BBC monthly outlook
Monday 27 February—Sunday 5 March
Chilly and showery at first, a touch milder later
The week will get off to a chilly start, as a slow moving area of low pressure and its associated cold air drifts in from the northwest. Heavy and often thundery showers will affect most parts of the UK through Monday, although some good spells of sunshine can be expected in between such showers. The showers will turn wintry at times, even to low levels, and particularly across the northern half of the UK, where there could even be some settling of snow on higher ground. Frost will be particularly prevalent overnight into Tuesday, along with some patchy ice.
Tuesday will be a similarly showery day, but although the showers will be just as wintry, they are unlikely to be as heavy. Through the midweek period, conditions will settle down across the north of the UK, but it will remain cold. Further south, weather fronts are expected to cross from the west at times, with a slightly milder feel developing. Through Friday and into Saturday, another Atlantic weather system is expected to move up from the south, introducing the possibility of a spell of heavy rain to many areas for a time. Any rain on Friday and into Saturday could also briefly turn to snow over higher ground in the north. An unsettled theme is expected to continue through Sunday across most parts.
Monday 6 March—Sunday 12 March
Still changeable but changes happening more slowly
With low pressure still anticipated to be centred just to the west of the UK, it is likely that the first full week of March will start on an unsettled note, with bands of rain moving up from the south or southwest at times. Any wet spells will be followed by drier interludes and a few showers. It is likely that the northern half of the UK will be colder than the March average for much of the time, so some periods of (chiefly hill and higher ground) snowfall are possible, both from rain bands and any following showers. Milder conditions are expected across the south. The colder regions of the UK are likely to experience some overnight frosts, with patchy fog also possible at times.
As we progress through this period, it is possible that although the changeable theme will remain, the changes in weather will tend to be slower, with lengthier dry spells in between weather systems. Confidence in this forecast scenario is reasonable. However, some computer model solutions do hint at the possibility of an extensive anticyclone centred broadly to the north of the UK drifting close to or over northern and eastern areas of the UK. Should the high move in this fashion, a cold east to southeasterly flow will develop across all parts of the UK, resulting in widespread cold, settled conditions with overnight frosts, bright days and the possibility of coastal showers in the east.
Monday 13 March—Sunday 26 March
A chilly end to March?
Moving into the second half of March, the suite of different of computer models that we utilise to produce the longer range forecast are offering an unusually broad range of different forecast solutions. This broad range does not inspire particular confidence in any given individual forecast solution. That said, the solutions can be broadly grouped into two categories; those that allow the continuation of Atlantic weather systems moving across the UK to bring a succession of wet and windy spells followed by drier interludes, and those where an anticyclone centred over Scandinavia brings colder, drier weather to our shores from the east. At time of writing, the former scenario is slightly favoured, but there are increasing signs that as we move towards the end of March, a colder, drier and more settled theme could well begin to develop. As always we will continue to monitor trends in the forecast model and keep you updated.
Next week
If high pressure does set in across the UK towards the end of March, a typically showery start to this coming April will not happen. Be sure to stay up to date with the latest thinking on April's weather, and all other weather matters, by staying in touch with the BBC Weather Centre.
http://www.bbc.co.uk/weather/2635167#outlook