The theme of weak, sheared storms continues in the Atlantic Basin this morning as we see that Karl has weakened to a tropical depression in the overnight hours.
Strong upper level winds have taken a toll on Karl and as such, the NHC has reduced the wind speed down to 35 mph. It is possible that Karl has completely fallen apart and is now just a sharp tropical wave again. We won’t know for sure until more satellite images come in later this morning and we can see from visible pictures whether or not there is a coherent low level center.
Assuming that Karl is going to survive the next 24 hours, it could still strengthen as it moves westward and eventually turns north and northeast away from the United States. The turn should be sharp enough to avoid any direct impacts for Bermuda.
Meanwhile, TS Lisa is up to 50 mph now over the open tropical Atlantic. There’s not much to say about this storm except that it will remain well away from land and will track harmlessly over open water until it dissipates in a few days.
I am also keeping an eye on a curious feature that the GFS model in particular seems to develop rather consistently run after run as of late. It comes from energy that will emerge from the coast of Africa in a couple of days over the deep tropics. In fact, the development takes place near 10N latitude and moves generally west towards the southern Windward Islands. This lower latitude would likely shield the system from the strong upper level winds we’ve seen prevalent as of late across the Atlantic. I won’t worry about this too much yet since it’s still five to seven days out. There are other global models which show a similar scenario as well and so it’s worth keeping an eye on, especially in the Windward Islands. I’ll go over this in more detail during my video discussion which I will post later this afternoon.
M. Sudduth 7:45 AM ET Sept 21