Thursday, September 02, 2010

Hurricane Earl, Tropical Storm Fiona and Tropical Depression Gaston - 021400Z

Hurricane Earl, an intense category 4 cyclone, is now about 300 miles south of Cape Hatteras. The storm is moving north at about 16 knots (30 kmh/18 mph). It is packing sustained winds of 125 knots (232 kmh/144 mph). The centre of Earl is expected to be abeam the North Carolina Outer Banks by tonight. Sometime in the next 8 hours Earl should peak in intensity. The ocean buoy at Diamond Shoals is showing a significant increase in wave height, dropping sea level pressure and increasing ENE winds.

The NHC has issued Hurricane Warnings for North Carolina from Bogue Inlet northeastward to the NC/Virginia border with Hurricane Watch and Tropical Storm Warnings or watches along a majority of the US east coast. (Click the link for details).

The Canadian Hurricane Centre has issued a Tropical Storm Watch for Yarmouth, Shelburne and Queens Counties in Nova Scotia. (Port Maitland to Medway Harbour)

Earl is now moving around the western edge of the subtropical ridge and will encounter the base of the Westerlies in about 24 hours. An upper trough moving out of the Great Lakes will interact with this cyclone causing it to accelerate its speed of advance as it begins to track more toward the northeast.

For the Canadian Maritimes the problem is high air temperatures over the region and sea surface temperatures that are as much as 4 degrees Celsius higher than normal. There is a possibility that Earl will retain its tropical features as it approaches the Nova Scotia coast. Earl will likely arrive at the Canadian Maritime coast early Saturday morning, somewhere between the New Brunswick Fundy shore and the South Shore of Nova Scotia.

TS Fiona is tracking north-northwest at 15 knots. This storm is challenged by a lot of northerly wind shear. While it still has sustained wind speeds of 45 knots (83 kmh/52 mph) it is expected to weaken in the next 36 hours and dissipate by late Sunday.

A Tropical Storm Warning is in effect for Bermuda as Fiona's current track takes the cyclone directly through that island late Friday or early Saturday morning.

Tropical Depression Gaston is one to watch after Earl passes. It was downgraded as a result of the lower intensity winds estimated in its centre. However, it is in a position where conditions will exist to allow strengthening in the next 96 hours although that will be fairly slow. Gaston is moving slowly towards the west at about 6 knots (11 kmh/7 mph). This slow advance will give Gaston time to develop once the upper air conditions change.

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