johnholmes

As I posted yesterday NO synoptic model has any background signal(s) in them, they all run out to the end of the period be it 144h or 384h based on thermodynamics only.

sit back and watch and wait, it is for sure a very interesting situation.

After my usual close morning look at the EC-GFS anomaly charts I wrote this tue 11novtue 11tue 11nov Ec-gfs Certainly changes on both with the uk shown more under ridge than trough conditions, from the original n Russia/n Europe/Scandinavia area, not sure of the way each treat the uk area trough, rather differently. One thing in common is the deep low over ne America; not too different from noaa 6-10 here, and the area close to uk, not that similar really, but all 3 suggest a fairly slack flow for the uk area. The deep cold off ne America and the strength of the flow across the atlantic coupled with the decrease in flow strength just w of the uk suggests to me some pretty deep lows coming close to the uk in the 6-10 day time scale. Have to wait and see if this does happen? 60dm difference at 500mb from n florida to the far n of the gt lakes! There is no sign yet on any of the models or Met Fax at 120h of any of this but it does look like something to watch out for. Essentially a diffluent trough is just about showing on these charts close by the uk(w of), an area where fairly rapid deepening of lows does occur. Of course the old fella could be talking rubbish again. A week ahead should start to show how right or wrong this idea is. sorry missed adding the links EC-GFS http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html NOAA http://www.cpc.noaa.gov/products/predictions/610day/500mb.php also interesting to see the statistics at day 6 for the models, EC as is often the case in the lead, but over the last few days watch the newcomer? http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz6.html

Yes it does make one wonder just how such a huge difference can be created and from the same stable so to speak.

May we ask for you to put your location in your avatar as it means so much more when you report your weather? - thanks

fascinating that Matt and thanks. As you say one will be right, or will it? Perhaps some kind of in between is possible with both 'sides' able to claim their version is more correct. What puzzles me is how the two sets can be so different. Surely Met and EC input things like SAI etc, not sure of course about anything else.

Mild here with a low at midnight of 9.8C, now on 10.2C, cloudy but dry with a breeze from the SSE

maybe Santa will bring me one, I've got a decent sized pool!

do you not understand why? Much like many areas of Russia and other areas with very large land masses.

oh you cynic! Just to be clear I am not suggesting their model output is correct, simply posting what it shows. I never keep these charts so I have no idea how far out they have been over the last 5 years or so. They did of course solidly predict some weeks ahead of the Nov-Dec 2010 cold spell pretty well. Other outputs have been best thrown away. But as you are well aware from your work in winter predictions we/they know so little of how many parameters connect up. That is why, to me, the OPI is such an interesting idea, not totally new of course and has yet to be peer reviewed but interesting. I posted some time ago about lrf work, 1 month ahead in the Met O in the mid 70's. All down to the jet stream the experts there suggested-really, how things have moved on since then.No doubt what we think is a break through at the moment will look equally old hat in 40 years time. Who knows in synoptic meteorology by then main weather cebntres MIGHT even be able to predict it will be rain or snow, how much, where and when. Mind you I would suggest folk don't expect this to happen with anything like total accuracy more that maybe 36-48 hours ahead by then! tara

I love the penguin ad!

coldish waters in the north Atlantic for starters? a minimum % of 60 sometimes higher for 2m T to be above normal? not very good at puzzles mate, so please enlighten me, no doubt I have missed something totally obvious?

the latest Met O winter model output is below NOT a forecast from them, just the basic computer output for Dec-Feb. http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/glob-seas-prob No doubt this will cause some discussion given the view that most model outputs out to normal synoptic range and some that go further show what appears to be a different idea? admin/mods - if you feel this should be moved to the winter thread then please do so. There is already a copy in the technical area.

To stop this being 'lost' in other threads, the latest (November) Met O model output for the winter, link below http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/glob-seas-prob The 500mb anomalies are somewhat different for the 3 winter months ut the 2m temperatures continue to show average to above. No doubt this will cause some raised eyebrows on here.

I am not sure I can agree with this comment Tamara? As expected, the models are converging on a solution in the 10 day period that excludes height rises over Greenland and any meaningful attempt to back Siberian cold westwards 3 of the main anomaly charts show this process still continuing after showing it over the last 3-4 days pretty consistently? Or am I misreading you there. I would also add that the AO and NAO at intervals beyond about 7 days show fairly poor accuracy but otherwise your eloquent comments on how things seem to be shaping up seems fine to me. By the way it is rare, at this time of the year, for the AO or NAO to stay -ve for more than 3-5 days according to something I read many months ago somewhere. Just to add a comment about models and supposed bias. I say supposed as in my view this is something folk on here like to bandy around. So I wrote to UK Met asking about this, see my e mail and their reply. In my understanding as the models started to become operational there was no model bias nor any human input to bias a model in any way. On a weather site I belong the comment below is quite often seen Can you please pass this e mail on to the Forecast Operational side for their comments please? I really would be most grateful if they can give me an answer, is their model bias input from human or nor not? Very many thanks John Holmes Also in reference to your post, All models will have a starting platform & somewhere deep in the mix will be the long term mean & part of the build in terms of what the broad pattern characteristic will look like. If the starting patter was the total INVERSE of what the characteristic should be - ALL models would mute out the signal over time to return to that normal base state- Time X The GFS due to its eastward bias resets the pattern a lot quicker than the euros hence its hopeless in extended blocking scenarios.. Dear John “The weather forecasting and climate models used by the Met Office and most other Met/Climate services are physical and not statistical models, which means that they work by trying to solve the equations describing real world atmospheric processes. Unlike statistical models, which work using analysed statistics of past events, physical models are more likely to produce a reasonable forecast in an unusual (or even not previously occurring) situation. This also means that there is no pre-programmed or hard-wired “mean stateâ€, but that the model should be able to reproduce the true mean state of the atmosphere when run over a long enough period (this is an important point for climate projections). “That said, any model will still contain statistical biases, which in this case are due to imperfections in our modelling of physical processes rather than a mismatch between a pre-programmed mean and the “true†mean state. In the example provided, if a model has an “eastward†bias in the Atlantic, this is likely to be due to the model not quite capturing the correct physical processes to maintain N. Atlantic blocking. It is our role, as model developers, to improve the physical accuracy of the models to reduce these biases and improve the likelihood of the model producing a correct forecast in an unusual synoptic situation.†I hope this helps? Kind regards Dan

Picking up from the post by Nick F above and the anomaly charts have been pretty consistent in predicting the pattern shown in the links below. About 4-5 days ago when they began to show the idea of this extended trough into Europe with +ve heights and ridging north of this, see below http://www.cpc.noaa.gov/products/predictions/610day/500mb.php http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html Monday/Tuesday for EC-GFS and the following day for NOAA, so good consistency here which gives a high probability of it actually developing. Just what detail will transpire from this basic upper air pattern is yet to be decided but perhaps not the deep cold some hope for and a few try to make out will happen in the 7-10 day time range?

As the outlook covers the transition from autumn into winter, there can be big changes in how UK weather is influenced by prevailing weather patterns during the period. Confidence in how the weather patterns will develop later in the period reduces and this is reflected in the outlook when it states “the risk of occasional colder outbreaks increases later in the period.†why or why can some of you not put in '....' exactly what WAS printed not your own version? this is the exact copy from their web site and as W-H has linked to As the outlook covers the transition from autumn into winter, there can be big changes in how UK weather is influenced by prevailing weather patterns during the period. Confidence in how the weather patterns will develop later in the period reduces and this is reflected in the outlook when it states “the risk of occasional colder outbreaks increases later in the period.â€

similar here, it is dry but cloudy after dropping to 2.9C in the early hour, it's now on 4.3C with a light drift from SSW

very true V but others please be aware that their comments relate to upwind of and over the N American sub continent although obviously everything is linked. Just a word of caution from me. It looks good but as chio as pointed out not all the building blocks are aligned properly yet.

raining and has been for a while, lowest at midnight on 9.1C currently up to 11.9C in an easterly breeze.

I know 1 or 2 well respected members don't believe in the use of 500mb anomaly charts and at the most one can only take the 8-14 day NOAA chart as the main guidance, although there is an output with NAEFS further out, but until they show at 8-14 and 3-4 days later still show and so does the 6-10 the trough working east of the UK then it is not likely to happen. link to NOAA is below and the charts from EC-GFS are very similar. If 3-4 days down the line and the trough is moved (on the 8-14 day chart) east of the UK with marked ridging as well as large +ve heights showing to fit this idea we can then pretty confidently believe this will happen. I believe 1 or 2 are suggesting something along that time scale for the synoptic models to start to show this in the same time frame. We just have to wait and see. 2010 is being mentioned, it was only the last 6-8 days in that month that went really persistently cold with snow becoming fairly widespread, at least over central and eastern UK. That was well predicted by UK Met and fairly well 2 weeks ahead on the anomaly charts. Patience is needed with some of you IF a cold end to the month occurs. One thing to look for on the anomaly charts is for NO sign of marked +ve heights in the Aleutians area! http://www.cpc.noaa.gov/products/predictions/610day/500mb.php A sign of the excitement building for cold hopers is the number on here 228 as I type, only a few days ago if was 30-40 on line at once.

do you mean this link Pit? http://www.netweather.tv/secure/cgi-bin/premium.pl?action=modeltracker;sess=0146e2b643b9df7a335b67f1465a0860=# working fine for me?

just copying the main para as to what the ENSO is predicted to be Similar to last month, most models predict El Niño to develop during October-December 2014 and to continue into early 2015 (Fig. 6). However, the ongoing lack of clear atmosphere-ocean coupling and the latest NCEP CFSv2 model forecast (Fig. 7) have reduced confidence that El Niño will fully materialize (at least five overlapping consecutive 3-month values of the Niño-3.4 index at or greater than 0.5°C). If El Niño does emerge, the forecaster consensus favors a weak event. In summary, there is a 58% chance of El Niño during the Northern Hemisphere winter, which is favored to last into the Northern Hemisphere spring 2015 (click CPC/IRI consensus forecast for the chance of each outcome. with thanks to cpc.ncep

this may be relevant but mods please move to winter thread if felt this is the wrong area. latest ENSO official forecast for winter into spring for the northern hemisphere http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.shtml

white frost on everything but not quite an air frost with a low of 0.2C, no wind, fog earlier