Hurricane Dennis has strengthened overnight, now with winds of 105mph and a well-defined eye on infrared and visible satellite imagery. A hurricane hunter aircraft is en route to check out the storm; it is possible that they find a major hurricane in the next couple of hours. Interactions with Cuba and Jamaica as it navigates the narrow passage between the two islands should keep intensity in check until landfall in Cuba, at which point some weakening is likely.

What is not yet known, however, is how much of Cuba that the storm will pass over until it emerges in the Gulf of Mexico. A turn slightly towards the west is likely with the current steering flow, but that should be temporary as the storm should gradually turn northwest and north-northwest once again as it approaches the Isle of Youth and Havana area. If this turn does not occur, more of Cuba will bear the brunt of the storm, while the storm will emerge into the Gulf in a weakened state. Best thinking right now, however, is for a track near Havana over the next day and a half, skirting the rest of the island as it goes along, as a borderline category 2/3 hurricane. Waters are very warm south of Cuba, but the aforementioned interaction with land and relatively large size of the storm should keep intensity from exploding a la Charley for the time being.

Overnight and into the early afternoon, model guidance has been shifting progressively further east. The full suite of surveillance data has been ingested into the models and the upper-air features over the U.S. are becoming better defined, leading to these changes in some of the forecast guidance. For instance, the GFS, which just a few runs ago was calling for a New Orleans landfall, is now calling for a landfall just east of Apalachicola as of the 12z run. The GFDL has shifted similary towards the east as well. The UKMET and NOGAPS models largely have not changed, though the NOGAPS was on the right of most of the global model guidance beforehand in calling for a MS/AL landfall. Given the current situation with the shortwave troughs over the United States -- and potential enhancement from mesoscale convective systems that fire up along the front range of the Rockies -- this eastward shift should maintain itself in the models that have already done so, while the others should progressively come in line with this thinking.

The western extent of the subtropical ridge is weakening and the storm may well slow down in response to the weakened steering currents as it emerges off of Cuba. This may also allow the storm to quickly reorganize over very warm waters and in the favorable upper-air regime west of the Florida Straits. The projected path takes the storm very close to the lower Keys, where preparations should be rushed to completion for the arrival of a category 2 hurricane in 48 hours. Those in the keys should strongly consider evacuating, as this storm will place them largely in the eastern -- stronger -- half of the system.

From there, indications are that the storm should gradually turn to the north and north-northwest in the Gulf, passing a short (100-200mi) distance offshore of the west coast of Florida. Residents from the Keys northward to Cedar Key should be prepared for very strong waves and heavy rainfall, if not tropical storm-force winds. If the storm were to track closer to shore, hurricane-force winds are not out of the question. A path mirroring Floyd of 1999 as it passed offshore of the Florida East Coast is entirely possible with this system.

From there, while model guidance is still spread out as mentioned above, the Florida panhandle appears to be the region most under the gun for this system. Regions west of New Orleans are sufficiently outside of the probability cone and model guidance -- plus on the weaker west side of the storm -- to be able to rest a bit easier today (though still keeping an eye on the storm nevertheless). Regions between Cedar Key and the MS/AL border are now the primary areas under the gun for a landfall in 3-4 days, potentially as a major hurricane (similar to the NHC intensity reasoning). I believe that the 5p official track will shift to the right once again, highlighting a potential track just offshore of and parallel to the Panama City to Apalachicola coastline. Intensity may wane a bit as it approaches final landfall due to the relatively shallow and cooler shelf waters in and near Apalachee Bay, but the potential is still there for a system similar to Ivan's intensity. Heavy rainfall and massive coastal flooding are possible in Apalachee Bay with a landfall anywhere along the Florida panhandle coast due to the low-lying nature of the counties in the region.

Bottom line: the Florida panhandle is under the gun for a direct hit from a potentially major hurricane late this weekend. Residents from New Orleans to Miami should be prepared for some impact from the system, particularly those from Pascagoula, MS to the Florida Keys. Areas west of New Orleans should be in the clear, but no one should let their guard down. Residents in this threat zone should be reviewing their preparation and evacuation plans in anticipation of tropical storm and hurricane advisories being posted in the next 24 hours.

This is a very large and potentially very dangerous system and its impacts will be felt well away from the center of circulation. The error cone highlights the areas still under the gun and should be focused on moreso than the precise track forecast. And, as always, the NHC and your local authorities are the ones to turn to in understanding and following the official forecasts and making preparations for an impact from Dennis. While myself and others here may have insight to add into the storm, as the disclaimer says: when in doubt, take the word of the NHC.

I'll try to add updates through the day on the boards as I can, with a full new post likely from either Jason or Ed (or myself) late tonight or tomorrow.