The mysterious gust of 194 mph
Apparently on the 19th of December 2008 a gust was observed somewhere on the Cairngorm mountain of a 169 knots or 194 mph. I say somewhere because the Daily Telegraph doesn’t say exactly were it was and it was only seen by the head of the ski patrol on a machine that stores data for 48 hours before deleting it! The report mysteriously goes on to add that the reading was taken at the entrance to a tunnel that transports people up the mountain. The tunnel the Telegraph article mentions is probably the top of the funicular railway which came into operation in 2001, and emerges at the Ptarmigan restaurant. So for the purpose of this article I’ll assume the gust was recorded at the top of the funicular and not the base station! Luckily hourly observations are available from the Met Office SIESAWS observation site close to the summit of Cairngorm itself at 1244 metres, the Ptarmigan station lies lower down the north side of the mountain at the top of Coire Cas at 1085 metres.
Here are the hourly SYNOP reports from the SIESAWS and although the mean wind speed and gust were extremely high that day, as high as 120 knots in fact, they were much lower than the 169 knots claimed.
In my own experience gathered from many years of watching Cairngorm observations the mean to gust ratio for the 120 knot gust reported in the 17 UTC SIESAWS observation does look excessive, but could be explained by the cold front which was crossing the area west to east at the time, notice how the temperature* shot up above freezing for an hour or so. We will never know if the wind didn’t veer more sharply into the northwest on the passage of that cold front, and allow the wind to funnel directly up Coire Cas and produce that record gust seen at the Ptarmigan station.
The only reason I know about this event at all is that it was mentioned and referenced in a Wikipedia article about UK extreme weather I was reading. So for now the highest gust in the UK remains the 150 knots (172 mph) recorded on the 20th of March 1986, again on the blue mountain.
*For those not familiar with the SYNOP code the sixth column in the tabulated list. For example in the top line 11033 indicates an air temperature of -3.3°C.