Mods, feel free to shut down if inappropriate but its not often you get a precipitation chart like below less than 48hrs away so lets milk it for all we can!
Straight off, and just to clarify, this is an event driven by cold air sourced from northern Canada. It is not related to the extreme cold in Poland etc so don't expect expect extreme cold or anything like that. With the windchill though it will feel very cold on Thursday and Friday however. It will get milder as the weekend goes on but there is some chance of a more easterly sourced cold then mid week next week (a 25% chance say - Eastern areas best positioned for this).
So to the current precipitation chart from GFS (the American Model):-
What this GFS precipitation chart shows is widespread snow for everywhere except the outer east and extreme south at noon on Thursday. Now straight off these are snow showers and will be hit and miss. Equally its perfectly possible the showers will go all the way to Dublin so don't lose heart east coasters. Equally any Cork city boardies worried that it is on the verge needn't worry overly about showers reaching us as we usually do well in such NW flows (think xmas day '04 and 17 Dec 2010). Equally no guarantees at all that the areas in pink will see snow, let alone settling snow - though the further North and west you go the better your chances.
In my experience the GFS overdoes snow on its precipitation charts so this afternoon's update of the short range tools like euro04 (which only goes out as far as 12am on 13 Jan at the mo) will give a better idea of the breadth and extent of the snow.
No guarantees at all this won't be a damp squib but we frequently have these dedicated threads for borderline wind events two days away and this country is a lot better prepared for wind than it is for snow.
Best of luck to coldies awaiting their fix....