Winter/Spring 2013 (Model Output Discussion)

Larbre34

Met É seem to have gone all-in 'from monday N/NE winds, highs 2-5, lows -5 -6, severe frosts and from Wednesday showers of sleet and snow North and East.'

Speak Now

And yet it's still only Thursday this week, if it's showing an Easterly from next Monday i'll believe it. Expecting shortwave drama between now and then!

munsterlegend

Larbre34 wrote: »

Met É seem to have gone all-in 'from monday N/NE winds, highs 2-5, lows -5 -6, severe frosts and from Wednesday showers of sleet and snow North and East.'

the Uk Met Office are still very cautious about next week and they are further east than us! While it will be cold uncertainty yet as to how wintry it will be.

I am sure there will be more upgrades/downgrades before its fully resolved.

maquiladora

Well, that epic ECM from yesterday was never going to be repeated!

Everything looks a lot less interesting and more realistic this morning.

munsterlegend

maquiladora wrote: »

Well, that epic ECM from yesterday was never going to be repeated!

Everything looks a lot less interesting and more realistic this morning.

the overall cold trend is positive though Maq?

Redsunset

Ecm was down the pub in last run. Yes it will get cold but not severe cold. I like to see much colder upper air over us like -10 or more before that tag is justified.

ok we could get some sleet/snow off the Irish sea but it's no November/December 2010.
I think a 4/5 day colder spell that will be underwhelming for many.

maquiladora

munsterlegend wrote: »

the overall cold trend is positive though Maq?

Cold but not deeply cold. No true easterly, weaker block, uppers only sometimes getting beyond marginal for snow. It would only take one or two more downgrades to water it down to something really insignificant.

Tom Cruises Left Nut

Redsunset wrote: »

Ecm was down the pub in last run. Yes it will get cold but not severe cold. I like to see much colder upper air over us like -10 or more before that tag is justified.

ok we could get some sleet/snow off the Irish sea but it's no November/December 2010.
I think a 4/5 day colder spell that will be underwhelming for many.

Get yourself a coffee there man, don't be too down !

I would agree with you though, I amen't getting excited yet (I did lose it a bit on the 12z runs yesterday though ha)

The runs at the weekend are going to firm this up, looking forward to them :pac:

pistolpetes11

maquiladora wrote: »

Well, that epic ECM from yesterday was never going to be repeated!

Everything looks a lot less interesting and more realistic this morning.

Whilst not as good as yesterdays run , which I dont think any one expected it to be I am at a loss towards "everything looks a lot less interesting" part of your statement.

Its still game on as we stand , its looks 60% likely we are going to enter a decent cold spell(not severe) , a far cry from last winters dross,

I know everyone has there own expectations and sets there own barometer to what they would define as interesting but I feel next week is looking very interesting.

It does look like there will be some Atlantic influence and a slight breakdown at some stage but thats in FI but that also shows the PV moving towards Siberia.

Anyway thats just my take on things at the moment

munsterlegend

maquiladora wrote: »

Cold but not deeply cold. No true easterly, weaker block, uppers only sometimes getting beyond marginal for snow. It would only take one or two more downgrades to water it down to something really insignificant.

Or maybe an upgrade to something more significant?! Unlikely I know but MT is not ruling out a severe and extended cold outbreak. The weekend and early next week will reveal all..

pistolpetes11

munsterlegend wrote: »

Or maybe an upgrade to something more significant?! Unlikely I know but MT is not ruling out a severe and extended cold outbreak. The weekend and early next week will reveal all..

Il be honest that of most has my interest peeked , 20% chance of severe cold ,I am a glass half full type of person, but in reality this will not happen

From keeping a keen eye on what MT has being saying , I dont think this winter is a write off (5 days in !) if this spell just ends up an average cold spell as he is seems to think its a case of when and not if we get a really good cold spell

M.T. Cranium wrote: »

OUTLOOK ... Near normal temperatures may develop for a day or two early in the week with highs 5-7 C in a dry if foggy pattern, but much colder air is massing over the Baltic regions and will begin to make a westward push around Tuesday possibly overspreading most of Britain before arriving in Ireland with sub-freezing temperatures and the potential for snow mid-week, and this spell could last several days, a week or even longer. My speculation would be that this cold spell will break down in stages around the 23rd-24th leading to a milder spell Christmas Day to about the 28th with rain and strong winds possible then. Confidence in that is only moderate because this cold spell seems to be "on time" otherwise you'll very likely hear that this severe cold could intensify and dig in for a long time. I think it will come and go several times before a more severe spell later in the winter, so we'll see how that plays out,


.

Caff Caff

I agree with pistolp. Stop comparing to 2010 too. That's getting old. We were so fortunate to experience that event. Yesterdays 12z was something else but if anyone thought that it would happen precisely like that...

What we have is a consistent trend with an easterly winning out for a few days ...perhaps even just two days with help from a cool pool from the north. It's still very early in the winter but as I said earlier, this easterly would have needed to stay were it is for a while longer, building up enough strength to bring those -10 or -12 uppers but -8 will do... beggars can't be choosers!! So, IMO it is all very interesting. Roll on the weekend models so we can hopefully see that easterly again giving that atlantic the One Two UNIFLU!

leahyl

Ideally, I would love to see a dusting before Christmas (just make it all that little bit more festive:)) but I'm happy (sort of!) to wait till the New Year for the real beast to attack:D

Rebelbrowser

Both ECM and GFS this morning show -6 850hpa over the whole country (and some -8's) for a few days.

Firstly, when winds are easterly, isn't -6 ok for snow if there is precipitation? Secondly, would I be right in saying that given ssts at this time of year are 11c in the Irish sea (just checked), that's enough for Lake Effect Snow?

I don't get people saying they wouldn't get excited about a 4 day cold spell. I'd love 4 days of 2c max day temps and some snow. People should stop comparing everything to Dec 2010 (which was almost too cold I thought and, even if the extreme cold floated your boat, lacked the dramatic windchill of Jan 1987).

pistolpetes11

Rebelbrowser wrote: »

Both ECM and GFS this morning show -6 850hpa over the whole country (and some -8's) for a few days.

Firstly, when winds are easterly, isn't -6 ok for snow if there is precipitation? Secondly, would I be right in saying that given ssts at this time of year are 11c in the Irish sea (just checked), that's enough for Lake Effect Snow?

I don't get people saying they wouldn't get excited about a 4 day cold spell. I'd love 4 days of 2c max day temps and some snow. People should stop comparing everything to Dec 2010 (which was almost too cold I thought and, even if the extreme cold floated your boat, lacked the dramatic windchill of Jan 1987).

With a warm sea track if the flow is slack there would be some modification of the temps plus lower temps would be a lot more conducive to stirring up convection which we will need or we will only see slight flurries on the east coast , nothing to write home about.

whitebriar

Rebelbrowser wrote: »

Both ECM and GFS this morning show -6 850hpa over the whole country (and some -8's) for a few days.

Firstly, when winds are easterly, isn't -6 ok for snow if there is precipitation? Secondly, would I be right in saying that given ssts at this time of year are 11c in the Irish sea (just checked), that's enough for Lake Effect Snow?

I don't get people saying they wouldn't get excited about a 4 day cold spell. I'd love 4 days of 2c max day temps and some snow. People should stop comparing everything to Dec 2010 (which was almost too cold I thought and, even if the extreme cold floated your boat, lacked the dramatic windchill of Jan 1987).

-6 850 temps would only be good for hill snow.
For decent showers and to mitigate marine mixing over the Irish sea and for heavy as opposed to light showers, you need -8 air and lower up at 5000ft.

Dew points otherwise will linger round a marginal zero or 1c.

pistolpetes11

http://forum.netweather.tv/topic/75182-model-output-discussion-5122012-18z-onwards-the-one-after-that-ecm/page__st__320

As if NWP didn't have enough on its plate with the disturbance to the PV, MJO forecasts consolidating on a phase 2 projection. That will expose the GFS in particular (it has a large bias to tropical convection in the longer range) to greater pressure to turn the jet northward over Iberia. This will be a false bias given that the GWO is in phase 8/1 - and this is the superior measure. That lobe of the pv cut off over NE Siberia also rolling around like the preverbial loose cannon.

GEFS H5 day 10 a reasonable depiction however (huge snow potential btw):




Substantive ridge between Greenland / Iceland / Svalbard. Tonight's CPC 8-14 dayer will pretty much look like this. That will keep the jet well to the south and only when the ridge pulls fsr enough west will it be able to come up from the south. Always the risk however of shortwaves, but these likely to maintain our cold pool in situ by advecting the cold air westwards.

Stick with your ensemble means!!

Speak Now

Rebelbrowser wrote: »

Both ECM and GFS this morning show -6 850hpa over the whole country (and some -8's) for a few days.

Firstly, when winds are easterly, isn't -6 ok for snow if there is precipitation? Secondly, would I be right in saying that given ssts at this time of year are 11c in the Irish sea (just checked), that's enough for Lake Effect Snow?

I don't get people saying they wouldn't get excited about a 4 day cold spell. I'd love 4 days of 2c max day temps and some snow. People should stop comparing everything to Dec 2010 (which was almost too cold I thought and, even if the extreme cold floated your boat, lacked the dramatic windchill of Jan 1987).

Agreed it seems if it does snow this year we'll get the "oh its not as bad as 2010" type posts. Well you know what that wouldnt be a bad thing. The country is bad enough without the place grinding to a halt a week before Christmas.

Of course the worst of all will be the "after hours" feel about this place. I got more snow that you bla bla bla.... Dublin snow capital, Cork no snow boring oul rubbish rinse and repeat :rolleyes:

Anyway still all FI at this stage

I still want my snow of course :pac:

BEASTERLY

whitebriar wrote: »

-6 850 temps would only be good for hill snow.
For decent showers and to mitigate marine mixing over the Irish sea and for heavy as opposed to light showers, you need -8 air and lower up at 5000ft.

Dew points otherwise will linger round a marginal zero or 1c.

Agreed. And remember December 2010, the night of the very heavy fall in the east a warm sector played havoc around Dublin. Reports of rain and thawing during the most severe night of the legendary cold spell.

munsterlegend

pistolpetes11 wrote: »

http://forum.netweather.tv/topic/75182-model-output-discussion-5122012-18z-onwards-the-one-after-that-ecm/page__st__320

As if NWP didn't have enough on its plate with the disturbance to the PV, MJO forecasts consolidating on a phase 2 projection. That will expose the GFS in particular (it has a large bias to tropical convection in the longer range) to greater pressure to turn the jet northward over Iberia. This will be a false bias given that the GWO is in phase 8/1 - and this is the superior measure. That lobe of the pv cut off over NE Siberia also rolling around like the preverbial loose cannon.

GEFS H5 day 10 a reasonable depiction however (huge snow potential btw):




Substantive ridge between Greenland / Iceland / Svalbard. Tonight's CPC 8-14 dayer will pretty much look like this. That will keep the jet well to the south and only when the ridge pulls fsr enough west will it be able to come up from the south. Always the risk however of shortwaves, but these likely to maintain our cold pool in situ by advecting the cold air westwards.

Stick with your ensemble means!!

Looks positive from my reading of it!

Musicman2000

Some peoples expectations are way to high on here, Its not going to be a repeat of 2010, but some very cold weather is on its way next week as the models will change between now and then. and some falls of snow can be expected, Most likely around the north, east and south east so cheer up:)

Tom Cruises Left Nut

Looking ok at 120 !

munsterlegend

BBC Weather ‏@bbcweather
Looking further ahead, increasingly likely that next week will bring cold easterly winds and a chance of snow.

I suppose all the major weather professionals are agreed on the Easterly - now is to determine how severe and when the Atlantic will get the upper hand.

Villain

It was only ever going to Downgrade from the ECM run yesterday, an Easterly is still on the charts but this will downgrade and upgrade over the coming days. It could turn out to be a few cool days with hill snow only or it could get down below -10c and see snow at lower levels.

Nothing is certain and anyone looking for a repeat of 2010 will be disappointed that was a 1 in 20 to 25 year event, keep expectations low and you won't get dissapointed.

Tom Cruises Left Nut

Villain wrote: »

It was only ever going to Downgrade from the ECM run yesterday, an Easterly is still on the charts but this will downgrade and upgrade over the coming days. It could turn out to be a few cool days with hill snow only or it could get down below -10c and see snow at lower levels.

Nothing is certain and anyone looking for a repeat of 2010 will be disappointed that was a 1 in 20 to 25 year event, keep expectations low and you won't get dissapointed.

The key is not to compare, I really wish people would stop mentioning 2010 !

mickger844posts

Very positive set of runs overnight and this morning. Great potential at less than 7 days out.

Spindle

What are the current temperatures on main land Europe, do they already have cold in place? Will this not come into play to moderate the cold making it a bit warmer when it reaches us?

Also what are the SSTs looking like at the moment?

Whats the bets we are sitting here next week crying as south west England is covered in snow and we just get a chill

munsterlegend

New from UKMO:
" 4. Trend for Days 10-15 : Probably staying colder than normal with frequent overnight frosts and some wintry ppn, especially in the N and E. Potential for some milder, wetter interludes in the W/SW.
5. Discussion : After days of prevarication with SW types, the GM has now come into line with all other models (and their ensembles) with the transition to an easterly. The ensemble mean (see fig 1 below) is a good a guide as any, and shows the progression from a cyclonic NE to a cyclonic SE. In the trend period Atlantic systems will push against the block, but getting this detail right will be very difficult."

As ever on a knife edge for Ireland. this update for our neighbours does not indicate anything severe but still time for upgrades.

Pangea

Villain wrote: »

Nothing is certain and anyone looking for a repeat of 2010 will be disappointed that was a 1 in 20 to 25 year event, keep expectations low and you won't get dissapointed.

Except it came in 2009, and twice in 2010

Tom Cruises Left Nut

GFS Ensemble Mean looks good this morning