-- Temperatures will average 4 to 5 deg below normal.
-- Rainfall, or melted equivalent of snow/ice pellets etc, will amount to 25-50 per cent of normal although snowfall itself will be more than the average amount (which blends about 90% no snow with 10% cases with variable amounts).
-- Sunshine will be near normal at least in some western counties, may be reduced to 50% of normal in the east.
FORECASTS
Note -- the guidance has come together somewhat for this forecast period so you can assume these forecasts still have a possible range, albeit a narrower range than in previous discussions.
TODAY will bring variable cloud cover with best chances for some sunny breaks in parts of the inland south, midlands and later perhaps the east coast. A band of showers is moving north along parts of the east coast and may remain in that vicinity while gradually weakening, then as low pressure reverses its course and starts heading back south by afternoon, showers or outbreaks of light rain will follow behind it into Connacht, west Ulster and eventually some parts of west Munster. Areas between those zones could have a largely dry day with isolated showers possible. It will continue relatively mild for one last day with highs 6 to 8 C.
TONIGHT will be partly cloudy with passing showers or outbreaks of light rain, in northerly winds backing later to northeast 30-50 km/hr. Lows near 3 C.
SATURDAY will be partly to mostly cloudy with some bands of showers, turning wintry on higher ground, moving in from the Irish Sea, especially by afternoon. It will feel rather cold in northeast winds of 50 to 70 km/hr, as temperatures stall near 3 or 4 C in many areas, possibly reaching about 5 or 6 C closer to the east coast and along the south coast.
SUNDAY will become windy and colder and a few bands of wintry showers likely, some brief sunny intervals, and temperatures steady in the range of 2 to 4 C, but with east to northeast winds 60 to 80 km/hr, it will feel more like about -3 C. At this same time, parts of southeast England could be seeing heavy snowfalls from the circulation around the low we've been tracking, which by then will be around the border of France and Belgium. Snow streamers will be hitting parts of eastern England, and the same process will be trying to start up over the Irish Sea although it may be rather weak by comparison as the deeper cold air won't arrive over Ireland until Monday.
MONDAY and TUESDAY will be similar days, cold and windy with localized heavy snow streamers from the Irish Sea and also into parts of Cork and west Munster from the Atlantic. Winds will be easterly 50 to 80 km/hr adding quite a chill to temperatures that will range from overnight values of -5 to -2 C, to daytime readings of about -1 to +3 C. Some of the localized snow streamers could contain mixed wintry showers at times, and there is potential for thundersnow or ice pellets. Further west, some areas may get brief sunny breaks but cloud will be fairly widespread. Snowfall potential is probably around 5-10 cm each day but those would be localized maxima and more generally you might expect 2-5 cm coverings topped up by similar amounts. Because of the banded nature of this snowfall, some places will inevitably fall between the chairs so to speak and miss out. The extent of snow through central counties might be fairly robust as some guidance shows the streamers still intact upon reaching Galway. In these setups there are places in the southwest and northwest that often miss out on snow and also remain a bit more temperate.
WEDNESDAY could just be a third day repeat of the above, but some guidance also shows the closer approach of Atlantic moisture and warm fronts, which means that some parts of the south could come under a snowfall advisory if these fronts move close enough. That process tends to cut off the streamers to some extent, so the chances of further snow in central and northern counties may depend on the opposite trend. Temperatures will likely stay in a similar range, -5 to +2 C.
The breakdown of this cold spell seems fairly quick on most guidance, with Thursday into Friday the most likely time for temperatures to begin to recover back towards normal mid-February values. The sequence of events is likely to be snow to sleet to rain then a dry, milder interval. Some guidance wants to reverse the anomaly altogether and bring in very mild air with temperatures of 12-14 C by about Saturday 13th or Sunday 14th. That could also be delayed into the following week but still come to pass then.
PETER for IWO