Magherally No 2 DCNN 9270 – A poor site amongst far too many equals.

54.35928 -6.19546 Met Office CIMO Assessed Class 5S Installed 1/1/1976

An unusual case study. Magherally is a small village in County Down, Northern Ireland. This site is rated as Class 5 S meaning its siting is adding up to a 5°C inaccuracy margin with additional issues relating to shading. Astonishingly the Met Office’s own unique rating system also suggests this site is “Excellent”. Looking at the image from the coordinates supplied by the Met Office the shading issue does not look particularly troublesome. Neither does the location look especially bad considering many much worse sites are often rated Class 4 or even 3. I would have considered this to be Class 3. A closer look was required.

This image is from July 2023 so what is so terrible about this site? Hard to make out but the screen is a measured 35 metres from the trees and in an open rural, flat site. Although there is no obvious enclosure there are also no obvious extraneous heat sources to cause problems. Looking further the screen was pretty much the same in back in 2016 but going back to the same viewpoint in November 2008 revealed it was not there at all.

The archives give no indication of a relocation so where on earth was it? Theoretically, if the move is not over an ill-defined distance and does not significantly alter the site’s likely readings, then renumbering is not required so presumably it was originally nearby. A tour around the maps and street-view finally found this quaint little nearby back garden site back in 2008……….Clearly Class 5 and subject to shade!

It appears that some time between 2011 and 2016 the site was moved approximately 80 metres from a back garden low grade location to a much better one but the Met Office have not since opted to update the CIMO site rating. Unusual for the Met office to underrate one of their screens or possibly an oversight as their own “Excellent” rating is their default setting. This site represents even more that is peculiar about the Met Office’s operations in Northern Ireland – it is notably worse than England, Scotland or Wales.

There are 28 currently operational CIMO assessed weather stations in Northern Ireland, 20 automatic and 8 manual reporting units. NONE OF THEM ARE RATED CLASS 1. Just 2 stations are rated Class 2 and one of those (Giants Causeway) is highly debateable. 2 stations are Class 3. 11 are Class 4, and 13 are Class 5.

In the entirety of a constituent country of the United Kingdom of Great Britain and Northern Ireland, the Met Office seems unable to find any premium quality sites…..is that really plausible?