In reply to ianstevens:
Just a quote,
This scenario would allow for the development of some severe and sustained cold blasts and significant snow (even to lower levels). From mid-March onwards there is the risk for a dominating period of cold and snow to develop for at least 30-60 days, due to a favourable pattern change to a more negative NAO and in consideration of certain stratospheric influences leading up to this period.
PLEASE NOTE - A strengthening and more active phase of the MJO does not reflect in a negative NAO until 14-21 days later (the reason why computer models are still indicating a positive NAO for the foreseeable at present).
It must also be noted that abnormalities in temperatures near Greenland also suggest a continuation of more recent weather types due to a stronger jet-stream. This would also prevent above average heights pushing into Greenland. However, the characteristics and wavelengths of the MJO for this particular phase (phase 8) should eventually allow for a more negative NAO to develop (my estimation for signals of this occurrence is from mid-March onwards).
The start to March and the spring period is also likely to begin on a much drier note than of late in terms of rainfall amounts, with more in the way of developing sunny periods. This will also bring some interludes of near average daytime temperature to places for this period. However, some showers and very windy periods are still likely to develop at times, in particular, in the northern half of the country. Some of these showers may also turn wintry in parts of the north for in or around the 3rd March. Thereafter, is likely to bring progressively colder temperatures and the increased risk of widespread frosts and some notable snow.
So although March may deceive us in thinking that spring has arrived early due to some decent intervals of sunshine and somewhat drier weather than of late to begin with, do not be surprised to see weather models adjusting to this scenario and a more negative NAO as we progress throughout the March period and into the remainder of spring.