What will the hurricane season be like this year?

[bascule]

The hurricane season is underway and we're in the middle of what's shaping up to be the worst heat wave on record. What do you think the hurricane season will be like?

[D H]

The poll asked how this year would compare to last, which was a doozy and then some. I doubt we will fare worse than that. My answer would have been different had you asked for a comparison with the average year.

 

NOAA predicts 13-16 named Atlantic storms this year, far above average but far fewer than last year's 27 named storms. Colorado State predicts 17 named storms this year.

 

A heat wave far north of the tropics won't contribute much to hurricane intensity. Don't fall into the false premise that just because it is hot where you live that it is hot everywhere. The Gulf coast, for example, has been mild this summer. (Mild by Gulf coast standards, that is. You Yankees would still die of heat exhaustion.)

[oatjay]

i think it'll still be an above average year, but nowhere near the level of last year. a year ago today, tropical storm gert formed in the bay of campeche..that was the 7th named storm of the season. we've only had 2 so far this year. things will likely pick up in a little while, but last year was a little crazy.

[SkepticLance]

bascule.

Come clean and tell us what you are getting at.

I know you are smart enough to realise that this is unpredictable.

[herpguy]

Seeing how there have only been two tropical storms so far, and last year there were a few hurricanes by now, I'm guessing it won't be as bad. The water is also cooler, and warm water is the key to hurricane strength.

 

So, I think it will be an above average season (we are at the pinnacle of a cycle, and there's global warming), but not quite as bad as last year.

[herpguy]

bascule.

Come clean and tell us what you are getting at.

I know you are smart enough to realise that this is unpredictable.

 

Erm...

 

SkepticLance, you are far too skeptical, and that's not good. We know enough to tell us that this will be an above-average season.

 

Edit: Sorry about the double-post if that's a problem. I totally missed SkepticLance's post.

[JustStuit]

I don't think we will have as many, but I think it could be worse. Living in Florida, I want to point out there is a HUGE difference between quantity and quality in the case of hurricanes. Judging the season by the number of storms is not accurate.

Last year in Florida we had a lot of tropical storms, but we just stayed in the house and wait them out. It wasn't that bad for us (Katrina didn't hit us that bad.) The year before that we had 4 major ones hit near us (I think) and it was bad.

I'll try to take pictures and videos when we have them (safely inside or during an eye if we have one again) if you guys want. Hopefully I won't lose power for two weeks again.

[herpguy]

I don't think we will have as many' date=' but I think it could be worse. Living in Florida, I want to point out there is a HUGE difference between quantity and quality in the case of hurricanes. Judging the season by the number of storms is not accurate.

Last year in Florida we had a lot of tropical storms, but we just stayed in the house and wait them out. It wasn't that bad for us (Katrina didn't hit us that bad.) The year before that we had 4 major ones hit near us (I think) and it was bad.[/quote']

I heard somewhere that there could be an extremely large "supercyclone" instead of a bunch of smaller storms. I don't really understand the theory, though. If I find anything on it, I'll post it.

 

I'll try to take pictures and videos when we have them (safely inside or during an eye if we have one again) if you guys want. Hopefully I won't lose power for two weeks again.

That would be nice.

[DrCloud]

I heard somewhere that there could be an extremely large "supercyclone" instead of a bunch of smaller storms.

 

I seem to remember reading about such a thing in one of Clive Cussler's "Dirk Pitt" adventure/action novels. It gave me a good laugh. HPH

[SkepticLance]

As I have pointed out elsewhere, high temperatures alone are not the trigger for hurricanes. What is needed is a high temperature differential. Typically, a warm patch of ocean surrounded by cooler waters. Air moves from cool to warm and starts rotating. It is the temperature DIFFERENCE that drives the storm.

 

The stormiest place on Earth is Antarctica, which shows just how little high temperatures are needed. The stormiest time on record (British Admiralty records) was in the Little Ice Age, when a series of North Atlantic gales buffeted the British Isles.

 

The point I am making is that simply having a warm summer does not necessarily mean lots of powerful hurricanes.

[herpguy]

Hurricanes are obviously far more complex than that. This quote gives the general idea of how they form. Just do a google search for more.

 

"Hurricane" is the term used to describe the strongest of the windy, circulating storms –- or cyclones – in the Atlantic and eastern Pacific oceans; in the western Pacific these kinds of storms are referred to as typhoons. Most Atlantic hurricanes are born in the southern Atlantic Ocean, off the coast of Africa, in the months of June through November each year.

 

During this time, winds off the west coast of Africa sometimes converge, circulating counterclockwise. Often, these winds maintain a low speed and travel across the Atlantic Ocean as tropical waves, causing little more than rainfall on land masses they strike.

 

At other times, when water temperatures are warm enough and atmospheric conditions are correct, the wind speeds increase and begin to form around a center, or eye. Hot, moist air from the ocean is pulled up into the eye of the storm, which is now called a tropical storm. As the air rises and cools, moisture condenses and is released as heavy rain into the torrential winds circling the eye. The released energy is pumped into the rotating cloud mass, making it rise and spin even faster. By the time the winds reach speeds of 119 kmph (74 mph), the storm has become a hurricane.

 

http://www.lacoast.gov/education/willfulwinds/how.htm

[SkepticLance]

Herpguy

Hurricanes are indeed complex.

However, the basics are simple. A large mass of warm water, surrounded by cooler water, leads to a flow of air inwards, which due to coriolus influence, spins. If temperature differential is enough, we get a storm.

 

High temperatures alone are not enough. We need high temperature differentials. This does not come from recent history.

[DrCloud]

Sorry, Lance, you don't know what you're talking about. "Surrounded by cooler water" has nothing to do with it. And comparing hurricanes with mid-latitude and polar cyclones shows how far from the real world your thought processes are.

 

I suggest you go out and get yourself a solid meteorology textbook (Wallace and Hobbs comes to mind) and do some serious reading. But be prepared for differential equations. HPH

[SkepticLance]

OK DrCloud. I was over-simplifying.

The main point still remains. High temperature is not the cause of hurricanes. High temperature differentials are.

[DrCloud]

Wrong again, sport. Where's your evidence? Got data? Got theory? Got anything? You can make all the authoritative-sounding assertions you want, but without substantive, credible source material, you're just blowing smoke.

 

"High temperature differentials" (whatever you may mean by that -- it's certainly not the terminology that either meteorologists or oceanographers use) have little to do with hurricane formation or intensification.

 

What does have to do with those things are high temperatures, along with a variety of other factors such as the vertical and horizontal wind shear and the overall pressure pattern -- whether it's causing general lifting or sinking.

 

The jury is still out about whether there are real trends in hurricane activity (yesterday, another brief paper was published arguing that the data in the 70s and 80s are just not good enough to use for this type of analysis, for example -- a good point). It's an interesting discussion to follow, a discussion being conducted by people who are making entire careers out of studying this.

 

Interestingly, everyone involved in the discussion -- both sides -- recently put out a statement to the effect that it really doesn't matter what hurricanes are doing. What does matter, they say, is US government policy that, in effect, subsidizes people who choose to build in hurricane-prone areas. This subsidy (whatever the economic effect) puts people in harms way, and this is the real problem. So these folks are trying to figure out an interesting scientific puzzle, but they are working together on what really matters -- saving lives. HPH

[SkepticLance]

DrCloud

Your comments are leading me to believe of you exactly what you accused me of - ignorance.

 

It is really, really basic.

 

Air movements in the atmosphere, including that which leads to hurricanes, begins with warmer air rising, and cooler air coming in to take its place. For this to happen there needs to be a site which is warmer than another site. A temperature differential. This is as true for Antarctic storms as tropical hurricanes. Sure, the detailed mechanism is different, but the basics are the same.

[bascule]

bascule.

Come clean and tell us what you are getting at.

I know you are smart enough to realise that this is unpredictable.

 

That's... why the poll is phrased in the form of a question.

 

As I have pointed out elsewhere' date=' high temperatures alone are not the trigger for hurricanes. What is needed is a high temperature differential. Typically, a warm patch of ocean surrounded by cooler waters. Air moves from cool to warm and starts rotating. It is the temperature DIFFERENCE that drives the storm.[/quote']

 

Wow, you demonstrated some basic atmospheric science knowledge. Congratulations!

 

And hey, someone, who will remain nameless, mentioned all that before, and gave substantially more information about the formation of intense hurricanes. Hmmm...

 

The stormiest place on Earth is Antarctica, which shows just how little high temperatures are needed. The stormiest time on record (British Admiralty records) was in the Little Ice Age, when a series of North Atlantic gales buffeted the British Isles.

 

That'd be a red herring, if this thread were anything more than idle speculation...

 

The point I am making is that simply having a warm summer does not necessarily mean lots of powerful hurricanes.

 

Cool. Want a cookie?

 

Hurricanes are indeed complex.

However, the basics are simple. A large mass of warm water, surrounded by cooler water, leads to a flow of air inwards, which due to coriolus influence, spins. If temperature differential is enough, we get a storm.

 

Sorry, you just forfeited your cookie... maybe you ought to click the unnamed person's link and educate yourself about hurricanes a bit more

[DrCloud]

Lance, I'm sorry, man, but you're just not getting it.

 

There's more, at a very fundamental level, to both tropical cyclones (of which hurricanes are a regional [Atlantic] manifestation) and mid-latitude/polar cyclones than simply hot air rising and cool air flowing in to replace it. If hot air rising and cool air flowing in were the only thing happening, there would be no cyclones, just thunderstorms.

 

Further, it's simply not true that rising air always forms over the hottest water, even locally. You can make this happen in simple, controlled laboratory experiments (heated pans of water, say, with extra-hot spots on their bottoms), but in the real world other dynamical factors enter in. In particular, the role of convergences set up in a quasi-random fashion due to the interactions in three-dimensional turbulence is critical to the location of updrafts.

 

(Yes: I used the word "random". There's lots of it out there in the world. It's one reason that the specific location of a given thunderstorm tomorrow or the next day is unpredictable. It's not that we're not smart enough to predict it; it's just flat-out unpredictable. If you want to know how climate change is "predicted", let me know in such a way that you persuade me that you're really interested and not just wanting to bicker. I'm happy to educate people, but I'm not going to fall for debate tricks or the absurd "designated skeptic" role you've contrived for yourself.)

 

You're the one who's asserting a particular phenomenon as the cause of something this time, so it's your responsibility to provide evidence to back up your assertion -- evidence that's credible. And, with all due respect, your own personal common sense and self-ascribed authority don't count. I've already given you a nice hint in the form of a text book. Like I said, I think some serious reading is in order. HPH

[SkepticLance]

DrCloud

You have taken my statements way beyond anything they were intended for. The single point I was making, as even bascule admits to be true, was that it is temperature differential rather than absolute temperature that is important. Fullstop.

 

This was not an essay on the mechanics of hurricance formation.

[DrCloud]

...it is temperature differential rather than absolute temperature that is important.

 

And what I've been saying, over and over, is that it's not. You're wrong. Further, you haven't provided any evidence to support your assertion (bascule's "admission" hardly constitutes evidence).

 

I'll be off-line for some time now due to a travel commitment, so you'll have the chance to play with yourself in public and mislead these other folks into believing whatever they'll swallow without my interference. Have fun. HPH

[SkepticLance]

DrCloud.

The origin of hurricanes is linked to the convergence of surface winds that move from cooler and higher latitidues to warmer and lower latitides. These winds are driven by solar energy due to (wait for it) a major temperature differential between colder and warmer air masses. Without that air temperature differential, the surface winds that converge and trigger hurricanes could not exist.

 

Sure, the later development of the hurricane is more due to release of latent heat of condensation from rain droplet formation, driving an amazing heat engine. However, the start requires surface winds formed from temperature differentials.

[herpguy]

Sure, the later development of the hurricane is more due to release of latent heat of condensation from rain droplet formation, driving an amazing heat engine. However, the start requires surface winds formed from temperature differentials.

There, you are finally mostly correct. Now what was this thread about, again?

[SkepticLance]

herpguy

The original question was what will the hurricane season be like?

 

To me, this relates to the formation of hurricanes, and how many form. In other words, we need to look at the origins of hurricanes, and this relates to surface winds driven by temperature differentials. The later mechanisms which drive a hurricane seem to me to be less relevent to the question.

[Cyberman]

As far as I know there is no real way to forecast something as complex and broad as a whole "hurricane season" with any certainty. Barring some sort of crystal ball . . . .

[DrCloud]

I've been trying to understand where the communication gap is in all this, and perhaps it's related to the following.

 

At the most basic level, the general circulation of the atmosphere (as large-scale global wind patterns are known) is driven by the differential solar heating between the tropics and the polar regions. This heating differential sets up a latitudinal temperature gradient that is strong enough that, in combination with gravity and Earth's rotation, hydrodynamic instabilities in the atmosphere occur, resulting in winds. So all of the winds, from the jet stream to the trade winds, owe their existence to temperature gradients in a basic sense. But ascribing the "cause" or hurricanes to this really doesn't lend any insight to the problem of the topic of the thread.

 

Hurricanes are tropical storms that reach a certain strength; tropical storms, in turn, are tropical depressions that get strong enough to be called storms; so the root cause of hurricanes is formation of depressions. There's also the issue of how many depressions turn into storms, and the thread implicitly deals with both of these.

 

But neither of these is directly related to temperature gradients, beyond the fact that the trade winds themselves, as part of the general circulation of the atmosphere, are the result of the differential heating between the tropics and the polar regions.

 

Depressions form via (positive) feedback mechanisms that amplify small disturbances in the trade winds (and, generally, these disturbance don't have any relationship to temperature gradients). The feedback involves evaporation from the ocean, rotation, and heating by condensation in clouds. Depressions strengthen into storms and then hurricanes if conditions are such that nothing interrupts this positive feedback process. Changes of wind speed and/or direction with height, for example, tend to slice off the tops of clouds before they can grow deep enough to turn into really violent thunderstorms, which would keep the depression growing. Or movement of the depression over cooler water tends to shut off -- or slow down -- the supply of water vapor from surface evaporation.

 

So the real issue with hurricanes and global warming has less to do with temperature gradients directly than it does with these other factors as well as the overall response of the atmosphere to warmer ocean temperatures. And all this is a topic of study among the folks who do this for a living. The best way to keep up with current thinking is to follow the literature and be patient, because the point-counterpoint of the technical discussion is ongoing.

 

The latest salvo was in Science last Friday, when one of the "natural cycles" advocates pointed out that recent papers claiming an increase in big storms in the past few years relied on (possibly) biased data. This won't be fully resolved until that data is re-analyzed using up-to-date methods, which is undoubtedly in progress. So, as I've said before, stay tuned. HPH