Metservice Rain Radar hopeless

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Eva888

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#2609804 24-Nov-2020 14:15

My favourite is Windy

https://www.windy.com/?-41.919,174.946,5

I find it pretty accurate and for Wellington in exposed places where wind matters I can set the layers to show wind in coloured animation. You can add other layers such as waves, swell, snow and many other features. Best to join so you can save preferences and save the layers. There’s also a forum of users and apps.

Been following them since they started and see they are up to 15 staff now.

https://community.windy.com/topic/4/about-windy

neb

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#2609822 24-Nov-2020 14:33

minigopher17:

Good on you. We'd all be a lot better off if the Metservice was simply shut down and WeatherWatch provided all of our forecasts. Since you're obviously the officially appointed spokesperson for WeatherWatch :-), would you guys take a feed from PWSes like Wunderground and similar do? There's a massive amount of data available from NZ PWS users that you could take in directly...

WeatherWatch already uses PWSs - https://www.weatherwatch.co.nz/maps-radars/observations/live-observations

It used to be controlled by WUnderground until IBM bought it out and we continue to use them.

Oh, cool! Just checked and my feed is on there... one comment on IBM's WU, you may want to make provisions for getting direct feeds from NZ users, the way IBM have been driving it into the ground there's no telling how much longer you'll be able to rely on WU for anything.

Do you guys have a discussion forum anywhere for feedback? One annoying thing about the Android app is that you can't drag a forecast timeline to scroll it but have to tap the tiny, barely-visible chevrons at the side of the screen, because drag is reserved for switching between the three virtual desktops of which I would guess most people only ever use one. It's really annoying not being able to scroll back and forth down the timeline... if you don't feel like hosting it yourself you could try WxForums, they have a section for weather orgs.

RunningMan

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#2609826 24-Nov-2020 14:40

GV27:

The old website used to have a progress bar you could skip forward and back on with the rain radar and forecasts, the current one is garbage IMO.

You can grab the row of thumbnails and slide that back and forth, but very clumsy.

Batman

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#2609871 24-Nov-2020 15:32

Rain radar is always hopeless. I know that from watching years of Formula 1. They have experts watching rain and they convey the forecast to their drivers. About once or twice a year it goes like this

Team - no rain forecast for next 30 mins
Driver - but there's rain on the track
Team - are you sure
Driver - yes it's on my visor too
Team - but there's no rain on the radar

neb

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#2609879 24-Nov-2020 15:42

Batman: Team - no rain forecast for next 30 mins
Driver - but there's rain on the track
Team - are you sure
Driver - yes it's on my visor too
Team - but there's no rain on the radar

I can see that happening, rain radar shows general trends over time, not what's happening in this exact spot right this minute. You can see this from the timeline on the links posted earlier, rain concentrations fade in and out over multiple snapshots but the overall trend is visible. In particular if rain is likely, say 80% chance of rain over the 2pm-4pm time period then you shouldn't be surprised if it rains even though the radar may indicate, at the last sweep through the general area, that there's no rain at your exact location.

gzt

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#2609882 24-Nov-2020 15:47

myopinion:
I use the 300km one hour loop. This is very handy for seeing how far away the rain is.

Rain radar is excellent. Love it. I get better perspective from watching the whole country. Zooming in to my region only is something I don't find useful at all.

minigopher17

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#2609883 24-Nov-2020 15:47

Oh, cool! Just checked and my feed is on there... one comment on IBM's WU, you may want to make provisions for getting direct feeds from NZ users, the way IBM have been driving it into the ground there's no telling how much longer you'll be able to rely on WU for anything. Do you guys have a discussion forum anywhere for feedback? One annoying thing about the Android app is that you can't drag a forecast timeline to scroll it but have to tap the tiny, barely-visible chevrons at the side of the screen, because drag is reserved for switching between the three virtual desktops of which I would guess most people only ever use one. It's really annoying not being able to scroll back and forth down the timeline... if you don't feel like hosting it yourself you could try WxForums, they have a section for weather orgs.

Let's just say there are plans in motion regarding PWSs. There isn't currently a discussion forum for feedback anywhere but feel free to give feedback via the contact form on the WeatherWatch website. I'll check out WxForums too as we value feedback and we are always looking to improve our products. I've noted your piece, thank you, and will get it on the action list - sometimes you just use what you're provided by third parties until you put in that extra effort to make it even better for everyone.

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daringpeter

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#2610726 25-Nov-2020 18:33

I believe that there are three taxpayer funded and (at least) one 'privately' funded forecast service. I also understand that these forecasters use 'super computers' domiciled overseas to provide their forecasts. This must cost. I know that NIWA bought a high powered system to help with their local forecasting. It seems to me to be a wasteful duplication...either we need one open taxpayer funded service, or pay (in other than taxes) for a commercial service. Is the weather forecast an essential infrastructural service? Or one that could be left to the commercial market? Commercial media, for example, could pay for a forecast to serve their audience. These are the questions that people should think about.

And, a while back I drew up a chart to compare the competing services. MetService was, marginally. the better.

tdgeek

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#2610820 25-Nov-2020 20:49

I have no issue with the radar, what I have an issue with is a forecast of occasional rain this afternoon, then the hourly graph shows no ml of rain. Its raining but no ml? Dry rain?

Technofreak

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#2610826 25-Nov-2020 21:36

neb: What blows my mind is that anyone still pays attention to the Metservice. Even airline pilots, who are required by law to go with Metservice weather reports, make some token motions for it and then if the can get away with it use a weather service that can actually predict the weather. It's a nasty catch-22, one person explained it to me as "we know it's almost certainly wrong but if we ignore it and there's a problem, we're liable".

I don't know where you got this idea from. I don't know of any airline pilots (and I know quite a few) who go out of their way to use a forecasting service other than the Met Service.

The Met Services forecasting accuracy from an aviation point of view is not too bad.

However their Met Service (metservice.com) website sucks big time.

My two big beefs are with the presentation of the rain radar and rain prediction images. Firstly the scrolling method is back to front. You have to drag the images backward across the screen to go forwards in time. How backwards it that?

The other gripe I have is the way the main images are positioned on the screen. You cannot see the whole country at once which is quite useful when you want to see the progression of a weather system across the country.

When I've provided feedback I've got a standard reply along the lines of we welcome your feedback and we might take it onboard at some future date when we update the website.

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neb

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#2611058 26-Nov-2020 12:05

Technofreak:
I don't know where you got this idea from. I don't know of any airline pilots (and I know quite a few) who go out of their way to use a forecasting service other than the Met Service.

Sorry, I was using "airline" to distinguish from any other kind of pilot, I should have used "aircraft". This was during a bitching session by a group of private aircraft pilots complaining about how useless the Metservice forecast was for getting info on flying conditions. MetVUW was popular IIRC, as well as a few non-Metservice ones.

The Met Services forecasting accuracy from an aviation point of view is not too bad.

That's not the impression I got, mentions of the Metservice were typically accompanied by eye-rolling and comments along the lines of "you know it'll be wrong anyway".

You just have to look at the way they report the weather to see how bad their service is. "Sunny with a chance of rain". Great, that forecast is almost entirely useless, there's a chance of rain 365 days a year. There's a chance of rain in the middle of the Sahara desert, just not a very big one. In terms of predicting the probability of things like rain, meteorologists are pretty accurate. If an expert says there's a 40% chance of rain tomorrow, the chance of it raining is indeed about 40%. This is so remarkable that weather forecasters have been extensively studied to see how they manage this. It's such a well-known result that it's been applied in other countries for up to half a century, in the US weather was presented as absolutes or 'chance of X' before 1965 but then switched to percentages, in Europe they started to fix it in the 1990s, and in NZ the Metservice still uses the same known-bad way of doing it that they used in the 1920s. They know the actual probability of it raining [*] but hide it so you can't make any use it.

I could go on...

[*] Actually since it's the Metservice they could just be guessing, there's no way to tell.

frankv

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#2611130 26-Nov-2020 13:31

[quoted] neb:

Technofreak:

I don't know where you got this idea from. I don't know of any airline pilots (and I know quite a few) who go out of their way to use a forecasting service other than the Met Service.

This was during a bitching session by a group of private aircraft pilots complaining about how useless the Metservice forecast was for getting info on flying conditions. MetVUW was popular IIRC, as well as a few non-Metservice ones. [/quoted]

As a pilot myself, I can illuminate this a little.

IFIS (Internet Flight Information Service) is the official sanctioned, certified, ICAO-consistent, CAA-approved way of getting Met, as well as airspace and other information, for a pre-flight briefing. It provides weather in an abbreviated codified way which was probably appropriate when it was being telegraphed from place to place. e.g.

NZPM (PALMERSTON NORTH)

TAF NZPM 252232Z 2523/2617
VRB02KT 15KM -SHRA FEW020 BKN080
BECMG 2523/2601 10010KT
TEMPO 2523/2607 6000 RA
PROB30 TEMPO 2601/2606 3000 TSRAGS FEW020CB
BECMG 2606/2608 32010KT
TEMPO 2608/2615 4000 RADZ BKN006
2000FT WIND 03015KT
BECMG 2603/2605 32015KT
BECMG 2613/2615 32025KT =

So part of a pilot's training is how to decode this stuff. Any pilot, from anywhere in the world, should be able to figure out the above. Which is OK if you're an airline pilot and do it every day (or have someone else do it for you), but it's difficult and error-prone for the occasional user.

Using non-approved, non-certified weather information is not acceptable in CAA's view, because there's no guarantee of the accuracy or timeliness of it. So, if a pilot gets a weather briefing, it has to be an official one. And of course, any airline will take the cautious, safe approach, and require all their pilots to get the official weather.

In fact Metservice itself is not an approved source of weather information. I have no doubt the pilots were bitching about IFIS, rather than the quality of Metservice's forecast.

FWIW, I look at MetService, Windy, and MetVUW, especially if I'm looking more than a couple of days ahead. Where they all agree, it's likely that they're correct. Where there are differences, any one of them could be right. For less than a couple of days ahead, there's very little difference. Windy is really good because it has layers for low cloud & cloud base, which is probably the biggest problem for pilots going cross-country in NZ.

johcar

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#2611158 26-Nov-2020 13:51

Windy (https://www.windy.com/?-42.049,174.463,5) is a pretty good alternative to Metservice Rain Radar - not that it's difficult to be better...

neb

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#2611168 26-Nov-2020 14:01

frankv:
IFIS (Internet Flight Information Service) is the official sanctioned, certified, ICAO-consistent, CAA-approved way of getting Met, as well as airspace and other information, for a pre-flight briefing. It provides weather in an abbreviated codified way which was probably appropriate when it was being telegraphed from place to place. e.g.

I was a non-pilot listening in on pilots, and it was a couple of years ago so yeah, expect some data corruption in my report :-).

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