Northerlies at the back end of the week - I would imagine that would be a possible indication of it getting worse if the eruption continues, however is a lot more dynamic than last year.
It's all very dependant upon the main thrust of the Northerly flow however, which is not a true northerly in the sense, rather a northerly flow developing as Low Pressure tracks Eastward.
Meteociel - Cartes du modle numrique GFS pour l'Europe
As the latest 12Z GFS Operational Forecast indicates, it's quite possible that a southerly flow will be developing over Iceland as low pressure pushes up from the South, whilst the Northerly flow gradually clears the UK and Ireland.
The IAA have also announced that there will be no closure of Irish Airspace for at least 48 Hours.