Does anyone understand weather warnings?

[MrsAvocet]

Just idle curiousity really, but does anyone know how the Met Office determine weather warnings? Are there objective criteria?
The weather is pretty terrible today where I am, and my Facebook page is full of pictures of trees down in people's gardens and on local roads, yet we don't have a weather warning in place. We regularly seem to have yellow warnings and a few weeks ago there was an amber one, but if anything today is worse!
And before Christmas, my DD's area had an amber warning in place whereas we had yellow, but if you compared the forecasts for our respective homes they were virtually identical in terms of wind speed and direction etc. I find it all a bit confusing!

Well when I got out of the car the wind tried to Mary Poppins me across the car park. That's as far as my understanding goes.

I just go on the colours they dish out.

Absolutely no help, sorry 😅

It’s a combination of liklihood of the event and the impact. But beyond that I don’t know. There’s a sort of grid thing.

It’s not an exact science as to where, especially if you are on the edges of a warning.

This.

The likelihood of winning euro millions is vanishingly low but the impact, if you do, is massive. People do win it, though, despite the incredibly low likelihood.

It sounds like, in your case @MrsAvocet the likelihood of any adverse weather impact was deemed too low to issue a warning for your area, even if the likelihood wasn't zero.

They come along every other day in the West Country this winter, that’s all I know. Absolutely battered.

<surveys ruined garden sadly>

Where do you live? We have weather warnings here and there’s lots of flooding from overnight storm Chandra.

To answer your question, yes, there’s strict criteria but there’s a lot of uncertainty.

I don’t usually pay too much attention to the yellow ones down here. As you say there are several a week.

they were bang on about the amber one for rain last night. Thanks Chandra.

Yes, I'm familiar with how risk assessment works, but I am intrigued by how they come up with the different gradings when what they themselves are forecasting for particular areas looks nigh on identical. Last night we were forecast a greater than 95% probability of heavy rain and winds gusting in excess of 55mph and that indeed is what we got. It's not like they were predicting light winds and things were worse than anticipated. There have been other days when the forecast has been very similar when the whole county has been yellow but we're not even close to the edge of a warning today. Not that it really matters - I largely ignore the colours and just look at the actual forecasts anyway - I'm just interested to know what other data they factor in.

Does this help?

Roughly - red = signigicang risk to life
Amber - significant ridkto property
Yellow - disruption

There’s a 16 box RAY decision matrix in this link. The categorisation is a bit subjective because there are so
any risk factors and receptors.

I don’t ignore the colours. I usually ignore a yellow. I’ve never known amber or red here to not cause an issue.