Conditions will become very warm and increasingly humid well into next week with temperatures widely rising into the 20s, according to Met Éireann.
Some thundery rain is possible also with low pressure near the Bay of Biscay, the national meteorological office added.
Regarding today’s weather, most places will stay dry during the day with spells of sunshine in just light southwesterly breezes.
However, there’ll be isolated showers too, mainly along northern coasts initially and later in the south-west.
It will be dry and calm in general tonight with some clear spells – and just the odd shower along south and south-west coasts later. Lowest temperatures will be 7° to 10°.
A Status Yellow blight warning was issued by Met Éireann yesterday afternoon.
Warm and humid conditions early next week will be conducive for the spread of potato blight, according to the office.
Some reasonably good drying will occur today and tomorrow, moderate outside of showers today and tomorrow, but poorer on Sunday and variable next week due to high humidities and heavy downpours but warm sunny periods also.
There will be some spraying opportunities later this week as winds fall light and showers become more isolated. At present, today and tomorrow look to be the best days in preparation for blight type conditions expected next week.
There is some restriction to growth in well drained soils in some parts of Leinster and Munster. Little change is expected until tomorrow, but more soils will become saturated from Sunday onwards with the deficits improving.
Much of Ireland will hold fully dry on Saturday with some sunny spells, according to Met Éireann, with just isolated showers expected through the day, before heavier showers move into the south-west during the evening.
Highest temperatures will range from 15° to 19° or 20°, in moderate south-east breezes, mildest inland away from south and east facing coasts.
A mild and humid night is forecast with lows of 10° to 13°, in mostly moderate south-east breezes.
Sunday morning will see a locally damp start with heavy rain also affecting southern counties.
Heavy thundery rain in the south will slowly push northwards through the day with high accumulations possible in some relatively short durations.
Spot flooding is likely. Ulster may however hold dry and bright until later in the afternoon, with rain eventually easing off in the south during the evening.
Further widespread rain or showers are likely for Sunday night, with a chance of a few thunderstorms.