Sunday, 8 December, 2019
Forecasts for Ireland
TRENDS for the week will return tomorrow, no large changes foreseen from earlier.
TODAY will be quite windy all day but even stronger winds will develop by late afternoon in west Munster. This will be the first part of storm "Atiyah" which continues into tonight. With the strong winds today, westerly 70 to 110 km/hr, passing showers that may be squally at times with hail and thunder, temperatures fairly steady in the range of 5 to 8 C, and wintry falls possible on higher ground as freezing levels will be down around summit levels in general. Winds increasing in west Munster to 80 to 120 km/hr with some local damage possible especially where strong winds are enhanced by terrain.
TONIGHT the first batch of strong winds will rapidly move through Munster and south Leinster with further minor damage potential and gusts to 120 km/hr. A second part of the storm will follow further north, moving into the Donegal Bay region around 7-9 p.m. and then rapidly sweeping through central counties towards Dublin by about midnight. This portion of the storm will contain northwesterly winds of 80 to 130 km/hr and could produce some damage especially in places not as frequently visited by strong winds. This will be an unusual wind direction for very strong gusts, by recent standards, so would advise not to assume anything about local conditions only based on these wind speeds in previous storms which might have been more of a southwest to west wind direction. Temperatures overnight will be steady in the 3 to 7 C range with further squally showers, or intervals of pelting rain (those more likely in Ulster and north Leinster).
MONDAY the stormy conditions will rapidly moderate in the hours after sunrise and by mid-day the weather will be much more tranquil with partly cloudy skies, perhaps an isolated shower, and westerly winds of only 50 to 70 km/hr. Highs will be 9 or 10 C late in the day.
MONDAY NIGHT into TUESDAY MORNING another storm arrives, this one also fairly powerful but with the more traditional southwest winds at 70 to 120 km/hr. About 10 to 20 mm of rain is likely. Temperatures will edge up to about 11 C and remain there until a cold front passes after sunrise on Tuesday. Clearing will begin around mid-day, followed by squally showers in a colder air mass. Temperatures will begin to drop off slowly at first, then faster towards evening on TUESDAY with squally showers, gusty westerly winds and temperatures 2 to 5 C.
WEDNESDAY will be cold and windy with passing wintry showers, mixed falls likely except near sea level in the south where mostly rain or hail, and snow on some hills. Winds westerly 50 to 80 km/hr will add a chill to temperatures steady in the 2 to 5 C range. It may turn a bit milder late in the afternoon.
THURSDAY will be milder again with more rain, not expected to be quite as windy as the earlier events, but with some gusts around 80 km/hr, and temperatures back up to near 10 C.
FRIDAY and SATURDAY will stay a bit milder than average with some rain at times, highs near 9 C.
It is likely to turn cold again for several days around Sunday 15th, and then more variable conditions after that cold interval.
My local weather on Saturday was overcast with wet snow melting as it fell, more slushy conditions and temperatures around 4 C. It would be preferable to have either rain or snow and not the messy mix, but it looks like more of these set-ups down the road although a few days of dry and settled weather will intervene. Very cold air has formed over the Canadian prairies, we are not going to get much of that as it goes by to our east, but the Great Lakes and Midwest, northeastern U.S. will be getting it full blast soon, with much below normal temperatures in those regions, some locally heavy lake effect and perhaps light coastal snow events forming.
Watch for possible updates, and stay in touch with the dedicated forum thread on storm Atiyah which will give you all the latest views of our resident weather experts and gurus. As I've already noted, the northwest wind direction has the potential to drive strong winds further inland than many of the more typical southwest gales that are mainly coastal impacts. Some of the guidance still has slight differences in the details too, at this rather short lead time, so it's fair to say that the outcome is not precisely defined by any means.