St Swithun’s forecast correct in 20 of the last 86 summers

Figure 1 – Courtesy of Twitter

The Met Office have claimed on Twitter (fig 1) that the bit of St Swithun day weather lore nonsense about 40 days of rain has never come true – I beg to differ, and I can prove it using data that is freely downloadable from the Met Office website itself. According to the UKP daily rainfall figures for England and Wales, St Swithun has been proved correct in at least 20 of the last 86 summers. Of course, I am stretching a point to its absolute limit with this assertion, because the UKP series is derived from gridded rainfall data, and I’m counting days with at least 0.01 mm of rainfall, but as you can see (fig 2), the last time it occurred was as recently as 2015, in fact it seems to have occurred fairly regularly in the last twenty years for some reason.

Figure 2

For the purists amongst you who like to define a ‘rain’ day as being a day with at least 0.2 mm of rainfall or more, then the number of wet St Swithun forecasts is drastically reduced, but not to zero. Interestingly, the 15th of July 1931 did herald a spell of 40 days of rain, and here’s a detail graph to prove it (fig 3).

Figure 3

For any of my loyal followers, you may have read a similar blog from me a couple of years ago, but I lost that when I deleted the old WordPress blog in a moment of madness a couple of years ago and thought that I would rewrite it.

Filberts and Midsummer Eve

It’s the 23rd of June, and today is Midsummer Eve, and tomorrow is Midsummer’s Day or St Johns day. I was just perusing my copy of the Weather Lore book compiled by Richard Inwards in 1898 as you do, to see if there were any sayings concerning midsummer, and I found quite a few, one of the best of them is this one:

If it rains on Midsummer Eve,

the filberts will be spoiled.

I already realised that any proverbs, saying or rule concerning the weather were a complete nonsense, but the Weather Lore book which lists hundreds of them just reinforced it. A filbert by the way is a type of hazelnut, and it looks like the crop will be reasonably good this year, apart from parts of Wales. Another classic is this one, which seems rather apposite for this year:

Before St John’s Day we pray for rain;

after that we get it anyhow.

 

Three fine days and a thunderstorm

Weatherwise, it looks like there’s an interesting weekend ahead of us. The low that develops tomorrow, proves that the old adage of three fine days and a thunderstorm is still alive and kicking (figs 1 & 2). I never realised that the phrase was coined by George II, but it was, according to a 2011 Daily Telegraph article by Philip Eden. And we aren’t out of the woods even when that system has cleared out-of-the-way, because later on Sunday things look like they’re going down hill again, especially in the south. There’s a reasonable amount of agreement between the UKMO and the GFS models for Saturday as far as I can see, which is good, particularly when it’s just over 24 hours away.

Figure 1 – Courtesy of OGIMET

Figure 2 – Courtesy of the Met Office

It looks like the Met Office are going for both events in a big way as far as warnings that they’ve just issued is concerned. Strangely, they exclude the overnight rain tonight in the southwest from the first yellow warning (fig 3), they obviously don’t see the amounts of rain as causing any significant problems, we shall see.

Figure 3 – Courtesy of the Met Office

It looks like model guidance is indicating that the rain that will spread north later on Sunday will be a bigger problem in the south though (fig 4).

Figure 4 – Courtesy of the Met Office

Ne’er cast a clout till May be out

Figure 1

Another touch of frost in places overnight, with air temperatures down to -1.8°C across the southeast of England this morning (fig 2). There has been a more general and sharp ground frost across most of the southern and eastern England too (fig 1), which won’t have please a lot of gardeners.

Figure 2

In fact the cold air at the moment is quite widespread across much of northern Europe and eastern Russia (fig 3), nothing exceptional, but because it comes after another relatively mild Winter and Spring so far, it’s come as a bit of a shock to some. And remember – ne’er cast a clout till May be out.

Figure 3

‘Tis neither good for man nor beast

Figure 1

According to the latest forecast charts (fig 3) it looks like we are in for a spell of cold easterly winds right through this coming weekend along the south coast and especially in the southwest. In fact it might not be till the middle of next week before that nagging easterly starts to veer round to the south. Today feels more like January than the middle of March in our part of Devon, and it reminds me of the old rhyme:

When the wind is in the east,
‘Tis neither good for man nor beast;
When the wind is in the north,
The skillful fisher goes not forth;
When the wind is in the south,
It blows the bait in the fishes’ mouth;
When the wind is in the west,
Then ’tis at the very best.

 

Figure 2

Hopefully the frontal cloud that’s spinning around the low might start to thin and break by Saturday and at least then we might get some sun, although the easterly will still be blowing. Further north things look more quiet under the influence of an anticyclone that’s firmly anchored over northern England, so there it will be more a case of sharp overnight frosts, followed by sunny days.

Figure 3