TRENDS for the week of 23 to 29 Mar 2021
-- Temperatures will average near normal, often slightly above average
but briefly quite cold around Friday, it should balance out to near the
long-term average for late March.
-- Rainfall will gradually begin to pick up and could accumulate enough
to reach near average amounts by the end of next weekend, although parts
of the east and south are likely to remain relatively dry (50% of
average).
-- Sunshine will be rather infrequent and winds will become moderate for
several days and occasionally strong around Friday-Saturday.
FORECASTS
TONIGHT... Occasional rain, moderate southwest winds, lows near 7 C. Total rainfalls 5-10 mm.
WEDNESDAY ... Variable cloud, passing showers, relatively mild with highs 12 to 14 C.
THURSDAY ... Increasing cloud, intervals of rain, temperatures steady
near 12 C. Turning much cooler in the late afternoon and evening
especially in Connacht, west Ulster and parts of west Munster. Winds
southwest 50 to 80 km/hr. Temperatures will be falling steadily
overnight.
FRIDAY ... Windy and cold with passing showers, some sleety or even
wintry on hills in north and west. Winds southwest 50 to 80 km/hr. Lows
near 2 C and highs 6 to 9 C.
SATURDAY ... Continued windy, but turning milder in stages, quite mild
by afternoon and evening when temperatures will peak at around 14 C.
Winds southwest 70 to 90 km/hr, possibly stronger near exposed Atlantic
coasts. Occasional rain but it may only be intermittent or drizzly away
from the northwest coasts.
SUNDAY ... Little change now expected except that rain will be less
frequent than Saturday, continued windy and mild with temperatures
steady 13 to 15 C. Probably cloudy in most areas, but could become
brighter at times in parts of the southeast.
MONDAY to THURSDAY of next week now pose a challenge -- one leading
model continues that theme discussed earlier of higher pressure bringing
a pleasant spell of weather especially towards the first part of the
Easter weekend, and that's the U.S. guidance, but interestingly, the
Canadian now sides with the European model which often means this is
what will actually happen, as they often come at things from different
input, so when I see a consensus from them it makes a mark, let's see
what happens, in this case they both say it won't turn settled but back
to more unsettled conditions as disturbances drop south from near
Iceland and usher in a cold north to northeast flow that is supposed to
last through the Easter weekend (the U.S. guidance had this coming in
around Easter Sunday, so it does seem more or less high probability of
happening at some point during if not before that weekend). This could
all change before we get really close to Easter of course. The degree of
cold predicted by these various models (once they have it in place) is
considerable, like a late blast of wintry weather that probably almost
nobody really wants to see with spring gradually settling in. Current
maps would suggest potential for mixed wintry showers and temperatures
quite low, 3 to 6 C possibly. The main difference then is whether this
would wait until near the end of the weekend, or be in place for quite a
few days before that (from about the 31st on, according to the two
models in agreement).
Peter for IWO