TRENDS for week of 6 to 12 Jan 2021
-- Temperatures will average 2 to 4 deg below normal despite warming to near average for early next week.
-- Precipitation will average 25 to 50 per cent of normal, and a significant part of that could be snow in some inland counties.
-- Sunshine will average near normal.
FORECASTS
TODAY will remain very cold, with only a slow dissipation of frost, ice and some freezing fog in parts of the inland west and north. Eastern counties will be slightly milder with mixed wintry showers feeding in from the Irish Sea in north-northeast winds; the wind direction will keep the extent of these fairly confined to Dublin and Wicklow, possibly north Kildare. Highs only 2 to 5 C, with some chance of temperatures remaining near freezing all day in a few spots.
TONIGHT rain or sleet will move into parts of west Ulster and north Connacht, turning to snow further inland, where potentially 3-5 cm could accumulate by morning, most likely from central Connacht into the midlands. Partly cloudy to overcast elsewhere with isolated wintry showers; the mixed precipitation with snowfall potential will reach some parts of the east and inland south by morning.
THURSDAY the snow or sleet will continue to make gradual progress southeastward with more areas seeing 1-3 cm accumulations, more mixed or melting wintry falls near coasts. Once this band has passed, winds will pick up from a northerly direction with bands of wintry showers and further snowfall potential as the air mass will be quite cold, with morning temperatures near -1 C not moving up very much all day, highs 2 to 4 C. There is some potential for locally heavy snow showers in parts of Leinster.
FRIDAY will see further wintry showers and very cold temperatures with lows -4 to +1 C and highs 2 to 6 C.
SATURDAY will be partly cloudy to overcast, and there may be persistent freezing fog in some areas, as a weak warm front may have trouble mixing down in all areas, temperatures will likely start around -5 to -2 C and move up only slowly inland, north and east, while responding more readily to the weak push of mild Atlantic air in the south and west where it could reach 5-7 C.
SUNDAY this weak warming process will continue with more of the country escaping from the freeze, likely almost all areas will turn milder eventually, with highs 6-9 C.
NEXT WEEK continues to look a bit milder but not exceptionally so, in fact the push of milder air is so weak that high pressure areas coming in from the west may partially continue the cold spell in some inland areas, at least overnight lows may remain sub-freezing. Highs will probably be a in a somewhat higher range of 6 to 10 C in most areas.
This subdued warming will continue for a while, then I am expecting that a second cold spell may develop and there's already hints of that within two weeks, details on this will be rather slow to emerge into reliable guidance.
-- Peter O'Donnell for IWO