Eric Berger

One-sentence summary

Tropical Storm Lidia dissipated this morning over Mexico, but will bring rainfall and mudslides to part of the country; and its remains will merge with other moisture in the Gulf to bring rains later this week in the southern United States.

Tropics now: Goodbye Lidia, and hello Sean

After rapidly intensifying on Tuesday and slamming into the Pacific Coast of Mexico, Lidia has been shredded by the mountainous terrain of Central Mexico. The big concern with Lidia, accordingly, is now rainfall. The remnants of the system could cause urban flooding and mudslides in Western Mexico today.

After today, those remnants will be drawn into the Gulf of Mexico along with the remains of another Pacific storm, Max, as well as a warm front lifting north. This mess will eventually move to the northeast, toward Florida. We have zero expectations for these lows to congeal into something threatening from a tropical storm standpoint, but it should heighten rain chances for areas from Louisiana through Florida.

Overall rainfall totals look fine, with 1 to 3 inches from Southern Louisiana along the Gulf coast all the way to the Tampa area of Florida. Some locations may see higher amounts, but this system will be pushed out of the region by Friday and Saturday as a broad front brings drier air into the southern United States. So, not a huge concern.

Hi Sean, Goodbye Sean

Tropical Storm Sean has formed in the Atlantic tropics, about halfway between Africa and the Caribbean Sea. This system is expected to piddle along for a few days before it gets swamped by wind shear this weekend most likely. It will not threaten land. That’s probably about all we need to say about Sean.

Tropics later

Beyond Sean there are some mildly interesting features that we are watching.

The first of these is a tropical wave that just moved off of Africa, and should continue to move due westward through the weekend. The atmosphere isn’t overly favorable for development, so the National Hurricane System only gives this system a 30 percent chance of becoming a tropical storm over the next week. But eventually, and we’re talking at least a week to 10 days from now, this system might be something that eventually approaches the Leeward Islands. It’s not something I am really concerned about at all right now, but we will continue to watch it for you.

Beyond this, we probably need to be wary of some late-season development in the Caribbean Sea. Waters remain very warm in those sun-bathed seas, and there are some hints of potential storminess during the last 10 days of October. There’s not much of a threat to point to, just the potential for something to eventually spin up.

One-sentence summary

Philippe is finally lifting north after lashing the Leeward Islands earlier this week, and it may move toward Bermuda as a tropical storm by Friday or so.

Philippe is disheveled, but not dead

Tropical Storm Philippe has a rather ragged appearance this morning, and it continues to struggle with wind shear. After proving to be a rainmaker for islands such as Barbuda and Dominica, as well as the Virgin Islands, the storm should finally find a passage north as a high pressure system gets out of its way. It has open water for a couple of days before it reaches the vicinity of Bermuda. So what will happen to the storm’s organization over the next two days?

There is a ton of uncertainty, as Philippe could use this brief window of opportunity to strengthen into a Category 1 hurricane, or it could essentially be wiped out. Given its initial disheveled state, it’s difficult to parse whether the storm will, in fact, get its act together. The official forecast from the National Hurricane Center splits the difference, calling for a strong tropical storm with 60 mph tropical storm winds as Philippe nears Bermuda. This seems like a reasonable best guess.

After interacting with Bermuda, Philippe should begin transitioning into an extratropical cyclone as it heads toward the Canadian Maritimes and northern New England. The primary threat there will be some additional heavy rainfall this weekend before the system dies out completely over Canada. Areas including Maine and Nova Scotia should continue to track the storm’s progress for a few more days until we can say au revoir to Philippe.

Beyond Philippe: Some Pacific mischief?

After Philippe’s exit, the Atlantic looks quiet for a little while. The one feature we probably need to watch is a disturbance in the Pacific Ocean south of Guatemala that is likely to become a tropical storm over the next five days or so. Much of our model guidance indicates this will move across Mexico and into the Gulf of Mexico next week.

This could bring some heavy rainfall to coastal areas of Mexico, as well as the Gulf coasts of Texas and Louisiana later next week. But we’re at the point where there is just the threat of this happening, rather than any certainty. We’ll continue to watch it for you.

One-sentence summary

Overall things don’t look too concerning for late September, as Tropical Storm Philippe continues to be a fading force, and Invest 91L appears most likely to track north of the Caribbean Sea and its islands.

Happening Now: Some pesky storms

Let’s begin with Tropical Storm Philippe. Frankly, it does not look like much of a tropical system this morning, as the storm is battling against both the influx of some drier air as well as wind shear. This is kryptonite for a tropical storm, and the most likely outcome is that Philippe will dissipate over the next day or two. By this weekend a remnant low should approach Puerto Rico, bringing some elevated rain chances. But I am not seeing anything in this forecast that particularly concerns me.

Just behind Philippe in the Atlantic lies Invest 91L, which should become the better organized system over the next couple of days. It probably will become Tropical Storm Rina fairly soon as it tracks across the Atlantic Ocean toward the Caribbean Sea. Fortunately, the preponderance of our modeling suggests that this tropical system will mostly likely turn north before reaching the northern Leeward Islands. The continued evolution of 91L will be worth watching, but again it is not something which provides us too much concern at this time.

The medium range (days 6 to 10): Bahamas high jinks

We’re getting to the point of the forecast that is more speculative. However, after the remnants of Philippe move into Puerto Rico and Hispaniola, there may be an opportunity for some sort of low pressure system to congeal in or near the Bahamas about one week from today.

There is a definite signal in some of the global models ensembles for this scenario, and the ocean waters are plenty warm in this area. But the signal is not particularly strong, so I would not put too much stock in it. As we get to the end of September, this is the kind of thing we sometimes see in the tropics, with systems spinning up closer to land. If such a system were to develop it probably would get drawn north, perhaps toward Florida or the Eastern United States. But that is super speculative at this point.

Fantasyland (beyond day 10): Some noise, but not a whole lot

When we look even further into the future, well into the first week of October, there’s just not a whole lot out there. We’ll continue to watch the area near the Bahamas mentioned above, as well as the southeastern Gulf of Mexico for potential development. But again this is all pretty vague, and we can’t point to any specific threat. In my book, that’s a good thing.

One-sentence summary

Two systems are worth watching late this week or weekend, a deep Atlantic Cabo Verde wave and a subtropical system off the coast of the Southeastern United States.

Happening now

There’s not much beyond the slowly fading Hurricane Nigel, which is making a turn to the northeast and will race out to sea harmlessly. It should become a tropical storm in a day or two, and then transition to a post-tropical cyclone as it encounters much colder waters over the Northern Atlantic Ocean. Nigel was the kind of storm we can all live with, a powerful beast that remained at sea and never threatened any landmasses. Would that they all were that way.

The medium-range: Two things to watch

Let’s start with the system closer to the United States, an area of low pressure off the coast of Florida in the Atlantic Ocean. This system may develop into a subtropical storm by around Friday, at which point it is likely to get pulled north toward the Carolinas and Virginia. This will bring a surge of moisture into the region, some high surf, and wind gusts perhaps in excess of 40 mph along coastal areas of North Carolina and Virginia.

Probably the biggest threat this weekend to the Southeastern United States coast will come from heavy rainfall, most likely during a period from Friday through Saturday night, with some locations possibly seeing 4 to 6 inches. Tropical rainfall like this can come in bunches, so there will very likely be some localized flooding concerns regardless of whether this system develops or not. By Sunday, whatever this becomes should be pulling hard, away from the eastern coast of the United States.

African wave

As for the African wave, it only recently moved off the continent into the eastern Atlantic Ocean. Over the next few days it should find conditions well suited to further development, and it’s likely to become a tropical depression or possibly even a tropical storm by this weekend. After that? Well, that’s the big question.

The system should move more or less westward through the early part of next week. It seems fairly likely that the storm will get close to the Lesser Antilles, and perhaps Puerto Rico, about seven or eight days from now. At some point it will find a weakness in the high pressure ridge to its north, and lift away from the islands into the open Atlantic Ocean. But since this turn is not likely to occur for at least a week, and perhaps longer, our confidence in the details is understandably low.

The bottom line is that this system is worth watching, particularly for places like Antigua and Barbuda, the Virgin Islands, and Puerto Rico. This storm could miss these islands, certainly, but we’re also looking at the possibility of a significant hurricane coming calling. We’ll track it on a daily basis for you right here.

Fantasyland (day 10 and beyond)

There’s not much to see here, especially as concerns tropical weather close to land. That’s just fine with me.