Which rainfaill forecast, Met.ie or Yr.no, is more accurate? Trying to make plans

hatrickpatrick

Myself and a couple of friends were hoping to meet up for some socially distant outdoor chats in Dun Laoghaire over the weekend. I've been trying to decide which day is likely to be better, weather-wise, but the generally-in-agreement Met.ie and Yr.no have me stumped with their divergence this time.

These are charts for Dun Laoghaire Harbour, as "Dun Laoghaire" seems to target the centre of the county which is obviously a fair bit inland and thus prone to different weather conditions, we'd be meeting on the seafront near the East Pier.

Met Eireann:

Saturday -



Sunday:



vs Yr:



In general, which tends to have a better handle on likely rainfaill, accepting as always that rainfall is always notoriously difficult to pin down a day or two in advance? For Dun Laoghaire, Yr is clearly suggesting that Saturday is likely to be the nicer afternoon, while Met Eireann has been steadfast for a couple of days now in suggesting that Sunday afternoon will have far less rain. Obviously complicated by the fact that both models predict rain for both days overnight the night before and lasting well into the morning.

Any advice?

JCX BXC

My advise is don't pay any attention to them.

It's very hard/almost impossible to accurately pin down showers at an exact location a day or two in advance, or even a few hours in advance.

In order to give you that hourly forecast, the app simply looks at whether the model forecasts a shower in your exact location at whatever time. Now maybe, the model isn't showing any rain at your location, but there's a massive shower just south of you. The model won't be able to predict the shower to that level of accuracy, so it's entirely possible it could rain in your location, despite the model predicting the shower further South.

Any of those forecasts for rainfall should be taken with a massive pinch of salt and used only as a rough guideline.

FVP3

Well we should know by now, did it rain in Dun Laoighre this morning?

AndrewJRenko

I looked at three weather apps this morning before venturing out, the Apple native weather app, YR and Accuweather. All told me it was and would continue to be dry.

Once I stepped out, there was substantial drizzle, as you can see from the car wipers operating.

https://streamable.com/sli1o3

I'd swear that I was getting great accuracy from these apps about five years ago. I remember timing my exit from work down to a few minutes based on Accuweather, and finding that the rain would actually have stopped in line with their Minutecast forecast.

But it seems to have gotten worse and worse in recent years. Is there any reason for this, and is it really the best we can expect?

odyssey06

I use the Met.ie "Forecast Rain" weather map projection which at least shows the cloud movements fairly accurately. Depending on the cloud though, they can get it wrong either way as to whether rain will fall.

pauldry

I'd say look at all of them and make a decision yourself based on the numbers. However all the weather said there would be bright spells and dry in the NW today. But it's drizzling so theyr wrong. I'd say forecasting accuracy was about 50 to 60percent a few years ago but since theyv got supercomputer it's all wrong. The algorithm mustn't understand cloud and light rain.

kindredspirit

When I had the boat at sea, I used to use Theyr from Iceland. Always accurate with rain to within about 10 minutes. I had a free link, courtesy of Marcus Pfister in Switzerland but somewhere along the way I lost the link and Marcus' website is no longer there, I believe. If you want to pay, then you can't beat Theyr for accuracy.

zell12

"hoping to meet up for some socially distant outdoor chats "

Ah, the memories

littlema

Quite good site called Hyperlocal (which is a spinoff from Dark skies now no longer available on android) and the cajoling to join the Pro site only happens on the first login each time and then no more ads