x-y-no wrote:tronbunny wrote:x-y-no wrote:He's interacting more heavily with the ridge now. This is really obvious in both the visible and WV loops if one looks up just over and north of Cuba.
If the ridge were strong, it would accellerate him more westerly. But instead it's weakening, so just slowing him down on his WNW track. The slower he goes, the more time the tip of the ridge has to break down completely. That Atlantic mid to upper low is still headed into the picture and will contribute to that.
Hmmm, because the wind pattern in the ridge is clockwise, I'd expect a conveyor effect to the NNE.
Please help me out with this one.
The problem is the ridge appears to be weakening in front of him. I'll illustrate with the first few frames of the 12Z GFS which is just coming out.
Here's the initialization:
Note the 588 line just north of him, and the closed low at about 30N 55W.
Now here's 6 hours:
See how the 588 line has backed off and the low is now outside of it still moving W? Also note the weakness left behind by Frances over Georgia.
Now here's 12 hours:
The low is still moving W and the ridge still backing off. Steering currents for Ivan are real weak.
Here's 24 hours:
Now there's a split between the ridges right over FL, and the system MWatkins pointed out yesterday is coming in towards the Great lakes ready to make a connection and pull him north.
THANKS FOR THE GRAPHICS! This is the explanation I was looking for! Great!
