mountain shadow

Reading between the lines of the various output and commentary I believe there is a decent chance for Northern Ireland to be hit by a cracking wintry winter storm. With the increasing Greenland heights, any low pressure systems pushing through the islands will have increasingly colder air on its Northern and Western sides. So with strong winds, precipitation and cold air we could see white out conditions sometime over the festive break!

Well we normaly expect things to move further East as we approach T+0, so still all to play for.

Colder spell still showing between Christmas and New Year, unfortunately a white Christmas is looking less of a possibility this morning.

Happy with the ECM. Its slower with the evolution but the pattern change to something significantly colder is there.

Some BOOM charts this evening. If there still there in the morning I'm buying a sledge!!

Crucial E tonight. Really need to see a cleaner evolution on the Greenland ridge and no pesky short waves

If it does down turn out to be a technical white Christmas in the North and West then big up to the models which would have shown the potential from a long way out.

As ever Neiller, expect the worst and the usual what can go wrong will go wrong. Saying that, the models are still keen on the potential white Christmas in the North West with perhaps something more deep wintry afterwards. The good thing being in the North West is that we are closer to the cold action and more likely to benefit than those in the South and East.

Decent day for cold and snow lovers, here's hoping its still there for Christmas in the morning.

Come on ECM, do the business tonight. If it does, the senior Met man will be muttering away, with a wee bit of pressure on Come on ECM, do the business tonight.

Welcome back mate. Thought you had moved on. You've picked a great time to return. Increased risk of a white Christmas and perhaps something bitter beyond.

So, a mild and wet couple of days followed by a colder weekend. Average next week with the potential for a white Christmas (technical and perhaps not deep crisp and even) followed by the potential, and I stress potential for a significant colder spell kicking off between Christmas and New Year!! There you go, a ramp to cheer you all up.

You don't have to look very far to find it... Latest GFS P.. http://hib.nwstatic.co.uk/gfsimagesnew/gfs.20141216/06/384/h850t850eu.png NO forecast http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml NAO forecast http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml Iceland ensembles almost universally agree on pressure rises to between 1010mb and 1030mb and finally the height anomalys at 10 days clearly showing the potential for a cold spell.. http://hib.nwstatic.co.uk/gfsimages/gfs.20141216/06/240/hgt500-anomaly.png There is a clear potential there and found these links in about a minute, so to say you can't see a cold spell has no basis in the current model output.

No change today. No chance South of the Midlands, perhaps more of a chance the further North and West you get, usual altitude caveats.

Agreed Warren, IDO's continued use of the mean at t+million is irrelevant given the vast scatter the further out you get. Pointless.

No Daniel, just basing it on what I see. Today's runs firming up and pretty guaranteeing no white Christmas South of the English Midlands. Further North and West perhaps still a small chance of a technical white Christmas with a few flakes from a passing shower if a cold sector is in place, certainly no chance of anything deep crisp at low levels anywhere. It would take a miracle for a turn around now, even at 10 days out. Obviously places above 1000 feet or so may be different.

Pretty universal agreement on the NAO to return to neutral or negative by month end... http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html Whether that is enough to show a cold spell is unlikely but at least any Euro slug should be temporary. In the meantime, pretty mundane weather with the odd colder day in the North and West. As ever, patience, patience patience.

Given the pre Winter positivity the charts at the moment are a real let down. Hopefully something more interesting will appear tomorrow

Chances of a white Christmas now looking very very slim. If the 0z are similar tomorrow morning its all over.

I think that reaffirms where we are to be honest which has been pretty well modelled. A movement of the vortex towards Siberia in late December, no SSW until early January with the impact of that sometime later. In the meantime, its getting what we can from the occasional Polar maritime airstream whilst we await the SSW.

Thanks Karyo, as you say though, the run to run differences are quite marked. The blue dotted ensembles run from yesterday, must have been a cracker. The link would seem to indicate no decent -NAO until mid to late January.

Complete agreement on the NAO forecasts to start declining towards neutral, another few days though to see whether a -NAO is likely or not.. http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif Things are beginning to firm up on a New Year pattern change.

Snawing in Belfast City Centre, bodes well for the hills. Forecast this morning said any precipitation would be rain at low levels too.

Snowing here. Very wet stuff though.

Nought but rain in The Duff at the moment.