January
January is likely to start with the continued cold theme (or become cold if the stratospheric wave break hasn’t occurred yet). The risk of significant snowfall is most likely during these weeks of winter. The early winter Scandinavian block will fade as a more west based negative NAO becomes established. The cold will slowly fade in intensity as often in these situations, the block that prevented the westerly winds from reaching the UK moves west, allowing milder Atlantic air to break through. There still exists the possibility of further cold intrusions during this time before the stratospheric vortex reorganizes and influences the troposphere again.
Charts 36 and 37 Jan NH 500hPa heights and 850hpa temperature
The overall temperatures for January are likely to be below average for the start of the month before recovering later – I think that the better guides this year will be the 850 temps which show a below average month overall.
Precipitation is likely to be around average with the east coast wetter than the west - remember some of this is likely to fall as snow early in the month and the east is likely to hold onto the colder temperatures for longer than the west.
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