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 , 4:14 PM GMT on July 12, 2008
I'll echo the statement of Hurricane Specialist Lixion Avilla in the 11 am Hurricane Bertha discussion: "After a week or so...I am running out of things to say about Bertha." Hurricane Bertha has slowed to crawl, and remains in no hurry to recurve out to sea. The storm continues its rather sloppy appearance on satellite loops, thanks to the fact that the inner eyewall dissolved, leaving a new, much larger eye. Bertha's structure is sufficiently sloppy that significant intensification is not likely, despite the presence of wind shear less than 10 knots and water temperatures of 27.5°C. Shear is forecast to remain below 10 knots until Monday morning, when it should rise to 20 knots. At that time, Bertha should be over 26°C water, and will probably weaken to tropical storm strength. The Air Force Hurricane Hunters will make their second flight into Bertha this afternoon to check on the storm's strength. The outer spiral bands of Bertha are starting to affect Bermuda (see links below), and the storm is now visible on Bermuda radar.
Links to follow:
Current weather at Bermuda
Figure 1. Microwave image of Bertha from 5:45 GMT 7/12/2008 showing the vary large eye. Image credit: Navy Research Lab.
High surf of 9-15 feet is already affecting Bermuda, according to the Bermuda Weather Service. There is about a 61% chance the island will experience sustained winds of tropical storm force (40 mph), according to the latest tropical storm wind probability forecast by NHC. Given the very weak steering currents predicted to affect Bertha through Monday, the storm could easily approach closer to the island than the current official forecast. None of the computer models currently foresee that hurricane force winds will impact the island, and I don't expect this will happen.
Elsewhere in the tropics
There are no threat areas to discuss in the tropical Atlantic. The models are more scattered in their prediction of a tropical depression forming between Africa and the Lesser Antilles Islands 4-7 days from now. One model, the ECMWF, has dropped its forecast of a depression forming, and the two remaining models disagree on just when such a depression might form. There are not any impressive tropical waves near the coast of Africa presently, so I'm currently dubious of the model predictions of a Cape Verdes-type tropical storm forming next week.
I'll post an update Sunday morning.
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