Admittedly rainfall accumulations this month are completely topsy turvy, and it’s still been a very dry month in many parts of Scotland, but the meteorological drought that affected many parts of the south did come to an abrupt end this week with some heavy rain, as droughts so often do. I’ve tried to wheedle out plotting totals for stations where I had more than 25% of reports missing, having said that there are still a few oddities, Rhyll being one of them, although the 6.4 mm total there is kind of supported by the 13.6 mm at nearby Hawarden.
I’ve just rejigged the code for this application, and it now uses a combination of priorities to get the most accurate result. If there’s a 24 hour 06-06 total that’s great it will use that, and many of the main UK of stations have a 100% reception rate using that value alone. If there isn’t a 24 hour total, like in Ireland and parts of Europe, I add up the available 12 hour totals (06-18 & 18-06). Finally if there are only 6 hourly totals, as in the United States I add these up. The Americans, as far as I can see, don’t report nil rainfall totals as we used to do at one time, so you have to rely on the indicator in the initial block being correct. The whole area of rainfall reporting in SYNOP from different countries is a complete nightmare to program, and I still have to write code that throws back totals to the previous day, but for now this will have to do. If you have any complaints about any of the totals, please feel free to have a go yourself.
The temperature at 11 UTC was 16.3°C here in Bradninch Devon from my trusty Vantage Pro. I notice that it had reached 16.9°C just before 12 UTC. The sea breeze that’s keeping it cooler at Exeter airport, hasn’t quite made it this far north as of yet.
These are some plotted climate charts for yesterday across the British Isles and near continent. They include sunshine for yesterday, precipitation [06-06 UTC] and maximum [06-18] and minimum temperatures [18-06]. It’s not particularly exciting I know, but I was just looking at another way of displaying the charts that I generate from how I have done it in the past.
Figure 1 – Courtesy of Mount Washington Observatory
The last week’s weather has been quite eventful atop Mount Washington, in the (very) White Mountains of New Hampshire. The observatory reports every six hours and here are the plotted SYNOPs for the last week (fig 2). As the low that produced the nor’easter of the last 24 hours passed to the east, the winds at the observatory increased to mean 82 knots at midnight.
As you can see last week the freezing level was above the top of the mountain (6,288 feet) and there were rain showers in a force 10 southwesterly, and just three days later the air temperature had fallen to -38.0°C and the winds had increased to mean 65 knots and veered west northwesterly. There are a couple of things that puzzle me about their observations, and one of them is snow depth. Why do they even bother trying to report a representative snow depth? Last night for instance, the mean wind speed was 82 knots (94 mph) and was gusting to 128 knots (147 mph)? And yet between midnight and 06 UTC, they reported that the snow depth had increased from 20 to 21 cms (fig 3). There is no way on earth that could be level snow, and what snow that did stick would be on the lee side of the mountain or observatory and considerably drifted and corniced. By the way, I’m assuming that the local nine group they use in their observations (93128), is in fact a gust group that only seems to be added, when the gusts are 100 knots or higher. I know that the Americans, like the Australians, aren’t big fans of the SYNOP format, but why can’t they just use the WMO standard reporting group for reporting gusts?
In comparison and with typical German precision at the Zugspitze Observatory in the Alps they do things a little more by the WMO book (fig 4). They report hourly observations for a start, that includes gusts, a believable snow depth, it may well be that because the winds are lighter there that they can do this more easily. Snow depths increased in excess of 4 metres during the last week there. They also report rainfall (equivalents) and air pressure adjusted to the 700 hPa level, which Mount Washington don’t do in a four group, just a ‘as read’ pressure in a three group. One thing that the Americans do report, which I think should be adopted more widely, is six hourly max and min temperatures.
Temperature now 17°C in Bradninch at 1350 UTC a gloriously sunny spring afternoon which makes a change from the overcast weather of the last few weeks.
The AC layer has thinned, and it’s been sunny for most of the last hour.
As an ex-metman I don’t get round to doing many SYNOP observations of my own these day, so when the Exeter airport observation went missing (again) and the temperature here reached 60°F, I thought that I would make up a WMO designator (03838) for our village of Bradninch, and add one of my own SYNOP observations with a little help from my trusty Vantage Pro.
I’ve just been putting some finishing touches to an application that generates a meteogram of climate data for any SYNOP station in the world. I call it a meteogram, because it attempts to generate a cross-section using graphs of the weather for a location. Because OGIMET allows you to access hourly observational data for any station, this provides a very good way of looking back at the climate of a place in the absence of NCM data being available. Here’s one hot of the press for last month at Exeter airport. Although reception was 100% for all observations, some climate sections could still be missing resulting in incomplete totals for rainfall and sunshine.
Because of the anticyclonic nature of this meteorological Winter with 58 days of it gone so far, the air frost count across the British isles is looking fairly respectable as you can see from figure 1. There is certainly a cold pole in central southern England due to the frosts of the last week, but there are still a number of stations holding out at zero air frosts so far this Winter.
An interesting chart plotting the total number of ice days (fig 2) across Europe so far this Winter, so if you think you that we’ve had a few hard frosts or even the odd ice day in the last week or so, have a look at further east and think again.
Of course, before someone points this out to me, ice days are when the temperature fails to rise above freezing over a 24 hour period, usually from 0900 to 0900. This chart is a count of days when the 06-18 maximum is less than 0°C, that’s because not all countries (including the UK & Ireland) report a 18-06 maximum along with their 18-06 minimum in their SYNOP reports, or an 06-18 minimum to accompany the 06-18 maximum come to that, so this will have to do. I won’t even bother trying to sort out the time zone issues a chart like this one (fig 2) that spans multiple time zones throws up.
Interestingly the French do report both a 12 hour maximum and a minimum in both their 06 and 18 UTC SYNOP observations, which is very sensible, they also report hourly rainfall totals which again I applaud them for, but I still won’t buy any French apples, not after they sank the Rainbow Warrior in 1985!
Image 1 – Aïn Séfra (Algeria) on the 20th January 2017 – Courtesy of MSN
I notice that a plunge of cold air has brought snow to the Atlas mountains of North Africa this morning. It’s quite usual for the Atlas to get snow at this time in winter, but snow lower down is a little rarer, and at places like Aïn Séfra in Algeria, which is at an altitude of 3,546 feet (image 1) it hasn’t happened since 1979 according to the Wikipedia article. A little further east in Algeria this morning, El-Bayadh are reporting 25 cm of lying snow in their 06 UTC observation. El-Bayadh is just a little higher than Aïn Séfra at 4,419 feet (just 8 feet higher than Ben Nevis).
Figure 1 – 06 UTC 23 January 2016
Looking at the observations since the New Year, El-Bayadh looks quite a hostile place to live either in summer or winter. If you examine the plot grid (fig 2) you will see that the snow fell heavily on the 20th and 21st of this month, with a snow depth of 35 cm on the morning of the 21st. This is a very good SYNOP report which puts observations from a lot of other countries to shame.
Figure 2 – El-Bayadh