Spring 2021 General Discussion

Oneiric 3 wrote: »

I would like to ask Tyrone if it knows of a site that gives us daily data from stations acrossNorthern Ireland? (I know of Ogimet, but the figures they show are not quality controlled as far as I am aware) as it would be great to include updated data for the North as well on an ongoing basis to compare and include with the rest of the island and to help us create a possible all round Ireland average.

I don't have a clue tbh. There's a load of met office observation stations they don't show on their website. When you check NI observations it will give a list of wettest, warmest,coldest places over the last 24 hours and will often include locations I can never access anywhere else.

compsys wrote: »

Dublin Airport is unusually cold at times - especially on cool, clear nights in spring and summer where the temperature just seems to drop like a stone after sunset.

I remember one night in March a few years ago the temp was 7º in Casement and 0º in Dublin Airport at about 11pm.

While some have argued that the station is in a perfect location, I can't figure out how a coastal station which is kept cool by the sea breeze during the day loses this effect and then often becomes the coldest station in the country at night.

DAs daily highs in good, settled weather are usually similar to Sherkin, Malin Head, Johnstown and Roches Point due to the sea breeze - but at night it's closer to Mt Dillion for overnight lows and several degrees colder than the other stations mentioned.

The station has been moved a few times over the decades so LTA comparisons are probably worthless but its current location certainly seems to be in the perfect for cool weather.

Since when is Dublin Airport a coastal station? I never got why it's used in the coastal reports of the Marine forecast. The instrument enclosure is 11.6 km inland from the nearest coast. That's almost the same as Cork Airport is. Dublin's enclosure is 2.2 km from (and inland of) the previous site, so yes, longterm trends are unreliable.

I drove to north Co. Dublin on Saturday, and the car was reading 13.5 degrees all the way from Celbridge to Finglas, but as soon as I took the Ashbourne bypass it started to fall, reaching 11.5 a couple of km later, which was within 2 km of the airport enclosure. It stayed around that temperature all the way past Ashbourne and then further northeast towards Garristown. I've said it before, I grew up in that region and it tends to be a few degrees cooler than within and west of the M50 belt. The airport station is a good representation of that general area.

Was it not late June before the weather went to complete shoite last year?

giveitholly wrote: »

Was it not late June before the weather went to complete shoite last year?

for the east it was a poor month as a whole while the west got away with a good bit at the beginning. June tends be forgotten for how bad it was in the east because July and August both overshadowed it. it was still a poor month here regardless.

compsys wrote: »

I know Ireland isn't a big country but I think by any measurement being 11km (6.5 miles) from the sea would be considered costal. Though obviously it's further inland than places like Malin Head.

But it also doesn't change the point around day and night temps. Later this week I can almost guarantee Dublin Airport will be around 5 to 6 degrees cooler than more inland locations in the West during the day due to its coastal location and the moderating effect of the sea breeze. But then it will also be colder than these same inland locations at night. The sea effect suddenly goes. This is just what I find a bit unusual - DA obviously has a somewhat unique topography.

Dublin Airport will often be the coldest location in the country at night - sometimes by several degrees. Cork Airport, which you mention, never is.

At 10 km, the Phoenix Park station is actually closer to the coast than Dublin Airport's. Would you consider that a coastal station too? Johnstown Castle is also closer (7 km). Are you saying these will be as warm as western stations and only DA will be 5 or 6 degrees colder? Why aren't they reported as coastal stations?

The Phoenix Park station is poorly sited, being only 16 metres from a large building to its east and otherwise surrounded by high forest. It also has a city between it and the sea. If it were as open as DA then it too would be cooler by day and would cool down more quickly at night.

I would always trust DA data (and Johnstown Castle) more than Phoenix Park for the best representation of their general wider areas.

Any downgrades for the next few days folks? Might take a day off on Friday and enjoy the sun. Beautiful morning here blue skies and sunshine. Ground frost but that’ll clear shortly.

compsys wrote: »

Dublin Airport will often be the coldest location in the country at night - sometimes by several degrees. Cork Airport, which you mention, never is.

Mean minima for some eastern stations for April up to yesterday. All stations, apart from Johnstown and Dublin Airport are within 0.4c of each other, but the real outlier here is Dublin Airport, which bang on 0.0c now, still remains over a degree cooler than its nearest neighbours, and given that this average spans a sizable 20 day period, then it is only understandable that questions would be raised.



Datums: Met Eireann.

Oneiric 3 wrote: »

Mean minima for some eastern stations for April up to yesterday. All stations, apart from Johnstown and Dublin Airport are within 0.4c of each other, but the real outlier here is Dublin Airport, which bang on 0.0c now, still remains over a degree cooler than its nearest neighbours, and given that this average spans a sizable 20 day period, then it is only understandable that questions would be raised.



Datums: Met Eireann.

I'd like to see a longer term dataset, but your graph does indeed show the effect of station local effects. For example, how Phoenix Park's artificial influences keep it warmer than others.

Below is a table of eastern stations, sorted in order of their average distance from the nearest coast to their northeast, east and southeast. Johnstown Castle is the most coastal station, but as it's in a completely different part of the country it can't really be included in a comparison. Likewise Oak Park and Dunsany. Phoenix Park and Casement are greatly influenced by urban effects when it comes to talking about winds from an easterly sector, with Casement being well further inland than Dublin Airport and very close to artificial surfaces (apron, hangars, etc.).

In fact, no two stations can really be compared to eachother as they all have different characteristics, both on a local and wider scale, even down to different soil types (which was always a well-known factor in Kilkenny's temperature data). To repeat the point, the Dublin Airport station is perfectly sited and is a very good representation of that wider north Co. Dublin/east Meath area north of the M50. I challenge anyone to come up with reasons why it's not.

This thread shows all station details.

Gaoth Laidir wrote: »

At 10 km, the Phoenix Park station is actually closer to the coast than Dublin Airport's. Would you consider that a coastal station too? Johnstown Castle is also closer (7 km). Are you saying these will be as warm as western stations and only DA will be 5 or 6 degrees colder? Why aren't they reported as coastal stations?

The Phoenix Park station is poorly sited, being only 16 metres from a large building to its east and otherwise surrounded by high forest. It also has a city between it and the sea. If it were as open as DA then it too would be cooler by day and would cool down more quickly at night.

I would always trust DA data (and Johnstown Castle) more than Phoenix Park for the best representation of their general wider areas.

I'd report anything within 20km as coastal or at least being affected by the sea breeze. So yes PP too - which is not surprising as I think most Dubliners would agree they live 'close to the sea' - though maybe not ON it.

I'm saying PP, DA and Johnstown Castle (and Cork Airport maybe) will ALL be a few degrees cooler than the West this week during the day due to the sea breeze but DA will be the only one with the very cool nights.

I actually thought JC was right ON the sea. I didn't realise is was almost the same distance inland...

But as you've mentioned it - let's take 15th April - DA got down to -3º - that's a heavy frost. JC went to 2.3º only while Cork got to 3º. All relative similar distances from the sea.

Mainly on calm nights only though.

Quite often I've seen nights in summer where you have had 8º to 10º 850 temps over the country - temps widely over 20º during the day - a 13º sea - every station will have a relatively warm and sultry night and DA will stick out as having gone close to the freezer.

Many nights DA will go under zero when frost won't have been mentioned at all on the forecast.

BTW I agree that PP has its own issues too probably. Though nothing like Shannon.

Perhaps it's in a perfect location. My main point is that it's unusual for a station to be so heavily influenced by the sea during the day and to lose that influence during the night. Out of all the stations within 20km of the sea, I'd imagine DA experiences the highest number of frosts?

Was it really that bad last summer in cork? I don’t remember it being like that, maybe I’m mistaken.

Anyway, blue skies down here in cork city again with a gentle breeze.

Lovely day in cork city, blue skies, warm and a bit of a wind. Total change from the last few days. Brilliant.

A glorious day here too. We've had cloudless sky all day. Quite warm too. Long may it continue- which will probably be until the early days of next week

Nice if annoyingly breezy day here and I must say, never felt particular warm despite the 15c. Sky this evening looks like a summer evening sky that proceeds a good blast of a thunderstorm. Let's hope this is a sign of things to come :cool:

compsys wrote: »

Perhaps it's in a perfect location. My main point is that it's unusual for a station to be so heavily influenced by the sea during the day and to lose that influence during the night. Out of all the stations within 20km of the sea, I'd imagine DA experiences the highest number of frosts?

On average, according the Met.ie, Casement will record slightly more air and ground frosts in April than Dublin Airport:

https://www.met.ie/climate-ireland/1981-2010/casement.html

https://www.met.ie/climate-ireland/1981-2010/dublin.html

But then, the Dub A figures are probably taken from before the station was moved, thus rendering them completely useless.