Monthly forecasts can at times provide an insight into weather patterns in the month 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. Monthly forecast explained.
MONTHLY FORECAST, ISSUED 16:00 FRIDAY 15 JANUARY 2021
Week 1 (Monday 18 January to Sunday 24 January)
This week will be dominated by low surface pressure with a stacked upper low in the upper atmosphere over northern and northwestern Europe, establishing a mainly northerly airflow across Ireland. There is signal for average temperatures this week to be a degree colder than normal for the time of year. Parts of the northwest will have drier than normal conditions, with elsewhere experiencing a little more precipitation than average overall this week. Southern areas will most likely have the highest amounts of precipitation.
Week 2 (Monday 25 January to Sunday 31 January)
This week looks to be unsettled on average. Low pressure both at surface pressure and in the upper atmosphere remain dominant throughout this week over northern Europe. Signal is for Ireland’s airflow to most likely be northeasterly on average this period. There is a signal for precipitation to generally be higher than normal throughout this week, with the strongest signal on eastern and southern coasts. The northwest is signalled to have normal or slightly lower than normal precipitation this week. Average temperatures for this week are expected to continue to be around 1 degree lower than normal, but temperatures will be closer to normal for southern areas.
Week 3 (Monday 01 February to Sunday 07 February)
Uncertainty increases for this period but there is a signal for low pressure south of Ireland to dominate which would continue to bring a northeasterly or easterly airflow. Temperatures are signalled to be colder than normal across Ireland and Britain, suggesting that a cold airmass originating from Scandinavia may influence our weather. Indications suggest precipitation will be higher than normal in the east and south in this airflow, with drier than normal conditions elsewhere, further reinforcing the indication of a mainly easterly airflow.
Week 4 (Monday 08 February to Sunday 14 February)
Confidence is low for this period, however there is a weak signal for pressure to be high to the north of Ireland, and a weak signal for low pressure to be the main influence over southern Europe. There is signal for precipitation to be average or below average throughout this week, with no strong signal for anomalous temperatures. A more settled spell of weather is suggested with high pressure possibly becoming established in the Atlantic or the north of Ireland.