Regional mountain forecasts from the Met Office

There have been some major improvements made to the regional mountain forecast issued by the Met Office which have just been announced. I’ve just had a quick look at them, and as a retired Munro bagger myself, I think that the website and it’s content are perfect for anyone planning to go hillwalking  and trying to assess just how good or bad weather conditions will be.

Figure 1 – Courtesy of the Met Office

Thankfully, although the webteam use the same map component they use in the severe weather warnings (fig 1), it’s not zoomable, just clickable, and when you do click it you get quite a detailed forecast (fig 2). I imagine that in winter each regional area forecast will also include any warnings regarding avalanche risk. There, who said I couldn’t write anything nice about the Met Office!

Figure 2 – Courtesy of the Met Office

The shelter of mountains

Figure 1

An interesting number of examples of just how shelter from mountains can make the difference between a cloudy day and one with sparkling spring sunshine in today’s visible satellite sequence. There are clear skies evident in the air coming south southwestward from over the mountains of Norway and into the northern North Sea. There’s also shelter as the air is warmed and dried on the southern slope of the Grampians over Perthshire and Fife. The mountain and fells of the northern Lake district are doing enough to stop the passage of the SC sheet extending southwards from the Scottish Borders, and the Pennines are just high enough, and the gradient is just backed enough to keep the same SC sheet from invading Lancashire, as it’s done east of the Pennines in Yorkshire.

The Cuillins are calling

Figure 1 – In the days before the bridge

Most years in spring you always seem to find a spell of anticyclonic easterlies over Scotland, and the Cuillins in Skye start calling to any intrepid Munro bagger out there. This year has been no exception with the weather since the 1st of May being absolutely glorious in the Northwest Highlands for the Munroist, as these visible satellite images reveal (fig 2). It’s been well over twenty years since I’ve been on Skye but one day I will return, if I’m not too old, and try to finish what I started, that’s if my wife will let me.

Figure 2 – Courtesy of the Met Office and EUMETSAT

April snow for Cairngorms

Figure 1 – Cairngorm from Loch Morlich courtesy of © Winterhighland Limited

It’s proving to be a cold and showery Easter over Northern Scotland this year, and the showers affecting the area on Saturday afternoon look like they are putting snow down to ~3000 feet if this webcam image is anything to go by (fig 1). That’s because the cold air over Scotland is holding the air temperature on Cairngorm at a very cold -2.9°C (13 UTC) at the moment. The heatmap of air temperatures on the summit since the start of March shows that until this last week, it had been relatively mild since around the 24th of March (fig 2). It looks like the high ground might get a bit more snow overnight, but it might be a bit late to extend the skiing season from what I can see from the other webcams in the area.

Figure 2

At the same time it’s been quite a benign Spring as far as gales and storm force winds are concerned on the summit (fig 3).

Figure 3

The last week on Mount Washington

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.

Figure 2

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?

Figure 3

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.

Figure 4

Lake District weather for hillwalkers

Image 1 – Courtesy of www.lakedistrictweatherline.co.uk

I read about a very informative website for hillwalkers in the Lake District the other day in a Guardian article. The website is called lakedistrictweather.co.uk, and each day through the Winter someone from a team of volunteers legs it up Helvellyn and writes a report about the conditions that they found under foot, the guys that do this must know Helvellyn like the back of their hand and probably could do it with their eyes closed (well not Swirral edge perhaps) because they don’t seem to miss a single day! It reminds me of the Victorian meteorologist Clement Lindley Wragge – what a character and what a life – who would climb Ben Nevis each day (but only in summer) before the observatory was eventually built. Anyway I digress, after the report of conditions ascending the 3,120 feet to the top of Helvellyn, there is a full weather forecast for the next couple of days with extended outlook, and a list of all the hazards that you might face. If you do walk the fells in the Lake district, then you should bookmark this site.

Mount Washington Observatory – Home of the world’s worst weather

Figure 1 – Copyright W.Woods

Mount Washington as you may well know is located in the Presidential Range of the White Mountains, in the state of New Hampshire in the United States.

Figure 2 – Courtesy of Bing Maps

Mount Washington (called Agiocochook by some Native American tribes) is the highest peak in the Northeastern United States at 6,288 ft (1,917 m). The mountain is notorious for its erratic weather and on the afternoon of April 12, 1934 a wind gust of 201 knots (231 mph) was recorded at the summit. This stood has the world record for highest wind speed for most of the 20th century, and is still a record for a wind in an extratropical cyclone. The Mount Washington Cog Railway ascends the western slope of the mountain, and the a road climbs to the summit from the east. The mountain is popular with hikers and the Appalachian Trail crosses the summit. Thanks to the Wikipedia article for that information.

Figure 3 – Courtesy of Google Maps

There’s been an observatory on the mountain since 1932,  and recently the SYNOP observation from WMO station 72613 have become more available than they have in the past, although they’re still only available for main synoptic hours. I did think of volunteering to do a stint as an observer at the observatory, but never quite managed to submit the application. Volunteering would have been akin to what Victorian meteorologists did back in November 1883 when they started to continuously man the observatory that they had built on top of Ben Nevis. Anyway here is the latest pseudo anemograph (fig 4) that I’ve put together from the last month’s climate data.

Figure 4

A constantly windy place, usually from the west during the last month, with a mean speed usually of force 8 or 9, with occasional periods of force 12 or more, the yellow outlined line in the top chart by the way is the 24 hour mean centred wind speed in knots. It’s a real shame that Mount Washington observatory don’t include a gust group in their SYNOP reports which I download from OGIMET. Of course it could be a very constant high wind speed in a laminar flow with few gusts, but that’s a totally illogical reason for it being omitted. Take a look at Cairngorms anemograph for the same period (fig 5), of course they are around 2,951 miles apart on opposite sides of the North Atlantic Ocean, and Mount Washington at 6,288 feet is 2,204 feet higher than Cairngorm, but it will give you an idea of the gustiness on top of Cairngorm in the last month. Cairngorm does punch well above its weight for its height, and at times the 24 hour mean wind speed was over 60 knots and higher than Mount Washington, this was in mid-December as Storm Barbara and Conor were passing to the north.

Figure 5

Here is a list of some of the raw SYNOPs from Mount Washington for the last month (fig 6). I’ve looked using the WMO manuals for anything resembling a supplementary group that reports the highest gust for a period, but did not find one – let me know if I’m missing something. The odd thing is that although they don’t report a maximum gust they do report a snow depth, which I find very odd given that the mountain is constantly being subjected to storm force and at times hurricane force winds. I would have thought the ground would have been scraped clean of snow, and that the only real snow would exist either in the lee of the observatory buildings or in giant cornices around the edges, which would make snow depth reporting impossible.

Figure 6

Mount Washington is certainly very much colder than Cairngorm is. This is mainly due to the fact that it’s a much higher mountain and even though it’s situated further south at 44° rather than the 57° of latitude Cairngorm is. The other reason it’s colder is that it’s situated on the eastern edge of the North American Continent, and the Pacific Ocean were the prevailing winds are coming from are a very long way indeed, Cairngorm in comparison is probably no more than 60 miles from a comparatively warm North Atlantic Ocean. The thermograph for Mount Washington (fig 7) shows just how exceedingly cold it can get, with Arctic air rushing directly down from Canada in the winter to produce some massive wind chill values, it’s certainly not a mountain to get lost in winter on, and that’s for sure. The other thing to notice in the SYNOPs (fig 6) is how frequently the visibility switches between either excellent (code 89=>70 km) or zero (code 00=<100 M).

Figure 7

If you search the Internet for images of Mount Washington, you may find like I did that they are all heavily copyrighted to protect them, maybe because the whole mountain is now owned by the Florida based CNL Financial Group, who are trying to file a trademark for the name “Mount Washington”. There are many amazing images of a snow, ice and rime covering Mount Washington (in fact if you like rime this is the place to see it), but because I can’t seem to use any of these images freely here’s a list of hyperlinks to some of the best and most interesting ones, you’ll notice that most of them come from the Mount Washington website or Facebook page.

How does a low cross a mountain range?

Courtesy of freeworldmaps.net

The low pressure system that most of Europe know as low Axel thanks to the Institute for Meteorology in Berlin, demonstrated perfectly what a low does when faced with a mountain range in its path. Does it go round it or over it? Or is it maybe deflected in someway or maybe even blocked? Well in this particular case Axel seems to have almost jumped almost skipped over the Scandinavian Mountains or the Scandes straight from the Norwegian Sea into Southern Sweden. As the Wikipedia article says about the mountains of Southern Norway, they are not particular high (~8,100 feet) but they are very steep on their western flank and must present a formidable hurdle for a low-level vortex to surmount, and low pressure as a rule generally avoids centring itself over high ground. Of course Atlantic depressions coming up against the mountains of Norway happens all the time, but I think the one I captured yesterday was a classic example.

 Of course if the question and been why and not how does a low cross a mountain range, the answer would have been to get to the other side.