Model Outooks: Winter 2008/2009

Deep Easterly

I will emphasize one final time that this is a model outlook discussion thread and not a forecast thread; and to be frank, I am getting tired of reading innuendo and indirect personal attacks on those who like to watch and discuss trends based on a current model scenarios. Caution was always advised as far as I can see, and I think we are all mature enough to know that the "immutable law of physics", aka Murphy's Law, is always in force on this thread.

From here on in, any off topic posts, digs or innuendos will be deleted. It's a model outlook thread guys, enjoy them or despair at them. Just leave the personal stuff aside.

Supercell

Overnight GFS isnt pretty.

Looks pretty certain at this point that our high is going to sink south with probably mild southerly winds becoming established. Far out in FI there is a Greenland high developing, but it has to be said in FI there always are Greenland highs developing.
Southerly winds usually equals cloudy winds unfortunately at this time of year.
I'd rather zoneality that what we are having right now to be honest!

Mothman

Pangea wrote: »

after telling loved ones last week that we are in for a very cold new year, I have now begun to dismiss it .

Hi Pangea, I don't belive it has been spelt out in this thread, but FI means Fantasy Island, though personally I think Fiction fits well also :pac:

Even if you do know this, I'm sure there are others who don't.

Pangea

Deep Easterly wrote: »

I will emphasize one final time that this is a model outlook discussion thread and not a forecast thread; and to be frank, I am getting tired of reading innuendo and indirect personal attacks on those who like to watch and discuss trends based on a current model scenarios. Caution was always advised as far as I can see, and I think we are all mature enough to know that the "immutable law of physics", aka Murphy's Law, is always in force on this thread.

From here on in, any off topic posts, digs or innuendos will be deleted. It's a model outlook thread guys, enjoy them or despair at them. Just leave the personal stuff aside.

is that directed at me? Im not making personal attacks or innuedos.
Thats to do with BB and the likes
I didnt make a dig at anyone ,read my posts again.

Mothman wrote: »

Hi Pangea, I don't belive it has been spelt out in this thread, but FI means Fantasy Island, though personally I think Fiction fits well also :pac:

Even if you do know this, I'm sure there are others who don't.

It was spelt out, read back , not so long ago someone said a new thread would soon be needed for the cold spell

Anyways so it looks like the cold spell isnt coming yeah ? Shame

mike65

Pah I said it pages back!

Snowaddict

Well the GFS operational run overnight was not good news in the medium term certainly, while the Control Run was excellent from about the 5th of Jan onwards. However, I would definately agree that the first high pressure system is going to sink away to the southeast.

However, its model chaos overnight. We have had a late ECMWF run coming out. One thing I would like to note is that although it seems pretty bleak at the moment, there are still underlying trends to be found that may potentially still suggest a colder outbreak.

For example, if we take the 00Z GFS ensembles, and focus on the control run for a moment, and the others which trend like it:

The clear drop in upper 850hPA temps still occurs between the 3rd and the 5th of January, if we use the ensemble mean. Thereafter, several perturbations break the -10 line and approach the -15 line, including the control run.

Regardless of this being about 192 - 215 hours out still, there has to be some signal for those ensembles to suggest upper temperatures that low for Ireland. There is also the suggestion now of a slightly milder period from the ensembles as the first high sinks away south, for about 3 days. Furthermore, there are also milder perturbations in there which should be noted.

GFS 00Z Ensembles



GFS 00Z 2m Temperatures




Latest NOAA discussion suggest that:
This morning they have gone for a blended solution of the GFS 00Z ensemble mean and last nights ECMWF 00Z ensemble mean in their first update. This is good news IMO, as that ensemble mean has been fairly consistent over the last few days.

UK Met Model Output

This is not good this morning, with very poor potential. They may base their outlook on this model later on.

ECMWF Model Output 00Z

ECM Chart for T+192 is not that bad at all. Subsequent frames are not so great.

There is a clear battle going on this morning between the various model outputs. Some of the operationals are still suggesting milder outlooks into the new year, several of the GFS ensembles suggesting very very cold outlooks. There is great uncertainty at this point as the main possible developments are still around the T+200 timeframe.

At this point and over the next 48 hours, it could go either way.

Regards,
SA.

Mothman

mike65 wrote: »

Pah I said it pages back!

Pah then it needs to be at top of every page

Danno

Lads, do not despair... yet. There is still time for this to come back in line. As mentioned earlier, there is less data available for the runs over the Christmas. Lets wait this thing out. There is going to be a cold spell coming up - whether or not it will bring much snow remains to be seen.

Snowaddict

Danno wrote: »

Lads, do not despair... yet. There is still time for this to come back in line. As mentioned earlier, there is less data available for the runs over the Christmas. Lets wait this thing out. There is going to be a cold spell coming up - whether or not it will bring much snow remains to be seen.

Indeed Danno. GFS Operational 06Z is out now and is much better than 00Z. Although it does not bring in screaming easterlies to us, the amount of cold air plunging into the near continent on this run by the 5th is simply severe. It would only take a few changes such as a stronger low in med to transfer that colder air to here. In the more reliable, this run is definately a bit better also.

Lets see how the ensembles work out.

Danno

Exactly... we are a million times better off now that there is going to be a severe cold pool in Europe. Remember last week when Black Briar was in Prague commenting about the mild there. Well if a "screaming" easterly had to develop then we'd be getting very piddeled off about the lack of cold.

Let the cold pool develop, watch out for a strengthening southerly jet [we got that ALL summer long - so not too hard for it to get going again] Height rises over Greenland will occur and we have a great chance of severe weather of cold and snow in the first half of Jan.

Snowaddict

So far, I have seen the ensembles for the 3rd to 5th of January period and yet again they are showing a pronounced drop in upper 850 hPA temps.

For the third run in a row, GFS control is bringing in an increasingly bitter easterly into Ireland, starting at T+ 204 hours from now. Of course this is still in FI at T+204, but it does show that there is still possible potential there for the wintry outbreak.

Edit: GFS Ensembles for 06Z run now fully out, and its mixed news, as is seen on the graph.

The sharp drop is still there, but I have noticed that there has been a small decrease in the number of perturbations going for very cold solutions. Either way, the mean from about the 5th is still very impressive. There does appear to be some agreement also for somewhat milder temps around the 10th... This is still deep FI though.

Either way, its not a completely bad story at this point.

SA.

GFS 06Z Ensembles 26/12/2008

Snowaddict

UK Met Office Latest Medium Range Update

The Uk Met Office have now trended back towards colder and possibly wintry conditions in their medium term outlook.

The bottom line at the moment is that there is huge uncertainty as to what is going to happen, but the wintry spell still has a fair chance:

''UK Outlook for Wednesday 31 Dec 2008 to Friday 9 Jan 2009:
For New Year's Eve and New Year's Day, the weather will be generally fine but cold, with frost and fog patches morning and night. The only exception being the far west of Northern Ireland and the far southwest of England where it's more likely to be cloudier and breezier with a little light rain or sleet. Little change is expected as we head into the first weekend of 2009, in that the generally cold and settled theme is set to continue with frost and fog patches morning and night. The only exception to the predominantly dry weather will probably be a few wintry showers towards the east coast. Beyond the weekend, the weather looks set to remain cold, with an increasing risk of sleet or snow showers.

Updated: 1154 on Fri 26 Dec 2008''

Pangea

Yes indeed ,nice post SA,

Danno

Good news SA. Now on that summary, rain and sleet is forecast for the NY period. I wonder will Midland and Midlands east of Ireland have build up enough of a land based cold pool to turn this light stuff to snow?

snowfan

Hi guys,

Hope you all had a nice Christmas!

Great to see all the good work done on this board (particularly by Snowaddict) - thanks for sharing so much information with us all and educating us with the charts, for someone who is interested in weather I find it very interesting and informative

As my name suggests, I love snow. However unfortunately (from a weather point of view), I live in Ireland. An island in the north west of Europe which boasts a mild temperate climate. Its also a well known fact that our island is at the mercy of the Gulf Stream which allows bands of rain and mild weather to envelop the island on a year round basis.

This is a fact and cannot be ignored

While some of my colleagues have gone back for the Xmas break to Poland & Hungary, they are in the enviable position of a good possibility of snow. This is due to their location and the cold pool of air currently in place over Eastern and Central Europe. This has always been the case and will be for the foreseeable future; Ireland is not located there so we have to prepare like with like

My own view is that this winter is definitely (so far), the coldest start to winter for the past 30 years. Hopefully early January will bring us a cold blast, however on experience I would be more inclined to believe that any snow fall will come to Ireland in late Feb / early March.

Then we are back to the usual mild muck, wet and cool summer for the rest of the year .This is normally the scenario!

While it gives me hope to see temps for Dublin of -10 to -15 in T240 etc, this is all fiction to be honest. My own rule of thumb now when reading the charts is to stick to Met.ie/BBC etc and only look 2 to 3 days into the future. The idea of looking 10 days into the future (I am not beating up on anyone here and realise its only trends) is just too open to disappointment. Look at what just happened to that High we were all speaking of ...it will move south and not to Greenland.

Alas, given our location, I am now resigned to the fact that this island will not be subject to any decent snow falls for the foreseeable future

Think I better move to Scandinavia!

Snow Fan

Snowaddict

Danno wrote: »

Good news SA. Now on that summary, rain and sleet is forecast for the NY period. I wonder will Midland and Midlands east of Ireland have build up enough of a land based cold pool to turn this light stuff to snow?

Hey Danno. Well I suppose it depends on how cold the air gets over time. Certainly as you said midland and eastern areas would definately have the highest chance with this type of setup. Its definately a better output anyway and means that the UK Met have scrapped their own model output this morning, which shows clearly the uncertainty in the models at the moment.

Its definately some better news, so lets hope things keep trending this way.

Regards,
SA.

kerry1960

Hi snowfan , so your giving out about your location are you (dublin ?):D ,

just look where im stuck :rolleyes:,

meh ........

Pangea

kerry1960 wrote: »

Hi snowfan , so your giving out about your location are you (dublin ?):D ,

just look where im stuck :rolleyes:,

meh ........

lol Yeah i guess kerry dont get much snow ,whats the record snowfall for kerry?
I live in donegal :P

Danno

Interesting swings and roundabouts going on at the moment. It is fair to say, IMHO, that recent changes by the models are indicative to the missing data being input from less flight data and unsupervised "semi-automatic" reporting stations.

However, come Monday when everything should be back online full belt it will be interesting reading then. The cold will still come I think. Just whether or not we'll get snow from it remains to be seen.

Snowaddict

Danno wrote: »

Interesting swings and roundabouts going on at the moment. It is fair to say, IMHO, that recent changes by the models are indicative to the missing data being input from less flight data and unsupervised "semi-automatic" reporting stations.

However, come Monday when everything should be back online full belt it will be interesting reading then. The cold will still come I think. Just whether or not we'll get snow from it remains to be seen.

Very much agreed there Danno. I think it should be well known by the 18Z runs on Monday whats going to happen. If we were in a standard zonal pattern at the moment, it would be easier for the models, but giving the more rare synoptic setup that we are currently in, the missing data could very well be having a huge impact on the latest outputs.

The fact that the UK Met Office went completely against their own model output this morning is indicative of this IMO.

SA.

Snowaddict

Another piece of information I would like to point out is that the National Weather Service Climate Prediction Center in the United States have been very bullish about their predicitons of height rises over Greenland. Their latest charts are at complete odds with some of the recent model outputs and are suggestive of some extremely positive height anomolies over the Greenland area for the next 10 days, as shown in the chart below.

Of course height rises over Greenland are just part of the puzzle, but these once again just add to the uncertain situation regarding the model outputs at the moment.

Atmospheric Blocking Charts - NOAA - US Climate Prediction Center

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/blocking/real_time_nh/mrf1.nh.shtml

That chart above takes us up to the 29th, and is strongly suggestive of the retrogression of positive height anomolies towards the general Greenland area and the area to the North West.

IMO, something will have to give over the next 36 hours. Lets just hope its in favour of cold, a trend which has gradually made it slowly from the deep realms of FI and the beginnings of which is now some 195 hours out, if several of the GFS ensembles and the GFS control run are to be believed. Although there are also milder solutions amongst these ensembles

Heres also a quick bit of information regarding the GFS 06Z run:

http://theweatheroutlook.com/twocommunity/forums/p/23050/651997.aspx#651997

Regards,
SA.

Danno

Personally I think that our current High Pressure will split in two, One half migrating to Greenland and the other to Greece.

This will set up a cold NE and with some shallow low pressures working themselves in to Bay of Biscay. Any snowfall will occur over the south and east and extreme NW of Ireland in the form of showers.

But that is my Opinion only.

Snowaddict

Look at this chart from T+177 on the 12Z GFS run...
Just goes to show what a difference one run can make, even in the more reliable timeframe:

A low over Scandinavia, Very High pressure over Greenland and the assoicated area, and bitter polar sourced air travelling southwards...

This is though, an encouraging frame given the recent operational outputs.



This subsequent T+204 frame shows how truly close things could be and that nothing is still certain.



The final third of this run revets to the usual zonal GFS default, but for the somewhat more reliable timeframe at least, this GFS 12Z operational run is good news. However, I think all of these runs still need to be taken with a pinch of salt due to potential data input issues.

Lets see how the ensembles pan out, along with the GFS Control and the new GFS Parallel run.

EDIT: There is indeed important missing data from this run:

http://theweatheroutlook.com/twocommunity/forums/p/23050/652058.aspx#652058

Regards,

SA.

Snowaddict

Not the best of news from the GFS 12Z ensembles it must be said.

12Z GFS Ensembles

Positives:

1. The sharp drop in upper 850hPA temps is still in evidence, taking place between the 3rd and the 5th of January. [However, the start of this cooling trend is still 192 hours out from now, so still in the lower resolution FI range].
2. Several perturbations trend towards and below the -10 line, however this is still also in FI.
3. Several of the ensembles are still going for this wintry outbreak. However it will be another 36 hours before these ensembles begins to enter the more reliable timeframe.

Negatives:

1. When compared with previous runs, the 850hPA temps ensemble mean has warmed somewhat, by about 1.5 degrees out into deep FI.
2. There is a huge amount of scatter past the 3rd of January, with many milder solutions also on offer.

We are still in a deadlock with regard to the outlook, with no certainty still in evidence. If you were to base an outlook on the ensembles, there has been a slight warming trend when compared to previous outputs, which is certainly not encouraging.



UK Met Office Model Output - 12Z

Nothing spectacular from this run in terms of wintriness, but on the T+144 frame, the high looks to have split. If this run was to verify, things would stay relatively chilly, with frost and fog.

There appears to be a trend on the T+144 frame, in comparison with the previous frame for one area of high pressure to possibly move to the northwest, with the other remaining over Europe at that point.

Of course this is but one run, but there is certainly nothing very mild suggested on it. In fact, if it verified, things would be quite cool to cold.

In conclusion, we are still really none the wiser as to what is going to happen. ECMWF run will be out over the next hour, and will be very important. Either way, by Monday we will have a fair idea as to what is going to happen. If that GFS ensemble mean continues to rise on the next few runs, that will also spell difficulty for this potential cold spell into the new year.

However, I do remain somewhat optimistic at this point and there is still a chance of this colder outbreak (albeit somewhat reduced from the latest outputs) into the first third of January.

Regards to all,
SA.

shamwari

Met Eireann are predicting that the current dry nondescript spell will continue into the early days of the new year:

New Year's Day: Dry and calm with some bright or sunny spells. Rather cold with frost and fog that night and there is no sign as yet of any break in the weather to the end of next week.

snowfan

Guys,

CNN weather seems to back up the prediction that Ireland is in for a cold spell from Jan 3 onwards noting a daytime high of 1oc or 2oC from Jan 3 -

http://weather.cnn.com/weather/forecast.jsp?celcius=true&locCode=EIDW&zipCode=336562986788

Snowfan

shamwari

snowfan wrote: »

Guys,

CNN weather seems to back up the prediction that Ireland is in for a cold spell from Jan 3 onwards noting a daytime high of 1oc or 2oC from Jan 3 -

http://weather.cnn.com/weather/forecast.jsp?celcius=true&locCode=EIDW&zipCode=336562986788

Snowfan

A quick check on the same link shows that it will be cloudy and dry. A look at London's weather shows it a degree or two colder, but again it is dry without precipitation. Given that we are expecting any potential cold spell to come from the east then I think the fact that London is dry is somewhat telling..:(

Danno

Guys, anything we see this week from the charts must be taken with a pinch of salt due to the lack of data.

Villain

Yea just reading on NetWeather how the BBC's forecasts of late are not in line with what the Models suggest and Sky are the same, posters seem to think the BBC's models are showing something the GFS etc aren't due to data missing over the xmas.

It will be interesting to see how the models change next week.

Snowaddict

Well this run is certainly a bit better than previous, in that raging zonality is not really present at all, only during the last two frames.

We come very very close so seriously cold air on this run, but never really tap into it.

The T+144 chart demonstrates clearly the amount of potently cold air flooding down into Europe. We miss out by about 400 miles at this point of the run.



At T+264 and T+276, there is actually a marginal snow event included for Ireland on this run. Upper 850 hPA temps are at about -5 at this point, with plenty of precip around.



Thereafter, until almost the end of the run, potently cold air remains about 300 - 400 miles away from our shores. From a snow potential point of view, this run is very frustrating, because subtle changes could make the difference between the setup shown throughout this run and a severely cold incursion.

Further outputs are needed certainly, but at this point, I wouldn't rule out it being a case of so close and yet so far for Ireland. Equally, it may turn out milder or potently colder charts could appear.

In the more reliable timeframe, with continuous high pressure influence, things will be quite cold at night and cool to cold during the daytime.

Lets see what the 18Z Ensembles consist of....

Regards,
SA.