Weather Turning Colder, More Unsettled

The transition from the present mild, overcast period of weather will be replaced by a 24-hour reminder of the season we are about to face into - winter. 

As we indicated on Wednesday of last week (read), Friday (Oct 26) will see a colder airmass sink south over Ireland. Friday night though Saturday morning  will see temperatures dip as low as -3 or -4c, while some scattered, mostly light, wintry showers will occur on high ground in north and east Ulster and East Leinster on Friday afternoon. It will be largely dry and bright elsewhere. The season's first dusting of snow may also occur on the highest summits in these regions. However, the threat of wintry showers occurring at lower levels here is very low.

It will turn milder on Saturday and Sunday before temperatures dip to below average for the time of year again on Sunday night through Monday. The outlook is for cooler, often windy and unsettled weather to persist into the first week of November.


Brighter clearer weather will extend slowly south overnight resulting in a considerable drop in temperatures as it does so. By morning, much of the country (with the exception of the south and southwest) will see the mercury levels dip to between 2-5c (about 6-7c lower than recent nights).

It will be rather cold start to tomorrow with highs of just 6-8c, perhaps a degree or two higher in coastal areas of the south and southwest.  Friday will be a cloudy, raw sort of day in most of the eastern and northern counties with some rather sleety showers in north-east Ulster and north Leinster, winds northeast 20-40 mph adding quite a chill after this warm spell, and highs 6-8 C. Further south and west, there will be a little more sunshine in the mix, and less chance of showers. Highs there of 8-11 C.'s GFS chart for midday, Friday, showing showers in northern and eastern coastal areas.
On Friday night, although there is potential for frost and lows of -3 to -1 C this may be hit or miss due to persistent low cloud that may keep temperatures higher in some spots, with the chance of fluctuations between frosty and thawing temperatures during the night. Some icy patches are likely and because of the variable conditions this may be more dangerous (if the frost was more widespread everyone would be more aware of it on their journeys). Winds will fall off light or calm in some inland areas but coastal margins will retain northerly breezes of 10-20 mph; this and the marine exposure will keep overnight temperatures near 3-5 C in some coastal areas, so no frost there.

This cold spell will quickly get overwhelmed on Saturday by the return of milder Atlantic air in Ireland (although not in Britain) so expect cloudy skies. Rain arriving in north late in the day. A slightly milder feel once the scattered frost is flushed out, highs 9-12 C, winds backing to NW 20-35 mph.
On Sunday, showers or periods of rain (10-15 mm) will be accompanied by moderate SW winds 20-40 mph veering to west and northwest late in the day 35-55 mph at times. Morning lows near 5 C and highs near 11 C but turning colder again by evening.

For Bank Holiday Monday and the Dublin Marathon, it will be raw and cold with passing showers (1-3 mm). A brighter afternoon should develop, despite some sleety showers mid-day on higher ground Lows near 2 C and highs near 7 C. Winds northerly 25-35 mph abating somewhat later.

OUTLOOK ... Temperatures are likely to stay a degree or so below average for the time of year during the last few days of October and into the first week of November. The Atlantic, which has been kept at bay in the past week, will be more active as the jetstream slips over or slightly to the south of Ireland. This means that showers or longer spells of rain can be expected in the coming ten days. It will however, remain cool throughout. GFS output for next Wednesday showing the position of the jetstream.