TRENDS for the week of 10 to 16 May 2021 --
-- Temperatures will average about 1 deg below normal, but closer to 2
deg below during the daytime, as nights will be cloudy and therefore not
overly cold.
-- Rainfalls will average 25 to 50 per cent above normal in parts of the
inland south, southeast and east towards eastern Northern Ireland.
Further west, especially near Atlantic coasts, rainfalls will average
about the same amount below average.
-- Sunshine will be limited to brief intervals and may be challenged to
reach even half of the normal amount at this sunniest time of the year
normally (July is equally sunny in the southeast, by statistics, but
otherwise most of Ireland enjoys its highest daily averages in May, 5.5
to 6.5 hours, but in this coming week, 2 to 3 might be closer to the
outcome). Winds will continue to drop off towards lighter wind speeds in
general, with a southerly to easterly component for most of the week,
turning southwest by next weekend.
FORECASTS
TODAY will be rather cloudy in general with outbreaks of light rain at
first, turning heavier by afternoon around Cork and Waterford. This
heavier rain with some embedded thunderstorms possible will spread
gradually through the inland southeast and towards Kildare and Meath,
probably avoiding the east coast with its 15-25 mm downpours. Elsewhere
just spotty showers in the 2-5 mm range. Highs 12 to 16 C.
TONIGHT this rain will die off to scattered drizzle and mist, with overcast skies and lows 7 to 9 C.
TUESDAY will see a similar pattern but this time the rain is more likely
to stay near the south coast and move into Wexford eventually, with
areas further north seeing perhaps small amounts or locally staying dry
in a few places, with variable amounts of cloud, highs 11 to 15 C.
WEDNESDAY yet another cycle of heavy showers and this one is most likely
to affect the midlands into central Ulster, as the very last remnants
of the spinning and decaying low pressure system head into those regions
from the Atlantic south of Cork, the results could be 10-20 mm
rainfalls in central counties and smaller amounts on both east and west
coast. Lows 6 to 8 C and highs 11 to 15 C.
THURSDAY some of that rain may stall over Ulster and begin to loop back
around in a slow southward progression, making the inland western
counties perhaps the wettest part of the country, with 5-10 mm
rainfalls, once again, other regions likely to be closer to dry but
somewhat damp conditions under widespread cloud. Lows 5 to 7 C and highs
10 to 14 C.
FRIDAY there won't be much break between this decaying low and a
resumption of travelling weather systems in a southwesterly flow, but
some places could get longer dry spells and sunny breaks with a few
showers in the mix, lows 4 to 7 C and highs 11 to 15 C.
SATURDAY will be showery with 10-15 mm rainfall potential and highs near 14 C.
SUNDAY will be partly cloudy with showers and highs near 15 C.
MONDAY 17th will be overcast with rain that may become rather heavy into
Monday night and early Tuesday, temperatures steady around 12-15 C.
The longer term guidance, while less reliable, indicates more of these
Atlantic frontal rainfalls at intervals of two or three days with
another strong one shown for Thursday 20th, and more beyond that with no
obvious end in sight to this new pattern of unsettled southwest flow,
temperatures rather cool especially for daytime highs with all the
cloud.
Peter for IWO