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 19 NOVEMBER 2024
Week 1 (Monday 25 November to Sunday 01 December)
Week 1 is signalling a return of high pressure and more settled conditions. High pressure will likely be situated to the northeast of Ireland bringing in a predominantly dry southeasterly airflow. Temperatures are likely to be around average for most but with settled conditions at this time of year, night-time frosts could lead to below average temperatures for midland areas. Rainfall amounts will likely be below average throughout the country. Fog may develop due to light winds and may be slow to clear the following day.
Week 2 (Monday 02 December to Sunday 08 December)
In Week 2, high pressure is signalled to become more established and perhaps centred closer to Ireland with a more easterly airflow. Rainfall amounts are expected to stay below average throughout though the change will be that temperatures will likely be a bit above average. As in Week 1 though, fog is possible during the nights and may be slow to clear the following day.
Week 3 (Monday 09 December to Sunday 15 December)
High pressure is signalled to remain a feature of our weather in Week 3, it is signalled to decline southeastwards introducing a more westerly airflow with some rain and showers at times leading to above average rainfall over much of the western half of the country with more normal amounts further east. Temperatures will continue above normal.
Week 4 (Monday 16 December to Sunday 22 December)
There is less of a signal for Week 4 but there are indications that the high pressure to the southeast will edge closer to Ireland though the western half of the country is still likely to have above average rainfall amounts. Above average temperatures throughout the country are also likely to persist.
SEASONAL OUTLOOK FOR DECEMBER 2024, JANUARY AND FEBRUARY 2025 (DJF)
The signal from the C3S seasonal models for Ireland during the DJF period is for above average temperatures. Rainfall amounts are less certain with the possibility of precipitation trending near average overall.
Mean temperatures during DJF are signalled to be above average overall. Temperatures during the period are likely to trend between 0.5 and 1.0°C above normal. However, colder than average periods, where all winter hazards are possible, could still occur at times throughout DJF.
The rainfall forecast is less certain. There is a slight signal for average to above average rainfall for the north and northwest of Ireland. There is also a slight signal for the south and east to have average to below average rainfall overall through the DJF period. There is potential for wetter and drier spells within the three months for all parts of the country.
The sea surface temperatures (SSTs) around Irish coasts and over the Atlantic are expected to continue above average during DJF. SSTs are trending 0.2 to 0.5 degrees higher than normal off the west and north coasts, with a trend of 0.5 to 1.0 degrees higher than normal off the south and east coasts.