TRENDS for the week of 27 Dec 2020 to d2 Jan 2021
-- Temperatures will average 3 deg below normal values.-- Rainfall will average 25 to 50 per cent of normal, and some of it will take wintry forms.
-- Sunshine will average 25 to 50 per cent above normal, although closer to average in western counties.
FORECASTS
TODAY will be windy and very cold with passing wintry showers, any snow accumulations will be either temporary or confined to hilly areas, but showers may take a variety of forms including hail, sleet and snow. Winds northwest 50 to 80 km/hr, except some higher gusts likely near Atlantic coasts. Highs 3 to 6 C, but feeling colder due to the wind chill factor (around -2 C).
TONIGHT some more organized areas of sleet or wet snow will move south into Ulster and parts of Connacht, Leinster, with some slushy accumulations of 1-3 cm possible. Continued windy in most areas with a few more passing wintry showers in west and south. Lows near 1 C.
MONDAY the area of sleet and wet snow will move further south, mixing with rain near sea level, but leaving behind some slushy accumulations in parts of Leinster. Snow will also accumulate on hills in all regions in passing wintry showers. Any temporary abatement of the strong winds near the low centre (over the Irish Sea during the morning half of the day) will be followed by resumed stronger winds that will continue uninterrupted elsewhere, northwest to north 50 to 80 km/hr. Highs only 2 to 5 C.
TUESDAY will gradually become a little less windy but it will remain cold with passing wintry showers, heavy at times on some hills in the west and north. Longer sunny breaks are also likely especially in eastern and southern counties. Lows near -1 C and highs 3 to 6 C.
WEDNESDAY will be partly cloudy with just isolated wintry showers, lows near -2 C and highs near 5 C.
THURSDAY (31st) will be partly cloudy to overcast with isolated wintry showers, possibly a more organized band of snow moving south during the night (after midnight mostly). Morning lows near -2 C and highs near 5 C.
FRIDAY (New Years Day 2021) will be breezy and cold with occasional light snow or sleet, lows near -3 C and highs near 4 C.
The OUTLOOK is for an interval of cold, dry weather that may persist (according to most guidance) for a week but there are some indications of a return to milder Atlantic driven weather systems as early as the 4th in some other guidance, so we're waiting to see if a new trend is emerging or if this contrary view fades back out of the picture again (which can happen in these long blocking episodes). I would repeat the earlier observation that this will be a prolonged spell of marginal (for snow) wintry parameters, certainly colder than average, but with snow rather hit or miss mainly due to the slightly less than ideal upper parameters; however, that will not rule out some snow in both northern areas and higher terrain, even if it doesn't happen everywhere.