The tropical wave about 500 miles east of the Lesser Antilles Islands, 94L, has become better organized today, and has the potential to become a tropical depression on Friday. Visible satellite loops show a limited amount of thunderstorm activity, but the circulation has gotten much better defined in the past few hours. Low level cumulus clouds are now starting to spiral into the center, and there is the beginning of a spiral band with heavy rain trying to form on the southeast side of 94L. This process is being slowed by the presence of a large, dusty area of dry air on its northwest side, and thunderstorm activity will be slow to build on this northwest side over the next day or two.

Water vapor satellite loops of the region show that 94L has not significantly moistened its environment. However, now that it is better organized, it should be able to build more thunderstorm activity and moisten its surrounding environment. Wind shear is a favorable 5-10 knots over 94L, and may decrease some by Saturday, allowing further development. It looks like 94L will stay well south of the shearing winds of the upper-level low spinning north of Puerto Rico.

94L has slowed down its forward speed to 10-15 mph, so should be entering the Lesser Antilles Islands on Friday night, bringing gusty winds and heavy rain. None of the reliable computer models forecast that 94L will develop into a tropical depression, but it now appears that it has a legitimate chance of becoming one Friday or Saturday. Due to the dry air, I think it unlikely 94L will be stronger than a 50-mph tropical storm when it passes through the Lesser Antilles Islands. The southern portion of the islands will get the most rain, due to the dry air on the north side of 94L. The Hurricane Hunters are scheduled to investigate on Friday afternoon.


Figure 1. Infrared satellite image showing the various disturbed area of weather in the Atlantic today.

The storm track has not shifted. As mentioned previously the most likely tract is Saint Lucia on the north to Grenada on the south.

Weatherman