|Hurricane Katia Satellite|
The first trough that affected Katia has already moved off into the Atlantic waters. While between troughs, Katia will move on a more westward track. Trough number "2" should turn the storm more northerly, but only briefly. This second trough is weak and eventually will die out; this process is already happening. (These events are part of the easy part of the forecast.
The turning mechanism for Katia is over the Heartland of the U.S. It might or might not combine forces Lee over the coming days. Without Lee and the next trough combing, Katia will get dangerously close to the Southeast U.S. (This include Florida), before lifting out. If Lee does not help to amplify the ridge in the Northeast and, in fact, acts as some sort of mechanism to deepen the trough, the threat from Katia will be much higher up the East Coast.
Here are possible future scenarios:
1) If Lee moves towards Texas...Katia will be a FL/GA Threat
2) If Lee Continues to propagate around Louisiana...Katia will be a Threat to SC/NC
3) If Lee dies out over portions of the Southeast...Katia will be a Threat GA/SC/NC
3) If Lee only makes it to the Tennessee Valley...Threat will be north of North Carolina and include the Northeast
Any threat from Katia, to any coastline, would not come before September 9th.
The Navy NOGAPS model, a model that has a lot of weight in my tropical decisions, has Katia making landfall, as hurricane, in Southeast Georgia next week.