Model output discussion - 1st December onwards

[knocker]

6 minutes ago, feb1991blizzard said:

Just wondering Knocker if you have seen the Control run of the EC32 tonight yet?

Only just this minute.

[knocker]

2 minutes ago, Ali1977 said:

And? Same old story of mild PV?

I haven't had much chance to look at it but essentially yes but temps becoming average in January.

[feb1991blizzard]

Just now, knocker said:

I haven't had much chance to look at it but essentially yes but temps becoming average in January.

Thanks.

[bobbydog]

yes, its the last frame of F.I.

but.... a glimmer of hope that there is a way out of this mild dullness...

 

[bobbydog]

10 minutes ago, knocker said:

I haven't had much chance to look at it but essentially yes but temps becoming average in January.

the plot thickens.... 'average' temps in january are not mild.....

[feb1991blizzard]

The thing to look out for over the next few weeks are those thin slithers of high heights over Scandi / W Russia ridging right up into the pole, these are very often pre-cursors to bitterly cold easterlies.

[bobbydog]

3 minutes ago, feb1991blizzard said:

The thing to look out for over the next few weeks are those thin slithers of high heights over Scandi / W Russia ridging right up into the pole, these are very often pre-cursors to bitterly cold easterlies.

yes. its the massive cold HP over eurasia at the end of the run which caught my eye.

that could knock the vortex off its perch....

[feb1991blizzard]

4 minutes ago, bobbydog said:

yes. its the massive cold HP over eurasia at the end of the run which caught my eye.

that could knock the vortex off its perch....

 

 

Its a double whammy, they induce a strat response so as to give us a better chance but also can load the gun by bringing the brutal upper atmosphere temps to a similar latitude so when the trigger shortwave is ejected into Iberia from a disrupting Atlantic trough a few 'Go's' later there are no blanks being fired, instead its like Inspector Callaghan's 44 magnum and results in a powerhouse Easterly!

Edited December 15, 2015 by feb1991blizzard

[Daniel*]

11 minutes ago, bobbydog said:

yes. its the massive cold HP over eurasia at the end of the run which caught my eye.

that could knock the vortex off its perch....

Indeed but I worry the vortex will be knocked to where we do not particularly want it for example Greenland instead of Eurasia side going foward we'll have to be looking towards the NE for cold routes...which can certainly deliver but it makes it harder.

Edited December 15, 2015 by Daniel*

[Johnp]

5 hours ago, feb1991blizzard said:

The thing to look out for over the next few weeks are those thin slithers of high heights over Scandi / W Russia ridging right up into the pole, these are very often pre-cursors to bitterly cold easterlies.

It's certainly there again on the 00z!

Doesn't deliver for us on this run,but certainly interesting.

[knocker]

 

A brief overview of the latest EC32 update. Keep in mind as always this is the broad brush output and not the full suite.

Starting with the 500mb anomaly on Xmas Day. A familiar story with LP over the Pole, and Greenland with associated troughs  western N, America, eastern Europe and eastern Atlantic. High Pressure NE N. America and Central Europe. Ergo warm moist SW flow but wintry outbreaks further north and possibility of strong winds.

Moving on through the week to New Years Day finds the east European and west N. America trough weakening and the HP Central Europe ridging just to the east of Scandinavia. The trough to the west of the UK remains solid so although the flow is more meridional it’s still from the WSW/SW with the trough in charge so periods of unsettled wet, windy weather with temps varying around the norm but on the whole slightly above average in England.

Through to the 9th the trough in the eastern Atlantic becomes negatively tilted into Scandinavia this pushing any ridging east. Thiis results in the veering of the flow over the UK and possible more influence of the HP pushing north into southern Britain, So still Scotland prone to wintry outbreaks but remaining relatively mild in the south.

No great change until the 15th except the trough moves to a more neutral position over the UK and some ridging over Russia so no significant change in the general outlook.

Summary

No significant change to the outlook with the main flow from a westerly quadrant, mainly SW becoming W/NW. Thus periods of wet and windy weather, accompanied by strong winds with the north feeling the brunt of this as HP makes an attempt to push north later in the run. Quite mild in England with temps around average or a little above but varying below in Scotland with the wintry incursions.

The NAO and AO mean remaining positive throughout.

At this stage there doesn't appear to be anything sinister lurking in the woodshed but a reminder to remember Oedipus

Edited December 15, 2015 by knocker

[knocker]

The interest this morning centers around how high will the temps get this week. Well quite high with Saturday looking ready to take the biscuit at the moment. The Xmas day chart out of interest  It does look increasingly likely that we will be in a W/SW flow and it just depends on the precise analysis on the day.

Charts weatherbell

 

Edited December 15, 2015 by knocker

[booferking]

I have no interest in the charts above haha  plenty of time to see charts like that in the start of spring .

 

[Timmytour]

1 hour ago, Johnp said:

It's certainly there again on the 00z!

Doesn't deliver for us on this run,but certainly interesting.

I'm increasingly pessimistic that it will deliver.  Though an La Nina winter rather than El Nino, to me looking at the models back in 1974 would probably have yielded similar thoughts of potential, later....only to be constantly dashed as time wore on.   That high pressure keeping the jet too much to the north for our liking looks like a Premier defence that has successfully parked the bus,  

[MPG]

Same sort of idea on the 18z and 00z.

[Polar Maritime]

So according to Cohen changes are still expected in January. With the PV becoming more disorganised.

Quote

We anticipate additional energy transfer pulses from the troposphere to the stratosphere beyond next week.  We anticipate that the additional energy pulses will be of sufficient duration and amplitude to significantly weaken the polar vortex, most likely in January.  Following the weakening of the polar vortex we expect a reversal to much colder winter weather for the Eastern United States and/or  Europe for the latter half of January and into February. 

 

[Ali1977]

5 minutes ago, Polar Maritime said:

So according to Cohen changes are still expected in January. With the PV becoming more disorganised.

Perfect, re-run of 1947 then..

Edited December 15, 2015 by Polar Maritime
To separate post from quote..

[knocker]

The GEFS temp anomaly for Xmas week

Edited December 15, 2015 by knocker

[IDO]

Not much change this morning, the GFS op, as it will, over does height rises when it spots another slower Atlantic period, but the mean keeps it real:

  

Amazing how boringly consistent the CFS week 4 charts are run to run and it is clear the pattern we are in has little sign of waning at the moment: 

Cohen doesnt sound too optimistic: 

• We anticipate further energy pulses that if are of sufficient amplitude and duration will eventually significantly weaken the polar vortex, reverse the positive AO and lead to colder temperatures for the mid-latitude continents. However, if anticipated strong energy pulses do not materialize, there is little reason to anticipate a change in the overall mild pattern.

As we have said before a SSW maybe our only saving grace this Winter.

In the nearer term the overnight temps could be close to July averages for 2/3 nights this week in favoured places! Christmas Day looks a N/S split with 10-12c from the Midlands to the coast:

Mean 2m temps 1pm on 25th:    GEFS:   Strat heights: 

After that temps moving above average again for the south with the uppers at +5c above average at D16 (mean) with many members going a lot higher (CET +4.4c above av. after 13 days)! 

Looking at the strat it is a slow process with still a stretched PV at D16, and this may or may not result in something further down the line. Best to treat it as a bonus, as last year showed, even with greater expectations we were left high and dry re a SSW.

Although temps have been way above average it would be nice to get a bit of sunshine rather than this grey gloomy vista that greets us at sunrise, though the synoptics suggest otherwise, heres hoping.

[johnholmes]

34 minutes ago, knocker said:

The GEFS temp anomaly for Xmas week

I cannot recall, since we were able to see temperature anomalies, anything quite like this one in December

but the link below to Met O model output for Europe back in early October has a similar look to it. Certainly not as marked but the cold area off western UK and Europe above average are pretty similar to my eyes.

http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/glob-seas-prob

Edited December 15, 2015 by johnholmes

[Vorticity0123]

Impressive mildness

Insane, that is probably the best word to describe the weather in the coming days in Western Europe, especially in the Netherlands. We can be sure that some daily records for temperatures will be broken the next few days. To show how mild mild can be, look at the ensemble forecast of the ECMWF below:

ECMWF ensembles of De Bilt, the Netherlands from yesterday 12Z run. Source: Weerplaza.

For clarity, I have put the daily average maximum and minimum temperatures in red and blue lines, respectively.

The coming days, the average maximum temperature will be in the double digits, up to 8 degrees above normal on Thursday. And also on the long term it seems that the temperature will stray close to the 10 degrees mark. Narcisses are starting to flower already.

Even more impressive is the minimum temperature. Because we are entrenched in a mild and humid southwesterly flow, most days stay cloudy. As a result, there is almost no diurnal cycle. And this results in minimum temperatures of more than 10 degrees (!) above normal. Such temperatures at night would not be misplaced in an average Dutch summer.

No significant change in the pattern for the time being?

For the time being, it looks that this pattern is not going to change, judging from the 8-14 day anomalies from NOAA.

NOAA 500 hPa heights (green) and anomalies (red and blue) for 8-14 days forward from 14 December.

All model ensembles generally agree with that scenario. The main pattern remains a southwesterly feed due to anomalous troughing over the western Atlantic and anomalous ridging over Europe. As a result, our source of air remains located near the Azores.

December record overwhelmed?

Most impressively, it looks like our heat record of average temperature in December will be litterly shatterred. On average, the December temperature up to now has been 8,5 degrees, 1,2 degrees above the previous record from 1974. Usually, the average temperature would drop steadily as we progress more into December, but judging from the ECMWF ensembles above it seems like the average December temperature will only rise. At least until Christmas the average daily temperature will hover around the 10 degree benchmark.

Therefore, it is almost certain that we will beat our Dutch average temperature record for December. The question is: will it be beating or shattering? A difference of more than 1 degree between the old and new record is definitely a sound possibility. This "Winter" is looking more like Spring for the time being, very impressive to say the least!

Courtesy to weergegevens.nl/ for data about temperature records

 

 

Edited December 15, 2015 by Vorticity0123

[carinthian]

Amazingly mild charts for this side of Christmas. Though I am more encouraged to see post Christmas Charts ( Boxing Day onwards) both shown on the latest ECM and GFS models of a significant rise of pressure over the British Isles. A developing slow moving trough in Mid Atlantic outwards the Azores should slow things down. So turning Less Mild possible rather cold and significantly much drier post Christmas. Lets hope this trend continues during todays later runs .

 C

Edited December 15, 2015 by carinthian

[IDO]

11 minutes ago, MPG said:

 

Two conflicting posts regarding Cohen.

Yes as you would expect a SSW (trop led) is dependant on wave attacks from the trop. If we can get a sustained attack, say a Scandi/Euro ridge for a week or so, that would more than likely get a strat response for mid-Jan onwards and a resetting of the NH profile. That does not necessarily mean the UK will get cold (knowing our luck, but greatly improves our chances). I think Cohen anticipates that wave 2 is incoming and hopefully he is correct, but a sensible proviso, that if these further attacks don't happen, then all bets are off! Last year is a good reason why we need to show caution. I am hopeful as another two months of this would be the pits.

Edited December 15, 2015 by IDO

[feno13]

8 minutes ago, MPG said:

 

Two conflicting posts regarding Cohen.

Why don't you go and read the report for yourself ???. Anyway , I have nothing more to add that already hasn't been said , more of the same it seems for at least the next 10-14 days.

 

[MPG]

46 minutes ago, IDO said:

Yes as you would expect a SSW (trop led) is dependant on wave attacks from the trop. If we can get a sustained attack, say a Scandi/Euro ridge for a week or so, that would more than likely get a strat response for mid-Jan onwards and a resetting of the NH profile. That does not necessarily mean the UK will get cold (knowing our luck, but greatly improves our chances). I think Cohen anticipates that wave 2 is incoming and hopefully he is correct, but a sensible proviso, that if these further attacks don't happen, then all bets are off! Last year is a good reason why we need to show caution. I am hopeful as another two months of this would be the pits.

 

Thanks for the constructive reply IDO explaining what Cohen was saying.