I'm not going to give a blow by blow of these storms, but I do want to show you the progression of how the ebb and flow progresses until the storm either steers clear of the east coast and goes spinning off in to the much cooler waters of the north central Atlantic or actually hits the mainland.
As you can see, Ana is still only packing sustained winds of 40 MPH, but her speed has increased from 17 MPH to 23 MPH. That small but significant change in speed (hopefully) will not allow Ana to gain any strength as she passes over the bath tub commonly referred to as the
Gulfa Mexico (see previous post for spelling explanation) and will prevent her from becoming a devastating hurricane. The other really important factor that you have to keep an eye on is the central pressure. Ana's is currently 1005
mb (measured in millibars)
millibar (ml-bär)
A unit of pressure equal to 0.001 bars. It is equivalent to 100 newtons per square meter, or 0.0145 pounds per square inch. Standard atmospheric pressure at sea level is 1,013.2 millibars.So Ana's minimum central pressure is not much less than what is normally seen at
sea level, but don't let a mere 8.2
millibars fool you. It can make all the difference in the world as the pressure continues to drop.

Bill, on the other hand is still traveling at a whopping 16 MPH, but his strength has increased to 60 MPH sustained winds. Just a mere 13 MPH increase and it will be a full blown hurricane. Bills pressure at 11AM is down to 997
mb. However, if you will notice, there has been a slight change in Bill's projected path, making it more of a problem for South Carolina (hopefully not). If it continues to keep swinging north this early, there's a good chance it will keep swinging become one of those storms that
visits the middle of the north central Atlantic.

Central barometric pressure of a hurricane tells the strength and damage potential. Here are a list of the worst hurricanes to hit the states and their associated central pressure.
The Labor Day Hurricane, Florida Keys, September 2, 1935, Category 5,
892 mb, Approaching 200 mph
Hurricane Camille, Mississippi, August 17, 1969, Category 5,
909 mb, Approaching 190 mph
Hurricane Katrina, New Orleans, LA, Mobile, AL, and
Gulfport, MS , August 31, 2005, category 3,
920 mb, 125 mph
Hurricane Andrew, Southeast Florida, August 24, 1992, Category 5,
922 mb, 165 mph
Hurricane Charley,
Punta Gorda, Florida, August 13, 2004, Category 4,
941 mb, 150 mph
One more thing, to show the unpredictability of these storms, here's the path that Katrina took. Notice the sharp turn at south Florida... you just can't trust these things to follow any logic.

Thought I'd throw this one in just for laughs... they don't call it
"Crazy Ivan" for nothing...