
The eye of hurricane Matthew passes directly over a weather buoy - matt2000
http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=wdpr&uom=E&time_diff=-5&time_label=EST
======
gilgoomesh
That's a beautiful graph but NOAA's insistence on non-metric units frustrates
me endlessly. Knots for speed are bad enough but "inches" for pressure is
multiple levels of wrong.

~~~
Justin_K
FYI a Knot is standard for navigation world wide because the unit is
standardized on earth's size. 1kt = 1 nautical mile per hour. 1 nautical mile
= one minute of Earth's longitude. Learned this in sailing class :)

Wikipedia: "Worldwide, the knot is used in meteorology, and in maritime and
air navigation—for example, a vessel travelling at 1 knot along a meridian
travels approximately one minute of geographic latitude in one hour."

~~~
gilgoomesh
Using "Knot" because it's tied to longitude and latitude is the exact point
the metric system is designed to avoid: needless and _inaccurate_ attachments
between system of units and specific phenomena that actually complicate rather
than simplify and hinder interoperation with every other system.

As you state:

1\. a knot is only _approximately_ equal to 1 min of latitude per hour (there
are numerous cases where it's unusably wrong)

2\. doesn't really help for longitudinal travel

3\. maps are continuously projected to favor this mediocre form of navigation
instead of something more accurate (see Mercator projection)

4\. you could easily put kilometre lines on your charts instead of minutes of
latitude and fix all the previous problems

~~~
Ultimatt
No Mercator projection is used because its the least weird conformal
projection (you draw a straight line its really straight in the real world).
If you are trying to plot a bearing at the scale of the planet you want to be
using Mercator unless you are going over the pole :P That the same projection
is then used for everything even when you don't need to preserve local angles
isn't the fault of Mercator. That you think km lines on an atlas would be
better than lat/long makes you crazy. A decimal day might be useful but a
decimal year is not. A fractional decimal day is a completely useless
reference of time for doing quantum mechanics, but perfectly reasonable for
people planning their work. No one would get rid of the concept of "a day". A
map that maybe only shows tens or hundreds of km might be fine but
representing the whole world with an equal area map with all grid reference
based on km isn't useful to many people who use maps a lot, especially as the
world isn't describable in whole numbers of km! But does have absolute and
continuous angles from the gravitational centre.

~~~
NickNameNick
Lines on a Mercator map aren't straight on a globe. They are constant-compass
bearing, but that's not the same as straight.

Also, as defined by the French academy of science ~1800, the meter is
1/10,000,000th the distance from the north pole to the equator, on the
meridian through Paris.

~~~
kqr
Not sure what your metre comment is about, but it turned out that definition
wasn't accurate enough to confidently state the speed of light, so the speed
of light was set to 299792458 m/s and a metre is consequently the distance
light travels in a 299792458th of a second.

(The second is in turn precisely defined by particle physics.)

~~~
dalke
It's a reference to Justin_K's earlier statement "a Knot is standard for
navigation world wide because the unit is standardized on earth's size".

If that justifies knot then it also justifies kilometers, because it too was
originally standardized on the earth's size.

Neither are exactly the size as originally defined.

A modern knot is 1852 meters. One minute of latitude is "about 1,855.325 m on
the WGS 84 ellipsoid" says
[https://en.wikipedia.org/wiki/Nautical_mile](https://en.wikipedia.org/wiki/Nautical_mile).
The difference is 0.16%.

A quarter of the Earth is:

    
    
      1855.325m * 60 seconds/degree * 360 degrees/circle /4 = 10018755.0
      = ~10018 km.
    

The difference is 0.19%.

------
chadclan
Some other neat data from the same buoy.

Wave height
[http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=wv...](http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=wvht)

Wind direction
[http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=wd...](http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=wdir)

Air temperature
[http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=at...](http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=atmp)

Water surface temperature
[http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=wt...](http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=wtmp)

Dewpoint
[http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=de...](http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=dewp)

I just tried the data format codes from the link someone posted earlier
[http://www.ndbc.noaa.gov/measdes.shtml](http://www.ndbc.noaa.gov/measdes.shtml)

Cool stuff!

~~~
josh_carterPDX
Being a former QuarterMaster in the Navy, all of this is so fascinating. 20
years ago this data was not easily accessible to the public so you had to wait
for some sort of published journal to come out to see this information. I love
that we all have access to it so easily.

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dluan
If anyone wants to see where it is, the hurricane's moved further up north
away from the buoy's location.

[https://earth.nullschool.net/#current/wind/surface/level/ort...](https://earth.nullschool.net/#current/wind/surface/level/orthographic=-83.54,18.91,1666/loc=-76.935,14.522)

~~~
harlanlewis
That's a great visualization. Reminded me of one posted to hacker news a few
weeks ago that let's you cycle through visualizations of cloud cover,
atmospheric pressure, precipitation etc in addition to wind:

[https://www.windyty.com/?20.551,-74.487,5](https://www.windyty.com/?20.551,-74.487,5)

I really love seeing all these conditions moving in concert at a global scale.
As someone who's never experienced a hurricane, it makes the effects feel much
less abstract.

~~~
qvorak
Any idea what he used to make that? Super impressive

~~~
shpx
windytv is a fork of earth [0], which is open source [1] and made with D3.js
[2], I'm guessing windytv is also using d3.

[0]
[https://news.ycombinator.com/item?id=12415777](https://news.ycombinator.com/item?id=12415777)

[1] [https://github.com/cambecc/earth](https://github.com/cambecc/earth)

[2]
[https://earth.nullschool.net/about.html](https://earth.nullschool.net/about.html)

------
jpalomaki
I was surprised some time ago when I found out that the modern wind speed
measuring devices work without moving parts. I had expected them to all have
these spinning ping pong ball halves.

To do it without moving parts, they are for using for example ultrasound.
These devices have pairs on transducers, placed 10-20cm apart and the device
then measures how long it takes for the sound to pass through that distance.

[https://en.wikipedia.org/wiki/Anemometer#Ultrasonic_anemomet...](https://en.wikipedia.org/wiki/Anemometer#Ultrasonic_anemometers)

~~~
swehner
Does a speaker count as a moving part?

~~~
HeyLaughingBoy
Well, if you want to be pedantic about it, hot-wire anemometers have
absolutely no moving parts :-)

[https://en.wikipedia.org/wiki/Anemometer#Hot-
wire_anemometer...](https://en.wikipedia.org/wiki/Anemometer#Hot-
wire_anemometers)

------
matwood
Being in the eye of a hurricane is an odd feeling. Growing up I went through
Hugo, and when the eye finally passed over, it went from chaos to an eerie
dead calm. We went outside and to see the destruction, but knew there was not
much we could do yet. A tree had clipped the corner of the house so my parents
did what they could do to protect the exposed inside against the rain of back
half of the storm. Beyond that, we just prepared hold tight for another few
hours.

~~~
chiph
I lived near Charlotte during Hugo. The thing I remember most is going out
afterwards and smelling all the pine sap (smells like the Pine Sol cleanser)
from all the downed trees.

IIRC, the storm depressed the market for lumber for a year or more afterwards,
as it was flooded with wood cut from the trees that were uprooted and then
harvested.

~~~
matwood
I was in Charleston, SC. We literally had firewood for years afterwards. The
storm itself was bad, but no power for almost 4 weeks was really rough.

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isomorphic
One of the things I take away from this graph isn't just the peak wind speed,
but the amount of _time_ you'd be under hurricane-force winds.

A couple minutes of 90mph winds is one thing... _hours_ of 90mph winds is
entirely another thing.

~~~
dredmorbius
It's not so much the wind _as what is in the wind_ that really bowls you over.

~~~
ihsw
This is it -- much like how getting caught in a tsunami is not very
interesting itself, it is the debris (which includes vehicles and other large
objects) that will kill you and otherwise cause devastation.

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avs733
I would be immensely curious to see the raw data given how the point spacing
changes (assuming those aren't actual data measurements). The drop and
recovery around the eye are so staggeringly smooth.

~~~
sathackr
[http://www.ndbc.noaa.gov/station_realtime.php?station=42058](http://www.ndbc.noaa.gov/station_realtime.php?station=42058)

[http://www.ndbc.noaa.gov/data/hourly2/](http://www.ndbc.noaa.gov/data/hourly2/)

[http://www.ndbc.noaa.gov/data/hourly2/hour_01.cwind](http://www.ndbc.noaa.gov/data/hourly2/hour_01.cwind)

I love the ndbc site, have been using it for 10+ years now

~~~
avs733
Thank you!

------
sathackr
Wonder why we don't see winds at the reported speeds(130mph+) in the data?

Maybe it's a limit of the measuring device?

~~~
VLM
Check out

[http://www.nhc.noaa.gov/aboutwindprofile.shtml](http://www.nhc.noaa.gov/aboutwindprofile.shtml)

In summary the peak is highly variable for every storm but is usually
somewhere around 500-1000 feet above ground level.

Its not irrelevant that its so high off the ground ... a tree thats uprooted,
picked up to 500 feet, accelerated to 150 MPH, and dropped on you might land
on you in merely 100 MPH winds, but it'll still be flying at 150 MPH (maybe
faster?)

Note there are plenty of broadcast transmitter towers where the top will get
winds 50 MPH faster than the surface. 500 feet is only maybe 50 stories for a
tall building. So there is some impact directly on the largest constructed
things.

"How come the 150 MPH rated water tower survived but the 160 MPH radio antenna
next to it collapsed?" well the water tower was in 130 MPH winds and the
antenna was in 180 MPH winds at the same time so ...

~~~
sathackr
Thank you -- I climb towers and skydive occasionally so I'm aware that winds
aloft are often greater than surface winds.

But I was under the impression that the forecast wind speeds were surface
winds, and assumed that surface meant ground level.

I shall research.

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webkike
I love this graph

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dandelany
Call me a cynic, but my first thought on looking at this was "we can't do any
better than a datum per hour?!" :) Must be a bandwidth constraint.

~~~
lorenzhs
Here's a wind speed plot with a data point every ten minutes:
[http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=sp...](http://www.ndbc.noaa.gov/show_plot.php?station=42058&meas=spd&uom=M&time_diff=-5&time_label=EST)

I prefer the hourly binned one. It's much cleaner.

Just because the chosen visualisation doesn't have the accuracy you like
doesn't mean that the data isn't there.

~~~
dandelany
The hourly one is cleaner and more readable only because they've insisted on
using a symbol for each datum which obscures the line itself... I'd like this
one 6 times more than the original, otherwise.

Personally, I don't understand why anyone would want to look at timeseries
data with anything less than the maximum possible information density &
precision (accuracy is not the problem). Maybe if you're looking for
cleanliness/aesthetic reasons, but that's not really the point of these
charts. Obviously if they are noisy something needs to be done. But binning
only really makes sense to me in histograms, not timeseries.

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sp527
It's biuriful _tears up_

And now back to our regularly scheduled React component.

