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Major Hurricane Irma

NJwx85

By NJwx85,
in Tropical Headquarters

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skierinvermont

skierinvermont

Posted
Posted
33 minutes ago, LibertyBell said:

I saw someone saying earlier that models are better than human beings (or vice versa) and I don't think either is better than the other.  Models don't have some magical knowledge from some advanced alien species that we don't know about.  All they are is a combo of the data we feed into them plus our knowledge of atmospheric physics- both of which are far from perfect.  So if the models are wrong, that is just a reflection of our lack of complete knowledge.  They can by definition neither be better than us or worse than us, since they are an artificial construct.

 

Like the other poster said, this models are confused or wrong or humans are better nonsense needs to stop. 

Of course models are better than humans. No human can look at a real-time 500mb map or any combination of atmospheric parameters and make a 5+ day prediction about the weather any where close to as accurately as a computer model. They had accurate data in the 1970s and 1980s but they didn't even issue 5 day forecasts for hurricanes until 2003. And the track error today is less half what it was in the 1990s. It's not because humans were stupid in the 1990s or a lack of information. It's because no human can come even come close to a computer model for predicting the weather. Humans weren't even as good as computers in the 1990s. And models today are far better than the 1990s. Any human prediction today is almost entirely based upon model output.

Which is why the NHC basically copies the model consensus for hurricane track. And insofar as the NHC track slightly differs from the model consensus track, the model consensus track usually wins.

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LibertyBell

LibertyBell

Posted
Posted
3 minutes ago, skierinvermont said:

Of course models are better than humans. No human can look at a real-time 500mb map or any combination of atmospheric parameters and make a 5+ day prediction about the weather any where close to as accurately as a computer model. They had accurate data in the 1970s and 1980s but they didn't even issue 5 day forecasts for hurricanes until 2003. And the track error today is less half what it was in the 1990s. It's not because humans were stupid in the 1990s or a lack of information. It's because of no human can come even come close to a computer model for predicting the weather. Humans weren't even as good as computers in the 1990s. Any human prediction today is almost entirely based upon model output.

Which is why the NHC basically copies the model consensus for hurricane track. And insofar as the NHC track slightly differs from the model consensus track, the model consensus track usually wins.

I mean machine logic is faster than human beings sure, but the knowledge that is fed into the machine comes directly from our knowledge of atmospheric physics and our data.  What I was trying to say is you can't blame the model for it being "wrong"- what it outputs is directly related to what we know of the atmosphere and the data we feed into it.

Completely agree about models being much better than they were in the 80s and 90s, and that's a direct result of us improving them through gaining better knowledge of atmospheric physics.

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skierinvermont

skierinvermont

Posted
Posted
7 minutes ago, LibertyBell said:

I mean machine logic is faster than human beings sure, but the knowledge that is fed into the machine comes directly from our knowledge of atmospheric physics and our data.  What I was trying to say is you can't blame the model for it being "wrong"- what it outputs is directly related to what we know of the atmosphere and the data we feed into it.

OK I do get your point, the issue was more with a few of the other comments others have been making about models.  Models aren't some basic formula that can be reduced down to some basic human logic. They're millions of variables all interacting simultaneously according to complex mathematics. It would take 1,000 mathematicians doing computations 24 hours a day for a century to produce a 24hr forecast as accurately as a modern computer. Then it would take another 9 centuries to produce the 10 day forecast. And that's probably a massive understatement of their complexity.

Also from what I understand the bigger limiting factor for models in this day and age is the quality of the initialization data. 

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LibertyBell

LibertyBell

Posted
Posted
8 minutes ago, skierinvermont said:

Models aren't some basic formula that can be reduced down to some basic human logic. They're millions of variables all interacting simultaneously according to complex mathematics. It would take 1,000 mathematicians doing computations 24 hours a day for a century to produce a 24hr forecast as accurately as a modern computer.

Sure, that's why they must be run on supercomputers, what you described is actually atmospheric physics.  As we gain more knowledge of it, we improve the models further (and also being able to ingest more data through satellites, dropsondes, etc, than we could do 20-30 years ago because we're further into the space age and have better technology than we had back then.)  You're absolutely right that people weren't "dumber" in the 80s and 90s, but we did have less knowledge and not the level of technology we have today that makes the models so much better than they were back then.

But (as I'm sure you know) perfect forecasting will never be achieved (until the day that we are controlling the weather ourselves, that is) because what can be done is limited by chaos theory and random interactions (which, in addition to the possibility that our data might be slightly off, and both have a stronger influence at longer lead times,) is why we run ensembles and why they are more accurate at those longer lead times than operational runs.

 

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LibertyBell

LibertyBell

Posted
Posted
4 hours ago, MillvilleWx said:

You are not. Heading to Keys and will likely end up on western side of Southern FL. 

Question about this, the path up the western coast of FL- isn't that some of the warmest SST in the entire Atlantic Basin?  Every year when I look at SST I see that they are consistently the warmest in the eastern Gulf- usually in the upper 80s or even up near 90 degrees.

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olafminesaw

olafminesaw

Posted
Posted
3 minutes ago, LibertyBell said:

Question about this, the path up the western coast of FL- isn't that some of the warmest SST in the entire Atlantic Basin?  Every year when I look at SST I see that they are consistently the warmest in the eastern Gulf- usually in the upper 80s or even up near 90 degrees.

cdas-sflux_sst_watl_1.png mor

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MillvilleWx

MillvilleWx

Posted
Posted
2 minutes ago, LibertyBell said:

Question about this, the path up the western coast of FL- isn't that some of the warmest SST in the entire Atlantic Basin?  Every year when I look at SST I see that they are consistently the warmest in the eastern Gulf- usually in the upper 80s or even up near 90 degrees.

It usually is due to latitude and depth of the water off the west coast of FL. It's fairly shallow close to the shoreline and SST's will tend to run where you mentioned. The warmest in the Atlantic Basin reside around the Southern coast of Cuba, Jamaica and the western extension of the Bahamas towards the Florida Straits. Another warm pool sits right in the Florida Bay. All of these are where models take Irma and have high TCHP. Interestingly enough, TCHP is actually not as high directly along the West coast of FL, but still sufficient to maintain cyclone intensity. Once Irma crosses 70W towards the Turks and Caicos and southern Bahamas, she'll be in a ripe environment for strengthening with some of the highest TCHP in the basin (Highest is actually south of Cuba in the Western Caribbean).

 

tcheat_atl_2017.thumb.png.c7b2808d08805b9104338c94de17ea03.png

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LibertyBell

LibertyBell

Posted
Posted
7 minutes ago, MillvilleWx said:

It usually is due to latitude and depth of the water off the west coast of FL. It's fairly shallow close to the shoreline and SST's will tend to run where you mentioned. The warmest in the Atlantic Basin reside around the Southern coast of Cuba, Jamaica and the western extension of the Bahamas towards the Florida Straits. Another warm pool sits right in the Florida Bay. All of these are where models take Irma and have high TCHP. Interestingly enough, TCHP is actually not as high directly along the West coast of FL, but still sufficient to maintain cyclone intensity. Once Irma crosses 70W towards the Turks and Caicos and southern Bahamas, she'll be in a ripe environment for strengthening with some of the highest TCHP in the basin (Highest is actually south of Cuba in the Western Caribbean).

 

tcheat_atl_2017.thumb.png.c7b2808d08805b9104338c94de17ea03.png

Thanks for the indepth explanation. The area that you mentioned south of Cuba and near Jamaica- isn't that hurricane alley for Cat 5s- Gilbert, Ivan and Wilma were all Cat 5s in that area.  FL straights is where the (in)famous 1935 hurricane attained Cat 5 status.  And the SW coast of FL/eastern Gulf- there's an area there called "The Loop Current" where Katrina went south for a bit (maybe Rita too?), and I remember she rapidly intensified into a Cat 5 when she was in or near "The Loop Current."

 

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olafminesaw

olafminesaw

Posted
Posted
18 minutes ago, timnc910 said:

So with all the 0z models going way west of previous runs.. I'm taking it that the east cost is fairly safe from any impacts from Irma? If trends are the thing to watch you can't deny the trends that happened all day yesterday. . Can the models go back to showing it's going east of Florida and making lf on east coast this very unlikely at this point.. all focused goes to Florida and the gulf coast.. the east coast will be spared from this storm..

Sent from my SM-G900R4 using Tapatalk
 

 

All it takes is a slow trend back to the east to put the entire east coast under threat of impact. I'm not sure it's likely, but very possible.

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olafminesaw

olafminesaw

Posted
Posted
2 minutes ago, MillvilleWx said:

Interaction with shortwave over Lower Miss Valley taking place. Storm will come due north along FL coast before dumbbelling back NW. In the meantime, Miami gets right in the eye. Absolute devastation


Sent from my iPhone using Tapatalk

The shortwave weakens so it looks like it won't hook back in to the west.

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