I think that Dorian is going to be gaining a lot more attention over the next few days as it moves quickly across the tropical Atlantic. The reason? It has potential to impact land and this includes the United States.
Right now, the storm is fairly strong at 60 mph with a pressure now below 1000 mb. This is not surprising considering the well defined structure easily seen in satellite imagery. Do not be shocked if Dorian becomes a hurricane over the next few days. Remember that intensity prediction is the key area that needs improvement when it comes to tropical cyclone forecasting.
On the other hand, do not be shocked if Dorian suddenly weakens and looks like it will dissipate. I say this to balance out the intensity forecasting issue. It works both ways and with such a small center where most of the convection is, it would not take much dry air and shear to deliver a knock-out punch to Dorian. We’ll see. One thing I do notice is a well defined “tail” extending off to the southwest from Dorian. This is no doubt feeding very moist air in to the storm from hundreds of miles away. Plus, the overall envelope of Dorian is large and once it encounters warmer water temps ahead, it may very well intensify.
The other question is obviously track. Where does Dorian go over the next five to seven days? The answer is quite simple so far: generally westward. The reason is a large high pressure area, like a huge balloon, that will be growing over the central Atlantic. This will not allow Dorian to move north and escape out to sea, not yet anyway. This is not September when we see deep troughs of low pressure plowing in to the western Atlantic, eroding the ridge down and easily turning storms and hurricanes out to sea. In fact, this time of year, we typically see large high pressure areas such as what is building now over the Atlantic. This will keep Dorian chugging along the southern side of that high, moving west day by day.
The GFS global model seems to have a good handle on Dorian so far. It shows the storm getting just a little farther west with each run. The latest run from overnight shows a potential threat to the Bahamas in about a week. It looks like a weak trough tries to build in and knock the ridge down some but then it lifts out and allows the Bermuda High to establish itself again, pushing Dorian west and towards the Bahamas. This is a week away and while the GFS is pretty good, there is plenty of room for error. I just want people to be aware that this does not appear to be an easy “out to sea” type of situation. That can still happen but this time of year, it gets tough to do so with that kind of deep layer ridge sitting over the Atlantic. Keep an eye on Dorian. It could be something that people have to deal with this time next week.
Meanwhile, TS Flossie has formed in the eastern Pacific and is of no concern to land right now. However, beyond the five day forecast period, it could pass close to Hawaii as a dying tropical depression. This would mean an increase in wind and rain chances for the area. Something to monitor as we get in to the weekend ahead.
I will have more on Dorian tonight and will also be posting the daily video discussion to our app, Hurricane Impact. I’ll have the video posted by early afternoon, once the 12z model guidance comes in and I can go over it. We are also about ready to release an Android version of our app. That should be ready sometime next week and I know a lot of people are eagerly awaiting that.