Weather warnings are a bit like busses none for weeks and then three come along at once. Low Arne as the Germans have named it – not for Schwarzenegger but more likely a Norwegian name meaning eagle – will do a pirouette across the Celtic sea early on during Saturday deepening as it does so. If the deepening of 24 hPa (09 UTC on Friday to 09 UTC on Saturday) in 24 hours is correct in the ICON forecast this would classify it as explosive. If Arne does turn out to be a weather bomb and is coupled with gusts of 70 mph on the coast and 60 mph inland as it comes eastward across southern areas this is still not good enough credentials to make it a named storm according to the powers that be.
Take a closer look at the two yellow heavy rain warnings that have been issued by the Met Office for this weekend and you’ll notice that the one for the south of Wales scores higher in the impact matrix than does an almost identical warning for eastern Scotland. The only conclusion you can logically draw from the impact matrix is that people and property in south Wales are more important than those in eastern Scotland. Perhaps the impact is assessed on the population of the area and the statistical likelihood of someone getting drowned? To illustrate just how ludicrous impact based warnings are – see if you can identify which of the following two pictures was taken in recent flooding in Aberdeenshire and which one in south Wales.