Weather: Watch out for a warning, and be wary of watches

Are we watching out for heavy rain, or being warned that it is imminent?

It seems that as technology improves the MetService's enthusiasm for warning New Zealanders of bad weather has improved as well.

Although when you are in the business of predicting weather, you get it wrong sometimes, so the service advances aren't always regarded as an improvement, or advances, for that matter.

Warnings aren't strictly warnings, either - some warnings are "watches" - not quite as serious as a "warning".

Northland had two weather watches issued by MetService on Monday afternoon.

One said heavy rain was likely across much of the region.

The other suggested there could be severe thunderstorms and heavy rain, in the early morning yesterday.

In Whangarei yesterday, though, residents awoke to blue skies and sunshine, before the humidity set in.

Many may have pooh-poohed the accuracy of the MetService's predictions - where were the thunder storms and heavy rain?

Here's the thing though - the predictions were "weather watches" - not warnings.

A weather watch is a "heads up" - it could happen.

A weather warning is a prediction that the weather is highly likely to happen.

The advent of rain radars means that anyone wanting to do their own short-term (as in the next dew hours) localised prediction can guess what is going to happen next.

About 2pm yesterday, it began to rain. There were also warnings that heavy rain was likely.

And 31.2mm duly fell in the two hours up to 4pm.

We know this because MetService posted the rainfall figure not long after 4pm.

That's pretty good information - not necessarily much use when it comes to predictions, but still, not bad.

MetService will never predict the future with such precision, but at least we can say we weren't warned, or told to watch out.