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kold weather

Hurricane Tutorial

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Right well finally had a little bit of time, and inspired by Nick F's excellent storm thread, I've both changed and added a few things, not quite done as there is more to add yet!

1: Added more about storm surge.

2: Epsilon and Annular systems.

3: Pinhole eyes and Wilma.

4: Low topped hurricanes- Vince/Epsilon.

5: Hurricanes that stall over Ocean- Frances 2004.

6: Fujiwhara examples and pictures.

There is a little more to do yet, but general corrections and things i wanted to add today has been done.

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Very good.

Further exploring detrimental conditions for hurricane formation might be usefull.

Perhaps explaining shear in relation to the jet stream with strong jetstreams across a region giving unfavourable conditions for hurricanes. You could also explore the QBO direction and explain that east phase means slower jet streams and shear. You could also explore the AMO and particularly how el nino and la nina affect hurricane formation.

Some hurricanes have supercells embedded and this is the reason why recently Florida has has more Tornadoes recorded per square mile than Tornado alley. These tend to form in a particular quadrant of the hurricane but I forget where.

Quite often hurricanes start as a group of thunderstorms which are triggered by a short wave coming off the coast of Africa. The interval between these waves directly reflects conditions across Africa and perhaps this is something to be explored.

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Hi BrickFielder, thanks for those suggestions.

1: Jetstreams/detrimental conditions, I'm gonig to do a little section on why hurricanes don't form in winter and include it in there, and that was gonig to be part of it, so thats going to put in it during the next update. I'll also probably add about El Nino and La Nina (Also AMO and maybe a little about the monsonal trough)

2: Totally forgot about the tornadoes, thats a must do!

They usually form in the RFQ (right front quadrant of the storms, thats determined by its foward direction.)

3: Yeah thats sounds like a pretty cool idea as well.

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Very good Kold. You said in there that 2005 had 26 named storms, i think it was 27, according to Wikipedia. Also something interesting on there i found just now was that a Subtropical storm had gone unoticed. Looks like it was going on at the same time as Stan. It was shortlived (Oct 4-Oct 5) and absorbed by the low that developed into Vince. So technically it should have been Subtropical Storm Tammy, but it's listed as Unnamed. It had 50mph winds and pressure of 997mb. Looks like it was an East Atlantic one given by the map.

Also, what would a subtropical storm be called if it reached Hurricane strength?

Edited by Paranoid

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absorbed by the low that developed into Vince

So that is what gave Hurricane Vince the injection of energy needed to form so north and east.

If i recall corectly, we did have a Tammy.

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Paranoid, I haven't got a clue what a sub-tropical storm would be called if by some chance it reached hurricane strength, they might put a number at the end of it to represent how strong it is in terms of category, but I certainly don't know of when a sub-tropical system has gotten strong enough for this to occur.

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Paranoid, I haven't got a clue what a sub-tropical storm would be called if by some chance it reached hurricane strength, they might put a number at the end of it to represent how strong it is in terms of category,

It would still be a STS I guess as the SS scale only applies to TCs.

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Hi BrickFielder, thanks for those suggestions.

1: Jetstreams/detrimental conditions, I'm gonig to do a little section on why hurricanes don't form in winter and include it in there, and that was gonig to be part of it, so thats going to put in it during the next update. I'll also probably add about El Nino and La Nina (Also AMO and maybe a little about the monsonal trough)

2: Totally forgot about the tornadoes, thats a must do!

They usually form in the RFQ (right front quadrant of the storms, thats determined by its foward direction.)

3: Yeah thats sounds like a pretty cool idea as well.

Kold Weather, when will you be making your update???

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What happens if a hurricane crosses really unusualy hot sea? I think this is what happened last year in the Gulf of mexico, but dont quote me on that (really, dont).

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Right I've made a few small changes but there will be more coming, more stuff to add in that I haven't added in yet as well as some facts such as record seasons, ACE and how its calculated, record low pressures, all cat-5's with a little info on them...in the end hopefully everything you could need will be ina sngle post...thats the idea anyway!

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I have a questionPosted Image

Why tropical cyclones on southern hemisphere became extratropical on lower latidudes?Example:Tropical cyclone Atu(Feb 2011)became extratropical on 31.4 south and Tropical Storm Grace(Oct 2009)formed on 41.2 north?Grace wasn't in Gulf Stream.Posted Image

Edited by Wobbuffet

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yeah sorry mate,

my only answer to this and im sure someone will come along with a better one.

is that they have different ways of naming the same thing in northern and southern Hemisphere

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I have a questionPosted Image

Why tropical cyclones on southern hemisphere became extratropical on lower latidudes?Example:Tropical cyclone Atu(Feb 2011)became extratropical on 31.4 south and Tropical Storm Grace(Oct 2009)formed on 41.2 north?Grace wasn't in Gulf Stream.Posted Image

Its simple a case that the S.Hemisphere has the Anartic and so the jets tend to run further south. Its not reall justy water temps that turns a system extra-tropical (though for sure they it does play a big role 99% of the time) but the combo of both the interaction with the jet which helps to promote fronts (primary tell-tale sign of an ET system developing) and the cooler water leading to increasingly shallow convective tops. In the S.Hemisphere that tends to happen closer to the equater simply because the arctic zone is so much bigger in the S.Hemisphere.

As for Grace, its all about the thermal differences between various layers of the atmosphere.

For example, you can have SSTs of 26C and upper temps of say -20C and you'll get a TC (I'm not sure of the exact figures off the top of my head!)

Then you could have waters of say 18C with upper temps of -28C and you'll have the same lapse rates. The convection will be more shallow but the system would still be warm cored.

Systems such as Grace and Vince, etc that started life as a cold cored system can become warm cored if the atmosphere is cold enough to balance out the cooler SSTs...thats why you nearly always see those sorts of systems in the Ne Atlantic in October/November, because the upper temps are that bit colder by then and its enough to balance it out.

Of course eventually if the SSt's and upper temps get too cold you get a totally different beast, the polar low!

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Thanks for professional and excellent answer!

But,is that possible?Subtropical storm frming south of Madagascar on 32 south and becoming extratropical on 36 south?

Edited by Wobbuffet

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What is the highest altitude - elevation that the eye of a cyclone (hurricane - typhoon) has reached? 100 m ASL? 500 m ASL? 1000 m? These wikipedia records did not help me:

http://en.wikipedia.org/wiki/List_of_Atlantic_hurricane_records

http://en.wikipedia.org/wiki/List_of_tropical_cyclone_records

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What is the highest altitude - elevation that the eye of a cyclone (hurricane - typhoon) has reached? 100 m ASL? 500 m ASL? 1000 m? These wikipedia records did not help me:

http://en.wikipedia.org/wiki/List_of_Atlantic_hurricane_records

http://en.wikipedia.org/wiki/List_of_tropical_cyclone_records

 

Good question, and one that isn't easily answerable when looking at normal satellite pictures. To give a rough estimate, a vertical cross-section of the temperature of Haiyan (2014) near peak intensity can be seen below:

 

Posted Image

 

What can be seen on the image above is the temperature anomaly of the storm system compared with the surrounding environment. On the x-axis, the longitude is given, while on the y-axis, the pressure levels are given (a measure for height). The deviation on the average temperature is indicated by colors.

 

Usually, the temperature in the eye of a tropical cyclone is much higher compared to its surrounding environment, due to the fact that air that rises in the core convection cools saturated adiabatically (to keep it simple, when air is rising, the cooling of dry air goes quicker than saturated air, because in saturated air heat is released during condensation when the air is lifted). In the eye, the air warms dry adiabatically during sinking (efficient warming), which provides a strong positive anomaly in temperature compared to its surroundings.

 

The temperature cross-section shows sharp positive anomalies extending through the 100 hPa level, which is usually the level of the Stratosphere. An approximation for the height of this 100 hPa level using the barometric height formula yields a height of 23 km (with an average temperature used of 263 K). 

 

Concluding, the maximum height of an eye of a tropical cyclone must be at least 23 km, possibly even higher. Because the cross-section doesn't extend up to more than 100 hPa, it is impossible to see to which altitiude the eye was actually present.

 

I hope this helps a little in answering the question.

 

Sources:

http://burro.cwru.edu/Academics/Astr221/SolarSys/earthatmos.html

http://www.wunderground.com/blog/24hourprof/final-thoughts-on-supertyphoon-haiyan

Edited by Vorticity0123

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Really lovely graph here, demonstrating the propensity of warmer SSTs to generate stronger storms... while also showing sufficient variability to demonstrate the significance/impact of vertical wind shear, the amount of water vapour in the air, and various other influences on hurricane development (or, as it were, non-development)
 

 

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