Weather Chat Megathread

[tater]

 

[DarkOwl57]

I just heard on the radio that people have been denied temporary hotel and housing arrangements because their ID got wiped away in the flooding. Just goes to show how one monstrous storm can change lives in a matter of seconds.

As for Irma, I'm definitely worried. Any amount of rainfall coming our way (Texas) Could spell disaster. However, I'm (kinda) Glad (ish) that Irma's heading north. Hopefully she'll either drift out to sea or hit an area that's prepared. NOT TO SAY THAT I WANT A HURRICANE TO HIT! God knows Florida's been through enough already. Just saying there if it does have to hit, it should hit an area that's well prepared

15 hours ago, Ultimate Steve said:

Okay, uh, this may sound a bit weird, but our sky was yellow. Then it was dark-ish green... then it turned light yellow-green... and now it's orange... I think it's turning pink.

I'm not lying, I promise. This is so weird... I'm sort of creeped out by it.

IT'S THE APOCALYPSE!!! RUUUUUUUUUUUUUNNNNNNNN

[Ultimate Steve]

Update: The weird clouds were from the wildfires. Afterwards, it turned grey-green-yellow, bright white, and then back to normal grey.

[DarkOwl57]

14 hours ago, SaturnianBlue said:

Jose better not pull a Jeanne...

THERE'S ANOTHER HURRICANE?!?!?!?!?!? 

[tater]

The second one is not likely to do anything, apparently.

 

 

[Green Baron]

20 minutes ago, DarkOwl57 said:

IT'S THE APOCALYPSE!!! RUUUUUUUUUUUUUNNNNNNNN

Certainly not. But we have to get used to more full blown weather events in the future.

Right now there is no other hurricane in the Atlantic, but this year's season is about to shake the legs. "Usually" lasts until November.

[tater]

1 hour ago, Green Baron said:

Certainly not. But we have to get used to more full blown weather events in the future.

This was also said in the wake of Katrina, then not long after that, we started a record draught of major hurricanes.

So the exact same thing was said over 10 years ago. How many major hurricanes above the historical average (and corrected for historical data not seeing most of them at sea) have to happen each year to demonstrate that this claim is true above natural variation, and for how many years must this occur. So far we might be in a situation where we've had 2 major hurricanes hit the US in 12 years. I think we'll need rather a lot more to not falsify the claim above.

The answer is 0.591 major hurricanes per year hits the US (since 1851).

So we're currently at 0.167 for the last 12 years (assuming Irma hits), so if we get 7 more this year, we'll be up to average.

[Green Baron]

 

The world is bigger than the US, dear colleague :-) And overall the intensities and frequencies have grown.

As to what hits or not: let's hope for the best !

 

Edit: just search this years monsoon and it's number of deaths, damage and its effect on water, agriculture and infrastructure.

 

Edited September 5, 2017 by Green Baron

[tater]

The number of hurricanes (not just those impacting the US) has been pretty constant. The numbers really need to be considered pre, and post satellite observation, since pre satellite storms might go entirely unnoticed short of landfall.

Edited September 5, 2017 by tater

[Green Baron]

And severe weather is more than hurricanes ;-) Draughts, monsoons, flooding, and their impact have increased and are increasing.

https://www.ncdc.noaa.gov/climate-information/climate-change-and-variability

(i just saw it's from 2014, things have further changed since then)

I linked to your countries weather service because it is clearly not exaggerating anything. Other countries services are by far less contained in their publications.

Edit: i am only echoing common knowledge here, dear mods :-)

Let's hope the Caribbean isn't hit too hard ... i see a new depression is forming in the central Atlantic ...

Edited September 5, 2017 by Green Baron

[tater]

NOAA is as political as any other gov entity since weather became politicized. I'm about actual data. Note that "average temperature" is not an observation, it is a complex calculation that different people can do in different ways. Stations that have not had landscape changes (urbanization, etc), that record temp using the same equipment have reliable data---though with whatever the uncertainty is for their particular devices. NOAA requires thermometers have an accuracy of 0.4 degrees F to be acceptable (well outside the signal of increased temp).

The current discussion is about tropical cyclones. Climate models apparently actually predict that warmer climate makes for fewer storms:

http://www.sciencemagazinedigital.org/sciencemagazine/30_january_2015?folio=540&pg=98#pg98

“Our work illustrates a major constraint on the large-scale global atmospheric engine: As the climate warms, the system may be unable to increase its total entropy production enough to offset the moistening inefficiencies associated with phase transitions. … On a warming Earth, the increase in perceptible water has been identified as a reason for the tropical overturning to slow down, and studies over a wide range of climates suggest that global atmospheric motions are reduced in extremely warm climates.“

This is important because even assuming the veracity of warming claims (I have said nothing about that issue at all), preaching doom and gloom over hurricanes when even the models suggest otherwise is counter-productive because when that fails to materialize (as it has for many years now), it convinces people that the models are obviously terrible.

Edited September 5, 2017 by tater

[Green Baron]

The discussion is about weather, or not ? Hurricanes will be forgotten in November ... ;-)

Climate models actually predict(ed) more and intenser hurricanes on the Atlantic and have apparently failed for the public until now, but a few cat 1 and even 2 this year have already formed on the Atlantic but dissipated when turning north, so there where hurricanes but unnoticed by the public.

And category 5 ones are a newer invention. I think we had already more this century until today than the whole 20th and half of the 18th century. I am talking of Atlantic hurricanes only. Can't remember where i read that ...

The problem is, weather doesn't stick to a tact or frequency. Imagine a state machine that has several switches that, when the trigger is pressed, release at lot of energy at once.

Whether climate (not weather, your linked text deals with a global model) can be seen as a heat engine is highly debated. Even if global warming leadsto less or more temperature differences in the lower or upper atmosphere is not quite clear, you can find models for both assumptions. Tendency lately goes towards higher differences in the atmosphere between latitudes which would weaken the heat engine position a little.

Atmosphere as a heat engine:

http://www.smithsonianmag.com/science-nature/climate-change-altering-global-heat-engine-180954079/

 

Edited September 5, 2017 by Green Baron

[tater]

You cannot compare modern data with old data. We see every single TC. We fly into many of them, if not most or all. 

Past data is at best spotty. Wind speeds would only be surface on land, and by less accurate devices. Sailing ships intentionally avoided that entire region of the Atlantic specifically because even a low cat hurricane was mortally dangerous. As a result, even less data for that era.

when you look at TC counts by year, you have a slightly lower count over a long time, then slightly higher, also flat when averaged over year spans. The small difference is likely just observational bias.

[tater]

Remember that ship speeds in the age of sail were done by the log. Literally dropping a piece of wood (the log) on a rope, marked with knots, and counting the number of knots fed out over a period measured by a glass (a small hourglass that did minutes). Most ships did not carry scientific instruments (virtually no merchant ships, and few navy vessels). Until the mid 1800s, all anemometers were of the plate type, which are very inaccurate for high winds, too. So anything before 1846 is pretty useless, as the instruments were nearly useless.

That's how we got the word "log" as in log book, and how we got "knots" since the knots were calibrated to nautical miles in the glass timeframe.

Edited September 5, 2017 by tater

[Green Baron]

26 minutes ago, tater said:

You cannot compare modern data with old data. We see every single TC. We fly into many of them, if not most or all. 

Yes, we can (see below).

Quote

Past data is at best spotty. Wind speeds would only be surface on land, and by less accurate devices. Sailing ships intentionally avoided that entire region of the Atlantic specifically because even a low cat hurricane was mortally dangerous. As a result, even less data for that era.

Here's the link i forgot, in general data is better than you think. What i know is that an 18th century clipper still sails in 11 beaufort with small for and aft triangular sails. It takes down sails and runs under bare poles in hurricane conditions. There was a lot of traffic on the oceans and terrestrial observations can be combined with ships logs (as is the case today, the fancy satellites are just an add-on). Saying that low cat hurricanes where mortally dangerous is to generalized, though it was surely stressier than today for men and material.

Edit: for those who question themselves: a bigger problem than the mere wind is a dynamic sea, especially from the side. But that leads too far here ...

Quote

when you look at TC counts by year, you have a slightly lower count over a long time, then slightly higher, also flat when averaged over year spans. The small difference is likely just observational bias.

 

Here's modern data: https://www.sciencedaily.com/releases/2017/01/170124111330.htm

;-)

 

Edited September 5, 2017 by Green Baron

[tater]

Beaufort 11 is not even a hurricane. In addition they had no instruments, so attribution of wind speed was a GUESS by the captains before the invention of the cup anemometer in 1846.

Plate types were not routinely carried, and even those that were were only accurate in a narrow range around "normal" wind speeds (useless at low and high speeds). Note also that that scale was invented in 1805, so basically 40 years of it not being well measured, and no data at all in the stated 18th century (or before).

5 minutes ago, Green Baron said:

YHere's modern data: https://www.sciencedaily.com/releases/2017/01/170124111330.htm

;-)

 

That's not data. This is data (a table of hurricanes that have hit the US):

http://www.aoml.noaa.gov/hrd/tcfaq/E19.html

Or total tropical cyclones in the Atlantic basin:

http://www.aoml.noaa.gov/hrd/tcfaq/E11.html

 

ObWeather: Smoky here in NM from wildfires elsewhere. Also:

 

 

[Green Baron]

15 minutes ago, tater said:

Beaufort 11 is not even a hurricane. In addition they had no instruments, so attribution of wind speed was a GUESS by the captains before the invention of the cup anemometer in 1846.

No, and i didn't state that, but 12bft is. Do you want to fight with me ?

Nonsense, it is not a guess but a rational assessment of the situation. Sure they had their methods and probably a higher knowledge than today's sailors. The wind (still today) is well judged by the sea (definition of the beaufort scale based on the image of the sea). And the sail configuration of a tall ship corresponds to the wind, wind strength is even named by sail configuration.

I am a hobby sailor and i tell you i can, single handed with a 13m sloop, easily navigate in 9bft that often blow here around the capes. Of course the sea is much calmer since the windfields are small. Those who say that is not possible simply don't know how to or how to handle their boat !

 

Records starting at mid 19th century are good enough for the weather services, so let's not make a question of belief out of it ;-)

 

Edited September 5, 2017 by Green Baron

[tater]

I'm not fighting, this is more like a discussion over a glass of wine or cup of coffee

My point is that the uncertainty in wind speeds is substantial for pre-modern instruments. The 1851+ records held by the US are all after cup anemometers, which is useful.

You said above, "What i know is that an 18th century clipper still sails in 11 beaufort..."

The beaufort scale was invented in the 19th century (as were Clipper ships I think). The bottom line is that we have maybe 200 years of data, of which the first 50 has huge error bars because they literally had no accurate way of measuring wind speed even on land, much less on sailing vessels (since they also had no idea how fast their ships were actually traveling, and apparent wind speed on a ship needs to subtract their own motion). After 1846, the small subset (to start, obviously, they become more and more common as time progresses) of ships with anemometers could actually get useful information, but that also requires they know their velocity accurately (and position for some data).

When discussing frequency of weather phenomena, I'd think you'd want many centuries of data to have useful ideas about what to expect.

[Green Baron]

5 minutes ago, tater said:

I'm not fighting, this is more like a discussion over a glass of wine or cup of coffee

I'll have the ... no, not now ... later :-) Every drink has its time :-)

 

[ProtoJeb21]

Irma is STILL strengthening! With the latest recon mission, it has winds of 185 mph and a pressure of 925 mbar. Considering the continued strengthening, Irma's very tropical cyclone-friendly location, and the 190+ mph models of the quite reliable Ventrusku forecast...well, this thing could possibly get even more intense. It may best out Hurricane Allen for the most intense Atlantic hurricane based on wind speed.

[Spaceception]

Holy crap, Harvey, and Irma in quick succession, I hope the people affected get as much help as possible, they'll need it.

Any idea how badly Puerto Rico will be affected? Where will they evacuate?

[ProtoJeb21]

Tropical Storm Jose formed today, right on schedule with Ventusky models. It's already slightly strengthened. Meanwhile, to my surprise, the low pressure area in the Gulf of Mexico has developed into Tropical Depression Thirteen. It is expected to meander over the Bay of Campeche while gaining strength over the next few days. Then, sometime next week, it will turn towards Mexico as a strong tropical storm or possibly a Category 1 hurricane. This thing will be as far away from Texas as it can get.

[tater]

 

[cubinator]

33 minutes ago, tater said:

 

That thing is hitting just about as much land as it could possibly hit from there.

[tater]

Well, it can only take one of those paths (or none).