Upcoming week - September 24-30

[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

This past week centered mainly on what Nadine would do. One thing I can say outright is that I definitely had a good feel for the track and intensity overall of what this storm would do. This storm followed a general northeastward and slowish path that grew slower as she neared the Azores. After reaching a point just south of those islands, Nadine did indeed move very erratically late in the week, though not quite in the kind of motion I had in mind. I was kind of thinking a “cleaner” loop that the jagged one she appears to be taking. I also pegged the intensity mostly correct too, keeping Nadine in a window of winds of 50-65 mph. However, I did think Nadine might weaken during the weekend, and that didn’t really happen. I say that because Nadine did briefly become extratropical, only to become tropical again, and then began to strengthen again on Sunday. Then again, I don’t know that I would have had any way of predicting that kind of evolution late in the week like that. The fact remains too that I also thought Nadine would still be a tropical storm by this time, a gutsy call to make for a storm in this location on a track like this. Overall, I did a very decent job predicting what I thought Nadine would do.

Finally, I also correctly predicted no other tropical cyclones would develop during this past week. One disturbance came very close in the middle to late part of the week near Bermuda that I didn’t see, but it didn’t develop either. Altogether, I give myself an A- for this past week.

Nadine continues to make me want to pull my hair out. She also isn’t going away quickly. Let’s see what she is up to…

Current situation and models

Nadine is currently gathering maximum winds of 60 mph south of the Azores and is drifting very slowly west-northwestward. There is not a lot of deep thunderstorms near the center of this storm and some shear may be responsible for Nadine’s current struggles. This shear may abate by late Tuesday or Wednesday and be replaced with an upper-level anticyclone, allowing for some strengthening. The National Hurricane Center shows no strengthening until 48 hours from now, and then slow intensification to a hurricane by Thursday. During this whole process, the slow motion westward will likely continue due to strong anticyclone north of this storm and weak overall steering currents. But by Friday, a weakness may develop in this anticyclone and start allowing Nadine to turn northward during probably the weekend. The GFS and Euro models also support this same type of evolution with Nadine, with neither model showing her becoming extratropical during the weekend either. Nadine is indeed the “annoying” storm of 2012 it appears.

Other than Nadine, neither the GFS nor the Euro shows any development apparent this upcoming week. The MJO remains unfavorable and the African monsoon doesn’t seem likely to churn many organized disturbances this week. While shear isn’t too high overall, the air is more stable than normal in the tropical latitudes, which would curtail such systems from developing to begin with.

Recent history

Since 1960, these storms have developed or were active coming into this week during typical El Nino years:

Carol in 1965 (already active)
Debbie in 1965
Frances in 1968
Gloria in 1976
Dorothy in 1977
Dean in 1983
Emily in 1987 (already active)
Charley in 1992 (already active)
Danielle in 1992 (already active)
Earl in 1992
Ernesto in 1994 (already active)
Isidore in 2002 (already active)
Kyle in 2002 (already active)
Lili in 2002 (already active)
Helene in 2006 (already active)
Isaac in 2006
Grace in 2009

That is 17 total storms, or an average of about one storm a year during this upcoming week in a typical El Nino year. Indeed, Nadine will make it eighteen storms. Speaking of Nadine, storms in positions near her included Carol, Kyle, Helene, and Grace. Helene continued straight on out to sea, but the other three storms were very erratic. Kyle was so erratic that he made it all the way across the Atlantic even! But Carol and Grace did eventually continue out to sea, but decided to execute loops on their way out. Only Grace was never a hurricane of these four, and topped out at 65 mph anyway. However, none of these storms were overly intense hurricanes either. Yes, Helene was stronger earlier in her life, but not by this point.

One thing of note if you’re looking for a development this upcoming week, is that the subtropical latitudes tend to heat up again in that department. Only Gloria in 1976 of the subset of newly developed storms became a tropical storm south of 25 degrees latitude – and she didn’t form very far south of there either. Also, only Debbie in 1965 developed into a tropical storm in the Gulf of Mexico. All the other storms intensified east of 70 degrees longitude.

So what does this all tell us?

Indeed, Nadine could and should be around all this week. Considering how weak her thunderstorms are and that her maximum winds are still 60 mph, if she gets her act together later this week, I do agree with the National Hurricane Center that she could be a hurricane again at some point. I’m not sure it will last long, but this storm certainly gets an A for effort and being a flat-out pain to try to predict. I’m just glad Nadine no threat to land other than maybe the Azores, and even that seems like a big stretch. Maybe she’ll finally learn to head north and away for good this time…

Meanwhile, it is getting increasingly more difficult for any kind of tropical storm to get going in this last week of September. Your best bet is in subtropical latitudes, but over open waters probably east of Bermuda even. But with Nadine swirling out there and trying to draw energy from wherever she can, that looks to be a tall order to pull of. Plus, no reliable model shows any such development during this week. Of course, the models didn’t show that Invest this past week either, but at least it didn’t develop. Given this, if something were to develop, it probably wouldn’t last very long.

The prediction

Nadine will you just leave the picture already? Unfortunately, it doesn’t appear likely this week until maybe the weekend. I predict Nadine will continue to track very slowly and somewhat erratically westward overall up until Thursday morning. Nadine will struggle to maintain an intensity of 50-60 mph until Tuesday night, when conditions become more favorable. Intensification will still be slow however, but Nadine will be a hurricane on Thursday. As Nadine becomes a hurricane, she will also start turning northwest into a weakness in the anticyclone to the north. This motion will continue until Saturday, when she will turn north. Nadine will also weaken back to a tropical storm that day after peaking with winds of 75-85 mph on Friday. Nadine will continue north and bend to right on Sunday, while still holding on to winds of 50-60 mph as a tropical storm. Confidence is 70%.

Elsewhere, I predict no tropical cyclone activity this week in the Atlantic. Confidence is 85%.

-Andrew92

[Ntxw]

Another great write-up, keep up the fantastic work NHC would be better if they could get you to share this weekly

[Sanibel]

Looks like the MDO positive phase exemplified by 2004 and 2005 has officially ended. I mean this is even worse than I thought and there is nothing out there. In the previous phase something would have rebounded and formed by now. Nino, no ridge, VI caps - wow, dead year like we haven't seen in a while.

[Macrocane]

Looks like the MDO positive phase exemplified by 2004 and 2005 has officially ended. I mean this is even worse than I thought and there is nothing out there. In the previous phase something would have rebounded and formed by now. Nino, no ridge, VI caps - wow, dead year like we haven't seen in a while.

I wouldn't say it's a dead year, it was very active in the first half of the season. It's more like a dead ending of the season.

[Florida1118]

Looks like the MDO positive phase exemplified by 2004 and 2005 has officially ended. I mean this is even worse than I thought and there is nothing out there. In the previous phase something would have rebounded and formed by now. Nino, no ridge, VI caps - wow, dead year like we haven't seen in a while.

I wouldn't say it's a dead year, it was very active in the first half of the season. It's more like a dead ending of the season.

Not only that, we still have two months left. Its not even close to a dead year, except perhaps in majors.

[Sanibel]

True, but this is unusual for prime-time.


That Atlantic wave looks like it has the juice but is too sheared. Spring-like shear throughout the Caribbean.

[Andrew92]

And with that it is time to evaluate. Sorry it's late, I just got home from a weekend out of town.

Once again this week relied on how well I did with pesky Nadine. I certainly was accurate in predicting that she would still (unfortunately) be around by the end of this week. I also had the right idea in going with a struggling Nadine early in the week, but strengthening later. However, I thought her winds wouldn't drop below 50 mph, and they did reach 45 at one point on Tuesday. Moreover, Nadine became a hurricane about 24 hours later than expected, on Friday instead of Thursday. Nadine was indeed an erratic mover in terms of track, but I never foresaw the far southward motion that took place in the first half of the week. But when Nadine became a hurricane, she indeed turned northwest as predicted. But finally, the path didn't bend right but actually left during the weekend, and Nadine surprisingly grew stronger and out of my peak range of 75-85 mph, reaching 90 instead.

But nothing else developed this past week either. Overall, I was a little rough in this very annoying little demon named Nadine, but still very much passable. I give myself a B- for this past week.

New week coming up in about a half hour as I am still writing it.

-Andrew92