It all began as a rather innocuous area of spin in the mid to upper levels of the atmosphere a little more than a week ago. What was once just an upper level low, producing some showers and thunderstorms over the warm Atlantic, is now hurricane Joaquin. Most hurricanes form from other sources such as tropical waves that emerge from Africa. Joaquin is unique – it is that rare hurricane whose origins can be traced back to a system that is cold in the middle, not warm like a hurricane. And so here it is and so here we go with the anguish of worrying about where it ends up. The potential for something historic is on the table and those who know my writing know that I rarely use terms like that.
First – the stats. As of 8am ET, Joaquin was a 75 mph hurricane moving towards the central Bahamas. This is the first region that will have to deal with the effects which may be quite intense as the hurricane continues to intensify over very warm ocean water. As such, hurricane warnings are up and people in the region are hopefully preparing. The slow movement is a problem too – it means a prolonged period of wind, rain and surge for the Bahamas.
Once Joaquin turns north, and it should according to the official forecast, things get very interesting. A lot was made about the fact that the ECMWF model, considered to be the world’s best by many, nailed the evolution of what eventually became devastating hurricane Sandy. Somehow, the model “saw” the track as far as seven days from the landfall in New Jersey. All the while, the American based GFS model handed Sandy’s energy off and sent it packing out to sea. We all know the end score – Euro > GFS.
Here we are three years later and another global model duel is at hand. This time, Joaquin is the name and the end result is still in question. Why? We are talking about less than five days, maybe six at the most. How can the global models not be locked on the solution that can give forecasters confidence that their track and intensity ideas have solid merit? Basically, it’s the pattern.
Sandy was very unique in that a Caribbean hurricane moved up in to the southwest Atlantic and was then pushed out to the northeast and away from the United States – only to be blocked by an enormous ridge of high pressure which sent it back towards the Mid-Atlantic where a deep, strong trough captured it. The set-up for Joaquin is similar yet different. This time, it’s going to be early October. The trough in question is going to cut off from the main flow and not be nearly as strong as the one that captured Sandy. Water temps are quite a bit warmer this time than what they were in late October 2012. Joaquin has a chance to make landfall purely tropical with a concentrated area of winds and the potential for a devastating storm surge. When and where that could happen remains to be seen.
This brings me to the GFS vs ECMWF duel.
Check out the graphic showing the GFS track from the overnight run (6z). Clearly it curves around the cut-off low and bends back towards the North Carolina coast. This would be a very bad scenario for obvious reasons.
Now look at the ECWMF position at the same time – 102 hours. The difference between the two positions of Joaquin is incredible and means a completely different outcome for each model.
One has to wonder why such a spread between the two global models? I wish I knew. Obviously, the GFS captures Joaquin with the cut-off low and swings it back towards the coast. The ECMWF, on the other hand, finds just enough of an escape route offshore to allow the hurricane to turn safely away from the United States. Which solution will turn out to be correct? Well considering that the ECMWF seemingly lies alone in its “thinking”, it looks more and more like the other models, the GFS included, have locked in on what will eventually be a nasty hurricane event for some location(s) along the East Coast.
If the ECMWF turns out to be correct, it will be an incredible turn of events and mean that the current track forecast that we see now will be turned almost sideways, pointed eastward instead of towards the coast. It’s possible but at this point, it’s hard to believe the GFS, which had more data from the NOAA G-IV mission last night, will be totally wrong and eventually flip to the “out to sea” track. I guess anything is possible with weather so we shall see.
All of that aside, what can you expect if you live along the East Coast? Well, for one thing, rain! The trough and upper level energy coming in to the Southeast and East will set off a significant heavy rain event even before the supposed arrival of Joaquin. Take a look at the precip forecast map from the Weather Prediction Center – notice how vast an area is covered by 6+ inches of rain over the next several days. Add the effects of a hurricane to the mix and we have the set-up for what I term a history making event. Flooding from freshwater is astonishingly lethal. The fact that the Appalachians could get excessive rain makes me very nervous. The Piedmont is also very vulnerable in this kind of set up. I urge people to make sure they are aware of the weather forecast for their local area. Use weather.gov as a source – read the warning info, the discussions and tune in to your LOCAL TV and radio sources. This much rain, combined with a potential landfalling hurricane, is simply too much to ignore and brush aside as hype. This situation could have lingering impacts for years to come and people better be paying attention.
As far as direct impacts from Joaquin – the Bahamas are up first, then we wait. If current forecast trends continue, it looks like a hurricane strike for North Carolina, Virginia or even points north. Swells will move out ahead of the hurricane which will make the already battered beaches even more battered. Surfers will love it but swimmers will need to simply stay out of the water. The rest is up to the hurricane and where it ultimately tracks. We can look at what impacts to expect when and if that time comes – there is still time for the ECMWF solution to be correct and save the day – wouldn’t that just be something?
I will produce and post a video discussing further outlining much of the content that I covered here. I expect to have that online by later this afternoon. As always, you can follow along in our app – Hurricane Impact (two words) in the App Store and on Google Play.
M. Sudduth 9:40 AM ET Sept 30