October 2016: Near-Record Dry in Stornoway & Sunny
Posted: Wed Nov 02, 2016 10:18 am
Greetings from the far NW of Scotland, where October has been the 2nd driest on record in Stornoway since 1873. Total precipitation was 36.0mm at the airport (less than one third of normal); only the October of 1946 was drier. So it's almost a 1-in-a-century event (but with some caveats, see below).
It was also a sunny month, with percentages exceeding 150% across large parts of NW Scotland and Hebrides - see the recent Met Office press release on this: http://www.metoffice.gov.uk/news/releas ... 2016-stats. In Stornoway, I estimate it was the 4th sunniest October since 1929 (so a 1-in-a-20-year event, but again not without possible caveats, see below).
All this marks a stark change from the prevailing weather over the past ~2years, during which we have suffered with considerably more than our fair share of very wet, dull and unsettled weather. How refreshing it is now to see high pressure build towards mid-Atlantic and Greenland; I feared it was never going to happen again!
Here are some graphs: And the caveats are the following:
- I don't believe the Stornoway Met Office precipitation dataset is homogenous, especially prior to ~1915. But even recently, there has been a change of rain gauge (it is contained within a turf wall) and values appear biased now when compared to other local rain gauges over long-term periods.
- Likewise, the sunshine record is hardly homogenous, especially since the replacement of the Campbell stokes recorder ~2000. Stornoway gets a lot of weak sunshine in the autumn/winter months - even today with a low sun, the pyramometer lies within the shade of the fence posts of the Stornoway enclosure for up to 5% of the time (see photo: pyranometer is on the left). Eddie Graham, Stornoway.
It was also a sunny month, with percentages exceeding 150% across large parts of NW Scotland and Hebrides - see the recent Met Office press release on this: http://www.metoffice.gov.uk/news/releas ... 2016-stats. In Stornoway, I estimate it was the 4th sunniest October since 1929 (so a 1-in-a-20-year event, but again not without possible caveats, see below).
All this marks a stark change from the prevailing weather over the past ~2years, during which we have suffered with considerably more than our fair share of very wet, dull and unsettled weather. How refreshing it is now to see high pressure build towards mid-Atlantic and Greenland; I feared it was never going to happen again!
Here are some graphs: And the caveats are the following:
- I don't believe the Stornoway Met Office precipitation dataset is homogenous, especially prior to ~1915. But even recently, there has been a change of rain gauge (it is contained within a turf wall) and values appear biased now when compared to other local rain gauges over long-term periods.
- Likewise, the sunshine record is hardly homogenous, especially since the replacement of the Campbell stokes recorder ~2000. Stornoway gets a lot of weak sunshine in the autumn/winter months - even today with a low sun, the pyramometer lies within the shade of the fence posts of the Stornoway enclosure for up to 5% of the time (see photo: pyranometer is on the left). Eddie Graham, Stornoway.