Warning systems – which is the most helpful?
I couldn’t help notice the discrepancies between the warnings the Met Office have in force for today – which is nil – and the ones Met Eireann have issued – which is two – one for strong winds and the other for ice and snow. Similar conditions are affecting western coasts of coth countries. I’m no big fan of impact based warnings which the Met Office simply adore. The reason for that is they can discount conditions depending on where in the country they occur depending on their ‘impact’. ‘Impact’ as far as I can see basically means that rules are not fixed but differ according to the population of the area and number of people it may affect. So gusts of 50 to 60 mph across the outer Islands of Scotland aren’t strong enough to trigger a yellow warning for strong winds, but would if they occurred over the bulk of England and Wales. That’s all very well if people reading the warning understand this is the case but it’s likely they don’t – and similar to the NHS postcode lottery. The Met Eireann’s warning system is threshold based – it’s simple, logical and easy to understand and no impact matrix. For instance the rules for a yellow warning of strong wind is issued if they are :
- Widespread mean speeds between 50 and 65 kph
- Widespread gusts between 90 and 110 kph
Notice that for strong winds they also include a threshold for 10 minute mean wind speed, which any meteorologist will know is equally as important as maximum gust, and which the Met Office never ever quote. Here’s this mornings 09 UTC plotted chart and the latest warnings board from the Met Eireann website as an example:
And here’s the Met Office view…
The screenshots illustrates the difference between the two warning systems with regard to wind and ice for today. I think that you will agree with me that the Met Eireann system gives anyone living in Ireland a much clearer picture of the weather hazards they may face if they venture out than does the UKMO system and “No warnings” guidance. You could argue that the local weather forecast for southwest England mentions the fact that winds will be near gale force around the coast of Cornwall, but in my opinion local forecasts should be reinforced by a yellow warning like the Irish have done today for county Donegal. Likewise many of the higher routes in Scotland today will be affected by ice and snow but you wouldn’t find a mention of it on the Met Office system.
I’m quite sure that in the near future the whole warnings system will be handled by computers interrogating mesoscale NWP models and issuing warnings automatically using a GIS based system. Hopefully when they do warnings will be issued dependent on thresholds rather than impacts, but I somehow doubt it.
I couldn’t help notice that Met Eireann yellow warning for strong winds really could do with extending to cover county Galway as well as Donegal judging by the wind speeds at Mace Head. I never realised that there was an atmospheric research station there until I wrote this article just now.