Upcoming week - September 12-18

[Andrew92]

Evaluating last week

With three storms to track this past week, Katia, Maria, and Nate, it’s probably best to just look at each storm individually. We’ll start with Katia. Looking at Katia, the track and timing of it were pretty much perfectly nailed. I predicted the northward turn to start Wednesday night and a northeastward turn on Friday morning, both of which happened at about their prescribed times. I also predicted Katia would stay offshore of any land areas, including south of the Maritime Provinces, and this also happened; though rough conditions were still present as the storm was not too far offshore either (this was also a correct prediction). The issue with Katia was the intensity. Katia was a C4 hurricane with winds of 135 mph as the week began, and I predicted she would hold her own if not gradually weakening for the first couple days. But Katia was in a big hurry to weaken instead, dropping to a C1 in only a little over 24 hours. After that, Katia started to hold her own in intensity, and on Friday remained the C1 storm I had predicted her to be by then. But she didn’t weaken to a tropical storm on Saturday, though did become extratropical that night, close to when I said she would. Overall, a very good track prediction, and a so-so intensity prediction, means I did slightly above average overall this week for Katia.

Now we’ll evaluate Maria. Maria was another storm that I had a good handle on in terms of track, and unlike Katia, I actually didn’t do too shabby all things considered on intensity. First off, I predicted Maria’s development on Tuesday, followed by intensification to a tropical storm on Wednesday – both of which were correct. I also predicted a very quick-moving west-northwestward track across the tropical Atlantic, which indeed happened. I was a little off on the timing of reaching the Leeward Islands, but not too much – I called for this to occur on Friday, and it happened early Saturday morning instead. Maria then did go a little further north than projected, passing north of the Virgin Islands and Puerto Rico on Sunday, but is moving close to northwest at least. Now, when looking at the intensity, I was not high on much of a storm until Friday, thinking Maria would struggle. This happened, though by the time Friday rolled around, I was predicting a more steady intensifying trend. This did not happen, and Maria is still struggling as a tropical storm, though doing a decent job of overcoming some moderate shear as she gathers winds of 60 mph – but not the hurricane winds I had been expecting. Overall, the errors with Maria were again mostly with intensity, but came late in the period when it is harder to get these things right. All in all, I think I did a very good job with Maria this past week with what I had to work with.

Finally, we have Nate. This was decidedly more difficult to predict than either Katia or Maria. On one hand, I did correctly see a very slow-moving storm out of this, and the maximum intensity I had for him was 60-70 mph by week’s end, and it indeed reached winds of 70 mph but no stronger. However, this storm developed two days earlier than anticipated, on Wednesday instead of Friday. I also went with a slow northward crawl over the weekend, and it instead drifted west. I don’t think I would have been able to see Nate having its northern most latitude be as far south as it was, but this storm’s track was overall very shaky for me. I never saw the landfall coming for Sunday, I would have predicted it for this coming week instead. Overall, I did not do the best job ever on Nate.

So let’s average it all out. I did slightly above average with Katia, very good with Maria, and not so good with Nate. Overall, this was not great, but not a bad week either for me. I give myself a B- for this past week.

Maria still churns in the open Atlantic. Could more threats materialize? Let’s take a peek.

Current situation and models

Maria continues to churn just north of the Virgin Islands and Puerto Rico. The track should be pretty much a no-brainer to nail, at least when speaking generally. This is a storm very much on its way to re-curving north and northeast. However, Bermuda and Newfoundland could get hit by this storm on its way out. As for intensity, Maria is very much sheared but a fighter. These kinds of storms have a knack for finding a way to really ramp up if conditions get just right. Conditions may indeed reach that point on Tuesday or Wednesday as she heads north and gets uncomfortably close to Bermuda. That will probably the best chance in terms of time for Maria to become a hurricane. However, there has been a general downward trend in how strong Maria will get at her strongest, and as said before, “the trend is your friend.” After that, shear should start to increase, and Maria will be speeding into cooler waters. Should Maria hit Newfoundland, it will probably happen on Friday morning as a somewhat strong storm that is becoming extratropical.

Looking elsewhere, I am hearing whispers that models are sniffing out a developing depression on Friday or Saturday off the west coast of Africa. Looking at graphics, I can see what is being talked about, but it doesn’t appear to be all the well-organized as it heads westward across the tropical Atlantic. Especially with all the stable air there has been this season, anything that does try to ramp up will probably have its struggles in that area, like Katia and Maria did.

Finally, there is a lot of talk about something brewing from the Caribbean and maybe making its way to the United States sometime next week. Obviously, whether that happens will be for the next prediction, but that isn’t really entirely why I bring this up. At a minimum, models are showing lower pressure in the Caribbean during the weekend. It is not entirely clear if this would develop during the weekend or early next week, as models aren’t in full agreement in that area. However, given that Lee and Nate both developed a couple days earlier than expected, this could easily happen a third time where the development takes place just sooner than we all think.

Recent history

Maria’s path is pretty rock solid to predict, and her intensity actually does not look to be too challenging either. For what it’s worth, history does say that the majority of storms in Maria’s area tend to re-curve quickly out to sea as forecast, while generally holding their own in intensity or slightly intensifying. Maria is also coming off of the heels of C4 Hurricane Katia, and as shown in prior predictions, storms in these kinds of situations just have a much harder time amounting to much, possibly due to the upwelling of warm waters that storms like Katia do. Katia’s rapid weakening also says that shear and dry air may really curb what Maria is able to pull off in terms of intensity.

Now, when taking a more formal look at storms developing in the tropical Atlantic this upcoming week, 22 storms have developed in that area since 1960. Of those storms, 16 have become hurricanes, and 11 were C3 or higher (with eight of those become C4’s even). The storms that failed to become hurricanes of this set include:

Celia in 1962
Edna in 1968
Dorothy in 1970
Fran in 1984
Iris in 1989
Ingrid in 2007

Also, of the ones that became hurricanes, there are a couple of big ones we all know of: Gloria, Marilyn, and Georges all developed in that area during this upcoming week. All of the other storms that became hurricanes either fizzled in hostile environments, or re-curved out to sea without hitting land other than Bermuda or Newfoundland.

As for the Caribbean, there haven’t been many storms develop in that area during this upcoming week since 1960. Storms that have include:

Fifi in 1974
Eloise in 1975
Greta in 1978
Gert in 1993
Karl in 2010

Only five total, though all of them became hurricanes at some point. Most of them also went westward into Central America and Mexico. Even Eloise grazed the Yucatan before turning northward.

So what does this all tell us?

Maria may become a hurricane, but her chances are very limited as she re-curves north and the northeast. If she does become one, it will likely only be for a brief period as a C1 storm with winds of 75-80 mph, probably southwest of Bermuda or so. Maria will probably not be a hurricane upon reaching Newfoundland, though tropical storms can cause plenty of problems without the wind.

History really loves the chances of a developing Cape Verde-type hurricane. The models do not. Something has to give, but when looking at this season as a whole, it doesn’t seem like anything that develops in that area will be very strong, at least during this upcoming week. The general trend this year also obeys history, suggesting a likely track out to sea.

Finally, it can happen, but it is very hard to get storms to develop in the Caribbean during this upcoming week. Conditions are just not usually all the way there yet. However, if they are, they take full advantage of what is given and often become hurricanes. Most also plow westward, though if Eloise can re-curve into the Gulf of Mexico, it still shows that it could indeed happen again.

The Prediction

After a crazy last couple weeks, this week looks to be much calmer. A couple storms may develop, but I wouldn’t fully bet the farm on much in the way of intensity for either if they both happen. But first, we have to finish dealing with Maria. The real things with Maria are, will she become a hurricane, what effects will Bermuda get, and how strong will her effects be in Newfoundland? Here’s my best shot: I predict Maria will change very little in intensity through Wednesday as she first heads northwest, turn turns north on Tuesday night. By Wednesday, Maria will begin accelerating north-northeastward and chug past Bermuda, bringing some tropical storm-force winds and heavy rains to the island. Maria will not become a hurricane as her maximum winds will reach 60-70 mph, and then weaken as she continues further north. On Friday, Maria will become extratropical just before hitting Newfoundland with winds of 45-60 mph. Very heavy rains capable of producing dangerous floods will take place as Maria passes through that day. Confidence is 70%.

In the tropical Atlantic we go, where history says one thing while this season and models say another. I think it’s a bit better to go with the current situation as a whole, but something still appears to develop, however strong or weak it may be. I predict a tropical depression will form on Saturday and become Tropical Storm Ophelia on Sunday, but have winds no higher than 40-50 mph as the week ends. Confidence is 70%.

And in the Caribbean, I do believe the pressures will lower and there will be some sort of monsoon trough in that area as the weekend rolls around. But a developing depression or tropical storm? I think it’s coming, but not until early next week. I predict no tropical cyclone development in the Caribbean or anywhere else this upcoming week. Confidence is 75%.

-Andrew92

[Andrew92]

Week over, time to evaluate.

Well, this was another mixed bag overall. We’ll start with Maria. The track was pretty easy to figure out, with a track at first slowly northwest, and then curving north and north-northeast, passing just west of Bermuda but close enough to produce tropical storm force winds, and then over Newfoundland on Friday while becoming extratropical. This was executed nearly perfectly, though the timing of passing by Bermuda was off by a day; I predicted this for Wednesday but it happened on Thursday. However, I was correct in pinning down a landfall in Newfoundland on Friday while becoming extratropical. The real problem was that Maria got stronger than I predicted. I thought Maria would fall short of becoming a hurricane, but reach winds of 60-70 mph. However, she was able to pull it off, and actually reached Newfoundland as a hurricane with winds of 75 mph. It’s not like she became a really strong hurricane, but this did hurt my performance a little with Maria, especially when considering I also thought she would have winds of 45-60 mph upon reaching Newfoundland. To sum it up, the track was good, the intensity not too great.

Elsewhere, I brought up two areas for possible development. I predicted that one would develop, and one wouldn’t. Well, neither one developed. The one I was correct on was the Caribbean development that some models had been picking up on for the weekend. I didn’t go along with it due to inconsistencies in model runs, which was a very good call. However, there was another interesting area to watch out for off the coast of Africa, that I unfortunately predicted to develop over the weekend into Tropical Storm Ophelia. Really, it became a rather bizarre set of Invests 97L, 98L, and 99L, but that’s it. A slight mitigation in this area is at least I saw that conditions weren’t all the way favorable, and I kept Ophelia very weak as a result. But I still thought she might come, and she hasn’t.

When piecing it together, I really kind of did just OK all across the board, with Maria and elsewhere across the Atlantic, though the areas I did well on were done pretty well. Predicting landfall in Newfoundland on Friday that far in advance, and then seeing it come to fruition, is very worthy of an honorable mention. I give myself a C+ overall for this past week.

New prediction coming up shortly.

-Andrew92