9 AM ET Thu Sept 21
After a devastating, crushing landfall across Puerto Rico this time yesterday, Maria is now out over the warm waters of the southwest Atlantic. The eye has become quite large with hurricane force winds now extending out from the center some 60 miles. Maria has regained category three intensity and I think it will get stronger still once it moves farther away from the island of Hispaniola.
As the people of Dominica, St. Croix and Puerto Rico labor to begin the process of rebuilding their lives and their communities, there remains one more chapter to the Maria story still unwritten. I say unwritten, though the outline sure seems to be solid at this point: Maria never makes it to the USA coastline.
All of the available track guidance suggests, at least at first glance, that Maria will turn a graceful curving path away from the Southeast coast over the next five to seven days. The closest it is likely to get to land again will be today and tomorrow as it approaches the Turks and Caicos islands – but remaining just east in terms of the dangerous core of the hurricane.
After this time period, it seems almost certain that the lack of strong high pressure over the western Atlantic, due mainly to the presence of Jose, will allow Maria to eventually lose its western progress and begin turning back towards the east and eventually on out in to the open waters of the Atlantic.
Sounds like all is well for the East Coast…except for one thing: it hasn’t happened yet.
Now I know this sounds obvious but a forecast is subject to error; whether by humans who lay out projections on a map for the center position of a tropical cyclone or by computers which use numerical prediction to guide the humans. If it hasn’t happened yet then it is only a forecast and remains under the limitations of modern weather prediction – even if it looks like a lock.
Let’s look at it from a different perspective. Instead of “why is Maria turning out to sea?”, let’s approach it from “what would it take for Maria to turn back towards the coast?”
Here is my answer: If we see more ridge (high pressure) developing north and east of Maria then it will not fade east and has a chance to continue to gain longitude (westward progress). Right now, something very important is occupying the space that would normally be filled with a dome of air and that is a tropical storm named Jose.
As a hurricane, Jose literally moved up in to and split the ridge, causing an alley-way or weakness for Maria to follow. As long as this alley stays open, Maria will turn out. This is quite likely what will happen. However, if Jose turns back west and comes inland over the Northeast or Mid-Atlantic states then what does that tell us? Why would Jose turn back to the west? Blocking high pressure. That’s why. The atmosphere is forecast to build what we call “heights” over the coming days in a fashion that would normally steer something like Maria in to the Southeast coast. But, with Jose having cut the ridge out enough, Maria is probably going to gain more northward progress with a turn out to the east with time.
Probably. Not certainly.
What we need to look for is how far west Maria tracks over the next 48-72 hours. We also need to watch what Jose does. I believe from what I have read and seen in the model guidance, that if Jose turns west and even south of west, and is driven in to the coast of say, New Jersey (however weak Jose may be it is still something to watch for), then Maria could pinwheel in as well as the models seemed to suggest yesterday. It’s a long shot but there are several members of the 51 runs of the ECMWF model that show this scenario. I cannot display that model output here as it is licensed for use by commercial weather companies. This is the advantage of having an ensemble prediction system – it allows the “what if” cards to be played. In the case of Maria, we are not yet seeing all 51 members of the ECMWF model depict an “out to sea” path.
To be fair, the 21 members of the GFS ensemble group do show 100% “out to sea” as far as USA impacts go. Which model will be correct? Wish I knew.
So the bottom line here is that while the odds favor the East Coast of the USA having to never deal with Maria directly, those odds are not 100% just yet. We’re getting close but close is not the same as there.
I’ll post a video discussion this afternoon after the 12z GFS and ECMWF models complete their runs and we’ll see if the odds have changed any.