If you think that it’s been wet here in the UK so far this August, then spare a thought for the Norwegians, because it’s been much wetter in the southwest of Norway than it has here. Take a look at the inset hyetograph for Bergen (fig 1), and you’ll see that in the first two weeks of August they have already had 190 mm of rain. The wettest place in the UK in comparison is Capel Curig in Snowdonia with a total of 127.6 mm. I didn’t realise this until now but Bergen is apparently the wettest city in the world.
Tropical storm Gert passed close by the weather buoy 41047 yesterday, but you would hardly have known it (fig 2), Gert is still a relatively shallow tropical storm (~1011 hpa), I’ll let you make up your minds when it came closest to weather buoy 41047 (fig 1). The gusts to 80 and 101 knots are spurious groups in the SYNOP reports, either that or my parsing isn’t doing too well with the American buoy reports.
The latest forecast for Gert from the NHC has it close to hurricane force at T+48 early on Wednesday (fig 2), if it makes it that’ll be the second one of the season.
It won’t make landfall on the United States, as its forecast to take a sharp right in the next day or so (fig 4).
It looks like the remnants of tropical storm (possibly hurricane) Gert will find their way to this side of the Atlantic next weekend by the looks of this tracking chart from the GEFS model on the wxcharts.eu website (fig 5). The likely track looks likely to be one between the northwest of Scotland and Iceland.
The Independent today has an article entitled ‘Scientists find what they think is largest volcanic region on Earth hidden in Antarctica after student’s idea’ (fig 1). I can’t believe for one moment that this work hasn’t been previously done before by the Americans or the Russians, but apparently it was all the idea of a third-year student at the University of Edinburgh, Max Van Wyk de Vries, that would be a great collective name for the 91 volcanoes that they discovered – the Van Wyk de Vries volcanoes. They found 91 volcanoes which range in height from 100 m to 3,850 m in a massive region known as the West Antarctic Rift System.
I had to take exception with the bit that Paul Ward has written, because with a story like this there just has to be a link to AGW no matter how weak:
Previous studies have suggested that volcanic activity may have occurred in the region during warmer periods and could increase if Antarctica’s ice thins in a warming climate.
I don’t know about the reference to a previous study he carelessly throws into the article, but what it (or he) is suggesting is that if the ice cap begins to thin a little, this could encourage the dormant volcanoes to reawaken. I am no geologist, or volcanologist come to that, but I find it hard to believe that these volcanoes were effectively plugged by an icecap that formed on top of them, and that they’ll suddenly spring back into life if ever the icecap starts to thin. Surely it’s got more to do with what’s going on under the mantle, and the tectonic forces that are at play, rather than waiting for the icecap to thin? I imagine that volcanoes would have no problem finding the ir way to the surface, despite being sat under an icecap which is 4 km thick in places, isn’t that what recently happened in Iceland with the Vatnajökull volcano.
That just leaves one important question as far as I’m concerned, and that is, what are all the scientists in the many Antarctic ice stations that the nations who have staked a claim to their piece of Antarctica actually doing with their time?
First off I will admit I haven’t fully read the study “Changing climate shifts timing of European floods” by Günter Blöschl and numerous other contributors from across Europe. The study has been picked up on by the BBC in this news article (fig 1), because they obviously see that it’s just another byproduct of AGW, rather than just climate change, and yes I do think there is subtle distinction. As far as I can see, none of the many contributors are employed by the UKMO, which I find unusual.
I have highlighted in yellow the areas in the news article that I have misgivings about, the first one is from Matt McGrath
The scientists believe this is due to changes in the North Atlantic Oscillation (NAO), the weather phenomenon that pushes storms across the ocean into Europe.
The North Atlantic Oscillation is simply an index of the pressure difference between the Azores and Iceland, as far as I know this index doesn’t push anything across any ocean, you might say that the Azores high or Icelandic Low are weather phenomena, but surely the difference between the pressure at two points is just a number?
Günter is the quoted as saying:
In southern England, it has been raining more, longer and more intensely than in the past. This has created a rising groundwater table and higher soil moisture than usual and combined with intense rainfall this produces earlier river floods
I refute that, unless the changes that the study is talking about have suddenly started to occur in the last five years. Cue some evocative pictures of rivers in southern England that have dried up in recent years that I’ve found on the Internet (figs 2 & 3). (N.B. to the BBC, two can play at that game!). Yes, I know these images are from 2012, but what about the River Derwent in the Lake District in May 2017 (fig 4). So it’s a well-known fact that river levels and groundwater tables do fluctuate, and can do so very quickly, that’s what they naturally do.
I can’t get any daily rainfall climate data for anywhere in the UK without paying loads of money to the Met Office, so I am stuck with the free 1910 monthly rainfall gridded data that they produce, I wonder if they used this kind of data or if the Met Office felt pity on their research and gave them the ‘real’ rainfall station data that they guard so jealously on our behalf? From that data here are some graphs with a simple linear trend for the southeast and central southern England region for winter, spring and summer (figs 5-7). I can’t see any discernible upward trend in rainfall in any of those three seasons, although I will admit that the 10 year moving average for summer is on the rise, and won’t be any lower after this wet summer.
Günter goes on further to say:
Half the stations recorded floods at least 15 days earlier than previously. A quarter of the stations saw flooding more than 36 days earlier than in 1960.
This one is a hard one to counter, especially without daily rainfall climate data and the dates of all fluvial flooding incidents since 1960, which I simply don’t have. But I don’t see that there is some kind of flood or monsoon season across the UK that starts at any precise date that you can readily identify, and if you can’t identify it, then how can you then go on to say that it’s starting 15 days earlier than it did in 1960? I do know from my interest in CET, that the spring is probably around 15 days earlier and it was in 1960, and that temperature is linked to increased convection and heavier rainfall, but I see little sign of it from the rainfall climate data that I can access.
Finally, here’s the last 12 months rainfall over southeast England (fig 8). It’s been a funny last 12 months as far as rainfall goes, up until mid May there was talk of an impending drought later in the year across southern and eastern areas, but the wet summer has put paid to that. There have definitely been some wet days in the last 12 months across the southeast of England, but they can occur in any month as far as I can see, and the accumulated rainfall is still only 84.7% of the annual average at the end of July 2017. What I really need is now is data from the environment agency, some kind of daily count on the number of alerts that they issue for rivers across the UK, a bit like the NAO, but not a phenomena, just a daily count.
PS I’ve just download the report to read – for a change it’s free to do so – and better still it’s only four pages long.
The mobility in the weather patterns that started around the 20th of July, continues unrelentingly into the third week of August according to the latest forecast charts of the GFS model. The only difference that I can see this week is that the discrete areas of low pressure are generally a little to Iceland than to Scotland, and high pressure gets closer to southern areas by next weekend.
In fact the whole week can be summed up as changeable, windy at times, with spells of wet weather, cool at first but gradually becoming warmer by next weekend.
Tuesday doesn’t look half bad, bright and breezy with showers more frequent in the north and west. Next Saturday looks a fine day across the whole country, if this T+156 forecast can be trusted, as does next Sunday away from Scotland, when it looks almost summer like in the south, but this is not the first time that the GFS has promised this scenario in the last few weeks.
I wrote an article about KISS this week, and the forecast chart below (fig 2) is another perfect example of “not caring one hoot “about that principle looks like, from the forecasts in Barad-dûr. I often wonder what forecasters in the other Met agencies across Europe make of these convoluted forecasts and analyses from the Met Office.
The coldest August since 1910 was that of 1912. It was both wet, cold and dull. At many coastal stations around the UK the sea temperature was higher than the air temperature. In the monthly weather report for 1912 the review of the month concludes by saying
Observers in various parts of the United Kingdom noticed in the rare intervals of fine weather the sky seldom assumed its ordinary blue tint, but appeared to be covered with a hazy film “producing grey whiteness of the unclouded sky, and extreme weakness of all sunshine”. A similar appearance was noted by several continental observers.
The mean temperature for the UK was just 11.7°C which is 3.26°C below the 1981-2010 long-term average. The mean maximum anomaly for the month was even lower at 3.94°C below average. Looking at the regional temperature anomalies (fig 2), the cold was across the board.
As well as being very cold, it was also very wet, especially in more southern regions, and particularly in East Anglia which saw over three times the monthly average rainfall (fig 3).
In fact August 1912 was and still is the wettest August in the entire EWP rainfall series that started in 1766 (fig 4).
As you probably noticed in the daily charts for the month (fig 1), August 1912 was a very cyclonic month as you can see in the Lamb Circulation types for the month (fig 5).
As regards the CET for the month, I can’t remember ever seeing a summer month as cold as this one (fig 6). August 1912 was, and still is the coldest August on record back to 1659, beating even the cold year of 1695 into second place.
Not only was it the coldest August on record, it was also ushered in the start of a three-month cold spell in central England, with a cold September (mean anomaly -2.5°C) and October (mean anomaly -2.4°C) to follow (fig 7).
At this point I would like to produce some statistics to show that August 1912 was also the dullest on record, but I can’t, the Met Office maintain that they only began measuring sunshine from 1929. The MWR comes to the rescue though, because it says about sunshine:
Sunshine was very deficient, a large number of stations situated in nearly all parts of the kingdom recording considerably less than half the average amount. In the Channel Isles and at a few places in the extreme southeast of England the mean daily duration ranged between 4 and 4½ hours, and was equal to about 30 percent of the possible. Over Central and Southern Scotland and at a few places in the northeast of England the daily duration was less than 2 hours; at Crathes, Glasgow and Eskdalemuir it amounted to only 1o percent of the possible.
What caused it?
Here’ a graph of 12 month rolling CET values for around that time, forget the date in the subtitle, another bug for the programmer to fix. I’ve overlaid the volcanic dust index events that were greater, or equal to 4, on the VEI on top of the line series, and as you can see the Novarupta event (VEI 6) looks like it may well have been responsible for global cooling that also affected our own CET series back in 1912 across, and fits well with the reports of a greyish white haze from the Monthly Weather Report for August 1912.
I had never heard of the Novarupta eruption until I started researching this article today. I never even realised it was the most powerful volcanic eruption of the 20th century, here’s what the Wikipedia article had to say about it:
The eruption of Novarupta in the Aleutian Range began on June 6, 1912, and culminated in a series of violent eruptions. Rated a 6 on the Volcanic Explosivity Index, the 60-hour-long eruption expelled 13 to 15 cubic kilometers (3.1 to 3.6 cu mi) of ash, 30 times as much as the 1980 eruption of Mount St. Helens. The erupted magma of Rhyolite, Dacite, and Andesite resulted in more than 17 cubic kilometers (4.1 cu mi) of air fall tuff and approximately 11 cubic kilometers (2.6 cu mi) of pyroclastic ash-flow tuff. During the 20th century, only the 1991 eruption of Mt. Pinatubo in the Philippines were of a similar magnitude; Pinatubo ejected 11 cubic kilometers (2.6 cu mi) of tephra. At least two larger eruptions occurred in the 19th century: the 1815 eruption of Tambora (150 km3 (36.0 cu mi) of tephra), and the 1883 eruption of Indonesia’s Krakatoa (20 km3 (4.8 cu mi) of tephra).
There’s a interesting article on the Geology.com website about the eruption that you might find useful.
The latitude of the Novarupta eruption was just about perfect at 58° north for maximum effect across the northern hemisphere, as was the timing of the 6th of June to coincide with the cold months of August, September and October of 1912 in the CET series. I should imagine that the ash from the eruption would have taken at least a month or so to completely encircle the northern hemisphere and reduce the amount of sunlight. I am of course completely guessing that this was the cause of the cold August of 1912, I’ll have to spend some more time looking at NCEP reanalysis surface temperature data for 1912 to see just what affect it had on other countries across the northern hemisphere to completely be sure of my assertion.
Finally here are the daily CET values for the Summer of 1912 (fig 11), which I think says it all. This is one of the better articles that I’ve put together for my blog, I found little evidence of any link between the cold August of 1912 and Novarupta in any of my climate and weather books, and even though Philip Eden does mention the poor summer of 1912 in his book ‘Great British Weather Disasters’, he doesn’t make the link with the volcanic ash of Novarupta. August 1912 does get a short mention as the worst on record in the book ‘The Wrong Kind Of Snow’, but again no mention of why. So if you thought that August 2017 has been cool in its first ten 10 days, the mean temperature for the first 10 days of August 1912 was 2.5°C colder still.
NOAA seem to believe that the signs are now there to indicate that the North Atlantic hurricane season is going to be a lot more lively that they thought back in June. So far we have had one short-lived North Atlantic hurricane, NOAA are now predicting between 5 and 9 this season. I’ve never seen them amend their forecast mid-season like this in the five years or so that I have been closely following the subject. I haven’t seen any tropical storm activity this year, although I could be wrong, that has originated from around the Cape Verde Islands, which I would have thought would have been one of the prerequisites for hurricane development, but what the hell do I know.
According to Wikipedia the acronym KISS means “Keep it simple, stupid” and was a design principle noted by the U.S. Navy in 1960.
The KISS principle states that most systems work best if they are kept simple rather than made complicated; therefore simplicity should be a key goal in design and unnecessary complexity should be avoided. The phrase has been associated with aircraft engineer Kelly Johnson (1910–1990). The term “KISS principle” was in popular use by 1970. Variations on the phrase include “Keep it Simple, Silly”, “keep it short and simple”, “keep it simple and straightforward” and “keep it small and simple”.
I’m usually reminded of the KISS principle when I see a forecast or analysis chart from the Met Office similar to the one above (fig 1), for some reason. You could argue, that a set of forecast charts is a system in its own right, and if it is, then why over complicate it? Met Office charts in the past weren’t always as complicated as they seem to be today, but try as I may, I can’t find any images of fax charts from the past on the internet to illustrate that fact.
If they had only fitted a rainfall gauge to the AWS at Broadness on the Thames at Gravesend, they probably would have measured over 50 mm of rainfall in the 24 hours ending 06 UTC this morning (fig 2). I still can’t understand why this heavy rainfall event didn’t cause any pluvial or fluvial flooding issues yesterday in this part of the world.