Red line and arrow, line of sight for Google Streetview, see below.
Killowen, County Down, Northern Ireland, Killowen Outdoor Centre, Carlingford Lough.
Data from 1997, as AWS from about 2000, older data somewhere near from 1961
24 hours ending 2200 on 27 Apr 2013:
UK Highest max 0900-2100 12.9 °C Killowen
54.076877° -6.184006° Bing maps, Google maps
Altitude 4 metres
Estimated Class 4, fails Class 3 on > 10% “Ground covered with natural and low vegetation (<25 cm) representative of the region;” and “at more than 10 m from artificial heat sources and reflective surfaces (buildings, concrete surfaces, car parks, etc.)” with 10 metres. (hedge / wall)
UHI, local, isolated marina, heated public centre, vehicle parking, signs of outfall close to lough edge. Distance, none.