Help running a new plugin - error on the Windy plugin page

[Gkikas LGPZ]

@ivo
... any progress ?

[ivo]

Wow @johnckealy your plugin is monster. Found the bug and fixed. Will be deployed next week. Will create some data loader so plugins will have access to our backend API

[johnckealy]

Great to hear, thanks @ivo! Sorry if the code is a little rough -- I'm a meteorologist learning programming, rather than the other way around... But would relish seeing it deployed with current data! :)

[ivo]

Now is fixed and your plugin is working. As I suggest now I should have make soma data loader

[johnckealy]

@ivo - Brilliant! I'm chuffed to see it working on the site :) Let me know if you need any help understanding the code. You just need to load the variables Tascent, Pascent, Tdascent, U, and V with spot data at each level. The comments should hopefully explain this.

[ivo]

Basically we can deliver the data we have. We download only part of ECMWF data to save the money. Can you check official ECMWF's domunetation and find their official name of these layers.

[johnckealy]

@ivo Windy appears to use pressure levels from ECMWF, with temperature, humidity, and wind at each of these levels already available on the site. So what needs to be done on your backend is to have a function that takes a lat/lon picker point as input, finds the nearest grid point on the model, and then finds the data at each of these pressure levels. You might be able to adapt this from my closest_latlon() function in plugin.html. The variable Pascent (the ascent data for P) will always be:

Pascent = [ 1000, 950, 925, 900, 850, 800, 700, 600, 500, 400, 300, 250, 200, 150 ]

Though I see you also use "surface" and "100m" instead of 1000hPa, so by all means use that if you also have temperature and relative humidity at those levels.

Then Tascent is the temperature (shortname is "T" in the ECMWF docs), U is the U-velocity (shortname "U"), V is the V-velocity (shortname "V").

One thing I'm now realising is that I used an equation to convert the humidity into the dewpoint while generating the sample data, so you'll need to add this into plugin.html. To get Tdascent (the dewpoint temperature ascent), relative humidity (shortname is "R" at ECMWF, and the Windy is named "Humidity") must be converted to dew point using this formula:

for (var p = 0; p < Pascent.length; p++) {
Tdascent[p] = 243.04*(Math.log(R[p]/100)+((17.625Tascent[p])/(243.04+Tascent[p])))/(17.625-Math.log(R[p]/100)-((17.625T)/(243.04+T)))
}

[rittels]

@johnckealy
cool plugin, you could use the interpolator in the meantime?

[johnckealy]

@rittels Sure, though I'd say nearest neighbour is plenty for now! Vertically there is some interpolation going on in the js, and horizontally, ECMWF's 9km is loads of detail :) Would definitely be a nice addition for later.

[rittels]

Hi John
Nearest neighbor is indeed plenty!!
However, you can use the W.interpolator to read data at the different levels. It is slow and cumbersome, but somewhat cute.
I gave it a go myself: windy-plugin-readlevels.

[ivo]

@rittels said in Help running a new plugin - error on the Windy plugin page:

windy-plugin-readlevels

Do not worry I will make dataLoader, so far I am finishing one big thing on Windy

[rittels]

@ivo Thx!!

[johnckealy]

@ivo great to see the plugin loader is ready for model data. I'll look into updating the skewt plugin when I get a chance (bit busy at the moment though).

There was a bug in my plugin that showed the error "TypeError: Plugin.instance is not a function" and you fixed this. Can you remember what the bug was? I'll need to patch in the fix to my original version.

[ivo]

@johnckealy It was bug on our side

[shashighedia]

@ivo hi can some one explain what the red line on the temperature is?- thanks

[Korina]

@shashighedia @johnckealy

[johnckealy]

@shashighedia

The red line is a parcel ascent. Drag the purple slider to the right, and this will change. The concept is that as the surface temperature increases, the energy of a rising parcel of also increases (known as CAPE). By comparing the red curve with the existing temperature profile, you can diagnose the instability (likelihood of showers, thunderstorms etc) of the atmosphere. In theory, you can even use this to predict the exact onset times of convective clouds, or even afternoon thunderstorms. Just google "radiosonde parcel ascent", "convective available potential energy", or "lifted index" to get started.

[shashighedia]

thanks for the explanation

• much appreciated

[shashighedia]

@johnckealy many thanks for the explanation- much appreciated.