Upcoming week - November 1-7

[Andrew92]

Evaluating last week

Really, I can sum October in a nutshell as being an overall very rough month. This past week was not all that great either, but was not as bad as a couple other weeks. I did accurately predict no development for Invest 90L, and I also accurately predicted a storm in the eastern Caribbean by the week’s end. Oh, and Richard also fizzled in the Bay of Campeche as expected, when it was expected.

Since I’ve also already described how I did on Richard, I’ll give myself a lowly-weighted A there. I also have already covered my accurate prediction for 90L never developing, so that too gets an A, and that one gets a bit more muscle as that one, albeit a fish, was a bit harder to pin down (though still not the bulk).

That sounds pretty darn good on the surface. However, going deeper is where I faltered more than a little. I predicted the eastern Caribbean storm to be Shary, and it was named Tomas. Now, the idea of development and gradual intensification is really what matters more than just getting the name wrong. However, it also shows that I was wrong somewhere else. Indeed, Invest 92L developed further north of the Virgin Islands and became Hurricane Shary on its way out to sea before this particular entity had any chance of developing. And yeah, Shary managed to defeat some enormous odds and become a hurricane anyway from that disturbance that seemed to sneak up on some people. Either that, or it wasn’t actually 90L that models were developing in that area, but something else instead. In any event, if I’m going to entirely miss a storm altogether, at least it was one that was little threat to land, merely providing just a little rain to Bermuda on its way out to sea. For not seeing this part of the past week coming, I have to give myself an F. However, with this being such a little-consequence event (if that term even exists), weighting will be a bit lower than elsewhere (except for maybe Richard dissipating).

Now comes the meaty part of this week, which was saved for the end. I did mention an accurate prediction of a storm on Sunday in the eastern Caribbean heading westward away from the Lesser Antilles. That is ongoing with now downgraded Tropical Storm Tomas, after it was a hurricane prior. For such a long-range prediction, the track was executed exceptionally well. The real problem is the timing of development, which usually also leads to intensity being well off. That is no exception here, as I predicted this storm would develop on Sunday in the Caribbean. Instead, it developed about 36-48 hours before I said it would, and it was still east of the Windward Islands. It also developed quickly from there, into a hurricane the next day after passing by Barbados towards St. Lucia. A weakening has since taken place, but the damage in this area was already done. Predicting the development of storms has been a difficulty all season for me, and end-of-week developments especially has really been an albatross. This one is no exception. Since I at least called for it to happen, and the positioning on Sunday was pretty good, I cannot ding myself too much in this area. Having the timing off as egregiously as it was, though, is not something I can exactly hang my hat on too much either. I will potentially be generous and split the difference of an A (for seeing it coming and its positioning at week’s end) and a D (timing and intensity issues) with a C grade for this area.

Wow, what a complicated evaluation. I totally didn’t see Invest 92L becoming Shary between Bermuda and the Virgin Islands. I did accurately predict no 90L development, and something at week’s end in the Caribbean. But the Caribbean development’s timing was also off. Overall, the Tomas portion of the forecast was the most significant by far, and this week will be weighted on there (the name of the storm itself doesn’t matter as much in my opinion here, only shows I messed up somewhere else). This is appropriate, as the Shary failure and the successes of Richard’s dissipation and no 90L development can probably offset each other. Therefore, I give myself a C for this past week.

A new month is dawning, maybe we can finally get back on the right foot with straight A’s and B’s again. Here we go…

Current situation and analysis

Tomas has been downgraded from a hurricane to a tropical storm in the eastern Caribbean. A combination of moderate to high wind shear and dry air has caused this to happen. This situation should continue for another day or two before letting up, potentially allowing Tomas to intensify. But by Friday, Tomas could also reach the mountainous Hispaniola. Models all tend to agree on a slow westward track at first. It will then be followed by a northward turn toward Hispaniola with the storm reaching that island around Friday or Saturday. The intensity will be very tricky to nail yet again. The NHC is currently forecasting the intensity to be on the high end of the guidance, calling for a C2 hurricane with 105-mph maximum sustained winds at landfall. But many other models call for more of a C1 hurricane, with maximum sustained winds of 75-85 mph before reaching the island. With Hispaniola as mountainous as it is, Tomas should be shredded to pieces as it continues northward, maybe even dissipating.

Nothing else seems to be noteworthy for this upcoming week in terms of development, or at least nobody is talking about it anyway.

Recent history

Looking at Tomas first, these storms were previously still intact coming into the month of November since 1995:

Tanya in 1995
Mitch in 1998
Katrina in 1999
Michelle in 2001
Noel in 2007

That’s only five storms, and two of them, Tanya and Katrina, would go out on November 1. That leaves really only three reliable storms to look at. Mitch was doing its damage in Central America at first, and would then re-curve into the Gulf of Mexico and strike Florida as a middling tropical storm before becoming extratropical. Noel was also out of position in regards to Tomas, being in the Bahamas and re-curving north and northeastward. I skipped Michelle though…because at least she was in the Caribbean and developing, similar to Tomas. Yes, she was much further west, but also became a significant C4 hurricane before reaching Cuba during the upcoming week. Michelle also re-curved rather sharply northeast after a very slow northward motion at first, allowing it to reach the Bahamas and miss Florida altogether.

When looking for new developments since 1995, the following have occurred in the first week of November:

Noel in 2001
Paloma in 2008
Ida in 2009

Wow, only three new developments. Two of the were, like Michelle, in the western Caribbean. Only Noel formed elsewhere, well out over open waters in the Atlantic. All three also became hurricanes, with Paloma being the only “major” hurricane. That said, Ida might have pulled that off if 2009 was not an El Nino year, as she became a C2 storm.

So what does this all tell us?

The tropics are winding down and it’s no secret. The Caribbean is the most likely place for anything to happen in the first week of November. Even in a year like 2010 has been, it is still only fitting that the one active storm coming into the new month is in the Caribbean, albeit in the eastern part for a change. Being in that area also suggests Tomas could very well re-strengthen before reaching Hispaniola, and then re-curve north and northeast.

There is still the issue of any other developments elsewhere, but the Caribbean is still the only real likely area. With Tomas already there, anything that would develop would be following closely in its footsteps, ala what I’ve said about Earl following Danielle, and Fiona following Earl. Anything that happens is likely to be weak, despite what new developments say since 1995.

Back to looking ahead

November is starting out fairly clear-cut. The prediction for Tomas will include a generally easy track forecast and very difficult intensity forecast. Confidence on this forecast will therefore be given different levels for each category. Therefore, I will first start with the track: I predict Tomas will continue very slowly westward until about late Wednesday night, when a west-northwest to northwest turn will take place. On Thursday night, a rather abrupt northward turn will commence, and Tomas will make landfall in western Haiti on Friday afternoon. From there, Tomas will re-curve north-northeast and northeast into the Atlantic, continuing on that path until dissipation (see below). Confidence is 75%.

As for Tomas’s intensity, quite a bit tougher, but here we go: I predict Tomas’s weakening trend will continue, but slow down gradually later on Monday. The unfavorable conditions will subside by Wednesday, and by then Tomas will have maximum sustained winds of 50-60 mph. Tomas will be a bit slow to organize at first after that, but still re-organize into a hurricane on Thursday night. It will then organize a bit faster, and landfall will occur as a C1 hurricane, but at the high end with maximum sustained winds of 85-90 mph. Rapid weakening will ensue upon reaching Hispaniola’s high peaks, and by the time Tomas reaches the Atlantic, it will be a badly shredded tropical storm with maximum sustained winds of 40-50 mph. From there, Tomas will head into waters churned by Otto and Shary and dissipate by Sunday. Confidence is 45%.

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

Lastly, I need to urge again that everyone in the path of Tomas do not take this prediction as an official forecast or to use it to make life-and-death decisions. Listen to the National Hurricane Center and your local authorities and what to do if this potentially dangerous storm threatens your area. I also have had a very rough October on these weekly predictions, and errors are subject to be large even on a forecast that appears clearly laid out on the surface. Thank you.

-Andrew92

[Migle]

Not bad at all Andrew. Alot better than the rough October that you had.

[Andrew92]

Thank you Migle, this was indeed a much better week! In fact, with Tomas now gone and nothing else about to develop, let's go ahead and evaluate.

After such a rough October, I’m screaming it out loud: FINALLY I had a very good week! The Tomas forecast was split into two camps, the track and intensity, and both were very well executed for the most part. Along with that, I predicted no other developments, and indeed that was the case, so that area gets an A.

Let’s start by evaluating the track of Tomas. I predicted a slow, westward track until Wednesday night, followed by a turn northward on Thursday towards Haiti. That is exactly what happened in the first three days of this past week. I did also call for a landfall in Haiti, and fortunately for the people stricken by the earthquake and a cholera breakout, that itself was avoided. However, the storm passed close enough that it could probably still count as being a strike. After that, I predicted an out-to-sea track to the north-northeast and northeast. Apart from passing through the southern Bahamas, that was also executed well. Overall, there were only some minor discrepancies in terms of the track. My grade for this portion of Tomas is an A-.

The intensity forecast was looking problematic on the surface, as I gave myself a 45% confidence for that portion. I called for an initial slowing to the early weakening trend, which did happen. However, I also predicted the storm would hold intensity of 50-60 mph maximum sustained winds by Wednesday, and it dropped to a tropical depression instead. That said, I predicted it would re-intensify to a hurricane by Thursday night. That actually happened a little after midnight, but timing being off only a few hours is not a bad thing at all, especially after this past month of roughness. I also was accurate on the intensity for when it hit Haiti, as I called for a high-end C1 hurricane, with maximum sustained winds of 85-90 mph, and it hit 85 as it passed to the west. However, the lack of landfall affected the last part of the intensity forecast. I do hold that a landfall would probably have shredded it bad enough to be a minimal tropical storm, but it didn’t do that. Instead, by staying offshore, it was able to hold its own as a fluctuating hurricane until it became extratropical on Sunday. I did predict dissipation on Sunday, though, and becoming extratropical may not be the same thing, but the last advisory was still written by the NHC. Overall, the real issues were the early weakening and the late part of the forecast. The crucial part was getting the Haiti part right, and that was executed probably as well as I could have. I give myself a B for the intensity portion of the Tomas forecast.

It does indeed all come back to Tomas this past week, and very good track forecast and a decent enough intensity forecast finally, FINALLY gave me a week I can pat myself on the back for. Couple with no other developments anywhere in the Atlantic, which was accurately predicted, I give myself an A- for the week. I was also among those who prayed for the people in Haiti, and am very thankful to God that, so far, the damage to Haiti from Hurricane Tomas has been much less than feared, and pray that that continues to be the case as time goes on.

November 8-14 in just a little bit.

-Andrew92