Saturday Evening Short Update On Invest 99-L

From the Crown Weather Service…

Invest 99-L Located Over The Central Bahamas: There have been some new developments today with Invest 99-L which has prompted me to post this short update for you.

The one development that is not different from this morning is that Invest 99-L remains disorganized and the earlier convection that had fired up around it seems to be dying now. So, it appears that we are going through another cycle of diurnal convection where convection dies down during the afternoon and then fires back up late at night and during the morning hours. So, until we see sustained strong convection that lasts more than 18 to 24 hours around the center of circulation that is Invest 99-L, development into a tropical depression or a tropical storm will not happen. Once we do see this, then the chances for development will increase substantially. Because of this, development is unlikely tonight or probably on Sunday and I think it is when this system is in the southeastern Gulf of Mexico that we could see it begin to develop.

Now, with all of that said, we need to closely monitor the progress of Invest 99-L once it moves into the southeastern Gulf of Mexico on Monday. Although the next 24 to 36 hours are going to be crucial in determining what kind of shape this system will be in when it reaches the Gulf of Mexico. If we see Invest 99-L organize and start to get its act together between now and Monday, then I am going to become very concerned with the potential for development and strengthening into at least a tropical storm. On the other hand, if we end up seeing a very disorganized system that doesn’t get its act together by the time it moves into the southeastern Gulf of Mexico on Monday, then I think we can say that development probably will not happen at all and we can all breathe much easier. Unfortunately I am leaning towards the idea of Invest 99-L getting its act together between now and Monday as the circulation seems to be gradually becoming stronger even though we lack sustained convection.

The biggest development of the day is that almost all of the model guidance now develops and strengthens Invest 99-L in the Gulf of Mexico and some of these models forecast substantial intensification. The European model has flipped once again and now forecasts substantial intensification in the Gulf of Mexico next week before making landfall next Saturday in the western Florida Panhandle. What is concerning is that the UKMET model also forecasts development and intensification. The reason why this is concerning is because when the UKMET and European models agree exactly like they do now (both with intensity and track), you really need to pay attention. Other model guidance members that forecast development include the Canadian, HWRF, NAVGEM and Japanese model and they all forecast a significant hurricane impact on the eastern US Gulf Coast. The one holdout that does not forecast significant development is the GFS model, which even though forecasts a favorable environment next week in the Gulf of Mexico, fails to intensify it.

Here Are My Saturday Evening Thoughts: First things first, I strongly urge everyone from Southeastern Louisiana to the West Coast of Florida to closely monitor the progress of Invest 99-L. Right now, it seems all of the model guidance are honing in on a direct impact with either the Alabama coastline/Florida Panhandle or the west coast of Florida from about Gulf Shores, Alabama to Tampa, Florida and this is going to be something to watch for very closely.

Based on all of the data that I have looked at today – I’m going with a 50 percent chance that Invest 99-L will become a tropical storm between Tuesday and Thursday when it’s tracking northward across the southern and central Gulf of Mexico. Needless to say, we are very closely monitoring Invest 99-L and we are going to try to provide you with at least 2 updates a day so that you are informed of what’s going on with this system.

I will have a full discussion for you tomorrow morning by 9 am EDT/8 am CDT.

Invest 99L Information: