Provisionally, yesterday the 6th of May was the 2nd warmest since 1878 in Central England with a maximum of 22.8°C, which was over 8°C above the 1961-1990 long-term average for that day (fig 1). Today’s maximum temperature is on course to beat the previous highest for the 7th of May set in 1976 of 23.3°C, with temperatures at 09 UTC already much higher than at the same time yesterday.
There’s a lot of talk at the moment about the possibilities of tomorrows Bank Holiday being the warmest on record. Call me an old stick-in-the-mud traditionalist if you want, but I like to think of the early May bank holiday as being linked to the pagan holiday of May Day, which tradition has it falls on the very first day of the month for some obscure reason, and not the first Monday as it does now. I could write some code to list the warmest, but to hell with that, I thought it was much quicker just to look at warmest May Day’s rather than the warmest Bank Holiday which flits around from year to year. Anyway looking at maximum temperature in Central England it looks like the warmest since 1878 was back in 1966 with a temperature of 23.7°C which was almost 10.2°C above the 1961-1990 long-term average (fig 1).
The synoptic situation back in 1966 was not that different from the one at the moment (6th May 2018), with high pressure to the east and a col over western areas (fig 2). Why back then in SYNOP reports we rounded temperatures to the nearest whole degree and reported pressure to tenths of millibars now looks rather odd, even allowing for low power communication speeds with Baud rates of less than 9600 (fig 3).
Looking back at the warmest May Day mean temperature since 1878 in Central England, 1990 and 2005 with 16.1°C tie for the honours for that (figs 4 & 5).
I was keen to publish the fact that Thursday – the 19th of April – had been the warmest for that day since 1772 in Central England, but because there’s be an ongoing communications or observational problem down at the Met Office, I was delayed till the CET data for Thursday finally arrived this morning.
The 19th also set an extreme maximum record (23.0°C) as well as a new highest mean of 16.4°C, which was 7.95°C above the 1961-1990 long-term average, and a full 1°C higher than the previous high set in 1870.
Extreme records like this don’t happen that often, but in my experience when they do you often get a pair, as was the case with the 18th and 19th of this month. These values are of course provisional but I doubt if they’ll change much.
There may be a chance that the 20th has also set a new extreme to make it three in a row, but because of the data problem I won’t know that till tomorrow at the earliest. Don’t forget you can keep up with the latest daily CET on my Meteograph website.
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).
There may well be a warm spell coming later this week, but I’m afraid that even with these high temperatures, April 2018 won’t be a patch on the exceptionally warm April of 2011 (fig 1), which in fact was the warmest since the data series began in 1659 (fig 2) with an anomaly of +3.93°C. It didn’t just sneak past the previous warmest April it smashed past it (fig 2) by over 0.6°C (2007), which in itself was over 0.5°C warmer than the previous warmest April. Is it just me, or do we all have short memories of memorable warm spells?
Here’s April 2011 in a little more detail from the daily series of the CET (fig 3).
To give you an idea of just how warm it was, here are the hourly temperatures and running 24 hour mean from Heathrow airport courtesy of OGIMET (fig 4).
Nothing very spectacular about this March as a whole despite the record cold start to the month. The mean temperature of 4.93°C was 0.74°C below the 1961-1990 long-term average, and made it the coldest since the record cold March of 2013 that everyone seems to have quickly forgotten about (fig 1).
Three new record low daily maximum temperatures since 1878 were set during March (blue diamonds fig 2), and of course the 1st of March as well as having the lowest maximum also had the lowest mean temperature since the daily series started in 1772.
The March of 2018 was only the sixth cold March in the last 30 years in Central England (fig 3), and March as a month has been warming at a rate of 0.114°C per decade since 1878.
Because Easter Sunday’s can fall on any date between the 22nd of March and the 25th of April so they are a bit of a moving target when it comes to measuring how cold or warm each one has been. I’ve measured Easter periods as the five days between Maundy Thursday right through to Easter Bank Holiday Monday since 1772 in the central England temperature series. It might surprise you to find that the mildest Easter on record occurred as recently as 2011, when Easter Sunday fell on April 24th, and the mean temperature for the 5 days was 14.5°C making it 5.6°C warmer than average (fig 2).
Conversely the coldest Easter on record occurred in the year 1883 when Easter Sunday fell on the 25th of March, and the mean temperature for the five days was only 0.7°C and 5.4°C below the long-term average (fig 3). The most recent cold Easter occurred in 2013 and currently lies 5th coldest in the 245 year series.
This article gave me the distinct feeling of déjà vue, so I did a quick look back through the 1,482 articles that I’ve published in the last two years, only to find that I had written a very similar article last year – perhaps I’m losing the plot! To be fair there is one slight difference between the two articles, in that last year I compared mean anomalies over 5 days rather than mean temperatures, so all is not lost.
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).
Punxsutawney Phil is the name of the groundhog in Punxsutawney, Pennsylvania, who on the 2nd of February this year, saw his own shadow and duly shot back down his hole again knowing full well that there were still six more weeks of Winter to come (fig 1).
A quick glance at the percentiles from the daily temperatures from Central England since then (fig 2), proves that Phil was absolutely right to bolt back down his hole, and miraculously for no reason other than pure chance, his forecast was correct for us even on the other side of the Atlantic.
I am reliably informed that the spring vernal equinox will occur at precisely 1615 UTC today this 20th day of March 2018, but the weather is in a fickle mood at the moment, and spring, well at least the start of it, looks like it will be a cold affair in our part of the world. The Met Office in their extended outlook till the middle of April (fig 1) is being its usual unequivocal self about the possibility.
In line with that outlook, the GFS model for April 1st (fig 2) is forecasting a northerly outbreak which is not at all unusual for spring across the British Isles.
Cold springs are somewhat of a rare commodity these days, and the last one to produce negative anomalies in Central England was back in 2013 (fig 3), and in the last 30 year there have only been three cold springs (2013, 1996 and 1991).