Invest 99L continues to quickly move through the Caribbean and as of Thursday morning its low level center is located just north of the Dominican Republic.
Thunderstorms began developing in close proximity to this LLC late Wednesday into the overnight hours. The wind shear continues as of Thursday morning with the LLC still exposed. A low level center without thunderstorms either over it or near it will not intensify into a depression. Also it appears that its close proximity to the Dominican Republic and the high terrain there has been disrupting it some.
Thunderstorms have started firing around the low level circulation as of mid-morning and this may be a sign that it is trying to get its act together. 99L is going to continue moving WNW over the next few days. It will have to deal with wind shear through later Thursday before conditions become more favorable for organization as lighter wind shear is expected and forecast over the Bahamas through Friday into the weekend. Also, water temperatures are running from the mid-80s to near 90, plenty of heat content for it to take advantage of and organize.
Computer model forecasts continue to differ on intensity, with the U.S. GFS model showing a weaker system passing through the Straits and hooking it into the eastern Gulf with landfall near the Big Bend by Wednesday morning. The European model shows a strong tropical storm or potentially a marginal Cat 1 hurricane tracking up the west coast of Florida with landfall potentially as a Cat 2 on the northern Gulf Coast. The GFS Ensembles are still spread out over the state but there is a tight clustering of the models through the Bahamas then through the Keys then straddling the west coast with a final landfall in the Panhandle anywhere from Pensacola to Cedar Key.
This is still a wait and see game for at least the next 24-48 hours. The rest of Thursday and Friday will be critical in how it eventually evolves. Based on what I am seeing (low wind shear in the Bahamas and very warm water temperatures), this system could ramp up quickly. Storms in the past have done this in the same area so it needs to be watched closely.
Don’t be surprised if you see things escalate quickly over the weekend as this is when it will be in the most favorable environment to intensify. Timeframe for effects on South Florida remain in the later Sunday/ Sunday night/Monday timeframe but this is subject to change based on how it evolves.