Now that we are getting into the stormy part of the year I thought that I would have a look back and see if the weather in the UK was getting more stormy in recent years. I don’t have access to climate statistics or any detailed anemograph records for the last 145 years, but I do have some thing that is probably a whole lot more useful in helping me to find the answer to that question a lot quicker, and that is the daily National Centers for Environmental Prediction [NCEP] reanalysis data back to 1871. Simply put, that is a grid of six hourly daily pressures values [MSLP] on either a 2° or 2.5° grid for the whole world. The Climate Research Unit [CRU] at the University of East Anglia [UEA] have done all the hard work really, because they used this reanalysis data to calculate daily statistics for the Objective Lamb Weather Type [LWT] series. Apart from producing a daily LWT, a by-product of these calculations is a Gale Intensity or Gale Index [GI] value. So there are a couple of caveats with anything that you find when using the LWT series, and those are that the GI is for a fixed place [55°N and 5°W] in SW Scotland, and the GI is just for the 1200 UTC observation, so it’s a little basic. But the good thing is that the data series is long and easy to use. The first chart is of annual gale index values since 1871, and a s you can see from the linear trend the index is 6.9% higher now that it was at the start of the series.
That 6.9% increase in the annual gale index since 1871 equates to an increase in 12.9 more days of gale in a year during that time. Incidentally the GI does not directly correspond to a wind speed in knots, so that a GI of 30 or more is equivalent to a gale (34-40 kts), a GI of 40 or more is equivalent to a severe gale (41-47 kts), and a GI of 50 or more is equivalent to a storm (>=48 kts).
The anomaly chart below shows more clearly when the gale index began to increase, and as you can see it’s been mainly since around 1980 that it’s shown a concerted increase. 1990 for instance was a remarkably stormy year, but equally there have been occasional quiet years like 2010.
If you look at the seasonal analysis through the year, all seasons show a similar ~7% increase in GI. This is the chart for Winter which shows an extra 5.8 gale days since 1871.
So the short answer to the question that I posed in my title is, yes, that’s if the gale index in the objective LWT series is anything to go by. Why it’s getting stormier is another question, and one that I am not even going to try to answer!