Wet in the Lake District

Figure 1

The cold front that’s been sat over the Northwest of England for most of the last 24 hours or so has finally cleared through (fig 4), but not before depositing over an inch of rain on Keswick since midnight (fig 2).

Figure 2

In fact some of the estimated totals for the Cumbrian fells are in the 75-100 mm pixel colour category (fig 3). The rain shadow effect is pretty spectacular too (Fig 1), with Leeming on the other side of the Pennines in the Vale of York, receiving only 0.2 mm of rain.

Figure 3

I noticed that the Met Office did issue alerts for possible flooding from the orographic enhanced rainfall event this morning.

Figure 4

Two big questions regarding Polar sea ice

Now that we’ve seen both the lowest Arctic sea ice maximum and the lowest Antarctic sea ice minimum records broken this year, the two big questions regarding Polar sea ice are:

  • How low can the Arctic sea ice minimum get this summer?
  • Can the Antarctic sea ice bounce back this winter after such a catastrophic melt in the summer?
Figure 1

The Arctic rallied towards the end of this Winter but the 14.447 still couldn’t quite match the previous lowest maximum of 14.554 million square kilometers set on 22nd of February 2015.  So just by looking at the stats, it seems that this summer may push the minimum of 3.34 million square kilometers of September 16th 2012, but the minimum that year was abnormally low even for the Arctic, and may take some beating.

Figure 2

The Antarctic sea ice on the other hand is starting the year extremely low at 2.075 million square kilometers. It will be interesting to see if it can catch up, but that’s a tall order, and this winter we might see a record low maximum, the previous lowest maximum was 18.027 million square kilometers set on September 18th 1986.

The end of Arctic sea ice in summer is still a long way off as far as I can see. A simple linear trend on each years minima puts zero summer sea ice in 2066. I’ve tried another type of polynomial line fitting curve but I can’t extrapolate a forecast from that, so that’s my best guess at the moment.

 

The Torrey Canyon and the Seven Stones reef

Figure 1 – Courtesy of Wikipedia

The Sevenstones Lightship (fig 4) is anchored 15 miles (24 km) to the west-northwest of Land’s End, and 7 miles (11 km) east-northeast of the Isles of Scilly (fig 1). According to Wikipedia, there has been a Lightship there since 1841, to warn vessels of the danger of the Seven Stones reef, which over the years has sunk 71 named ships, and possibly another 200 unnamed others. I would like to give you more details about the Seven Stones reef but it’s impossible to get a decent detailed bathymetric map for around the coast of the UK, it seems that although we may have ruled the waves for a long time, we now charge an awful lot for finding just out how deep the waters are around our sceptred Isle, perhaps the Ordnance Survey can take over the Hydrographic Office and free up some of this data, but I digress.

The Seven Stones reef is where the Torrey Canyon came to grief 50 years ago on the 14th of March 1967. The accident happened in daylight, when the ship was still to the southwest of the Lightship, but the reef is almost 15 miles long. The board of inquiry laid the blame on the Captain, who was apparently taking a shortcut to save time getting to Milford Haven (fig 2), maybe if their approach had been at night, he might have spotted the light and avoided the disaster, who knows.

Figure 2

Believe it or not this article started out being about the wave heights this Winter reported by the Sevenstones Lightship! I didn’t at first consciously connect the 50th anniversary of the Torrey Canyon disaster with the Sevenstones Lightship, so here’s what’s left of the original article that I’ve written.

Figure 3

The above chart is of hourly wave heights, as reported by the Sevenstones Lightship from the 1st of December 2016 through this last Winter (fig 3). On top of the hourly scatter graph I’ve overlaid four of this seasons five named storms. The highest reported wave height of 7.4 metres this Winter, occurred during the unnamed or Candlemas low of the 2nd of February. The other named storms align poorly with any of the peaks in the 24 hour moving average of wave heights that I’ve also plotted for Sevenstones though.

Figure 4 – The Sevenstones Lightship

Is the UK getting wetter?

I was just looking through the climate records that the Met Office provide for downloading across the country. I had written an application, as is often the case it was another one of my climate and weather applications that I had sadly neglected to finish off. The Met Office are very frugal when it comes to allowing people to access climate data, and it’s no different with this historic station data series. Take a look at the scanty coverage of monthly climate data they make freely available (fig 1). The monthly climate data is limited to just 37 stations across the entire UK, three of those stations have closed. Here in the entire southwest of England, there are just three long time series available to download, Camborne, Chivenor and Yeovilton. No climate data available for St Mary’s, Plymouth, Exeter or Dunkeswell, even with the headquarters in Exeter.

Figure 1 – Courtesy of the Met Office

Not that you get a great deal of climate information in the monthly data that they do release (fig 2). There is no information regarding the frequency of wind speed, direction or highest gust during the month, no MSLP information, no frequency of visibilities, no days of fog, thunder, gale, ground frost, hail, sleet or snow, just the barest of bones – why give it away when someone will pay you for it?

Figure 2

Following on from the article that I wrote about Climate changes in the UK since 1910, I thought that I would use this monthly data to see if I could find any long-term trends in annual precipitation from some of the 28 available climate records from stations across the country. I start with Sheffield, which has a long climate record that started in 1883 (fig 3). In my application I decided to display three charts for precipitation, the top one displays a 12 month rolling accumulation for the entire record. With the top graph you can select a period (yellow overlay), and display that period as a bar chart of monthly totals and monthly anomalies in the lower two charts.

As far as I can see using a simple linear trend in the accumulation series, there has been a +11.5% increase in annual precipitation in the last 133 years in the City.

Figure 3

Oxford has an even longer record that stretches back to 1853, but the increase there is only +2.6% in the 163 year record (fig 4).

Figure 4

Armagh has a rainfall record that also stretches back to 1853, but there there’s been a -1.4% decrease in annual rainfall (fig 5).

Figure 5

The Wick record which started in 1914 shows an increase in annual precipitation of +7.3% (fig 6).

Figure 6

The Stornoway record that started in 1874 shows a decrease in annual precipitation of -1.7% (fig 7).

Figure 7

It’s a bit difficult to find a climate station with a long climate record in the south so Heathrow which started in 1948 will have to do. It shows an increase in annual precipitation of +3.7% (fig 8).

Figure 8

These results obviously need plotting on a map if you are to try to make any sense from them, which I will get round to, but for now these results will have to do. I am surprised to find that a couple of stations did come up with drier trends, it could of course be down to the fact that I haven’t used a fixed time period for the linear trends.

To finish, I’ll just display the monthly England and Wales precipitation series that’s also free to download from the Met Office (fig 9). That series started in 1766, and shows a +5.3% increase in annual precipitation in the last 250 years across England and Wales. So I would say that it has been slowly getting wetter, certainly in England and Wales, but I need to do a much fuller analysis than this very limited quick look. There is one thing that I have found out conclusively though with this bit of programming, and that is rainfall records extend much further back than 1910!

Figure 9

Let me know if you spot any statistical howlers in this piece.

Met Office DataPoint changes

Figure 1 – Courtesy of Met Office

The Met Office have just announced a big upgrade to their DataPoint web service. I can see they have made many changes to the service, which in my opinion has been dying a death ever since it started around five years ago. They seem to like the idea of Big Data, but what I would like to see from them is MORE FREE DATA*, but there is absolutely no mention of any additional new data in their press release. By more free data I mean climate, observational and forecast data, because at the moment the service provides precious little in the way of satellite imagery or any detailed NWP data, I would like to think that’s all about to change, but I very much doubt it. In a recent request on the DataPoint Forum the Met Office asked:

The Met Office is currently evaluating how data users interact with environmental data held on DataPoint and we would like to hear your views on your experiences of using API data services, what aspects are important to you and what changes you would like to see?

I replied with the following comments:

If you mean by ‘environmental’ climate and observational data then Data Point continues to disappoint and I quite rarely run the applications that I developed to access data from it.

Observational data I get by using OGIMET to download SYNOP data. From that I can glean rainfall and sunshine totals, and extreme temperatures from across the whole world not just the UK and in real time. The ADDs web service run by NOAA provides me with the latest METAR and TAFs. I scrape the latest lightning information from Blitzortung. The latest analysis and forecast (fax) charts form the Met Office I get from Wetterzentrale. I scrape high-resolution satellite (tiled) images every 15 minutes from the Met Office and do the same for weather radar. I use OGIMET to look at the GFS NWP output at 3 hourly intervals, it’s not quite the same as getting your hands on the values like you can from DataPoint though. I use the Met Office for Daily CET data, as well as daily UKP (why can’t this be daily) and monthly EWR. I download polar sea ice data from the NSIDC, I download reanalysis gridded data for MSLP and air temperature from them well in NETCDF format, along with the latest ENSO data and the NAO and PDO indices. I shouldn’t forget the UAH and GISS global temperature data, although I do pick up CRUTEM4 data from the Climate research unit at the University of East Anglia, who also provide me with the Objective Lamb Weather Types for the UK.

So as you can see DataPoint as it is at the moment, almost pointless for either UK or global environmental data.

You could improve it of course, in fact very quickly, by the addition of hourly rainfall totals and perhaps 5 minute SFERIC data (forget the static image). Daily climate data from all the UK climate sites that the Met Office don’t publish would be extremely useful, perhaps this could be achieved by publishing the National Climate Messages at 0900 and 2100 each day.

Why not publish all hourly UK SYNOP & NCM data in a similar way to how OGIMET do it – this data is from a proper network of operational stations and so much more useful than the millions of observations collected by WOW. If I require observations for all SYNOPS in Poland for a specific day from OGIMET you just create a URL like this:

http://www.ogimet.com/cgi-bin/getsynop?begin=200912150000&end=200912152359&state=Pol

Just maintain an hourly SYNOPs archive on an FTP server – it really doesn’t have to be anymore complicated than this to work.

Recurring theme on a cold northerly (part II)

Earlier this month I wrote a piece on a couple of northerly forecast frames in the GFS model that came to nothing. Well instead of learning my lesson, and just keeping my mouth shut till at least next winter, the GFS have gone and done it again (fig 1). This time it looks a bit more certain, but then again I would say that to justify this blog, which I might live to regret. This time it’s not so much a classic northerly, but more of a complex area of low pressure, embedded in a trough of cold air, that transfers from the northwest to the southeast of the British Isles, with a strong north and then northeasterly airstream following on behind, as a belt of high pressure builds to the northwest. If this comes about all I can say is that it’s a good job Easter is later, rather than early this year, and it will certainly will put a stop to March being one of the mildest on record this year.

Figure 1 – Courtesy of OGIMET

As most readers will know, I’m no big fan of the ECMWF, but I thought that I would check out their forecast solution (fig 2).

Figure 2 – Courtesy of ECMWF

So instead of a strong north, veering northeasterly flow as forecast by the American model, the ECMWF have a strong (at least in the north) anticyclonic (at least in the south) westerly solution. I’ll revisit these forecasts in eight days time to see just how close these two models get, it certainly doesn’t inspire me with any confidence that two of the world’s best NWP models, come up with such disparate solutions at this kind of range.

Top ten mild start to March

The first 15 days of March 2017 have provisionally made it the 10th mildest start to March in Central England since 1772. Currently the mean to the 15th is 7.97°C or +2.77°C above the 1961-1990 long-term average. Whether it will be able to keep to through the rest of the month remains to be seen. I did make a rash statement that it wouldn’t beat March 1957 in one of my earlier missives, which may now be looking a bit rash on my part! The blue line in the top chart is the 2017 mean, and the red one 1957 (fig 1).

Figure 1

Dull start to March in the southwest

The first half of March has been disappointingly dull in the southwest of England and Wales. Camborne has only recorded 30.4 hours of bright sunshine, in comparison Boulmer in the northeast of England tops the list with 76.5 hours.

The same Atlantic feed of cloud that made the southwest of the UK so cloudy and dull has also affected much of northern and central France, whilst in comparison many places in Iberia have already clocked up well over 120 hours of sunshine already this month.

Recent changes in North Atlantic SST

Figure 1

I thought that I would compare changes in the North Atlantic SST by using two charts, one from the 14th March 2017 (fig 2), and one from the 13th of March last year (fig 1). It looks to me that in the last year sea surface temperatures seem to have warmed by 1 or 2°C in many areas where the North Atlantic has influence. The cold pool that has been resident in the central Atlantic for so long, now seems to have shrunk and become less well organised as it once was. Waters around the British Isles and for much of the North and Norwegian Seas have predominantly positive SST anomalies. I have no idea what the current SST setup in the Atlantic might mean for the weather in our part of the world for the rest of this year.

Figure 2