Metservice

[Battgirl 23]

As one who often finds Metservice forecasts off the mark I can report that my experience of their forecasts for Sunday, Monday just gone was that they were spot on and it was great sailing thanks.

But does that mean there is light at the end of the tunnel or was their accuracy just a shot in the dark?

[khayyam 78]

even a broken clock is right twice a day?

[Guest]

i've found the weather is usually the exact opposite to bob's forcasts.

[markm 30]

I've generallly found MetService not too bad, certainly much better than most would have you believe. Comments would be.

 

Helps to understand how the different forecasters like to quote their wind strengths. Metservice seem to like to forecast based on the peaks, they align pretty well with what you get off Nowcasting. Most of the computer models, WindGuru, PredictWind etc tend to do the average over time, so if they're saying 17kts then a peak a little over 30kt in Nowcast terms is about what I'd expect to see.

 

Metservice seem to be a bit slower on changes than the computer models. Models I think a right a little more often, Metservice usually change to match them but it can take up to 12-24hrs for them to get round tuit, maybe longer on longer range forecasts.

 

Biggest doubts I have with Metservice are the 5am forecasts. The number of forecasts I've seen which are identical to the previous evening bar the issue time are such that I end up treating them with a little scepticism and thinking that whoever's got the overnight shift is very junior and not at all inclined to stick their head out. The 11am forecast is generally much better, problem is 11am's a little late to be of use, something Metservice should think on.

 

As commented, once you get into the swing of where the different forecasts are coming from and the limitations like the thoughts above, they're not bad and combined with the models give you a good feel not only on expected weather, but a reasonable confidence level on their likely accuracy.

[Guest]

Ive found that Windguru is quite accurate, metservice goes off the chart all the time. At least for harbour cruising that I do.

marineweather.co.nz just takes its data from windguru but shows less details, but then again it has more locations than windguru

so all in all, I always check them all and measure them against windguru. Plus I look at the weather map for isobars and fronts to have my own idea of whats happening. I guess having a good understanding of weather can be better than just checking a forecast.

[Guest]

looking out the window can be a good idea.

[ab1974 1]

Sure this may have been discussed before but what is the concensus on the accuracy of using Predict Wind (either the Free, Basic, Standard or Pro versions) in NZ?

[PaulR 3]

looking out the window can be a good idea.

 

Being outside, looking to leeward, you can be 100% accurate of immediate conditions.

[PaulR 3]

I think the biggest problem is that MetService have to forecast in general terms for the great masses.

 

Windguru, Predictwind etc are forcasting for a more weather intelligent group, who are looking to remember the forcasts for several immediate hours, even into the next day or two or more.

 

The average non sailor general public will forget the forecast shortly after hearing it, go home andsleep at night.

 

A lot of people only consider their own backyard, possibly up to a 10km radius as their own part of the world, whereas the forcasters need to condisider a much greater area. Auckland "super" city is very big now, Cape Rodney to the southern shore of the Firth of Thames is about 65 nautical miles = 120km so most only look at 1/12th of the forcast areas.

 

It rains in the Hunas, Dome Valley and Waitakeres but I can't see them from my home, so the forcasted showers did NOT happen in my backyard.

 

So is the forecast Right or Wrong

[wheels 543]

A big problem with the forecasts and most especially those given out on Maritime Radio, is that the area they are covering is too large. So it maybe accurate in general in some part of that area, but mayb e completely inaccurate in another part of the area.

[Battgirl 23]

Thanks markm you make a lot of sense and knowing how Metservice etc do their forecasts is helpful.

Like nico82 Windguru is my first reference for weather and they now include gusts in their forecasts.

At the moment when out on the water my only supposed objective and expert reference is Metservice so it would be nice to have more confidence in their forecasting.

Meanwhile I use trends in nowcasting and monitor barometer, sea and sky. Its hard to beat those mark 1 eyeballs.

[Clipper 346]

in my totally uneducated, and off the cuff opinion, I believe a metservice forecast is worthless. I look at metvuw and windguru for forecasts, and metservce for a laugh.

 

I know there are many many reasons why metservice might appear to suck. I don't care. Why can other sites give me what I want for free, and metservice can't look out the window.

 

F*ck you metservice

[Guest]

I've been telling you metVUW for God knows how long.

 

They say they use the same incoming data but somehow metVUW's computer model seems to have an edge.

 

I spent four months on board earlier this year and they were slightly astray on only two occasions.

[PaulR 3]

Is there a web site that shows the "nowcasting" wind reports historical data e.g. for the day, yesterday & week. Yes it's Coastguard but nothing useful on their web site as of a while ago, not even pictures of the reporting sites.

 

BTW I think Tamaki Strait site should be renamed Passage Rock. After all Channel Island is not called Colville Channel etc.

 

I've looked at the web sites including underground weather, surfing sites etc and they all have a range of interesting dials, graphs & info.

 

What I was trying to get was the same or similar for the sites we get the marine reports from, that we hear when out there.

[Guest]

The forecast from Metservice definitely has its limitations but these are a reflection of what the Metservice is contracted and funded to provide. They are contracted (by the government) to forecast for public safety. So they are only required to forecast 'significant changes' which equals wind speed changes greater than 10 knots and wind direction changes of 90º. Some areas may have better forecasts available if funded by someone else e.g. harbor master. They can create much better models but there aren't the resources to make these available to the public. Trust me they know the limitations of their forecasts.

[wheels 543]

Thought this funny.

[SloopJohnB 322]

 

So true.