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(What’s it like over there?)
When I refer to local weather I mean the variation in weather conditions from one locality to another in the country on any given day. In Lucan our nearest Met Office synoptic weather station is Casement Aerodrome. It is approximately 5 kilometres from Lucan Village. Synoptic stations take hourly temperature readings and are used daily to forecast the weather and also report on it.
Climatological stations take readings less often and are consulted after weather events.
Mountains, valleys, proximity to the sea or lakes all play their part. Three questions arise:
“Where am I?”
“Where is the wind coming from?”
“What route does it take?”
With a southerly wind the Dublin area can sometimes be the warmest place in the country. This due to the warm wind and also to the minor fohn effect of the Dublin and Wicklow Mountains. This effect occurs when air rises over a mountain and heats up as it descends on the leeward side.
Interesting lenticular clouds can sometimes form with this process over Dublin. You can describe them as flat, cigar or flying saucer shaped.
In summer Dublin might reach 25 degrees under these conditions. At the same time the south coast might be cloudy or misty with temperatures only in the teens. This occurs because the warm southerly wind travels over a relatively cool sea off the south coast. Incidentally, the overall summer daily maximum temperature is approximately 19degrees, in Ireland.
Under normal weather conditions in mid-winter (January) the south-west of Ireland is the warmest place.
Valentia reaches nearly 10degrees, Dublin 8 degrees, Belfast 7 degrees. (West to south-west wind and Gulf Stream effect).
However, with a southerly wind originating close to the Sahara Desert and a minor fohn effect occurring due to the influence of the Dublin and Wicklow Mountains high temperatures can occur in the Dublin region. On the 10th of January 1998 January’s record high temperature for the month occurred. Dublin that day was windy (helping the fohn effect) with sunny spells.
Glasnevin reached 18.5 degrees (the record), Merrion Square reached 17.5 degrees. Dublin Airport reached 16.5 degrees (slightly higher ground). Casement Aerodrome reached 15.2 degrees (also slightly higher ground and being less influenced by the mountains than the other stations).
Local weather variation was really demonstrated here!
Of course, the West of Ireland can also experience temperatures above normal. Recently, on the 9th of May 2016, with 7 hours sunshine and a warm easterly wind, Belmullet, Co Mayo reached an impressive 25.4 degrees. Casement Aerodrome, with just over 1 hour sunshine and an easterly wind off the cool Irish Sea reached only 16.7 degrees.
During the hot July of 1983 some places in Britain experienced temperatures in excess of 30degrees. Meanwhile, many north-east coasts missed the hot spell for a few days with temperatures near 16degrees.This was due to low cloud and fog drifting ashore from the North Sea. Incidentally, Kilkenny reached 31.4 degrees on the 13th and 14th of that month.
An old weather saying:
“Be it fine or be it wet the weather will always repay its debt”, reminds us to be patient. Sooner or later the wind direction will change and the clouds will break.
Denis Torsney.
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