MyFoxHurricane.com blog

Earl bears down on the Leeward Islands

Posted by Andy Johnson under Daily updates

Danielle is accelerating to the NNE on strong southeasterly upper level winds. The satellite image below shows the drier air being entrained into the southern part of the circulation and the center is devoid of deep convection. When Danielle stronger on Saturday there was a large anti-cyclone above the low level circulation of Danielle. The clockwise circulation of the upper high was causing northeasterly shear on Earl, which was located south of the upper high. Now that Danielle and its accompanying upper level high have moved away, it allowed Earl to strengthen without being inhibited by northeasterly shear.

Of all the tropical systems currently in the Atlantic, Earl has the potential to cause the most problems. The most immediated areas that are being affected are the Leeward Islands. There is the possibility that Earl could directly or indirectly affect the U.S. eastern seabord from Wednesday through Friday of the upcoming week.

Invest 97L located east of Earl has shown a decrease in convection today. None of the models intesify invest 97L anywhere nearly as strong as Earl is forecast to become. Earl is forecast to be a Category 4 hurricane east of the Bahamas. For the same reason that Danielle inhibited Earl, Earl may also inhibit the development of Invest 97L. As Earl strengthens a large upper level high will develop over Earl. The ouflow and subsidence will likely prevent Invest 97L from any rapid intensification.

There is yet another wave moving off of Africa which bears watching. The latest wave located east of Invest 97L is exiting Africa even farther south than Earl or Invest 97L did. Earl is destined to track further west than Danielle did. Without Earl, Invest 97L would likely also track further west. However, the interaction between a strong Earl and a weaker 97L in 3 to 5 days could cause a Fujiwhara affect (where two cyclones rotate around each other) or more likely recurve Invest 97L out to sea further east than Earl.

The tropical wave in the western continues to produce large areas of clouds and convection but without any circulation. The low in the northern Gulf appears to have moved inland over Louisiana and is weakening.

The enhanced satellite image of Earl shown below indicates the circular central core in magenta where the strongest winds are, as well as a strong feeder band to the east. There is also a strong line of convection which preceeds the hurricane which spread over most of the Leeward Islands Sunday afternoon.

Even though Danielle, passed almost 300 miles east of Bermuda and much further away from Florida, large swells that were formed when Danielle was a Category 4 hurricane are impinging on the east coast of Florida causing dangerous rip currents. Seas of 8.5′ were reported at the buoy near Cape Canaveral on Sunday afternoon. Here in the Bay area we do not have to worry about rip currents since the swells will break on the east coast and our flow will continue to be east to northeast (offshore flow).

the graphic below shows wave height in the western Atlantic. They increase closer to the center of Danielle. Just about time the waves will start to settle down from Danielle, Hurricane Earl will produce more swell from the southeast. Thus, much of the east coast of the U.S. from Florida to Maine will experience large waves and dangerous rip currents this week.

The Martinique radar from METEO France shown below clearly identifies the eye of Earl located east of the Leeward Islands on Sunday evening. The improving structure can be seen between 23 UTC 8/28/10 (second image below) and 0215 UTC 8/29/10 (first image below). Notice the eye getting more circular and defined.

The warning map below shows the status of warnings as of 11PM Sunday night. Since Anguilla, St. Martin and St. Barthelemy are located the furthest northeast in the Leeward Islands they will experience the brunt of Earl first.

A NOAA P3 aircraft found flight level winds of 77 MPH on Sunday afternoon at 6:03 PM. However, Earl has continued to rapidly intensify since the image. The graphic below shows the flight path of the aircraft.

The storm surge is expected to be 2 to 4 feet above ground level near the coast in areas of onshore winds in the Leeward Island. The smaller islands are not as susceptible to high storm surge as are large coastlines with shallow continental shelves. I had the opportunity to visit St. Barthélemy earlier this year. I am standing in the capital city of Gustavia, St. Barthémely in the picture below.  Notice that many homes are built close to to sea level in the protected harbor city, which is is on the south side of the island. If Earl passes to the north of St. Bart’s, Gustavia should fare well regarding storm surge. Many of the the Leeward Islands are volcanic, so many homes are also able to built high on the hillsides above any potential storm surge.  

In the picture below, the downtown shops are on the right. Notice that the main street is only about 4 feet or so above sea level.

The map below shows the protected port area of Gustavia.

The picture I took below was from a ship off the coast looking northeast towards Gustavia. The downtown area is where the red roofed building are located.

As of 11PM, the British Virgin Islands were under a hurricane warning and the U.S. Virgin Islands such as St. Thomas shown below were under a hurricane watch. The warning may be extended westward on Monday. I took the picture below from a hillside above the capital city of Charlotte Amalie looking south-southwest towards the harbor and downtown area. Charlotte Amalie is also on the more protected south shore of St. Thomas, U.S. Virgin Islands.

In addition, as can be seen in the picture I took below looking southwest other islands are evident which serve to break up wave action.