Wet and very windy later this week
With a surge of colder Icelandic air across the UK the below average temperatures will persist until early next week before getting back to more average readings into December.
The drivers of this pattern will be high pressure in the Atlantic and a series of fronts moving across the country. Friday and Saturday this week will be particularly wet and windy with a deep low affecting the North Sea.
Temperatures should moderate next week but the weather will be changeable before drying out later in the week. High pressure becomes more established across west and central Europe over the latter half of period meaning England and Wales should trend drier.
A cold unsettled week; very windy from Friday
A series of troughs will move south-east over the country for the remainder of the week while high pressure is stationed in the north-east Atlantic. A cold front will cross the country through Wednesday. This will bring rain to most parts through the day, but it is likely to remain dry in parts of southern England as the front fragments.
A further band of more persistent rain will move across Scotland from Thursday evening, reaching further south through Friday. The rain will slowly clear the country from late Saturday, but a further band of rain moves south-east into Scotland later that day with low level snow possible. Temperatures will remain 2-4C below normal through the week in a cold northerly flow with the lowest recordings expected around Friday. Temperatures beginning to climb over the weekend but remain below average.
Light winds are expected over England and Wales at first, but stronger winds over Scotland and Northern Ireland will gradually move south from late Thursday. It will become very windy on Friday for most as the low moves across the country, with winds slowly easing from the north early Sunday morning.
Cold to start, becoming milder. Driest late week
The first half of the week will see a series of troughs moving south-east across the United Kingdom while high pressure persists near the Azores. Later in the week the high moves over Spain and France bringing a more westerly flow, and a series of troughs, across the UK. It will be a showery day on Monday with some snow possible over the Northern Isles. A more persistent band of rain will move across into Tuesday. This will be persistent and heavy at times.
The rain should clear overnight to give a day of scattered showers into Wednesday; these will likely be wintry in the north and more frequent in the east. Showers will clear by Thursday morning ahead of a further band of rain that will move across all parts through the day, with rain slowly clearing through Friday to bring in a more settled weekend except over Scotland. Temperatures will start the week around 1-3C below average, but then slowly get back to more average levels, or even a little higher, from later in the week.
The winds will be changeable throughout the first half of the week and will be mainly from a northerly or north-westerly direction, so it will feel cold. Winds may turn more to a more westerly direction later in the week while remaining breezy in nature. The main alternate scenario for this week is for the Atlantic high to push further into north-west Europe with a deep low near Iceland. This would bring windier conditions to the northern half of the UK but drier and calmer weather for much of England and Wales.
Changeable temperatures but with some warmth
For the second week of December, high pressure from the Atlantic periodically shifts across western and central Europe. Low pressure systems bring increased precipitation to Northern Ireland and Scotland. Winds remain elevated for much of the week due to the combination of high and low pressure systems moving across northern Europe. Changeable temperatures are likely. Some brief episodes of warmth are expected, especially over Northern Ireland.
Model guidance has been relatively volatile with the positioning of high pressure moving into Europe, which promotes a bit of uncertainty to the forecast. The risk for this week would be if the high pressure is more persistent over the eastern Atlantic and struggles to advance into western Europe. In which case, a cooler pattern would develop, and it would be wetter in England and Wales.
By the third week of December, the centre of high pressure becomes more favoured in western Europe, a bit closer to the United Kingdom. The pattern is still expected to remain unsettled across Scotland. Temperature variability is expected, but milder spells across Northern Ireland and Scotland should allow for the weekly temperature average to be a bit above normal. Drier, calmer, and sunnier conditions look to build across England and Wales.
The primary risk for this period would be if the high pressure shifts towards central and south-east Europe. This would usher in warmer south-westerly winds, and a wetter and windier pattern would also emerge
We will see how long any milder patterns will linger through December or if we will see a change to a cooler regime. We will also get a long range look towards Christmas.