My take on all this NW movement is this:

If by chance Rita is making her move to the North, the forecastors have the uneven task to report even more bad news for all the areas affected by Katrina. It seems to me that all the models now are trending more to the North and East, as the hours go by, and the contention between the high and Rita, I believe that Rita will win out just on her power alone, and she will go where she absolutly wants to go. This can and will be problematic for the forecasters cause I think they don't want this to turn, of course no one else wants it to. But again, we see mother nature in it's full fury, it's all a guessing game.