Another 'above-normal' hurricane season forecast for the Atlantic

[zboss]

Originally Posted by valhalla360

This is like saying our prediction of who will win next weeks game will be more accurate late in the 4th quarter. Of course it will be more accurate because you will know what the score was in the first 3 quarters.

In terms of pre-season predictions it's little more than a wild guess and they skew the results to predict more storms.

Of course it is - but that isn't bad is it?

[Jim Cate]

Hmmm.... If there are a long series of "below average" years, seems that the average will go down and these conditions will then BE average.

But really, even if you knew for sure that there would be more storms than usual, how would that modify your behavior? I thought that most folks in cyclone areas didn't do much until a storm actually threatened to strike their area, and then go into protective mode whatever that is for them. If this is true, then these predictions don't mean much to individual sailors no matter how good they are.

Jim

[valhalla360]

Originally Posted by zboss

Of course it is - but that isn't bad is it?

It's not bad to update predictions as you go thru the season. All the models do it.

It's bad to imply more accuracy in the pre-season prediction as a result of this process.

[StuM]

Originally Posted by Jim Cate

Hmmm.... If there are a long series of "below average" years, seems that the average will go down and these conditions will then BE average.

Depends on what you mean by "average". In meteorology, the WMO standard for "climate normal" is "the last three complete decades". This convention is adopted by almost all national agencies.

So the current "climate normal" is probably based on the period 1981-2010. In which case, even if the last six years were all well below average, that would have no effect on "average".

However, there is also another WMO convention that uses fixed 30 years period, the last one of which is still 1961-1990. If they are using that "average", then it doesn't matter what has happened over the last 27 years.

[Jim Cate]

Originally Posted by StuM

Depends on what you mean by "average". In meteorology, the WMO standard for "climate normal" is "the last three complete decades". This convention is adopted by almost all national agencies.

So the current "climate normal" is probably based on the period 1981-2010. In which case, even if the last six years were all well below average, that would have no effect on "average".

However, there is also another WMO convention that uses fixed 30 years period, the last one of which is still 1961-1990. If they are using that "average", then it doesn't matter what has happened over the last 27 years.

Interesting, Stu, I didn't know any of that. I'm struck by the thought that folks in general seem to believe that we are in an era of rapid change in atmospheric conditions. Using a fixed period of historical data as a metric under these conditions will lead to many such "above (or below) average) stipulations. Doesn't seem very meaningful!

Jim

[HopCar]

If you want to play with the average number of storms, here is the info you need going back over a hundred years. 2016 had 15 named Atlantic storms.

TCFAQ E11) How many tropical cyclones have there been each year in them

I don't pay any attention to how many named storms are predicted. They always are wrong. I only care if it's coming at me. They are getting better at predicting the path of storms.

The Cone of Death has gone from three days to five and gotten narrower. That's useful information.

[capt-couillon]

Oh No..... We're all gonna die.

[estarzinger]

another 'problem' with the data series and the "average" is that the measurement technology has changed/improved dramatically. We are now much better at seeing/identifying storms at sea than we used to, so the count goes up irrespective-of/on-top-of the real underling trend.

[Mike OReilly]

Originally Posted by Jim Cate

Interesting, Stu, I didn't know any of that. I'm struck by the thought that folks in general seem to believe that we are in an era of rapid change in atmospheric conditions. Using a fixed period of historical data as a metric under these conditions will lead to many such "above (or below) average) stipulations. Doesn't seem very meaningful!

I’ve posed this conundrum here in the past (and been soundly dumped on by the large anti climate change crowd that seems to inhabit CF). Those of us who traverse big waters rely on historic weather patterns to decide when it is safe to go, and when it is time to hunker down.

These patterns are developed from historic data collectives over decades or even centuries. But in a time of rapid climate change, how are we to view traditional passage routes and pilot charts?

At least (and as you say HopCar), our short-term forecasts have improved significantly. This gives me some comfort as I plan to head off soon.

[StuM]

Originally Posted by Mike OReilly

I’ve posed this conundrum here in the past (and been soundly dumped on by the large anti climate change crowd that seems to inhabit CF).

That can't have been me,then.

I'm certainly not "anti climate change". I'm all in favour of it if it changes to warmer. A bit more warmth would be great for most of the planet.

[Mike OReilly]

Originally Posted by StuM

That can't have been me,then.

I'm certainly not "anti climate change". I'm all in favour of it if it changes to warmer. A bit more warmth would be great for most of the planet.

Can’t say if you ever been a dumper Stu (I tend not to pay much attention to folks who actively ignore reality), but in response to your conclusion, let me just quote a current US President: WRONG!

[Pelagic]

Originally Posted by Jim Cate

Hmmm.... .

But really, even if you knew for sure that there would be more storms than usual, how would that modify your behavior? I thought that most folks in cyclone areas didn't do much until a storm actually threatened to strike their area, and then go into protective mode whatever that is for them. If this is true, then these predictions don't mean much to individual sailors no matter how good they are.

Jim

Hi Jim,
It actually does affect my behavior a bit as I live in an active Typhoon zone.

If projections are for above average that year.... then when I see one Typhoon forming, I am anticipating a 2nd or 3rd forming behind (Just like a family of Lows in higher Lattitudes).

This means that I don't stray too far from the best shelters in those years, when you get those post storm periods of fine weather..