Watching two tropical waves for development

Invest 97L Located Just East Of The Bahamas:

A small, but fairly strong area of low pressure was located about 275 miles to the east of the central Bahamas is getting better organized with time and has a decent shot of becoming a tropical depression or a tropical storm in the next day or two. Satellite loops show a very little movement and if there is any movement, it is perhaps in a slightly east or northeast direction.

Satellite imagery from the overnight hours into early this morning certainly shows that there is better organization and a definite increase in the thunderstorm activity. Being so small in size, the global models did not pick up on this development and even the higher resolution NAM model seems to be having difficulties resolving 97L. With that said, I think this system will become caught up in the trough of low pressure that is now tracking off of the US East Coast and become stretched out as we get into Friday and especially Saturday.

Before then, a tropical depression or tropical storm may briefly form at some point today or tonight before weakening and becoming stretched out by later Friday into Saturday. It should be pointed out that the Canadian model forecasts that a part of this system will be steered southwestward into the western Caribbean this weekend into next week where it may need to be watched closely. I am not discounted the Canadian model since it has done a pretty good job with the forecast of Invest 98L.

Invest 98L Located Just East Of The Windward Islands & Barbados:

Of more concern is Invest 98L which is located about 400 miles to the east-southeast of the Windward Islands. This disturbance is fairly robust and continues to become better organized. Additionally, tropical storm force winds are occurring on the north side of the circulation and this system has a fairly good chance of becoming a tropical storm either today or at the latest on Friday. So, the Canadian model may have been on something a couple of days ago and I should have given it more weight.

Invest 98L is expected to track very near Barbados later this afternoon or this evening and then across the Windward Islands late tonight into Friday morning. Residents and vacationers on Barbados and in the Windward Islands should be prepared for tropical storm conditions with wind gusts to 50 mph, heavy rainfall and very rough seas from this afternoon through tonight and into Friday. Since this is a pretty large system, much of the Leeward Islands will also be affected by strong winds of up to 40 to 50 mph, heavy rainfall and very rough seas from this afternoon right into Friday.

Once Invest 98L is in the eastern Caribbean on Friday it is expected to turn sharply northwestward and track across while intensifying to a moderate to strong tropical storm. I think a track right over Puerto Rico seems plausible on Saturday with tropical storm conditions likely across Puerto Rico and the US/British Virgin Island on Friday night through Saturday.

Once this system is past Puerto Rico and the Virgin Islands it is forecast to turn north and north-northeastward and potentially intensify into a hurricane and possibly impact Bermuda right around Tuesday.

I will be monitoring both Invest 97L and Invest 98L closely and will have an updated discussion sometime on Friday morning.

~ Rob Lightbrown, Crown Weather