Up to two inches of rain is forecast to fall in parts of Connacht, north Leinster and south Ulster from Monday evening through Tuesday before our weather turns colder once again.
Met Éireann has issued a Status Yellow rainfall warning for Connacht, Longford, Louth, Westmeath, Meath, Cavan and Monaghan where heavy rainfall will lead to accumulations of between 30 and 50mm. Higher totals will be recorded in mountainous areas bringing a risk of some river and localised flooding. The weather warning is valid from 9.00 pm on Monday and remains in effect until 9.00 pm on Tuesday.
10-25mm of rain is expected elsewhere with southern and south-eastern counties registering the lowest totals.
A slack area of low pressure approaching from the southwest will reach the west coast by early tomorrow evening and will deliver up to 24 hours of persistent rainfall for the Status Yellow region. The already saturated ground and elevated river levels will heighten the risk of flooding in these areas.
The system will slowly push away south-eastwards on Tuesday night with its back edge potentially producing some wet snow in inland Munster and Leinster. Accumulations are unlikely away from the highest ground.
It will turn colder as the system passes with a frost forming in Ulster overnight Tuesday. Colder conditions will slowly extend south on Wednesday, but it may stay milder in southern counties until Wednesday afternoon.
The outlook calls for a continuation of cold weather with wintry showers hail, sleet and snow affecting parts of west Munster, Connacht and Ulster during Thursday and Friday but some will push further inland during Thursday on a strong northwest wind. Snow showers will be restricted largely to hills and mountains. Daytime temperatures will range between 3c and 5c, coldest in inland Ulster. Overnight frosts will become more severe nationally on Friday and Saturday nights as winds become slacker.
Significant uncertainty remains about how long the cold spell will last but current indications are that milder air will push up from the southwest on Monday (25th) before another spell of cold weather of returns on Wednesday 27th.
IWO Senior Forecaster Peter O'Donnell will have an updated forecast tomorrow morning.