Long Range Weather Forecast For Ireland (20 February 2021)

TRENDS for the week of 20 to 26 Feb 2021 --

-- Temperatures will average about 2 deg above normal values.
-- Rainfall will average at least 50 per cent above normal values.
-- Sunshine will come in close to average thanks mostly to better prospects for sunshine late in this interval.


TODAY will become windy with outbreaks of rain, showery at first, then with some rather blustery showers and thunderstorms mainly focused on a cold front that will develop when low pressure arrives from the south by afternoon and reaches Galway, at this point (around 3-4 p.m.) a squall line feature is possible from east Galway through the midlands to the inland southeast, and some heavy showers and thunderstorms with strong wind gusts may develop. Winds in general will be southerly 50 to 80 km/hr veering to southwest 60 to 100 km/hr, but gusts to 110 km/hr are possible near this front along with hail and thunder. Temperatures will be steady around 10 to 12 C ahead of the front, and will drop to around 7 C after it passes. Some west coast locations may see intervals of less windy weather near the time that the low is passing due to its slack gradients near the core. But even so, winds in all areas will increase at some point later in the day when the low has passed by. About 15 to 30 mm rainfalls are possible, heavier amounts expected to be in the south coast counties and near the Atlantic coasts where it may be more of a steady downpour than a showery event.

TONIGHT will be blustery with passing showers, or longer intervals of light rain in some northern areas, a further 5 to 10 mm may fall there, with lows generally about 6 C and winds southwest 40 to 70 km/hr.

SUNDAY will become partly cloudy with showers more isolated in western and northern counties for the most part, and moderate southwest winds in the 40 to 70 km/hr range. Highs will be around 10 C.

MONDAY will start out dry and rather cold after morning lows of 2 to 5 C. For a while it will be relatively calm and bright, then with increasing cloud and southerly winds building in the afternoon, rain will sweep in from the southwest late in the day. Highs will be around 10 C but temperatures will be steady or rising slightly by evening. MONDAY NIGHT will be stormy with 30 to 50 mm rainfall potential in the 24 hours ending late Tuesday, and southerly winds 70 to 110 km/hr.

TUESDAY will continue very windy and wet as the rain continues for much of the day before finally tapering off to showers by evening. Winds continuing south to southwest 70 to 110 km/hr, temperatures in the 10 to 13 C range.

Flooding risks will be considerable by Tuesday morning into the rest of the day due to the persistent moderate to heavy rainfall rates. Another point of interest may be high waves and swells likely to develop as this storm will have had some intense phases while crossing the Atlantic, more so than its intensity near Ireland -- around Sunday night it could be as deep as 940 mbs north of the Azores, but luckily the intense centre weakens and rotates around towards Iceland and keeps away from the Irish coast, although the frontal systems it creates are strong enough to make it appear likely that perhaps orange level two warnings will be required at least in coastal counties.

WEDNESDAY will bring gradual improvements although it will still be somewhat unsettled and breezy with highs around 9 C.

The interval from THURSDAY to SUNDAY ending out this rather active weather month will perhaps be a contrast in terms of more sunshine and less wind than we have seen for quite some time, guidance has begun to come together on the idea of high pressure being fairly close to Ireland in this interval even though there are some signs of weak frontal passages in the westerly flow around the top of the high pressure. This won't be a cold high but nights may get a little cooler due to the clearer skies and lighter winds, while days remain in the near average 8 to 11 C range.

Peter O'Donnell for IWO