The extended range forecast, which includes the monthly and seasonal forecasts, can at times provide an insight into weather patterns in the months ahead. However, they should not be used for specific planning purposes as they have generally low skill compared with the 10-day forecast. This is because forecasts beyond one week become increasingly uncertain due to the chaotic nature of the atmosphere. Further information can be found here Monthly and seasonal forecast explained.
Images: Shutterstock/gabriel12. Met Éireann HQ during Storm Emma 2018
MONTHLY FORECAST, ISSUED TUESDAY 10 SEPTEMBER 2024
Week 1 (Monday 16 September to Sunday 22 September)
Week 1 is signalled to be largely settled. While some spells of rain are possible, high pressure is indicated to dominate our weather with a mainly dry easterly airflow bringing overall settled conditions. It will be drier than normal across the country as a result. Temperatures will be above average for most, with the warmest conditions likely in inland areas.
Week 2 (Monday 23 September to Sunday 29 September)
While confidence is lower for week 2, there is a signal that high pressure will remain near Ireland. As a result, our weather will stay generally settled, though occasional showers or spells of rain cannot be ruled out. Rainfall amounts will be near average over the eastern half of the country, with the highest likelihood of showers in these areas. The western half of the country will be slightly drier than average. Temperatures will be close to or just above normal.
Week 3 (Monday 30 September to Sunday 06 October)
There is a weak signal that low pressure will have more of an influence over Ireland’s weather during week 3. This will allow more frequent spells of rain to spread across the country from the Atlantic. Rainfall amounts are likely to increase compared to previous weeks, with slightly wetter than average conditions indicated nationwide. Mean temperatures will be just above normal also.
Week 4 (Monday 07 October to Sunday 13 October)
There is low confidence in the trend for week 4. There is a weak signal for a predominantly westerly airflow to affect Ireland, bringing above average rainfall for western and northern areas. Rainfall will be closer to normal or slightly below for parts of the east and southeast. Temperatures will remain above average.
SEASONAL OUTLOOK FOR SEPTEMBER, OCTOBER AND NOVEMBER 2024 (SON)
The signal from the C3S seasonal models for Ireland during the SON period is for slightly above average temperatures. Rainfall amounts are less certain with the possibility of precipitation trending near average overall.
Mean temperatures during SON are signalled to be above average overall. Temperatures during September and October are likely to trend between 0.2 and 0.5°C above average, while temperatures in November are likely to be between 0.5 and 1.0°C above normal.
The rainfall forecast is less certain with no clear signal for above or below average rainfall. There is potential for wetter and drier spells within the three months.
The sea surface temperatures around Irish coasts and over the Atlantic are expected to continue slightly above average during SON, trending 0.2 to 1.0°C degrees higher than normal generally. Sea surface temperatures are expected to be closest to normal in September, with a gradual increase in anomalies through October and November.