TRENDS for the week of 21 to 27 Feb 2021
-- Temperatures will average about 2 deg above normal, mildest around Tuesday.
-- Rainfall will average twice normal values in the west, about 50% above normal in the south, and closer to average amounts elsewhere.
-- Sunshine will average near normal thanks to an improving trend later in this weekly interval.
FORECASTS
TONIGHT the showers will gradually die out and a clearing trend will follow, rather cold in most areas with lows falling to 1 to 4 C.
MONDAY will start out bright and cool, and for the first half of the day relatively calm, then a southerly wind will begin to increase along with cloud spreading in ahead of a powerful frontal system, winds by late afternoon will increase to 50-80 km/hr. Highs near 10 C.
MONDAY NIGHT into TUESDAY will be windy and wet with temperatures steady in the 12 to 14 C range, southerly winds will slowly veer more to the southwest in the 70 to 110 km/hr range at their peak which is likely to be late overnight to mid-day Tuesday. Heavy rain will develop and spread up the western side of the country with 30-40 mm amounts expected, leading to localized flooding. While it will be frequently showery elsewhere with 20-30 mm totals, the flood potential will be less significant away from the south coast (and parts of the west as indicated).
WEDNESDAY this system will begin to die out but not before continuing the wet weather for the first part of the day in the east, while gradual clearing spreads into the west. Lows near 7 C and highs near 10 C.
THURSDAY will become partly cloudy and a little cooler with moderate southwest winds, lows near 2 C and highs near 9 C.
A high pressure area will build up later in the week and should control the weather pattern for several days through the final weekend of February. Guidance is not particularly unified on the details however. Some depictions show a relatively mild southwest flow continuing, while other maps suggest the high will get very close to Ireland and possibly build up further to the north allowing for a cooler southeast flow eventually. Either way it's likely to be dry with temperatures not too far from 10 C daytimes and 3-5 C for overnight lows (could drop lower if the high is in fact right over the country at any point). Any cooler turn to temperatures would be home-grown as the former frigid air mass lurking over western Europe earlier this month has been pushed back into the northern half of Russia. However, some charts are now suggesting that eventually, a new cold spell could develop from a northerly origin some time in March.