wilma is being strongly affected by this wind shear--the echoes are much less intense on that side.


Figure 1. Latest Miami radar shows strong convection on the east side of Wilma, but weak echoes on the southwest side where wind shear is affecting the storm.

Wilma's forward speed is 23 mph, up from 20 mph just one hour ago. Due to the fast forward speed, this will be a short but very intense hurricane event for South Florida. Hurricane force winds extend out about 80 miles from Wilma's center, so the longest duration of hurricane-force winds will occur on the coast at Marco, where about five hours of hurricane force winds will occur. Hurricane force winds will begin by 10 am near West Palm Beach and Fort Lauderdale, and continue for about four hours. Intereaction with land and high wind shear will weaken Wilma as she crosses Florida, but Wilma is expected to be a Category 2 hurricane as she crosses the east coast of Florida. Sustained winds of 95 mph with gusts to 120 mph are possible along the east coast of Florida near and to the south of the eye, primarily before the eye crosses the coast. Winds should be a full 20 mph weaker when the back side of the hurricane hits, as wind shear is substantially affecting the storm's rear portion. A period of calm of up to an hour can be expected along the center of Wilma's track. If you must go outside during that period, realize that the winds can go from calm to 100 mph in just one minute when the back side of the hurricane moves over you. If you are near the edge of the eye, the calm period may last only a few minutes, so do not venture far from safety if you must go outside.

Wind reports
Reports are no longer available from Key West International Airport due to communications outage. Winds there were 60 mph gusting to 76 mph before the failure. Recent peak wind gust reports from other gauges include 120 mph at 453 am on Cudjoe Key, 101 mph at Sombrero Key at 449 am, and 74 mph at Long Key at 455 am. By 10 am EDT hurricane force winds should end in the Keys.

The wind at Naples at 553 am was north at 56 mph gusting to 75 mph, Miami had 60 mph gusting to 74 mph at 7:34 am, Fort Lauderdale had 51 mph gusting to 73 mph at 7:16 am, and West Palm Beach had winds of 43 mph gusting to 54 at 6:53 am. Several tornados signatures have been detected on radar, and the threat of tornadoes is quite high for this hurricane, due to the presence of a cold front on the north side of the hurricane.

Storm Surge
A storm tide of up to 13 to 18 feet is now occurring on the mainland, south of Naples. Fortunately, this area is mostly uninhabited Evergaldes swamp. The surge is causing extensive flooding of local access roads to Marco Island, Everglades City, and Chokoloskee including state roads 92, 951, 953 and 29 and large parts of the Tamiami Trail U.S. Highway 41. Everglades City is likely flooded or will be shortly, and parts of Chokoloskee and Marco Island are also likely flooded. Further north along the Collier County coast, a storm tide of 7 to 9 feet is occurring from north of Marco Island to South Naples. Since the wind flow is offshore at Naples much lower storm tides are occurring from Naples north to Bonita Beach. Fort Myers has dodged a major bullet, and will be spared significant storm surge damage, and will receive only moderate wind damage at Category 1 hurricane levels.

A storm tide of 8 to 13 feet above mean sea level is now occurring on Cape Sable and in Flamingo. Much of Flamingo is now likely flooded. Along the Atlantic coast of Miami-Dade County, particularly Biscayne Bay, tides are running 2 to 3 feet above normal. A storm tide of 3 to 5 feet above mean sea level can be expected around 8 to 9 am EDT, with slightly higher amounts possible in canals and waterways. South winds will pile some water into the north end of Biscayne Bay causing some flooding of causeways and low lying beach access roads for a short time from early to mid morning Monday. Some flooding from surge will occur in low lying areas of Matheson Hammock and Fairchild Tropical Gardens and parts of Coral Gables and Coconut Grove and along the mouth of the Miami River. Flooding of low lying areas on the Bay sides of Key Biscayne and Virginia Key can also be expected. Over the Broward and Palm Beach County coasts, storm tides of 2 to 3 feet can be expected mid morning.

For Lake Okeechobee, a storm surge of 5 to 7 feet above Current Lake levels is expected from early morning to around noon Monday over areas inside the dike from Lakeport to Clewiston, with 2 to 5 feet above current lake levels
elsewhere from Buckhead Ridge south to Lakeport, and from Clewiston through Port Mayaca. This will cause some flooding of low areas outside Hoover Dike protection including Torry, Kreamer, and Ritta islands and some access roads.

I'll post an update later this morning. Special thanks go to the National Hurricane Center and the local Florida National Weather Service offices, whose reports I rely on very heavily for my blog posts! They are working very hard through this storm while their families and homes are being threatened.

Jeff Masters