actually they all average about the same speed of under 15 knots. It seems slow because once they leave landfall and are out of reach of the tracking beacons, it seems like they are not moving. you'll see that line "track" again when it comes closer to the East Coast, probably 7 to 8 days from now. Mine just went out of range (UNDINE) and should be trackable once near Cuba.
Btw, Marine Tracker has an Iphone app.....it's pretty sick