Upcoming week - November 12-18

[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

Last week there was nothing to start the week from a tropical standpoint. The only interesting feature was a developing Nor’easter during the middle of the week. I did note that this feature could cause headaches for the East Coast, but likely not become a tropical or subtropical entity. Along with that, I predicted no other systems would develop into a tropical or subtropical cyclone this past week. This happened exactly to fruition. I also cautioned not to look to me for advice on the Nor’easter, because for one thing this is only one man’s very unofficial opinion, but also because my knowledge on these storms is a lot more limited than it is for hurricanes. With all of that said, and with my very accurate prediction, my grade for this past week is an A.

Is anything coming this week? Let’s take a look.

Current situation and models

The tropical Atlantic is very quiet right now. Nothing appears to be about to develop anytime soon. That is, until you get to sometime on Wednesday near Bermuda. At that time, the GFS and Euro models both support a subtropical-looking feature organizing. This system would take a north-northeasterly path and move rather quickly, reaching Newfoundland by Friday. This system would also be short-lived as a subtropical (or perhaps tropical) system, likely becoming extratropical shortly after hitting that island. It appears to have potential of intensifying into a pretty decent storm on its trek northward in doing so, too. Afterwards, it appears to head very rapidly eastward over the North Atlantic, possibly reaching Europe by Sunday even if the Euro is accurate. The Euro was more accurate than the GFS on Sandy, after all.

Otherwise, nothing looks to be brewing for this upcoming week.

Recent history

Since 1960, these storms have newly developed this upcoming week:

Laura in 1971
A subtropical storm in 1981
Kate in 1985
Frances in 1986
Keith in 1988
Marco in 1996
Lenny in 1999
Gamma in 2005

You can tell the season is rapidly dying down, because that is only eight storms in the satellite era, or about one every six or seven years. Four of these storms became hurricanes, of which two – Kate and Lenny – became category 3 or higher storms at some points. These two storms and Marco, one of the others to become a hurricane, occurred either in the Caribbean, or in the case of Kate, a very short distance north of it. Frances, the other one to become a hurricane, occurred only over open subtropical waters far from land.

Since the focus this week looks to be from a subtropical system, we should look at what occurred in that area more specifically. However, only two storms developed in these areas during this upcoming week: the 1981 subtropical storm and Frances in 1986. Both got quite strong, with the subtropical storm peaking almost at hurricane intensity and Frances becoming a hurricane. Both storms required about 36-48 hours to reach their peak intensities.

All of the other six storms occurred in the Caribbean or close to it in the case of Kate, as mentioned before.

So what does this all tell us?
A new development this upcoming week is not at all common in the subtropical latitudes. Yet, that is just what the GFS and Euro models are portending. It will likely be a very fast mover and be out of the picture as a subtropical or tropical entity by sometime on Friday as it passes Newfoundland. The two other storms to develop this upcoming week needed about 36-48 hours to become the fairly strong entities that they became. This feature will likely be extratropical about 48 hours into its life. Therefore, unless this system, if it occurs, starts out quite intense, it seems like it will not be as intense as the others.

The Caribbean would be a more ideal place to see tropical development this week. However, none of the models are seeing any features doing so at this time. However, even though the likelihood is three times higher than the subtropical feature historically, the odds still suggest it happens once every eight or nine years too. The last time it occurred was in 2005, so if we’re to seriously play that game, it isn’t yet time to see a tropical feature in that part of the world this week.

The Prediction

It’s hard to argue against the GFS and Euro models, even if history says the odds are low. They have both done a very good job with just about every tropical and subtropical storm this season, and for that reason there is no way I can distrust them with this happening. I predict Subtropical Storm Valerie will form on Wednesday near Bermuda with a starting intensity of 45-50 mph. It will track very quickly north-northeast and peak with winds of 60-65 mph on Thursday. Valerie will weaken a little to 45-60 mph before reaching Newfoundland on Friday, and shortly after hitting there will becoming extratropical and race out over the open Atlantic. Heavy rain showers, some strong gusty winds, and some wave action can be expected in Newfoundland with the approach of this storm. I also do not expect Valerie to become tropical but to stay subtropical. Confidence is 60%.

Elsewhere, I predict no tropical cyclone activity this upcoming week. Confidence is 90%.

-Andrew92

[TropicalAnalystwx13]

Thanks Andrew92.

[cycloneye]

Andrew,is this the first time since you are doing this that is not even a invest up for something that you had more than 50% of confidence? You have done great for the most part this season.

[Andrew92]

Sorry for the slow response, been a busy guy this week! Let's evaluate.

This might have been one of my bolder predictions, even if the storm I thought would occur was likely to not actually be tropical but a hybrid and last only a couple days. Too bad it just didn't pay off. The GFS and Euro both looked quite promising for this feature too. I have to say, looking at satellite pictures, the feature was there and followed the track I thought it might, but it just didn't develop further. It simply just didn't have the thunderstorms or organization that these two models were saying it might. Based on that, and the fact that I also correctly predicted no other storms for the week, would this be a completely blown forecast? I would say no. The theory was a good one looking at the models and what a couple other Pro Mets from other places said. Also as mentioned, the feature followed roughly the track I thought, also about the time I thought it would. If it had developed into a subtropical identity, this would have been a slam dunk for an A. But it didn't develop further... tough grade to say because I didn't fail and probably wasn't much below average either. I think I'll give myself a C- for this past week.

Thanksgiving prediction coming up in a jiffy.

-Andrew92