Jump to content

Archived

This topic is now archived and is closed to further replies.

Jo Farrow

Met. Office weather warnings Yellow, Amber, Red.

Recommended Posts

I've just written a blog hopefully explaining more about how the Met Office create their weather warnings and how the 3 levels now include likelihood of severe weather and the possible impacts. 

 

http://www.netweather.tv/index.cgi?action=news;storyid=6466;sess=

 

Did you know this about the impacts?

Is this the right way to go for the public? 

With this explanation do you feel the warnings are now more helpful to you?

 

The Matrix is now a key part of the warning, but is there anyway to show high impact, lower likelihood

or medium likelihood of low impact event from just the 3 colours?

Share this post


Link to post
Share on other sites

Thanks Jo, nice explanation of a complicated matrix. I'm more familiar with the straight forward 'traffic lights' coding on the continent and it works well with people knowing the likely impact level. I can see complications in adding the impacts factor, especially where warning is enhanced through density of population or time of day. If people don't realise this and weather is not so severe it can downplay the response for future events.

Share this post


Link to post
Share on other sites

Comment from Craig D on Facebook Feb 20, 11:48pm

 

Very helpful comment and analysis but I question the impact severity justification.

Take example of a 70mph+ storm that uproot trees or causes flying debris or masonry.

Is the impact in Scotland any less than in central London?

Humans may be more accustomed to such storms in Scotland but the impact of a fallen tree is the same. Indeed on a certain view the impact nay be greater in Scotland - the road closure in central London simply means traveling an extra city block but in rural area that city block may be a 100 mile detour.

Good resilence and preparedness on the part of citizens does not equate to a lesser impact.

The best example I can give by way of illustration is as follows:

Friedhelm aka #hurricanebawbag on 8 Dec 2011 caused UKMO to go to amber in advance - and then red for a time on a now casting basis. 

And yet Ulli which meteorologically speaking was similar in terms of trajectory surface pressure and Windspeed on 2 Jan 2012 was the more ferocious storm and had a far wider and greater impact.
And yet UKMO was only yellow (moving to amber on a nowcasting basis).

No plausible explanations were given although Scotland felt badly let down with many thinking ordinary folks thinkj g UKMO had taken the view that the Jocks in Scotland will be sleeping off the Hogmannau hangovers. Not so in 21st century Scotland!

So whilst impact severity is all well and good, it needs to be properly applied

Comment from Craig D on Facebook

Share this post


Link to post
Share on other sites

I find the matrix helpful, I must say. Am I correct in presuming that say an Amber Alert is given, that it will only actually be an Amber event if the matrix comes to fruition, rather than a definite amber warning?

Share this post


Link to post
Share on other sites

I find the matrix helpful, I must say. Am I correct in presuming that say an Amber Alert is given, that it will only actually be an Amber event if the matrix comes to fruition, rather than a definite amber warning?

Tricky,

if the LIkelihood comes off, then the event occurs. The weather impacts happen but will there still be impacts on people's day to day business

 

It is impact of widespread disruption. Not impact of the actual weather, along the bottom of the matrix

If because of the warning, people stay indoors, trains are suspended, schools are closed - there are disruption impacts but hopefully not loss of life.

 

The Jan 2nd 2012 example Craig D mentions above, had more severe weather but because it was on a public holiday and a weekend, the Police weren't as concerned by the impacts on the roads.

Share this post


Link to post
Share on other sites

question regarding the current met office warnings... do you think in the future weather warnings will become more local, as in more detail per county especially in winter when it concerns snow? as many yellow warning get issued and cover certain regions but many lower lying areas see no snow what so ever and can by very frustrating to say the least. I know the text within the warning gives more detail but many people don't know the elevation of  where they live and if they will be affected or not?

Share this post


Link to post
Share on other sites

I find the colour coding quite easy to understand. However, you have to read the text very carefully looking for where commas occur in particular. Today's text for the snow yellow warning being a case in point, and the various projected total amounts of snow based on height and different location.

 

Today's text very poorly written as follows -

 

'Rain is expected at lower levels across northern England and the southern half of Scotland for a time, but further north snow will fall to lower levels for longer, especially the far north and northeast of Scotland, perhaps giving a few cm in places...'

 

Mmm shouldn't the first word have read 'snow'?. Also what is the definition of lower levels - very subjective.. really could have done with a figure.

 

The confusion goes on...

 

Accumulations of 2 to 5 cms are expected in places above 200m, with 10 cms or more over high ground above 350m.

 

Where though?  North and Northeast Scotland? Certainly not S Scotland and N England as you read the text as it is only meant to be rain......

 

I'd like to know what the Met Office defines as lower ground, sometimes they quote 150 metres, sometimes 200 metres, sometimes as low as 100 metres, out of season they often describe higher ground as high as 600 metres.

 

Some definitions would be good otherwise the use of the terms lower levels, lower ground, higher ground leaves one questioning.

Share this post


Link to post
Share on other sites

question regarding the current met office warnings... do you think in the future weather warnings will become more local, as in more detail per county especially in winter when it concerns snow? as many yellow warning get issued and cover certain regions but many lower lying areas see no snow what so ever and can by very frustrating to say the least. I know the text within the warning gives more detail but many people don't know the elevation of  where they live and if they will be affected or not?

The Met Office did used to do warnings by local authority area when they first used the yellow/amber/red alerts

What they found was that for some of the larger areas, like Highland, it could just be a tiny area within that likely to get the winds (for example). that is why they have changed to freehand areas

Snow and heights is always difficult, and if it is snow showers it adds another uncertainty into the mix, with some areas missing them all together

Share this post


Link to post
Share on other sites

The Met Office did used to do warnings by local authority area when they first used the yellow/amber/red alerts

What they found was that for some of the larger areas, like Highland, it could just be a tiny area within that likely to get the winds (for example). that is why they have changed to freehand areas

Snow and heights is always difficult, and if it is snow showers it adds another uncertainty into the mix, with some areas missing them all together

 Thank you for your reply, i remember when they use to issue those warnings and agree they were not very precise.... still think a time will come when  the warnings will get more localised for a specific area with a more detailed warning area style map (maybe zoom in to see an area under a warning, show specific places in that area that are most likely to be affected)

 

As i would say nearly every snow warning this winter for my area has been of no use as it has either not snowed or if it did was not severe enough to warren a warning.

 

I'm no expert of course and know how difficult predicting the weather can be.

Share this post


Link to post
Share on other sites

 Thank you for your reply, i remember when they use to issue those warnings and agree they were not very precise.... still think a time will come when  the warnings will get more localised for a specific area with a more detailed warning area style map (maybe zoom in to see an area under a warning, show specific places in that area that are most likely to be affected)

 

As i would say nearly every snow warning this winter for my area has been of no use as it has either not snowed or if it did was not severe enough to warren a warning.

 

I'm no expert of course and know how difficult predicting the weather can be.

https://forum.netweather.tv/gallery/image/21037-trafficscotroads/

This image shows button options bottom left for different road heights. Its from the Traffic Scotland twitter account. That is useful for journey planning. Maybe there could be something similar , with the more localised zoom, in the future to help with snow height forecasts to the public

Share this post


Link to post
Share on other sites

The impact matrix is fine and easy to understand. What needs to be changed, is the way they overlay them on a map. Last Winter was a prime example of that, so many warnings overlapping each other, i couldn't tell what warnings i was under.

Share this post


Link to post
Share on other sites

 

This image shows button options bottom left for different road heights. Its from the Traffic Scotland twitter account. That is useful for journey planning. Maybe there could be something similar , with the more localised zoom, in the future to help with snow height forecasts to the public

 

in Canada where I lived they have road condition maps as part of the local travel news...snow covered..partially covered..icy..or clear these are updated hourly during the day and are very useful for planning journeys during the winter months.

Share this post


Link to post
Share on other sites

×
×
  • Create New...