Cold Spell (of depth and duration uncertain!) starting Tuesday 7th March

There will be nothing more annoying than having trouble getting home from work, whatever about getting in there. Roll on the morning runs.

Roads will be gritted all the way

I am just stepping back in, day trip took me away from internet (shock and horror), so will update my thoughts in general by midnight I hope.

A beautiful Halo around the Moon tonight with some high cirrus cloud here in Castlebar. Cool in an Easterly wind . Even Belmullet down to just 1 degree.

Not a lot of change in my assessment after studying the latest obs and guidance ... low was recently located very close to 50N 20W heading almost due east ... key will be set-up of arctic front dividing transitional (sleety) zone south from cold enough for all snow zone north. That feature currently appears to lie around north Clare to Meath; Mullingar is just on the north side of it now. It may try to drift north despite the track of the low, but is probably constrained from going much north of Galway Bay to Louth. As precip gets heavier 09z-15z evaporational cooling will force the front to drift south to a line from central Clare to north Dublin. It will accelerate south once the low is past 5W.

Precip shields often materialize slightly further north than model guidance which probably ensures significant snow for Donegal and northern tier of NI counties but axis of heaviest snow is likely to be something like Tuam (yes really) to Armagh. Those posters high up in Mayo should do very well. Pauldry in Sligo may find he's in a bit of a subsidence minimum zone but it should still be 10-12 cm there (downsloping from higher terrain northeast). In general you'll perhaps notice minor differentials depending on whether your local terrain is rising or falling from northeast to southwest.

Thunder-snow seems likely at times with these strong dynamics. Would say 1500-2100h most favorable (perhaps later for Dublin though).

Will stick with my numbers although where I said 15-25, 12-20 might be more realistic. Eventually I think it will snow just about everywhere in Ireland on the wrap around portion early Friday. Note the worst of the storm in south Ulster is predicted to be midnight to 0300h Friday.

A lot of specific interest in Dublin so would say, intervals of sleety rain sometimes mixing with wet snow, accumulations on higher slopes to south of city, temps 2-5 C then slowly falling after 8 p.m., snow becoming dominant by 10 p.m. to midnight, 5-8 cm accumulations possible overnight, more if Irish Sea banding becomes significant. 15-20 cm on higher portions of Dublin-Wicklow mountains. Kildare maybe about 5 cm in total.

I will probably be around throughout the buildup and delivery of this event, will post forecasts and any updates in my forecast thread and just read here unless I feel there's something missing (so far I think the discussion has been excellent and covers all variables -- this does have some low-side bust potential due to marginal 850s and thicknesses but I am counting on evaporational cooling to overcome the handicap).

M6 buoy at 15W has been reporting temps near 7 C and dew points near -1 C showing that the cold air is flowing out into the circulation, as to the inland penetration of 8-10 C temps, this seems unlikely to go much past Waterville to Cork (city) to Waterford (city) to about Gorey on east coast. A zone of about 4-8 C will likely sit north of that line most of the day, to south Clare - south Kildare then it would loop around the mountains and emerge to cover the east coast to about Bray. A zone of 2-4 C would sit from there to the arctic frontal boundary north of which, mostly snow and 0-1 C (-1 C on hills).

Something not mentioned as far as I noticed was flood potential on Sunday after this snow melts and combines with rain on Sat--Sun and higher water tables in some cases from Thursday rainfall too. It may be minor, but worth keeping in mind where snow melt is rapid.

Speaking of Tuam, where is our friend from Tuam these days? I also thought this event might lure back Blackbriar/George Sunsnow.

Is this arriving earlier than planned?

I'm not far from Tuam at the moment, around 6/7 miles NNW. 1.5 degrees right now where I am and no precipitation so far.

Never thought I'd see the day Tuam get mentioned in one of MT's snow forecasts...especially as the axis of power:)

Light rain Galway City. Might be sleet, don't know but it's fairly light.