11am friday 7/18 update
As of 11:00 a.m. EDT, Tropical Storm Bertha was located near 36.2 north, 52.3 west, or about 740 miles northeast of Bermuda. Bertha has maximum sustained winds of 65 mph. The storm has a minimum estimated central pressure of 995 millibars, or 29.38 inches of mercury, and is moving northeast at 18 mph. Bertha is a strong tropical storm, but no drastic change in strength is likely over the next day or two as Bertha will encounter a little more shear and cooler ocean water temperatures. Bertha will continue to pick up speed this weekend as it encounters increasing westerlies and accelerates to the northeast across the northern Atlantic while becoming extra-tropical.
Our eyes turn toward the southeast Caribbean as we monitor an area of low pressure located near 70 west and 19 north. It is moving to the west at around 20 knots and is causing an increasing area of showers and thunderstorms across the southeast Caribbean. Warm waters and low shear in its path could allow for intensification into a tropical depression or tropical storm over the next day or two, but its fast forward speed and closeness to the South American coast will be limiting factors in the short term. Once it gets into the western Caribbean and farther away from South America tonight and Saturday, there could be a more pronounced or rapid development. It should head toward Central America or the Yucatan Peninsula later in the weekend then perhaps into the southwest Gulf next week.
There is an area of low pressure spinning off the Southeast coast of the United States east of Jacksonville, Fla. It became better organized throughout the day Thursday. There is a shear zone east of the center and a swath of dry air to the west. However, this system is right where it has to be to develop and indeed it could do so. Since it does exhibit some tropical and non-tropical characteristics at this time, it is conceivable it will become a subtropical depression or subtropical storm over the next 24 to 48 hours, as long as it remains over water. We expect this feature to drift to the north or northeast through the weekend and it will bring increasing wind, rain and surf to the Southeast coast.
Elsewhere, there is a tropical wave along 47 west tracking west at 15-20 mph that will continue to be watched over the next few days. Currently, it has no deep convection associated with it.
By AccuWeather.com Meteorologists Matthew Rinde
manchild
AI
