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 , 4:06 PM GMT on June 23, 2006
A non-tropical low pressure system just northeast of the Bahama Islands has a surface circulation, and is expected to slowly grow more organized as it moves west-northwest towards Florida and the Carolinas over the next two days. Wind shear over the low was 10 - 25 knots early this morning at 5am EDT, but the 8 am EDT wind shear analysis from the University of Wisconsin's CIMSS showed that this shear dropped to 5 - 15 knots. The shear has continued to drop this afternoon, and was 5 - 10 knots at 2pm EDT (18 GMT). This should allow some modest development, and the Hurricane Center has scheduled a Hurricane Hunter aircraft to investigate the system on Saturday.
Figure 1. Preliminary model tracks for the Bahamas disturbance.
The low is very disorganized at present, with only a little intense thunderstorm activity near the circulation center. A QuikScat satellite wind estimate from 6:38 am EDT this morning revealed winds of about 15 - 20 mph in most of the region, with one tiny spot of higher winds in an intense thunderstorm near 23N 72W. Sea surface temperatures are in the 27 - 29 C range, which is well above the 26 C threshhold needed for tropical storm formation. However, as one can see from the water vapor satellite image below, there is a large area of very dry air over Florida. Upper level winds from the west are pushing this dry air into the center of the low, and this is inhibiting development. The low is forecast to move over Florida by Sunday, where it should bring welcome rains. It is also possible the low could turn northwest before reaching Florida, and move ashore over South Carolina or Georgia. Given the low's current poor organization, short amount of time it has to grow, and the presence of dry air and modest wind shear, the strongest system we can expect at landfall would be a 50-mph tropical storm. I think landfall as a tropical depression or a near-tropical depression is more likely.
Figure 1. Latest water vapor satellite image shows a very dry airmass (brown colors) over Florida, extending eastward into the Bahamas. The area of clouds northeast of the Bahamas at the edge of this dry air is what we are watching.
An interesting article from the New York Times yesterday described new super-strong homes being built in Florida and on the Gulf Coast. Insurers love them, and are offering up to 25% discounts on policies. With the high levels of hurricane activity observed since 1995 expected to continue at least another 10-20 years, expect to see this trend continue. I'd certainly be in the market for one if I lived in Florida!
I'll be back with an update later today if there is a significant change in the Bahamas system. I'll save my discussion of the large-scale weather pattern over the Atlantic so far this June for later.
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