Just looking out the window – can Metservice really do any better?

Over the years I’ve taken several swipes at the New Zealand Metservice. The thrust of these critiques has been that their weather forecasting results are little better than tossing a coin or looking out the window.

To make the point I’ve invited readers to take note on a Monday of the forecast for the following Monday, then watch how that original forecast gradually changed during the week to conform to reality.

On several occasions I’ve received replies from the Metservice’s ‘Weather Ambassador’, the lovely and hugely entertaining Bob McDavitt.

Bob usually points out that the closer you are to a weather event the more likely you are to get the forecast right. That is undoubtedly beyond question.

But you might have thought that with all the electronic wizardry that’s available to today’s forecasters and with our planet circled by weather satellites, they might be able to get it pretty well right a week ahead and absolutely right for tomorrow.

But they can’t and they often don’t.

I’m in a better position to pontificate on this now than I was a decade ago. A decade ago I took almost no exercise. Today Judy and I walk for at least an hour every day. So I’m interested in and familiar with the weather. I am, if you like, a weather-watcher.

This has led me to the conclusion that Metservice getting the forecast exactly right is the exception rather than the rule; getting it more or less right is closer to the norm; and getting it wrong far too frequent to justify the term ‘science’.

The Metservice has unwittingly assisted me in making these judgements by providing an excellent little app, which allows me to check the 10-day forecast for Auckland as I lie in bed each morning going through my emails and news on my iPad.

In particular, the on-line ten-day forecast is graphically presented with golden suns, fluffy clouds and rainy teardrops, either alone or in combination.

As I write this (on Monday), today’s Auckland forecast is shown as a golden sun with a fluffy cloud, which I take to mean ‘dry but some cloud’.

Looking out the window I see that it is indeed cloudy but not raining. I could just look out the window  anyway, but I don’t want to carp. At the moment the forecast for today is correct. (Based on our walking experience, I’m going to predict that the cloud will disappear later in the day, but I’m not putting money on it. The only satellite I have access to is the Sky dish on our roof.)

But today’s 10-day Metservice forecast for Auckland also gives me (and those of you who live here) a rare chance to check on my claim that they often get it wrong. You see, today’s graphic consists solely of nine golden suns, indicating nine fine, cloudless days starting tomorrow.

Here’s my prediction: there won’t be nine consecutive fine, cloudless days starting tomorrow in the City of Sails; There’ll be cloud and/or showers on one or more of those days. If you  live in Auckland and you’ve nothing better to do, check out the Metservice’s prediction and mine for the next nine days and see who was right(er). (You can do the same thing for yourself in your area – their prediction versus yours.)

Now I want to finish on a conciliatory note. It isn’t my view that the Metservice regularly gets it horribly wrong. They don’t. But nor do they get it acceptably right. ‘Sunny’ days turn out to be cloudy days; ‘cloudy’ days turn out to be showery days; ‘rainy’ days turn out to be cloudy days etc.

The trouble with forecasting that, our walking tells me, is more often partially right than totally right, is that it makes planning for the weather – from the layman’s point of view surely the most significant reason for checking the forecast – almost impossible. Which is why I’m so often chilled on ‘sunny’ days and char-grilled on ‘cloudy’ days, not to mention occasionally drenched on ‘dry’ days. 

Take it from me, there’s nothing more certain to turn you into a weather sceptic.

Got to go now – the sun’s coming out.

UPDATE: What actualy happened Monday
Metservice predicted sun and cloud; I predicted cloud would clear later in the day. It did. We were both right.