Upcoming week - October 8-14

[Andrew92]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

Evaluating last week

Nadine is gone! Hey, that’s one accurate thing I nailed this past week, down to the timing of that occurring on Thursday. Nadine’s track to that point, including the timing of it, was also pretty close to accurate, though I had her loop being completed on Monday instead of Tuesday. She did weaken a tad faster than I thought, to 45-50 mph as she reached the Azores late Wednesday to early Thursday, but overall I did well on this last little leg of Nadine’s life, enough to get an A- for it here.

However, I also called for no other tropical storms to occur, and I overlooked Invest 96L which did become Oscar. It wasn’t very strong, and I noted in a subsequent post that I thought it would be weak. Even 50 mph is stronger than I likely would have thought, but I should have been able to see this one coming. So I did pretty bad there, but Oscar also missed land and was short-lived.

Overall, with doing well on Nadine, but not sniffing out Oscar, I give myself a C for this past week.

How are things looking this week? Let’s take a look.

Current situation and models

There are no tropical cyclones in the Atlantic for once. However, Invest 97L is threatening to develop into a cyclone sometime in the first half of this week near the Bahamas, off the tail edge of a front. Models have been hinting at developing a system in this area for a few days, and the National Hurricane Center currently gives this area a 10 percent chance of developing over the next two days, down from 20 percent earlier today. A closer look at the GFS and Euro models show that this system will probably be weak and short-lived, likely absorbed into another frontal system by late Wednesday while heading generally northeastward, never threatening land other than maybe some rain showers in the Bahamas.

Things look pretty interesting late in the week just east of the Lesser Antilles. Both the GFS and Euro models show at minimum a potent disturbance in this area starting on Thursday. The GFS shows a decent little system by Saturday while curving northward a little east of the Leeward Islands, but seems to weaken it or hold it steady for Sunday. The Euro model shows a more westerly track for this system over the Lesser Antilles, with a similar intensity.

Nothing else seems to be showing up this upcoming week for any potential tropical or subtropical developments in the Atlantic.

It should be noted that the El Nino event that I have been calling this hurricane season does appear to be dying down, a very surprising turn of events for a typical El Nino year. Usually this would be a time for seeing no more than maybe one or two more storms, but one of them sometimes becoming a minimal or moderate hurricane.

Recent history

In light of El Nino perhaps fading, new developments – not storms already active – this upcoming week in all years since 1960 include (with asterisks next to typical El Nino years):

Isbell in 1964
Elena in 1965*
An unnamed hurricane in 1970
Fran in 1973
Evelyn in 1977*
Juliet in 1978
Floyd in 1987*
Joan in 1988
Jerry in 1989
Marco in 1990
Roxanne in 1995
Kyle in 1996
Irene in 1999
Karen in 2001
Mindy in 2003
Nicholas in 2003
Matthew in 2004
Subtropical Storm Nicole in 2004
Vince in 2005
Nana in 2008
Omar in 2008
Paula in 2010

That’s a rather impressive 22 named storms this upcoming week. If you only consider the typical El Nino years, the number drops significantly to just three storms, although 2004 was transitioning to more typical El Nino conditions, so you could make a case that the true number is five for that reason.

Eight of the 22 came from frontal systems, of which six came east of the East Coast (the other two were in the Gulf of Mexico: Marco in 1990 and Matthew in 2004). One of these storms occurred in an El Nino year: Evelyn in 1977, and it became a minimal hurricane on its way to Newfoundland. The only other one of the eight not to become a hurricane of this subset was Nicole in 2004.

Four tropical storms have developed this upcoming week from tropical waves in the Main Development Region: Juliet in 1978, Joan in 1988, Nicholas in 2003, and Nana in 2008. Juliet quickly got out of it as she developed very near the Leeward Islands. Joan went into the Caribbean after mostly struggling in this area. Nicholas was trapped in this area, but eventually became a strong tropical storm during its long life, but never a hurricane. Nana was a very short-lived, weak tropical storm. I will concede that Elena in 1965 was very close, but developed a bit too far north to occur quite in this region. It actually did become a hurricane as it headed out to sea.

So what does this all tell us?

It looks like a very tricky week is forthcoming to try to predict. First off, models have indicated a developing system from Invest 97L for a few days, and it may be slowly materializing. But the GFS and Euro do not show much intensity for this disturbance either, and it likely becomes extratropical by late Wednesday. If shearing is strong enough, this system may not even become a tropical storm. However, this kind of event at least can happen once in a while.

More unusual is what could happen later this week per the GFS and Euro models. Only four storms have developed in this area during this upcoming week in the satellite era. Moreover, none of these have occurred in a typical El Nino year. Granted, El Nino is fizzling, so it may be prime time for a system like this to perhaps take advantage of conditions possibly becoming more favorable. But keep in mind before you get worried or excited, that no storm since 1960 has ever become a hurricane in this area during this upcoming week either, nor has one been spawned by a system that developed here during this upcoming week. Elena was close in an El Nino year, but still developed just outside this region, which I guess goes to show that it can indeed happen.

A more favorable area for development would be the Caribbean. Though fewer storms have developed here during this upcoming week at four, all became hurricanes (though I have doubts if one of the four, Floyd in 1987, was truly a hurricane when it grazed the Florida Keys, and am eager to see what post-analysis looks like for this storm). Also, four of the 22 storms eventually became major hurricanes: Isbell, Joan, Roxanne, and Omar. Only the latter did not do so in the western Caribbean, but did so in the eastern part.

The prediction

Invest 97L is teasing at developing further. However, the National Hurricane Center’s probability for doing so is still only 10 percent, and it would last until likely no longer than Wednesday. Still, there has been somewhat of a structure, and a tropical depression cannot be ruled out at least. A tropical storm, even a weak one, seems like a stretch though. So what do I think? I do not think Invest 97L will become a tropical depression before it fizzles out by Wednesday. However, rain showers could still cause some flooding in the southern and central Bahamas. Confidence is 70%.

And what might happen later this week? It is very hard to make a prediction for a system I am not yet even seeing on the big picture, but the GFS and Euro do support a storm later this week. Tough call, but here is my best shot: I predict a tropical depression will form about 500 miles or so east of the Lesser Antilles on Thursday night or early Friday morning. It will become Tropical Storm Patty on Friday, but not intensify a lot while tracking northwest, staying east and northeast of the Leeward Islands through Sunday. Only wave effects will take place as this storm's rain shield remains offshore. Maximum winds will reach 50-60 mph on Saturday, but level off on Sunday to 45-60 mph. Confidence is 50%.

Elsewhere I predict no tropical cyclone activity this upcoming week. That includes Nadine not making any more comebacks. Confidence is 90%.

-Andrew92

[Hurricane_Luis]

Ex-Nadine is now very dead, centered over Eastern Ukraine

[Caribwxgirl]

Well you got the fact we'd get a Patty right but wrong location. I love reading your predictions though. So I'd say got about 50% this week you missed the development of 97l but got the development of 98l into a named storm.

[Andrew92]

Time to evaluate.

Two systems of note were noted for this past week. The first was Invest 97L, which looked like would be a very short-lived system before being absorbed in a frontal system. The other was an unknown at the time, but picked up by the GFS and Euro models as a potential troublemaker by the weekend.

I predicted no development for Invest 97L but that it would produce some rain showers in the Bahamas. Well it did not become absorbed as quick as the models were saying and managed to become a weak Tropical Storm Patty for about a day before fizzling out. I guess I kind of had the right idea that such a system would be weak and short-lived near the Bahamas, but I really didn’t think it would develop either with conditions appearing to go downhill for development and forecast to get even moreso at the time. At least it was a weak system that didn’t affect land too much though.

On the other hand, the system I did have becoming Patty – well, it became Rafael instead – I did reasonably well here. Two different solutions were provided in terms of track: the GFS suggested a quicker northwest track east of the Leeward Islands, while the Euro took the system over the islands. The GFS has done a marvelous job this year, and I therefore trusted that model again. However, the Euro beat the GFS this time as it did indeed head into the Caribbean. My prediction for intensity was pretty good, though Rafael did break my 50-60 mph window late Sunday by reaching 70 mph. Still, this was a decent enough prediction for this storm.

Overall, with what I had to work with, I didn’t do bad, but not that great either. I give myself a C for this past week.

New week coming up shortly.

-Andrew92