TRENDS for the week of 5 to 11 Jan 2021
-- Temperatures will average 2 to 4 deg below normal, with a gradual increase towards near normal values at the end of the interval.
-- Precipitation will be slight in most areas, 10 to 25 per cent of normal values in occasional wintry showers.
-- Sunshine will be near or slightly above normal values.
FORECASTS
TODAY will continue very cold with moderate northeast winds, although some parts of the inland west will have lighter winds for at least the morning hours. Bands of mixed wintry showers will continue to feed into central Leinster from the Irish Sea, snow is only likely briefly in mixtures, or on hills. Rain, sleet and hail will also be possible at times, however, coverage is not large and amounts will be generally small. Some sunny intervals will return further west. Highs 3 to 6 C.
TONIGHT will see some clearing in parts of the west and inland south, lows there could fall to -5 C. Rather cloudy with a few weakening wintry showers in the east, lows -1 or 0 C.
WEDNESDAY will see wind directions slowly turning back to north-northeast, which may allow areas of wintry showers to develop in Ulster and Connacht, but coastal Leinster may still see some as well (inland drift may be limited with these). Still quite cold with highs 3 to 6 C, mildest in the southeast and near the northwest coasts.
THURSDAY and FRIDAY will continue very cold as a new batch of arctic air arrives from a northerly direction. There won't be much change in the weather from this current spell as a result except that wind directions will vary from north-northeast to northwest in this spell, probably continuing the tendency for wintry showers to cover more areas of the north and west, but occasionally still to be found in the east. Some minor variations within this regime may lead to weak frontal bands of mixed wintry precipitation that could see wet snow or freezing drizzle turning to a cold rain at times. Amounts will not be large, but this could occur both days. Lows will continue in the range of -4 to +1 C and highs in the range of 4 to 7 C.
SATURDAY will see mostly cloudy conditions with a weak warm front approaching, but it may take most of the day to get temperatures up very much from their early readings near 2 C, eventually it could be as mild as 6 to 8 C.
SUNDAY and MONDAY at this point look milder again with highs closer to normal values, around 9 to 10 C, with some light rain at times.
The models are generally swinging back to seasonably mild weather patterns after that, although some have a cold day or two wedged into that milder regime. Not very confident of model scenarios past five or six days at this point and certainly seems quite plausible that a second and perhaps more severe cold spell could develop later in the month, but beyond the reach of the guidance at present.
-- Peter O'Donnell for IWO