Bahamas low slow to grow

A non-tropical low pressure system just northeast of the Bahama Islands now has a surface circulation, and is expected to slowly grow more organized as it moves west-northwest towards Florida over the next two days. 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. Wind shear over the disturbance has remained in the 10 - 25 knot range, which is keeping the deep thunderstorm activity to the east of the exposed circulation center. The wind shear is forecast to decrease by about 5 knots over the next day, which may allow thunderstorm activity to build in closer to the center. However, as one can see from the water vapor satellite image below, there is a large area of very dry air over Florida. This dry air is significantly inhibiting thunderstorms from building on the west side of the low. The dry air isn't going away, and the combination of the dry air and moderate wind shear will probably conspire to keep the low from becoming a full-fledged tropical depression. The low is forecast to move over Florida by Sunday, where it should bring welcome rains. A trough of low pressure swinging down from Canada should then pick up the low and move it northwards.


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 at the edge of this dry air is what we are watching.

Hurricane-resistant homes
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.

Jeff Masters