Model Outooks: Winter 2008/2009

Deep Easterly

Just thought I would open up a Model outlook analysis thread for anyone wishing to have a good yap (or a good moan) on how forecast models are favouring a desired weather type.

I will kick it off by not posting any charts from today's 12z runs, because they are, quite simply, offensive.

nacho libre

damnit. paddy1, when you say offensive, do you mean there is no sign of snow for the forseeable future:(

Snowbie

Well it's only one run

but horrid all the same

M.T. Cranium

I think that a better chance for cold weather will return later this month, wouldn't be too discouraged if there are two or three very mild days next week, that's part of the set-up, what's needed is for the flow over parts of North America to lift back northward later this month and then all that very cold air that has developed around Greenland, Baffin Island and Svalbard will all have fewer places to escape, thus more can come your way.

I think that the week starting around the 23rd of December may see a return to quite cold weather, before that it may be more of a battleground situation after the mild spell.

Snowaddict

I like the look of the GFS 12Z and the ECM latest run.
Both suggesting potential for Ireland even in the medium term, however this will most likely change.
Thought I would post this chart below, somewhat interesting I think.
Of course it can all change, but promising at least.

Deep Easterly

Snowaddict wrote: »

I like the look of the GFS 12Z and the ECM latest run.
Both suggesting potential for Ireland even in the medium term, however this will most likely change.
Thought I would post this chart below, somewhat interesting I think.
Of course it can all change, but promising at least.

Fantastic chart Snowaddict. Just ran through the ECM run and while a strong easterly flow, courtasy of a strong ridge into Scandinavia is shown as close as 168hrs:



the sheer unwillingness of that damn high in mid Atlantic to loosen its poisoness grip from our shores is evident throughout the rest of the run:

http://91.121.93.17/pics/Recm1921.gif
http://91.121.93.17/pics/Recm2161.gif
http://91.121.93.17/pics/Recm2401.gif

As grim as it looks, a small hope still prevails as models often have trouble handling easterlies, and often they spring up all of a sudden in the reliable timeframe. I hope this happens this time, because the charts shown are really terrible. Just weakly zonal with lots of cloudy drizzlely type stuff. :mad:

Somebody stick glue on that high and order it not to move untill it verifies [the scandinavian one !!]

nacho libre

not too pushed about a deep easterly to be honest. we had five days of fairly cold weather already. it would be good as a means to an end though if it meant the winds eventually swung around to the north and we eventually got a cold front from Greenland followed by a polar low to come down over the country before or during christmas. that would be the perfect christmas present.:cool:

Deep Easterly

nacho libre wrote: »

not too pushed about a deep easterly to be honest.:cool:

Sacrilege

nacho libre

Deep Easterly wrote: »

Sacrilege

sorry paddy1, but my priority is snow, a deep easterly doesn't bring much snow to this part of the world.

TheGreenGiant

The easterly winds brought snow last February. Only for there was a strong depression out in the Atlantic steadily making its way to our shores, the easterlies could have prevailed bringing more snowy conditions.

Deep Easterly

Another pretty bland ECM run this morning, but it does look a bit more interesting from 216hrs onwards:





Of note are pressure builds over Newfoundland and NE Scandinavia, which could leave Ireland open to some (severe???) wintry weather after mid month. All based on FI of course, but we must keep a clutching...:)

nacho libre

TheGreenGiant wrote: »

The easterly winds brought snow last February. Only for there was a strong depression out in the Atlantic steadily making its way to our shores, the easterlies could have prevailed bringing more snowy conditions.

When i said our part of the world i meant the west of Ireland.
They do bring snow to the east but give us sod all - a few snow flurries if we are lucky.

arctictree

The 12z GFS is the worst I have seen in a long time. Mild muck into and beyond FI. Hope it changes on the next run!!

A

arctictree

12z GFS has thrown up a surprise for next Saturday:

http://www.wetterzentrale.de/pics/Rtavn1621.png

7 days out and subject to change but interesting nonetheless...

A

mike65

Those of us who are cash strapped will not like this prolonged cold period.

Gonzo

starting to get fed up of all this frost now, ive slipped about 8 times in past week. The roads around Dunshaughlin today have been lethal all day as the frost has failed to melt yet again, all roads leading to dunshaughlin with the exception of the N3 have been covered in icey patchs all day.

nacho libre

well, i do enjoy this cold weather but then you realise it can't be fun for elderly people:(

forkassed

Monday night/Tuesday morning could be fun

Deep Easterly

ECM are keeping up the theme of potant Northwesterlies for the beginning of next week:



Of course it is way in FI at the moment, but the consistancy is encouraging at least. If it was to come off anything like that, then snow/thunder/gales could be on the cards for our wee nation at the start of next week.

nacho libre

The wait for snow goes on:( No sign of snow this week according to the Farming forecast.

mike65

Westerlies ha ha!

Mullaghteelin

mike65 wrote: »

Westerlies ha ha!

Its VERY possible to cold weather from Atlantic westerlies.

Imagine a record breaking Atlantic storm of 916hPa between Scotland and Iceland, giving Ireland SWly gales. Doesnt sound particularly cold does it? Well, it gave Ireland frequent heavy snow showers. Even the east coast managed to get a covering!
http://www.wetterzentrale.de/archive/ra/1993/Rrea00119930111.gif

http://www.wetterzentrale.de/archive/ra/1993/Rrea00119930112.gif

http://www.wetterzentrale.de/archive/ra/1993/Rrea00219930112.gif

When cold zonality kicks in, it can last for weeks on end, and we've been getting quite a lot of it on and off since the Summer. Im not saying charts like the above will happen, but I feel that this year the Atlantic Westerlies may not give us the relentless mild muck that we've come to expect.

ninebeanrows

Strange synoptics looking likely in the coming 2 weeks.

Staying cold all the time with cold zonality breaking through late this week.

And things are a stirring.

Deep Easterly

Weathercheck wrote: »

Strange synoptics looking likely in the coming 2 weeks.

Staying cold all the time with cold zonality breaking through late this week.

And things are a stirring.

Certainly FI charts are a peach WC. ECMWF sticking with the cold NW flow for the end of next weekend into the early days of next week, if a little toned down from ealier charts:



Even more interesting are charts beyond from this model:

Pressure rising over Northern Scandinavia: :eek:



Notice low over south Greenland, because next chart has it being forced south due to rise in pressure over north Scandinavia:



Possible snow laden easterlies in the run up to Christmas???? I won't believe it until they are being shown within the 120hrs range. But excellent charts this evening. I just hope the trend continues. :)

nacho libre

Saturday may deliver something:) hopefully as the week goes on they'll mention the possibility of snow at lower levels

met.ie:
Wednesday night will be mostly dry and calm, with clear spells, but patches of rain and drizzle will occur, mainly along the west coast, with the possibility of some patchy sleet further inland. Very cold, with severe, especially in the midlands and east, but less cold along the west coast. There is a risk of freezing fog also. Thursday will be mostly cloudy, with outbreaks of rain and drizzle becoming widespread as the day progresses, with some sleet in places. Cold, with mostly light winds. Frost will return on Thursday night, but it will clear quickly by morning. Friday will become milder, with rain and strong southwesterly winds spreading from the Atlantic. Saturday will be very cold with sunny intervals and occasional showers, with some hail and a risk of some sleet or snow over mountains. Breezy, with fresh westerly winds. Frost in many areas on Saturday night, despite the breeze.

{Russian spy accent} Zeee Veather iz varm in moscow right now {/Russian accent}

If we do get an easterly,it will take a long time for it to take a 1980's affect given the conditions over there right now.

From Experience in the 80's even when the temp in Russia was -18c by day and we got that air,it took the guts of a week for it to be felt over here.

Thats a long time for a Scandi high to stay in place and not calve to the affects of the Atlantic.
Temps of 0c in the day time in an Easterly like that would be modified so much by the time that they get here that we'd actually have higher temps than we have today ironically.

So when looking East the moral is-check the temps at the source..I'm afraid at the moment the news on that score ain't good

Matter of fact,it's probably colder in Roundwood than in Moscow at this very moment

danni2

Saturday night and Sunday looks pretty cold according to 12z gfs charts, dont know about lower levels but higher ground may see some snow out of this.

Looking ahead at T384 is really shocking:eek:, not a hope of a white christmas if that comes off:mad:

Deep Easterly

There is still hope though in that ECM keeps it average to cool for the next 10 days in the latest run. Still showing signs of building pressure to the Northeast of Scandinavia too over the next few days. In general. Looks cool and showery over Ireland for the foreseable with the odd band of not so mild rain passing over.

nacho libre

Deep Easterly wrote: »

There is still hope though in that ECM keeps it average to cool for the next 10 days in the latest run. Still showing signs of building pressure to the Northeast of Scandinavia too over the next few days. In general. Looks cool and showery over Ireland for the foreseable with the odd band of not so mild rain passing over.

so cold mostly- but not cold enough for snow:mad::mad:

Snowbie

Nothing really exciting from the 18Z either. Keeps a kinda cool spell going rather than even cold zonal type. Some mild interludes followed by cool RPM stuff, temps more avg than above or below. No N'ly outbreak nor our near continent looks threatening for cold. Although some more cold pooling wants to pool in Siberia, vortex after vortex make sure some modified air gets to mix it up more.

[pinch of] As for Christmas if you want to go that far ahead, some of us could wine and dine outdoors in T-shirts but thats miles away and not to be even looked at yet[/salt]

M.T. Cranium

Model trends past day five at present have low confidence due to difficult initial conditions over North America where pattern change is underway. Large scale retrogression appears to be developing across western regions and the east Pacific, with a very cold Siberian air mass making gradual progress into northwest Canada. This will have the effect of lengthening out the hemispheric waves but also, the energy centres being tracked from today to about the 13th have only moderate resolution at best, there is still a lot of discussion about where the current developing low (in the northern Gulf of Mexico) is actually heading for the next 48h. This is the strong low that is shown on the GFS exiting Newfoundland on the 12th-13th and heading for somewhere around the Faeroes to Iceland. Some recent runs have shown this feature becoming very intense (00z GFS had it to 947 mbs).

The earlier feature that crosses Ireland on the 12th and the UK early 13th is probably almost in the bag now, but its future evolution downsteam is not that certain either.

I think the model tendency at the moment is too mild past about the 18th and that there won't be an endless progression of Atlantic fronts as suggested, but more of a developing trough over the eastern Atlantic and possibly faster movement west of the Siberian high shown coming in from around Novaya Zemlya next week. This could be a bigger factor than shown after about ten days.

So I would remain optimistic about the chances for some snow and cold weather late December and some parts of January.

TheGreenGiant

just out of curiosity folks, what would we be looking for in models or charts that would bring a fall of snow? Like would we need a good easterly wind around the end of December or a northerly depression coming down from Iceland? Would be good to know what to look out for, especially since this year so far has been much colder compared to the mind winter we had last year.

A good decent Northerly/Northwesterly with polar air would do the trick nicely in late december or january for your area [not so much mine as we're too sheltered].
A prolonged Easterly either from a cold continent-it's not cold at the moment so the Easterly would have to have a very very deep fetch from way behind the Urals somewhere and would have to go on more than a week... [very unlikely but not impossible]
If you had a deep and cold snowy near continent recently cooled down by a few potent northerlies-then you wouldnt need a long fetch and maybe a few days of an Easterly would cool us down enough for the white stuff.

A Northeasterly with a direct feed from lapland providing it's very cold...which it could be as theres an artic high near it at the moment with some very cold air embedded.
Thats actually in my opinion an easier outcome from current synoptics [chart analysis] as all you need is a high to pivot correctly in the atlantic stretching towards Iceland to allow air to stream from that source.

A Scandinavian High preferably a thin one located over northern Scandi and greater than 1050 mb is what you need for your Easterly.
The current artic high located over Russia might do that so watch the charts in the reliable time frame [5 days out or less] to see if it is inching westwards.
Watch for the other things mentioned in that timeframe too.

TheGreenGiant

Thanks for that Black Briar, hopefully we get a better fall of snow than what we got last year:cool::D

Snowaddict

Just to add some optimism regarding potential wintry synoptics. If one runs through the average 850hpa temp charts for the 06Z run there is a definate consensus amongst all of the models of an easterly influence strengthening around the Xmas period. The first chart is the average chart for Xmas day.


This is a far cry from the operational run, and indeed is very encouraging IMO. It shows a strengthening of an easterly influence, travelling ever westwards from Northern Scandi and North Eastern Europe towards Western Europe (UK and Ireland), while at the same time the cold pool gradually intensifies.




Just take a look at P number 18, and if you run through the sequence you can see where it is going.



And Perturbation Number 15....



Perturbation 14.... (Don't write off a white Xmas just yet)



Perturbation Number 8.....



And finally, Perturbation Number 2.



In conclusion, we need to take all the perturbations into account.
There is substantial agreement on approx 60% of the members on the latest run of an easterly development towards the Xmas period.
Keep watching, because although the outlook is open to substantial change, it is very encouraging IMO, and there is the potential, and at the moment thats all it is, but there is the potential as others have said for very wintry conditions for the end of December / January.

Regards,
SA

TheGreenGiant

good stuff SnowAddict, those charts look pretty darn good, lets just hope that they come off in time for the Christmas period, but very encouraging indeed:D

Snowaddict

TheGreenGiant wrote: »

good stuff SnowAddict, those charts look pretty darn good, lets just hope that they come off in time for the Christmas period, but very encouraging indeed:D

Exactly, lets hope so.
I have no doubt that they will revert to milder options again and will continue to change between several setups, but I do feel that this could be the year in terms of a true easterly type setup, we have not seen one for so so long in Ireland. Possibly in the last third of this month or early January.

Lets hope something good comes from them, and its definately one to watch.

Rgds,
SA.

Lol lads
14 days hence those charts are-so very very very low resolution ie highly highly unreliable.
The slightest change in the near time of the position of a feature renders such out put useless
They are also a minority of the variants.

They are a tiny possibility.

You'll always find pertubations like that somewhere in GFS.

*important point to note* The GFS is píss poor at resolving potential Easterlies.It's an NWP biased in favour of Atlantic influences.
It's the ECM's that you need to watch for optimism regarding Easterlies and the UKMO.

arctictree

Some nice looking charts now on the GFS 12z now for Saturday/Sunday. They seem on the wrong side of marginal at the moment so hoping for an upgrade in the next couple of runs. The 18z for Sunday is interesting in that there is 'Potential' for an easterly to develop off a scandi high and a euro low:



Unfortunately, the Atlantic wins out over the next few runs and nudges all that east. Still quite far out so there is the potential for change.

Snowaddict

Once again, as on the 06Z run, several of the perturbations are going for the development of an easterly, some as early as the 19/20 December.

This is a bit early IMO, however I do feel that we will eventually see an easterly out of this and if things continue to trend as present, there is significant potential for a wintry outbreak to develop across the Ireland within the next 30 days IMO and going on the ensembles.

The following perturbations go for an easterly development over the UK and Ireland around the run up to or Xmas / St Stephen's Day period.

Indeed, quite a few of them:


http://91.121.94.83/modeles/gens/run/gens-16-0-324.png?12


http://91.121.94.83/modeles/gens/run/gens-20-0-360.png?12


http://91.121.94.83/modeles/gens/run/gens-17-0-384.png?12

(Very interesting)

http://91.121.94.83/modeles/gens/run/gens-15-0-324.png?12
(Very interesting)

http://91.121.94.83/modeles/gens/run/gens-10-0-360.png?12


http://91.121.94.83/modeles/gens/run/gens-9-0-300.png?12


http://91.121.94.83/modeles/gens/run/gens-7-0-384.png?12
(Very interesting)

http://91.121.94.83/modeles/gens/run/gens-6-0-384.png?12


http://91.121.94.83/modeles/gens/run/gens-3-0-360.png?12


Thats 9/20 or 45% of the perturbations showing cold to very cold air over Ireland and UK from time periods ranging from the 20th to the 26th of December.


These are open to change, however with 45% of them showing 850hpA's of between -4 and (-12 in once case) across various parts of the British Isles, the outlook does seem positive.


Of course this may all change and may not come to fruition, however it is encouraging.
Regards,
SA.


PS: I also think, going on the 12Z run, that Sat/Sunday could have potential, however as Artictree said above, we are currently on the wrong side of marginal. But its still a bit off, and GFS 12Z was certainly an upgrade in terms of staying cool to cold over the next few days as least, with only brief milder interludes (mainly on Friday for a time).

Well I suppose it's more encouraging than if it wasn't there.
But thats about it for the moment.
When I see Easterlies peering in ECMWF and the UKMO,I sit up.
Not much point in an Easterly right now though or even late next week as it would actually Warm us up!

That said,it's not an impossibility.

Deep Easterly

ECM 12z still showing big pressure rises to the north east. However, we seem to continue to stay in a cool, showery NW stream throughout most of the run. If anything, it looks a little cooler during the early days on next week that was shown previously:


Possibly enough to whiten high ground significantly at least. The above chart still showing plenty of potential for that easterly over East Europe to make inroads towards us. Depends of course on direction lows to the north will take beyond this charts. More importantly, if that Azores could just feck off away south and west, then chances would increase hugely of something bigger and better happening down the line.

Snowaddict

ECM tonight at T+168 screams potential. It is very close to an easterly with a trigger low thrown in for good measure.

Now I'm not saying that this will materialise, there is every chance that the raging atlantic will break in.

However, in the last 36hrs, things have certainly stacked up more in favour of the development of a wintry outbreak.

Although, prudence would lead me to say the chances are about 30 to 35% (maybe over optimistic) for an easterly / cold outbreak, if things keep trending this way.

This does need to be watched however because as I stated, I do feel that within the next 20 - 30 days there is significant potential for a wintry outbreak.

SA.

LEIN

It seems Weathercheck's optimism has rubbed off onto Snowaddict.

Hope your right SA an Easterly wind with lots of wintry potential is long over due around these parts.

Bring it on!!

patneve

I'd love a nice blast from the east:rolleyes::rolleyes::rolleyes::rolleyes:The one of Jan '08 didn't deliver in Dublin city, although areas North of Dublin had a bit of a snow fest...

Snowaddict

Damo9090 wrote: »

It seems Weathercheck's optimism has rubbed off onto Snowaddict.

Hope your right SA an Easterly wind with lots of wintry potential is long over due around these parts.

Bring it on!!

Indeed .

Seriously though, the outlook is interesting.

Even if we don't get an easterly, its going to quite cool / cold over the next few days at least.

Snowaddict

Snowaddict wrote: »

ECM tonight at T+168 screams potential. It is very close to an easterly with a trigger low thrown in for good measure.

Now I'm not saying that this will materialise,

Of course it wont materialise-T-168 is 7 days which is low resolution and even at that you are saying that out at that low resolution theres only a chance that something you want and I want might happen AFTER we get to that t-168 map which is far from set in stone anyway..

Put it to you this way not only is there only a chance at t-168...theres only a chance that that t-168 would happen at all as it itself is FI...never mind what you would be depending on following on from it.

To be honest with you thats Humpty dumpty forecasting and it's only going to disappoint you

Snowaddict

Deleted User wrote: »

Of course it wont materialise-T-168 is 7 days which is low resolution and even at that you are saying that out at that low resolution theres only a chance that something you want and I want might happen AFTER we get to that t-168 map which is far from set in stone anyway..

Put it to you this way not only is there only a chance at t-168...theres only a chance that that t-168 would happen at all as it itself is FI...never mind what you would be depending on following on from it.

To be honest with you thats Humpty dumpty forecasting and it's only going to disappoint you

Yes, your quite right there. Anyway, the outlook is not bad though all things considered.

SA.

chalkie

Snowaddict wrote: »

Yes, your quite right there. Anyway, the outlook is not bad though all things considered.

SA.

Hi SA.

It's certainly generating enough debate (friendly and otherwise) on various forums! I think a more realistic assessment was made earlier this evening by Will Hand on the uk.sci.weather newsgroup, albeit before the 12z ECM came out. He said;

"Well what a situation. All quite complex. As I have already said in another thread an eastern block will just fail to develop with a bifurcating jet and relaxing upper trough on Thursday into Friday. On Friday a warm front attempts to come in against the cold air perhaps giving some sleet. However, warmer air from Atlantic soon surges east and cloud and rain, preceeded by some snow in northeast should come in later on Friday, but it could be slower. It all gets very interesting on Saturday as deep cold air pushes in behind a slow moving cold front with warm air rapidly occluding out.
Probably rain on low ground but needs watching and possibly wintry on back edge, then on Sunday signs of even more slowing and a cut-off low forming as upper trough digs down into Spain. Then we will have an awful rain/sleet/snow mix. At least it won't be mild! After that I'm really not sure, I don't believe GFS, OTOH it looks feasible with a temporary easterly and vortex over France, though less cold before more zonality later. If I had to make a choice I'd say we will end up with a low just to the north of Scotland by mid-week and a rather cold westerly with rain and hill snow, but confidence is very low. It also looks like the Siberian high may extend across the Arctic, which would push Atlantic lows further south. I await the 12Z ECMWF and JMA with interest."

Will has made some good calls in the past in similar borderline situations. Of course he's been wrong too but given his experience and background I'd give him more credence than some of the guys.

I lurk on Netweather a fair bit and Glacier P's posts are of interest...to say the least. It's clear someone like GP has an extensive familiarity with teleconnections (and a specialised vocabulary to go with it!).
Occasionally I can follow what he says but a lot of the time the cold spell is tomorrow's jam"...i.e. the teleconnection signal for cold is at 10+days. He seems to be standing by retrogression and if his utterings come to pass we may continue to see shifts in the next three to four runs. I'd like to see him proven right but before xmas!

For me, I'll wait for another two ECM runs out to T+168 (MAX) before I'll make my own conclusions. Right now I think, SA, your call of 30% for Easterly isn't too far off the mark. Let's hope it improves but history tells us....;)

Joe

mike65

Here comes the westerlies and there is no chance of snow. You read it here first!