Tristrame

Yup front is bringing snow on high ground in South Wicklow 60kms South of Dublin on this side of the Irish Sea too I took this pic around 4pm (posted in the Ireland forum also)

It was snowing quite heavily from the occluded front in the hills of South county Wicklow when I was up there about an hour ago

To be fair to MVH and Ian F Theyre only reporting what the tools in front of them (and in Ian F's case Met office internal discussions) say in a character limited tweet Models are changing every day though like the weather pardon the pun so you'd expect Ian F and MVH to do likewise

Basically he's saying the met office think overnight output doesn't change where we're more than likely heading and that's a cold or very cold continental influence If you ever read the U.S technical discussions on how they put a forecast together (they're publicly available on wundergound) you'll see them dump one model in favour of another or blend them together with a human decision It goes on all the time It goes on here in this forum People looking at weather tools for years or decades have the experience to call these things Hence never despair with what one run shows

I always wonder when Ian summarises,Is he referring mainly to his own forecast area though when interpreting what the U.K. Met office think West/SW England would not be getting convective sea streamers from an easterly Ergo mainly dry and cold

Ok let's rephrase for clarity in what I said,don't take low probability as gospel then Its been thus all winter

No disrespect to Matt but Its wintry output depended on items happening in the nearer term which are chopping and changing run to run so I'd not take the above as gospel Its been thus all winter

It's a lovely chart if you like occasional cold rain showers in a northwesterly following the rain from the low in the channel

How would there be showers with pressure at 1030mb + ? That's high pressure

It's not bad,I forgot to include Meath in the snow county list coasts would see sleet but much of the counties mentioned are well inland,and far enough north to receive showers from the Northwest or North,they hit as far South as Dublin usually and much of the west too

Most of that -9 is actually in co Leitrim and Donegal Republic of Ireland,only about a quarter of it is in NI But that said if verified a lot of NI,Donegal,Sligo,Cavan Monaghan,Louth and Mayo would see snow in precipitation ,it's an upgrade

He is using the mean chart of all the members some of which are milder south of west others colder north of west so he's saying if it's the trend or accurate going forward then the main full run,the op run that's published twice a day on the 00Z or the 12Z could be a raging South westerly or a polar northwesterly The more likely scenario that verifies will be one closer to the mean or average of all the ensemble members but with chaos theory not necessarily especially with charts beyond 4 or 5 days Edit Sorry Jh got his reply in hope mine helps

Drove up Croghan mtn,about 6 miles due west of Arklow county wicklow at lunchtime. Sleety rain by the sea in Arklow but 6 miles inland and at 1500ft it was a white out,it had only been falling for about 2hrs at that stage. This pic was taken about a 5 minute slow crawl above the snow line. Its all ahead of ye up north and by golly,the front was well able to peg the snow!

Ian what was going on in the irish sea last night from about 6pm?If you look at the radar for the 6hrs to midnight,a big streamer developed and grew between Anglesea and south wicklow on the Irish coast. I got about 5cm's at the coast and theres a good 10cms on the hills here.It was falling very heavy,those cloud tops must have been more than 6k feet? Worth noting for the record I think when analyising the current set up.

I think he means its a rubbish outcome ie not nice.He doesn't mean it won't be right. Rubbish is a word sometimes used like that

As a rule of thumb,temperature drops a degree every 500ft you rise.So the 850 temps are at 5000ft which means there is a basic 10c difference warmer at ground level.Other factors come into play that can make it warmer still,like the strength of the sun,length of daytime and a big one is the urban heat island effect in towns and cities.Lying snow making it colder. Essentially no day and no place under the same 850 upper temp is guaranteed to have a certain 2m temp. You can be guaranteed though,that -11 uppers on high ground would bring ice days at this time of the year still,I think, and probably to areas with snow cover. 850 upper temps like that are great over a sea track for creating heavy snow showers. That's my understanding anyhow.

lol I remember jan 1982.10ft drifts at sea level at my location,very similar to last weeks Boston storm only lasting 2 days,with the snow not thawing for 10 days. Helicopters had to air lift supplies to rural areas even as low as 400ft asl.Up at a 1000ft asl and higher in the wicklow mountains the drifts were up to the tree tops.Now that was epic. At sea level my road was completely blocked for a week. I think the worries over the poor uppers are just that there would be little or nothing in the way of convective snow showers,lapse rates wouldn't support them.

Not that rarely,irish sea streamers were common in the 80's,we had a lot in feb '91 and of course much of Dublin had a foot of snow in dec 2010.I'm on the Irish east coast and had lying snow in that spell from nov 27th to December 26th,peaking at about 18 inches.That's better than a lot of the Uk at that time..Once -8 uppers hit the irish sea,streamers and thundersnow can happen. Usually its about 60% of the times it reaches England ,that it's also strong enough to back west to Ireland,in my experience. I do agree though,in terms of discussing current synoptics,they favour Eastern England at the moment not here but who knows. Personally what concerns me is,everytime I look lately,we're here praising a 144 chart.Tomorrow if that synoptic or similar is again at 144 and not 120,we are only chasing still.

Anyone that witnessed february 1991,where there was heavy snow at my location,the weekend after valentines day should rightly laugh at these ill informed suggestions that you can't get cold enough at that time. I remember washing freezing on the line in the daytime. I'd say we had about 8 inches and many icicles inside sheds! The air feed originated way over Russia somewhere but it passed over a frozen Britain before it got to us.

It's that pesky done gal low which dragged you and a lot of Ireland into the pesky mild sector by diverting the cold Gb air feed too far north, it should be back when that low heads away into the Atlantic.That's shortwaves for you.

Cork gets snow from westerlies if it's a false westerly ie a mad cold northerly driven down the mid atlantic near enough to Ireland but that veers southeast towards Ireland at it's southern tip.Xmas '04 I think was the last example of that. Generally speaking you'd need at least -7 uppers for low level snow in Ireland and at that it would be very marginal. So I can see why -5 uppers won't enthuse. It would mean snow only above 800ft over here and cold boring rain for most in Ireland.

Thats another thing I've not liked about this spell,the tendency for that high to meander around blocking an islands wide unsettled cold spell ie no widespread decent snow possibilities.Everything seems to be so slow and pushed forward [except SE England I suppose to an extent],that it is my fear that we'll be well into march before a decent Easterly will have set up and by then the continent will have warmed up.

Well I wasn't specifically talking about the greenie high should it appear,I was talking about decent cold islands wide always being at least a week away.Thats a trend I don't like

Ok I will rephrase. I don't think that looks tasty because it's indicative of yet another trend to put anything half decent in Ecm,one of the better models further out. If something appears half right to set up a proper islands wide unstable Easterly or northeasterly it should be getting closer, not staying out in never never land.

Yup and anyway-people are forgetting the cold surface air feed will eventually advect westwards too.This takes a little bit longer than the 850's and is more usefull-less warmer air for the precip to fall down through and ergo less fear of 850's rising a few degree's if they do. People-look East. Look where the 0c isotherm is on the continent and up in Scandiland. It's at sealevel right over to Holland even now and REMEMBER that means it's unlikely to go above zero there,it's not showing that it is likely to be several degree's below zero on the continent and it will be... This is a sustained feed folks,a sustained feed. People that are dissing it and worried they won't see snow at some stage in the next fortnight are frankly wrong. So chin up. Relax and take it as it comes.