Temperatures across England are already widely 2 or 3°C warmer than they were at the same time yesterday (fig 1), and a new record warmest 7th of May looks a possibility, although the previous record, according to the TORRO website of 29.0°C set in 1976, will take some licking. The warmest temperature at 10 UTC today (fig 2) look to be further east than they were yesterday, although if anything the easterly gradient is weaker than it was over London and the southeast.
We might see a week with higher mean maximum temperatures, but I think it’s a distinct possibility that we won’t see a week with higher maximum anomalies or more sunshine than we saw across the southeast of the country. The highest mean maximum anomaly for the week was 8.3°C above the 1981-2010 long-term average at Northolt (fig 1), and the sunniest place was Manston in Kent with 79.3 hours in the seven days (fig 2).
Central London might have been the warmest place in the UK once again yesterday but is it healthy? The latest forecast of carbon monoxide from the Copernicus site suggest that the air quality here and other European centres is very poor for so early in the year. I only came across the Copernicus website thanks to a tweet, but it does seem to have all the answers when it comes to aerosols, pollution and the quality of the air we breathe.
Provisionally, yesterday was the warmest 18th of April since the daily series of the CET began in 1772. The mean temperature of 16.7°C was a whopping 1.8°C higher than the previous for that day back in 1945, and almost 8.3 °C above the 1961-1990 long-term average (fig 1). There looks little doubt that today will see another extreme record set for the 19th of April as well. Here’s a look back at yesterdays 06-18 maximum temperatures (fig 2).
I’ve been trying to compare forecast temperatures from the Met Office and MeteoGroup to see which NWP model was the more accurate. Here are their forecasts for yesterday (fig 1).
As you can see they use a more or less common set of major cities across the UK which helps. On Twitter the Met Office seem to prefer labelling the 1400 temperature rather than the 1600 temperature as the BBC do, so a direct comparison is difficult. It might be a little easier if both of them displayed a much more useful maximum temperature [06-18] for the day, but that would never do would it? I noticed that in their video forecast for today, the Met Office had switched to labelling temperatures at 1500, although I can’t seem to figure out where that 11°C label is for in this mornings (fig 2).
As you know daytime temperatures are notoriously difficult to forecast with variable cloud at anytime of the year, but especially so in spring with breezes of cold seas, and as you can see there were was a large range in forecast temperatures from the two models for yesterday. Here are the actual air temperatures for 1500 BST for comparison purposes (fig 3).
Despite the timing differences I mentioned above, I make it that as far as yesterday goes, the Met Office forecast temperature was closer to the actual temperature (at 1500 BST) than was the MeteoGroup forecast at 60% of the 14 city sites. Of course I need to put in quite a bit of work over a longer period to see which model is the more accurate.
There’s a very similar circulation pattern in control of this weeks weather to the one at the end of February, with an anticyclonic easterly flow affecting all parts (fig 1). The big difference is that the air mass at the end of February was much colder, but additionally spring has sprung, and Eurasia has warmed, so the 06 UTC anomalies look very different (fig 2) despite the warming or cooling effect of the North Sea.
I’ve been putting some development work into what is a fairly complicated application that generates temperature anomalies across the world (fig 1). As you will realise, as well as requiring the latest observational data to calculate a mean temperature, you must also must have the average temperature for the same period to calculate an anomaly, which for periods that are not exactly monthly isn’t possible without daily mean temperatures for thousands of stations around the world which you won’t get without spending a great deal of money with the Met Office.
The cheapest solution is to take the monthly averages which they don’t seem to mind giving away. You then can, with a clever bit of curve fitting, come up with some polynomials to estimate a daily temperature. Once you have loaded your application with the historic data that’s freely available for the UK from the Met Office website, and added in the CRUTEM4 station data for the rest of the globe, you can generate an anomaly chart for the first 10 days of April as you can see (fig 2). There are a few obvious bad anomalies in the mix that I’ve plotted, but on the whole it’s workable, and can’t be too far from reality. It needs more work, and hopefully I can add 1981-2010 averages from the weather buoys and fixed rigs to help fill in a few of the gaps.
The output from the application illustrates extremely well just how warm the weather of the last week has been across Germany and eastern Europe, and how cold it’s been further north over Scotland and Scandinavia. I’ve still yet to verify my estimates just to see how close I am to reality. Here’s a bit more of a close up of the British Isles (fig 3).
A thoroughly miserable wet and dull start to April in many parts of the UK, in stark contrast to the unusual warm and sunny spring being enjoyed in parts of Germany and eastern Europe. In the UK the contrast between Cornwall and Devon is large, with Camborne’s 37.8 hours of sunshine over twice that of Exeter’s 18.5 hours and poor old Liscombe with just 7.6 hours. The north and west of Scotland and the extreme west of England and Wales along with southeastern parts have also seen more sun, and the sunniest place in the UK so far this month is Tiree with 47.3 hours, but that figure is low in comparison to the 60 plus hours on the continent (fig 1).
A thoroughly wet start to April across most of the country apart from the drier northeast of Scotland and southeast of England (fig 2). The 19.4 mm from Exeter airport looks dodgy as I’ve already recorded 45.7 mm so far this month only 10 km away to the north. I’m afraid that this spring is looking like it’s going to be a cold wet protracted affair in the UK.
Q: Are winters becoming milder and wetter?
A: The short answer is yes they are. The Central England temperature series [CET] reveals that winters [DJF] are now on average 1°C warmer that they were 140 years ago back in 1878 (fig 1), and the England Wales Precipitation [EWP] series indicate that they’re also 18.6% wetter (fig 2).