Met Éireann and UK Met Office issue long range forecasts for January and early February

In its latest long term forecast issued today, Met Éireann says there are no signals for very severe cold weather during the next fortnight.

The national forecasting service says temperatures will remain around normal for the time of year with rain or showers likely for the remainder of the month.  There are indications however, that high pressure will build from Scandinavia into Britain keeping it drier than average over Ireland at the beginning of February.

Met Éireann Monthly Forecast (updated 11 January 2021)

Week 1 (Monday 11 January to Sunday 17 January)

As high pressure becomes situated between Spain and the Azores, it will allow a more Atlantic zonal flow to move in over Ireland early in the week. It is expected to be more unsettled across the country with rain-belts affecting the region in this westerly airflow. This will allow temperatures to recover to near normal values for the time of year with frost unlikely. Winds will be fresher for a time too. There may be a drier slot following on Wednesday and/or on Thursday but overall it will stay unsettled with further rain or showers, especially for the weekend and the possibility of a developing low pressure area coming close to Ireland towards the end of the period. Frost may return later in the week and over the weekend as temperatures fall back a bit. There is the risk of spot flooding in parts early in the week. Towards the end of the period there is the risk of some strong winds.

Week 2 (Monday 18 January to Sunday 24 January)

Initially, pressure is expected to be low close to Ireland bringing rain or showers and blustery, possibly strong, winds. Current indications suggest a changeable pattern following which could be easterly for a time over Ireland with eastern areas having more showers fed in, possibly wintry. This would mean that western parts could average out a little drier than average. Pressure is likely to remain high to the northwest of Ireland. Temperatures are expected over this period to average close to normal across Ireland. Frost is likely too but there are no signals for very severe cold weather, though confidence is lower for this period.

Week 3 (Monday 25 January to Sunday 31 January)

With an upper level low extending from the southwest over Ireland during this period, it looks like it will be a more unsettled week. This would suggest an Atlantic regime or southwest regime developing with spells of rain or showers. There is a chance that some northwest fringes may be a little drier than average but most places look like having near to or above average rainfall. Temperatures are expected to average out close to normal. Extremes of weather especially wind/rain cannot be ruled out.

Week 4 (Monday 01 February to Sunday 07 February)

Confidence is low at this stage. There is a signal that high pressure will build from Scandinavia into Britain keeping it drier than average over Ireland but this is by no means certain and there could be wintry showers. There is no strong signal regarding temperatures but hard frosts are likely at times.

Met Éireann says "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."



Meanwhile, the UK Met Office (UKMO) says there is a growing risk of cold outbreaks for the second half of January, but the coldest weather is expected to stay off to the east.  It added that there aren't any strong signals at the moment pointing towards a prolonged very cold outbreak for the UK.  The UK will find itself stuck between higher pressure to the east and lower pressure to the west for the rest of January and into early February.

UKMO long range forecast (updated 9 January 2021)

Saturday 9 January – Sunday 17 January
Less cold, but some large temperature swings.

The weather is expected to become a bit changeable.  As low pressure slides across Scandinavia, we will likely see the first half of the week bring some milder air.  Although, some chilly nights are still likely with frost for many.

Colder weather is expected around midweek, with the end of the week and weekend seeing chances for another mild spell. It will also tend to be wetter than normal with low pressure systems bringing frequent bands of rain in. There is a growing risk of some snow later in the week.

But there is still a lot of uncertainty on the day-to-day specifics as the UK sits between the two dominant weather systems for Europe.  So in short, we expect a volatile week of temperature swings and frequent rain, along with a chance of some snow in places later.

Monday 18 January – Sunday 24 January
Wetter weather with some volatile temperatures.

As we enter late-January, the forecast gets a bit more complicated. There are some strong signals for possible return of low pressure track, which would bring milder but wetter and windier weather.
However, this comes with a rather large caveat, the polar vortex. This is a circulation of winds in the stratosphere, about 40-60 kilometres above the surface, and typically keeps cold Arctic air trapped at the pole.

In early January, the vortex weakened and became displaced over Europe, and it's still overhead now.
It usually takes a few weeks for the effects to reach the surface, so around mid-to-late January we expect an increased chance of cold outbreaks.

At the moment, it looks like the coldest weather will miss us to the east, staying in Scandinavia and West Russia.

There is still a lot of uncertainty on the westward extent of the cold air, and we could see a few cold blasts mixed in with our overall milder, wetter weather. As a result, this week is likely to continue to see some volatile swings in temperature along with some wet and windy days.

Fronts moving in over a cold snap will bring a chance of snow, even to low levels, but it is still too far away to pick out the specifics. Confidence is medium on the forecast, mainly due to the uncertainty in the temperatures.  There is risk of more widespread cold, as we have seen in previous years with a displaced polar vortex.

Monday 25 January – Sunday 7 February
Unsettled and milder with a risk of cold.

Towards the end of January and into early February, there continues to be strong signals for a return of low pressure tracks from the south bringing wetter, windier, and milder conditions. This will be coupled with the polar vortex strengthening again back to normal levels by the end of the month. Although, there is still a delay in the impacts reaching the surface, so cold outbreaks are still possible into early-February.

As with the previous week, we expect the cold to mostly stay to the east of us and low pressure to be the dominant feature, especially in February.

The UK will tend to find itself on the boundary between the cold high pressure to the east and the milder low pressure to the west, so confidence is pretty low.

A minor shift in the weather pattern will lead to some large changes in the expected conditions for the UK, so some caution is needed at this range.

In general, it will likely be on the milder side of average with frequently wet and windy weather, along with 1-2 day cold snaps bringing frost and a chance of wintry weather at times.

Further ahead

The UKMO says it monitor the weak polar vortex and see if we can more accurately pin down where the coldest conditions in North Europe will be.

View the IWO long range forecast here.