Hurricanes rarely sustain such extreme winds for much time. However we see no obvious large-scale effects to cause a substantial weakening the system and it is expected that the hurricane will be of Category 4 or 5 intensity when it reaches the coast.

The primary concern is very heavy rains.

It should have more time over the water so it could potentially be stronger than (Tropical Storm) Charley.

We have the unpleasant possibility that the cyclone could linger near the southeast United States through five days.

The big questions are how soon this turn will occur, and how far to the right Lili might go during the next few days. This has a critical bearing on south Florida.

The main impediment to strengthening will be land. But Jamaica and even western Cuba are unlikely to have much impact.

When you start inferring lots of things from the hurricane climate data, then you're on thin ice because that climate data is not very good.

The big question continues to be what will happen beyond the five-day forecast period. It is still impossible to state with any confidence whether a specific area along the U.S. coast will be impacted by Isabel.

Even weak systems can strengthen.