| in his blog today 93L COMING TO LIFE AND A WORD OR TWO ABOUT THE GFS It looks as though 93L is coming together as it moves through the Caribbean Sea. Shower and thunderstorm activity is increasing and it looks more and more like a developing tropical cyclone. The intensity guidance suggests that it could become a tropical storm and perhaps a hurricane before reaching the coast of Central America in a few days. A fairly potent area of high pressure to the north of the tropical wave will likely steer it west or even slightly south of west towards the coast of Honduras, Nicaragua and Belize. Interests in that region need to monitor the situation closely as there is a tremendous amount of heat content in the ocean along the forecast path of this system. This means there is very warm water not just at the surface but deep below as well and the western Caribbean is notorious for this phenomenon. If upper level winds allow, it would not surprise me to see 93L become the first hurricane of the season over that very warm water. I am not sure that recon will fly out there today since the system still looks rather weak overall. However, the organization is increasing at a steady pace now and so if the Hurricane Hunters don't fly today, my bet is that they will tomorrow and we may have another depression or even a tropical storm brewing at that time. People in Jamaica and the Caymans need not worry about this system, it will pass well to the south of those islands. In the longer range, that heat ridge over the central U.S. will keep what ever becomes of 93L far to the south of Texas and probably even mainland Mexico. It's possible that the energy will cross Central America and in to the east Pacific- we'll see, could be an interesting story there since that is a rare occurrence. Meanwhile, I know a lot of people are talking about the GFS and its long range depiction of a hurricane threat to Florida and the Southeast. I have seen the runs, they take place every six hours with incredible consistency as of late. The model, the main U.S. forecasting model, takes the large tropical wave currently southwest of the Cape Verde Islands and slowly develops it in to a large and presumably strong tropical cylone and brings it in to the Southeast via Florida. There has been other model support as well from the ECMWF- the European powerhouse global model - and the Canadian CMC model to name a couple. What I wish to address is caution. Most people have no idea how to interpret these models and what to really look for. I see the same thing you do and it makes me wonder if in fact we're looking at a hurricane threat over the next 10 days for the Southeast. But the bigger picture is the pattern. What do the global models show in terms of the pattern? Is it one that can support a hurricane coming west out of the deep tropics or is it still too hostile? How about steering patterns? We've had this persistent pattern of a trough over the western Atlantic for a long time- will that continue? What about the MJO or wet phase of the Madden-Julian Oscillation? When it is favorable in the Atlantic this time of year, the odds go up considerably for hurricane formation. These are the larger puzzle pieces to look at- not the details of the run to run hurricane that shows up. What I see is a pattern that lends itself to allowing a hurricane to develop out of the deep tropics next week. Where it goes and how strong it is remains a question that cannot be answered now. It may also be that this tropical wave dries up enough to lose much of its energy or vorticity and never has a chance to develop. Just because the long range guidance is screaming "hurricane!" does not mean it is a lock to happen. The bottom line is tha we are in mid-August. Hurricanes are supposed to be more frequent from here on out. There are a couple of areas to watch for possible hurricane development but that's about it for now. The long term model output is subject to huge errors. Once in a great while, a model like the GFS will get it generally right a week to 10 days out. What ever happens, we'll know about it from the get-go. Don't get too caught up in the hurricane hype- it gets exhausting after a while. It's August, we know there will be hurricanes. We don't know where they're going, not precisely. Just be ready in case they come your way and don't lose sleep over what the next run of the GFS or Euro shows. One day at a time, trust me on this. I'll have more tomorrow. |