The 5-day outlook continues to look busy in the eastern Atlantic.There are a few healthy waves that need to be watched, the orange and red "x's" (the orange 'x' is Invest 91L), and then another wave that will enter the Atlantic on Sunday, the eastern orange area. I think we will see development in this region early next week but there is a lot of uncertainty on timing and location. The good news is that there are no serious threats to the US soon, although the Lesser Antiles may see something mid to late next week. Also, not shown is a wave in the western Caribbean that forecasters have been watching, but doesn't show any strong signs of development, for now just know it's there.
The forecast has two major issues that are driving a lot of uncertainty. One is that those three orange and red areas along with a few other waves are expected to interact. Where, when, and how that occurs is mostly unknown so until it plays out we won't have a good idea of where a storm, or multiple storms, may form. We're probably looking at the Monday/Tuesday time frame before this settles and we start to see serious development. What the models seem to agree on is that the red 'x' will pinwheel around the leading orange 'x' and become the leading system (leading as in more western, not necessarily stronger). After that, models disagree on where the dominant development will occur. The Euro develops the red 'x' once it becomes the lead system and then a wave coming off of Africa next Thursday. The GFS doesn't do much with the first two and instead develops the trailing orange area that enters the Atlantic Sunday. The European ensemble isn't too crazy about any of these and instead tries to develop a wave coming off of Africa next Thursday. The GFS ensemble tries to develop the red 'x' once it is in the lead and then also the trailing orange area. This is neat to see in the models, so I've shown the Euro and GFS below, but I'm telling you all this to highlight the uncertainty. We know something is going to happen, just not where or when.
The other forecast issue is regarding where these storms go if they do form. Right now, a track out to sea away from the US looks possible but there is debate whether the mid term forecast is correct. We've had a high pressure sitting in the western Atlantic that has steered a lot of the storms we've had to the west into the US. This is what happened with Laura. The models are showing a strong front (for this time of year) coming through and breaking down this high, allowing potential storms to escape to sea. The debate is that a lot of forecasters aren't really buying into the idea of this strong front. So if this doesn't occur then steering conditions could be such that potential storms stay on a more westward track, again threatening the US. It'll probably be later next week before we get a better feel for what will happen with this.
To sum things up the Atlantic is busy and we need to keep watching. I think we will see one or more storms develop in the next 5-10 days but it'll be early next week before we have a feel for where development will occur and maybe mid-week or later before we know if the US is at risk.
I don't mention it a lot, but all of these emails get posted to Twitter @DeepSouthWXUS and my blog: https://www.deepsouthwx.com/. There are also some weather maps on the blog and links to other resources. The models shown today are from Levi Cowan's great site: www.tropicaltidbits.com. He also does excellent video updates on YouTube when there are storms that we need to start watching here in the US.
Have a great Labor Day weekend. I'll send out another update early next week.
Chris
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