Cold Spell Media Forecasts and Model Output (General Chat)

BEASTERLY

FFS sake why do the showers keep coming right for us only yo turn away at the last minute..grrrrrr:mad:

TheMilkyPirate

BEASTERLY wrote: »

FFS sake why do the showers keep coming right for us only yo turn away at the last minute..grrrrrr:mad:

Streamer only really built up in the last hour and a half beast could be 2 hours even before we see anything if we do that is

Mollymawk

ME's latest warning, seems they expect some snow for the North West:


It wouldn't surprise me - the sky has gone black here in the last few minutes.

force eleven

Big battle coming between the strong pool of bitter arctic air and the mild Atlantic . Under normal circumstances I would be confident the Atlantic would blast the cold air way back. But the Atlantic looks flabby and tired and may struggle to win through completely. Will be a nightmare for forecasters from T120 onwards. Will the cold win back through with an easterly blast?

AloKildare

Could someone please show me where to view the latest forecast models? Im new to this game, thanks!

darkman2

Hi, they are all available here

www.meteociel.com

or

www.wetterzentrale.de

homolumo

http://www.netweather.tv/index.cgi?action=modelcomp;sess

I have just discovered this one myself, it is very handy as it puts all the models on one page. Just click the timeframe and type of output you want at the top. Only downside is that it is only 72 hrs onwards.

Harps

meteociel.fr

Click on gfs Europe, UKMO, ECM etc along the menu on the left

AloKildare

Thanks lads

thetonynator

homolumo wrote: »

http://www.netweather.tv/index.cgi?action=modelcomp;sess

I have just discovered this one myself, it is very handy as it puts all the models on one page. Just click the timeframe and type of output you want at the top. Only downside is that it is only 72 hrs onwards.

these days 72 is long into FI anyway!

fizzycyst

I'm not getting my hopes up but, ME latest forecast says there may be a sprinkle in the SE tomorrow, hope it reaches Waterford, the last hurrah!
(for now)

hotwhiskey

BBC NI weather just said snow for St Stephens day no mention of rain.:)

Musicman2000

Looking at the BBC national weather, they have a high right over the UK and Ireland for the weekend, no sign of the atlantic what so ever

th3 s1aught3r

Musicman2000 wrote: »

Looking at the BBC national weather, they have a high right over the UK and Ireland for the weekend, no sign of the atlantic what so ever

Thats becasue its 'in the mix'

thetonynator

hotwhiskey wrote: »

BBC NI weather just said snow for St Stephens day no mention of rain.:)

norn iron was always more likely to see snow from this than the rest of the country anyway. Don't get your hopes up too much! If only owenc was here for this . . :P

irish1967

thetonynator wrote: »

norn iron was always more likely to see snow from this than the rest of the country anyway. Don't get your hopes up too much! If only owenc was here for this . . :P

Hmmmmm. We could end up with a situation up there hi.

Brianmeath

Maybe this could continue:D for another month

hotwhiskey

BBC NI was giving a weather watch this morning for heavy snow on St Stephen's day and again the have not mentioned rain.

While ME are giving a Monsoon!! I don't know who is right but i will have to take the half way scenario here. SLEET.

Off to see what MT is giving.:)

DOCARCH

hotwhiskey wrote: »

I don't know who is right but i will have to take the half way scenario here. SLEET.

Have you actually read the ME forecast?

Outbreaks of rain, sleet and snow will start to develop along the west coast early on St Stephen's morning, which is Sunday morning, and gradually through the day that will slowly spread eastwards, reaching the east coast by the early afternoon. It may snow heavily for a time but by the end of Sunday the snow will have turned back to rain.

In addition, the Eagle on RTE Radio 1 just mentioned a (and I quote) 'serious snow event' on St Stephens Day before snow turns back to rain.

TheMilkyPirate

DOCARCH wrote: »

Have you actually read the ME forecast?

Outbreaks of rain, sleet and snow will start to develop along the west coast early on St Stephen's morning, which is Sunday morning, and gradually through the day that will slowly spread eastwards, reaching the east coast by the early afternoon. It may snow heavily for a time but by the end of Sunday the snow will have turned back to rain.

In addition, the Eagle on RTE Radio 1 just mentioned a (and I quote) 'serious snow event' on St Stephens Day before snow turns back to rain.

That's another big back track from met eireann this morning, Will the mild air find it harder to push east with the heavy snowfall in front of it i wonder.

M.T. Cranium

Some factors that may influence the forecast evolution (and perhaps why the models have such a spread of outcomes) ... use this map from 00z to visualize:



Note first of all, the storm heading northeast into France. This has not been totally resolved by models all through the past 72h and uncertainty remains on its exact position and intensity by Christmas Day somewhere near Denmark or northern Germany. This feature could hold back the west to east progression.

Then, see the blue circles near the western part of the grid, these are pressure rises. These indicate where high pressure is most likely to build next 24 hours in advance of the expected cresting arctic high over Ireland and UK on Christmas Day. But you can see from satellite imagery that there are a lot of weak features out that way needing to be resolved and factored in. The high may be slower or more intense which would slow down the progression, or vice versa.

Notice also how much cold air is banked up over northern Europe. This won't be disturbed much for 72 hours, and could play a role in creating a blocking high that would link to the arctic high near Ireland. There are also some rather unusual developments near Iceland that could intensify northerly flow there and form yet another barrier to mild air forcing it south and weakening low pressure.

Off this map well to the west is a slowly advancing storm south of Newfoundland. Anyone who has been following models and forecasts for the past month will know that the models have been having major problems with track of low pressure, with a mean error at 72h of about 5 deg of latitude. All this low has to do, in order to screw up the forecast model consensus, is to drag its heels, cut further south, or weaken. If it did all three, it could leave the stage unoccupied and the cold spell could continue.

This seems unlikely but there could be a splitting of the low around the cold high. Now if you follow such things regularly, you'll realize that surface events don't drive upper patterns, upper patterns drive surface events. But there is some feedback from surface to uppers. However, when we say something like "the low split unexpectedly" we usually mean "the upper steering patterns changed unexpectedly." The surface lows will follow the strong steering influences.

I've listed some alternative outcomes in today's forecast and this is the short explanation of why. Greater clarity will come perhaps tomorrow, as the models get better handles on the real track of some of these players.

TheMilkyPirate

Great post MT. Interesting few days ahead.

snowbabe

Wow,that's the short version!!!Thank you so much for the brilliant explaination,I only had to read it twice to get it,normally it takes a bit longer for me to understand.Sooo very interesting,as are all your posts,many thanks again

Mollymawk

Great explaination, thanks MT.
After years of learning about weather systems, this cold spell has been fantastic for just sitting down, studying charts and making a bit of sense of them, getting a feel for it.

I only discovered boards in the last few weeks, and it's amazing to get such informed, intelligent discussion about meteorology going on.

Cheers guys - every time you explain something in a fresh way, my understanding grows. One of these days I might actually understand all the book-learning.

Aside from that, it's still -8 in Co Sligo this morning, and there's a robin and a blackbird in the back garden that have given up fighting with each other and have both taken to perching on the windowsill at dawn together begging for food. If this cold continues, I might actually have them eating out of my hand soon!

Cosmo Kramer

http://www.bbc.co.uk/blogs/opensecrets/2010/12/met_office_seasonal_forecasts.html

Thought this was an interesting article about the pressure the UK Met Office are under to get their forecasts right. I remember them dropping the seasonal outlook from their main page alright, I didn't realise they had just hidden it elsewhere in the site though...I must not be 'intelligent' enough for them.

hotwhiskey

DOCARCH wrote: »

Have you actually read the ME forecast?

Outbreaks of rain, sleet and snow will start to develop along the west coast early on St Stephen's morning, which is Sunday morning, and gradually through the day that will slowly spread eastwards, reaching the east coast by the early afternoon. It may snow heavily for a time but by the end of Sunday the snow will have turned back to rain.

In addition, the Eagle on RTE Radio 1 just mentioned a (and I quote) 'serious snow event' on St Stephens Day before snow turns back to rain.

Sorry Docarch but ME don't be on my mind first thing in the morning. So ME have back tracked once again. (sigh)

Pangea

Just seen on the Donegal Democrat that Michael Gallgher will be making apperances on the sky news chanel throughout the day today.
It seems he thinks the cold will be back soon enough too, he said "They can talk about warm fronts or whatever but the cold spell is too deeply entrenched and it is going to take some time before it moves on for any considerable length of time"

Pangea

More snow predicted for the North West region over the Christmas period.

More snow is predicted for the North West region over the Christmas period.

Met Eireann says the snow will return on St Stephen's Day and it will become very windy.

Christmas Eve will be dry and frosty, while Christmas Day will be cold but it will become much milder with minimum temperature of 2 or 3 degrees

Clara Finkella from Met Eireann explains what we can expect over the coming days.
http://oceanfm.ie/article/More-snow--predicted-for-the-North-West-region-over-the-Christmas-period/

cherryghost

12Z is incoming

My opinion of the St. Stephens day event: Anywhere North of Tipp and about 40-50 miles inland will definitely see some prolonged snow of some sort, perhaps about 6/7 hours of heavy snowfall, turning to a few hours of rain (freezing perhaps) towards the end of the day. South will have sleet before rain for sure, but 12Z tomorrow will give a clearer indication.

irish1967

Thanks Cherryghost. Been looking for a forecast on that for a while now. Anyone any update on what the 12z is telling us. I have a few trips to make on 25/26th and if 6/7 or even 1-2 hours of snow is on the way I am staying in front of a warm fire with my bushmills.:)