Spring 2021 General Discussion

Long term April data for Northern Ireland. However cool (or not) this April will finish up here it won't even make a dent on the clear upwards trend:



Coldest April in this region was in 1922, when the finishing mean came in at a miserable 4.1c, which is closer to the average January temperature for the Province.

Data from the UK Met:
https://www.metoffice.gov.uk/pub/data/weather/uk/climate/datasets/Tmean/date/Northern_Ireland.txt

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.

compsys wrote: »

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

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Yes, I recall not just this occurrence, but many other similar ones.

Just thinking, 'Marine Layer' would live in a similar region ( a couple of miles in from the east coast) with similar geography to Dublin Airport and I wonder, does he record similar unusual lows? Now, I can't claim to be familiar with the east coast all that well, but a region prone to extremes (with regards temp, high or low) I seriously doubt it to be.

Is there frost promised for Midlands tonight? Cannot figure it out on met.ie

sryanbruen wrote: »

April been great here near Howth besides temperatures, which there definitely has been a chill at times. Lots of sunny and dry days to get out on walks. Sunrises especially have been so beautiful.

Does feel like we will greatly pay for this once again like last year though. Leaves me a bit apprehensive with regards to this summer.

Oh we will pay alright. Grand total of 6mm of rain so far this month at Dublin Airport. Right on track to equal last year's final 12mm for April.

Which was followed by rain, rain, rain in Jun, July and Aug.

Ah well enjoy it while we can!

Gaoth Laidir wrote: »

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.

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.

Some nice sunshine to start the day in Kildare but very cool in that already keen wind.

giveitholly wrote: »

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

It was June 3rd in the East of Ireland. It started raining then and didn't stop until September.

Artane2002 wrote: »

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.

The weather was very dry and sunny here in the west for much of June (plenty of thunder too at times) but after the overnight storms of I think the 26th or 27th, the cloud came in and didn't shift for the remaining summer months. I don't recall all that much rain for the rest of that summer though.

Oneiric 3 wrote: »

The weather was very dry and sunny here in the west for much of June (plenty of thunder too at times) but after the overnight storms of I think the 26th or 27th, the cloud came in and didn't shift for the remaining summer months. I don't recall all that much rain for the rest of that summer though.

Sligo escaped with a good enough Summer last year.

March 18th to June 26th mostly fine... then the thunder.
Bad a couple of weeks until mid July then bland weather but milder and drier.
Good couple of weeks in August with temperatures over 20c many days.

Well a rather dissapointing morning. Total cloud cover and cool. The forecast was somewhat different.

At least its not raining.

Co.Leitrim

Cloudy passing through and dull but brightness is following once more soon

Lovely to see the sunshine back to its best today.

It was cloudy this morning on my way to work but turned into a beautiful day.

Definitely warming up at last, think it got to about 15 degrees today.

Oneiric 3 wrote: »

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:

East Clare was the same today, car said 17.5c at one stage, looked lovely out but the breeze had a cut in it..

Looks like West is best for the rest of the week!

compsys wrote: »

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.

I would like to see actual data to statistically back this up because I've been keeping an eye on it for years and I've not found anything out of the ordinary. Oneiric's Met.ie data show 29 air frosts per year versus Casement's 39. Both have 82 ground frosts (noting the relocation of the DA station within that climate period).

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?

There is a sweetspot of X km inland where a location is affected by both sea breeze during the day AND a land breeze during the night. DA could be in this location. Both Dunsany and Casement may be too far inland to be greatly affected by the sea breeze during the day, meaning they will start the night off warmer and hence won't as easily cool to the level of Dublin Airport, which will have been cooler during the day.

There have been some comments here down through the last few years claiming that the DA station has to be reading incorrectly, along the same lines of the complaints about the bad radar coverage in some areas of the country. I've never accepted these claims as I know both the station and area well. I'd have more of an issue with other stations around the country, such as Shannon Airport, which we've seen reads high in easterly wind regimes due to the huge 21,000 m² carpark surrounding its station. This is therefore feeding erroneous data into the weather models. These models take into account the local topography and soil properties, but to have the artificial effect of a manmade influence like that can only lead to model error. Garbage in, garbage out.

Gaoth Laidir wrote: »

I would like to see actual data to statistically back this up because I've been keeping an eye on it for years and I've not found anything out of the ordinary. Oneiric's Met.ie data show 29 air frosts per year versus Casement's 39. Both have 82 ground frosts (noting the relocation of the DA station within that climate period).



There is a sweetspot of X km inland where a location is affected by both sea breeze during the day AND a land breeze during the night. DA could be in this location. Both Dunsany and Casement may be too far inland to be greatly affected by the sea breeze during the day, meaning they will start the night off warmer and hence won't as easily cool to the level of Dublin Airport, which will have been cooler during the day.

There have been some comments here down through the last few years claiming that the DA station has to be reading incorrectly, along the same lines of the complaints about the bad radar coverage in some areas of the country. I've never accepted these claims as I know both the station and area well. I'd have more of an issue with other stations around the country, such as Shannon Airport, which we've seen reads high in easterly wind regimes due to the huge 21,000 m² carpark surrounding its station. This is therefore feeding erroneous data into the weather models. These models take into account the local topography and soil properties, but to have the artificial effect of a manmade influence like that can only lead to model error. Garbage in, garbage out.

I think in that case DA has definitely hit the sweet spot.

For example this morning DA fell to -0.3º between 3 and 4am or so. The coldest in the country apart from MT Dillion.

This compares to lows of 8 degrees or so for JC and Cork. Even Dunsany, which is more inland, held warmer.

Last April and May are good examples of what happens during settled weather. They were both very sunny, warm and very settled months. Here are the temp stats against LTAs for Dublin.

April
Casement +1.4º
PP +1.5º
DA +0.4º (coldest location in the country)

May
Casement +1.3º
PP +1.5º (warmest location in the country!)
DA +0.2º (coldest location in the country - its average max for May was actually a good bit above its LTA but its average min was below average).

I know the station has been moved to a 'colder' location making comparisons difficult but given the huge LTA anomalies posted for the other Dublin stations you'd have expected something a bit warmer.

Again it only happens on clear, calm nights which is part of the reason I find it interesting - it means DA is often a 'warmer' location during wet, and cloudy months when the weather is poor than it is during dry, sunny and settled months as the temp usually drops like a stone in these conditions after dark.