Snow showers Sunday Night/Monday 29th-30th Decmber 09

Gonzo

i highly doubt we'll get snow, temps already 4-7C in parts of the west in advance of the rain and temps appear to have leveled off in the east over past 2 hours.

Danno

-1c currently... depends on how long the cold can hold on for... 7am or 8am would be great.

Jesus Wept

noob question: What are the ideal conditons for it to snow? What needs to happen?

M.T. Cranium

I expect some sleet or freezing drizzle along the leading edge of this misty rain band, but mostly over higher ground. The factor that is less favourable here is that cold air is being flushed out ahead of the falling precip, so this takes away the period of opportunity for snow to develop.

What makes snow happen? Bear in mind that a lot of winter rainfall starts falling as snow and melts somewhere overhead on its way down. This is why mountains are often covered in snow before lower elevations see any.

So, what brings snow to lower elevations is one of two things. Either the snow falls faster and harder, and has no time to melt, or, the mechanism happens over top of sub-freezing air and snow has no reason to melt.

A third possibility not seen very often in Ireland is freezing rain. This is where snow falls into a mild layer above the surface, melts to rain, then freezes on contact with a cold surface. If it freezes in the air of that lower cold layer, it falls as ice pellets or hail.

If all these factors are somewhat marginal and indistinct, you can get sleet, which is a mixture of various forms of precip.

snaps

we had snow here for about 20minutes (Ballinrobe, mayo) now pissing with rain but still cold 2.9c