Katia becomes season's 2nd major hurricane

The intensification trend I mentioned in Sunday's update did indeed continue, and on Monday at 21Z, Katia was upgraded to a Category 3 storm with 100kt sustained winds... then just six hours later, was upgraded again to a Category 4 storm with 115kt winds.   In the 18-hour period from 09Z on Monday through 03Z today, the pressure fell 26mb and the winds increased by 30kts.
As of 15Z today, the intensity is down a little to 105kts with a central pressure of 954mb.

The tiny yellow speck you see on that image near 32N 65W is Bermuda... and they now have a tropical storm watch in effect.  Models are now in excellent agreement on the track, and they indicate a recurvature by about 72W, safely off the US east coast, and safely west of Bermuda (though Bermuda could certainly feel some outer effects like tropical storm force winds and very large ocean swells).
The shear is also expected to increase again, and the mid-level relative humidity is quite low, so it appears that Katia will be on a steady weakening trend now until it ends up in the TC graveyard of the north central Atlantic.

The easterly wave that exited the African coast on Sep 2 (AL95) is now near 35W, or almost 1800 miles east of the Lesser Antilles.  It continues to show signs of organization, and will likely be upgraded to TD14 or even TS Maria within the next 24-48 hours.  The environment it's moving into isn't the best, so if it does develop, it should be slow to intensify for the next several days.  It is very far from land, but it will be something to keep a close eye on simply because of its location and potential track (the southeast US is about 11 days away).

Please visit my tropical Atlantic headquarters.