TRENDS for the week of 2 to 8 Feb 2021 --
-- Temperatures will average 1 to 2 deg below normal mainly due to falling temperatures by this weekend.
-- Rainfalls will average 75 per cent of normal values.
-- Sunshine will average near normal as the cloudy regime begins to trend more partly cloudy over time.
FORECAST by Peter O'Donnell
TODAY will be cloudy with a few breaks in the overcast this morning, mainly in eastern counties. Some vigorous showers are advancing through Munster at present and will reach Leinster by mid-day. As they slow down, they will begin to merge into longer intervals of showery rain, and more outbreaks of rain will follow from the Atlantic into western counties later. About 15-25 mm rainfalls can be expected. Quite mild with highs 10 to 13 C.
TONIGHT will turn misty or foggy as rain tapers off to drizzle, lows 5 to 7 C.
WEDNESDAY will continue rather misty or foggy with a few intervals of light rain, possibly a bit of partial clearing later in the day, highs 8 to 10 C.
THURSDAY will be partly cloudy with isolated showers, lows near 3 C and highs near 8 C.
FRIDAY will be partly cloudy with isolated showers also, lows near 2 C and highs near 7 C.
The outlook into the weekend and next week has been trending colder in general; yesterday evening there was almost total model consensus for a strong cold spell on easterly winds and considerable snow potential -- this has now diverged with several models continuing to show that outcome but one in particular flipping back to a continuation of the current regime or at least only a very slight cooling trend over the weekend followed by a return to milder air.
I am assessing the probability of the cold outcome to be something like 2:1 in favour, so will describe what I think that outcome would mean for forecasts, with the caveat that this is not a certainty yet.
The weekend would likely turn colder in stages with temperatures near 5 C on Saturday and 3 C on Sunday. Any showers or outbreaks of light rain would begin to turn sleety and eventually could mix with snow.
Even colder air could then arrive by later Sunday and persist well into next week, with moderate to strong east winds at times adding more chill, and potential for temperatures to fall to freezing or below in the daytime hours, and quite cold at night (-5 to -10 C). With the east winds and passing disturbances to the south, the potential for snow especially in Leinster and parts of Ulster and coastal Munster would become quite high.
As I say, this is the "leading option" of those available, but there is still some chance of this cold outcome being avoided by a continuation of this current regime or at least the form it would be taking later this week when the Atlantic lows are weaker than today's. Hopefully the model consensus seen last evening will return later today and then stick around until we get to that cold spell.