Bryan Norcross: Odds are increasing that a tropical system will track toward the U.S. Gulf coast next week

Updated Saturday 11:00 a.m. ET 

There is now a broader consensus among the various computer forecast models that a tropical system will develop in the western Caribbean or the southern Gulf of Mexico and track toward the Gulf Coast next week. The assortment of predictions pretty much agrees that the system will be in the development stages by Wednesday and reach the coast Friday or over the weekend.

There is no agreement, however, on where the storm will form and where it will track, which is expected at this point. The final path is related to how strong the storm gets, how quickly, and exactly where it develops.

The sequence of events is the same as we have been discussing. A large low-pressure system spanning from the Caribbean to the Pacific Ocean is forecast to move into position over Central America and southern Mexico by Monday. It's currently developing over Nicaragua. This feature is called a Central American Gyre (CAG). It's a common development early and late in the hurricane season.

Forecasting where or if a tropical depression, tropical storm, or hurricane might develop out of the CAG very far in advance is always next to impossible. And in this case, the gyre is still moving into the position where it has to be located to spawn a storm in the Caribbean or the Gulf.

The change in the computer forecasts from the last few days is the general agreement that an organized system will form far enough north that a dip in the jet stream moving across the continental U.S. can scoop it north. There is broad agreement that a scoop will be in place around midweek, but not the exact shape and timing.

The angle of the flow around the jet stream dip has a lot to do with where the storm gets directed. At the current time, the odds favor the system moving towards some part of the Gulf Coast from Louisiana to Florida. The scooping jet stream should keep it away from Texas, based on what we know now.

The amount of heat energy in the seawater in the northwestern Caribbean and Gulf of Mexico is at record levels. The only obvious things that would prevent a significant hurricane from developing in the Gulf are potentially somewhat hostile upper-level winds and the short amount of time it has over water before it arrives at the coast.

We have all seen hurricanes intensify very quickly in the Gulf. That is certainly a possibility again, but there's no way to make an educated guess about a detailed outcome until a system is at least in the development stages.  At this point, everybody along and near the coast from Louisiana to Florida should keep in mind the possibility of a disruptive situation in the second half of the coming week.

On the current schedule, based on the loose consensus in the computer forecast models, the storm would likely not affect the Gulf Coast before next Friday, but it could be delayed until the weekend.

This system will be named Helene unless one of the low-odds systems out in the Atlantic beats it. In that case, it would be Isaac.

We're talking about a tropical system a week away, so obviously many things can change. But everybody along the potentially affected part of the Gulf Coast should plan to stay well informed.

Remember the rule: Forecasts for developing or disorganized systems generally have larger errors and are subject to change. This storm hasn't even begun to organize, so that rule applies in spades.

IN THE OPEN ATLANTIC, the National Hurricane Center is still following two disturbances. Neither of them is likely to develop, although the left one looks reasonably robust. They are not threats to land.

FARTHER SOUTH, a disturbance is forecast to move off the African coast next week. The computer forecasts are in disagreement, but it has a chance of developing as it moves toward the west.