Corkscrew Hill, Clare. Pic Pat Flynn
TRENDS for the week of 12 to 18 Feb 2021 --
-- Temperatures will average 1 to 2 deg above normal, the smaller departures expected in Ulster and Leinster.
-- Rainfall will average about 2 to 3 times normal amounts across the south, then closer to average in central and northern regions where some of that will be snow overnight and on Saturday.
-- Sunshine will start to appear a little but probably won't surpass half of the normal mid-February amounts.
FORECASTS (and a recap of Thursday's weather outcomes)
On THURSDAY the expected snow only materialized in Connacht and some parts of Munster, and was largely absent from Leinster. In fact, the snowfalls exceeded most forecasts in Galway and Mayo, were about as expected in Clare and some parts of Tipperary, and otherwise did not take place further east. The culprit was dry air at lower levels, some snow was falling into this dry layer and evaporated. Also the system turned out to be weaker in the east and stronger in the west than most guidance suggested. So that's where the expected snow went. The snow has largely stopped falling except for some light flurries here and there; more is expected to develop tonight.
FRIDAY (TODAY) will continue cloudy, windy and cold in most areas, with slightly milder air making a very slow advance into western counties as snow gradually melts there. That will lead to fog over hills especially, and a gradual rise to near 4 C with drizzle at times. The eastern half of Connacht, the midlands, southeast and parts of north Leinster will remain cold and largely dry with a few flurries or patchy drizzle, southeast winds 50 to 70 km/hr and temperatures steady in the range of 2 to 4 C. Most of Ulster will be partly to mostly cloudy with temperatures around 1 to 3 C.
TONIGHT as rain moves a little further east and begins to get heavier near the south coast, areas of sleet and snow are expected to develop over central and eastern Connacht, the midlands, and some although not all parts of the southeast. The same dry air problem may prevent some of the snow from being very heavy in Leinster, but 7 to 12 cm falls are expected in parts of Connacht and west, south Ulster by mid-day Saturday. The possible range for Leinster may be more like 1 to 5 cm, or even some local trace amounts, but we will keep an eye on this and possibly update amounts for Leinster closer to the time. ... Temperatures tonight will start out near 4 C in the south and west, and could rise slowly there. Readings near -1 to +1 C are likely elsewhere, where snow develops, rising slowly to +2 or +3 C as snow begins to mix with rain. Winds southeast 40 to 60 km/hr except stronger near the south coast at times (southerly 60 to 90 km/hr). About 10-20 mm rainfalls are expected in parts of Kerry, Cork, Waterford and Wexford.
SATURDAY will see the snow, sleet and rain areas all moving further northeast and eventually the wintry forms of precipitation will end leaving the entire country with rain and strong southerly winds 70 to 110 km/hr, and fog will also be rather widespread especially over areas of melting snow. Temperatures will rise to 10-12 C in the south and west, and 7-9 C over snow covered areas leading to a rapid melt. About 20-40 mm rainfalls are expected and some flooding is likely especially where streams are swollen with mountain runoff that may include snow melt.
SUNDAY will be breezy to windy and mild, south winds at 70 to 110 km/hr, temperatures steady 8 to 12 C and some patchy rainfalls that will be heavier in the south and west, where a further 15-30 mm could fall. Any flooding will be maintained or get slightly worse as a result.
The rest of next week looks fairly mild also, with highs between 6 and 10 C on most days, and winds generally south to southwest. There will probably be several intervals of rain with brief dry spells between them.
Peter O'Donnell for IWO