I don't know how to read those maps there isn';t a key - so what do those blue and red mean and what does this most likely do denote weatherwise!?

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Blue denotes low pressure anomalies, with orange/ reds as higher pressure. So based on that model we're in for a South Westerly based winter. 

"Blue denotes low pressure anomalies, with orange/ reds as higher pressure. So based on that model we're in for a South Westerly based winter."

Not quite.

Blue denotes area where the models shows pressure to be lower than the long-term mean when averaged over the 3 months, while red indicates pressure higher than the long-term mean.

It's a subtle difference, but vitally important. Lower-than-average pressure can still mean high pressure, and vice versa.

For example, if the long-term mean pressure over one area is 1025 mb, and the actual reading is 1015 mb, then that is lower-than-average pressure, BUT it's still high pressure.

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Indeed, but over a whole season, lower-than-average mean pressure would probably indicate a greater frequency of low-pressure systems in that area, even if the overall average was still "high pressure".

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No argument with that, Rob.

It's just that winter is the season when this can cause confusion, e.g. if someone with access to restricted 30-day anomaly charts excitedly tweets that they show high pressure to the north, when in fact they show higher-than-average pressure.

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Think today was the first snowfall of the season in Moscow http://classic.wunderground.com/history/airport/UUEE/2014/10/17/DailyHistory.html

 

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Nice to see first snow falling in Moscow in first half of October. Not seen that for a few years now (someone correct if I am wrong). I seem to remember in the 80's that used be a regular feature in early October, ie couple of days of snow followed by some milder days. Hopefully it would bring back 80's style winter to Europe.

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ill be sick if we see another mild winter,  seems like when HP  dominates its stubborn to go as we have seen this summer.. tho this is a similar setup to 2010 and we had a deep freeze,  if im making any sence.  cos ive confused myself

One factor I have yet to see mentioned yet is the huge amounts of SO2 currently being pumped in to the arctic's stratosphere. SO2 is known to warm the stratosphere whist cooling the surface ;-)

Below is a quote from a study on the effects of Mt Pinatubo

"OBSERVATIONAL DATA

As observed after several eruptions, including Agung in 1963 and El Chichón in 1982, stratospheric warming and lower tropospheric and surface cooling have been documented after the Pinatubo eruption. Labitzke and McCormick (1992) show that warming in the lower stratosphere (16 to 24 km or 30 to 100 mbar) of up to 2 to 3°C occurred within 4 to 5 months of the eruption between the equator and 20°N. lat., and it was also later noticed in middle northern latitudes (Angell, 1993). The warming distribution closely mirrored the dispersal pattern of the aerosol cloud; this mirroring strongly suggests that the warming was due to absorption of radiation by the aerosols. The warming was more intense in southern temperate-polar latitudes, perhaps due to the presence of aerosols from the Mount Hudson eruption. Such temperature changes can influence stratospheric dynamics (Pitari, 1992). Since the peak of stratospheric warming in late 1991, temperatures in the 18- to 24-km region have cooled considerably, passing the average in early 1993 (fig. 10); temperatures in 1993 were the coldest ever recorded (Christy and Drouilhet, 1994; Monastersky, 1994) and may be related to ozone destruction in the lower stratosphere. Stratospheric temperatures also plummeted and stayed cooler than average for 7 years after the El Chichón eruption."

http://pubs.usgs.gov/pinatubo/self/

Also you can view current levels/ spread SO2 in the northern hemisphere here -

http://satepsanone.nesdis.noaa.gov/pub/OMI/OMISO2/images/OMI_NH_SO2_DDC2.GIF

There is also an 8,000m one but I can't remember where it was I saw it.

 

Hmm!! - So 28th November - Looks like it will be the coldest day of the Autumn/Winter 2014/15 at +3c.

http://www.theweatheroutlook.com/twoforecasts/daily-ultra-long-range.aspx?region=1&page=1 

What a disaster - a deja vu of last winter is it not?

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Not sure where to put this question but I guess it is slightly winter related....

Q: When we have the shortest day (21st Dec) from then onwards does the daylight hours draw out by 1minute or 2mins a night? or how does it work from that date?

I was asked last night but wasn't sure on my app at mo we are losing 2mins a day in terms of getting dark etc

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Winter 2011-2012 was unlucky for the UK. We had cold and some snow in Feb 2012 but we were so close to it being incredible. Parts of Eastern and South-Eastern Europe like the Balkans got hammered!

Snow in Sarajevo February 2012

 

 

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Stunning scene. As our summer continues...this made me smile, the explanation as to what slush is...

Its mid October and almost a foot of snow of forcast, this place would go into meltdown (excuse the pun)

I have a feeling its going to be a long season.

 

http://weather.gc.ca/warnings/report_e.html?qc2#90403244191814711201410180504

 

Alerts for: Schefferville

Warnings

11:58 AM EDT Saturday 18 October 2014
Snowfall warning in effect for:

• Schefferville

A long period of snowfall, with total amounts of 15 to 25 cm is expected.

An almost steady low pressure system south of Schefferville will continue to bring significant amounts of precipitation through Monday. The rain will change to snow this evening and will melt as it reaches the ground at first but then begin to accumulate later overnight. A layer of slush (water saturated snow) could make roads slippery. Visibility will be strongly reduced by large snowflakes as well as the wind. The snow will continue all day on Sunday and ease Monday.

Be prepared to adjust your driving with changing road conditions. Visibility may be suddenly reduced at times in heavy snow.

 

At the winter solstice the difference in each day is merely a few seconds at one point, with the greatest differences in daylight being around the equinoxes.  

 

http://www.timeanddate.com/sun/uk/salford?month=12&year=2014 

 

This website i find very useful when trying to figure it all out.  

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And now shows snow for the end of January

They really are J F F Tally

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It seems as if recent patterns favour a mild winter, but developments in the stratosphere and perhaps across Asia (snow cover advance) are pointing towards a colder sort of winter.

Based on that, I can see how we could see a very sudden switch to a cold regime after weeks of persistent mild conditions, like what took place in December 2009, though I've seen plenty more comparisons with December 2010 due to the stratosphere being modeled to behave in a similar fashion in the next 10 days or so.

I've seen it go wrong often enough to keep expectations down at this stage, but at least it looks to be an interesting couple of months coming up from a scientific standpoint.

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Good post SC. Atmospheric conditions are the polar opposite of this time last year and we are in a far better position going into winter than last year, but as we all know things can and do change rapidly more so in the Hurricane season. A very interesting few weeks of model watching coming up, hopefully the foundations being laid now will be conducive for a cold and blocked winter later.

http://web.mit.edu/jlcohen/www/papers/Cohenetal_NGeo14.pdf

In this clearly presented paper by Cohen et al., there is a suggested synergy between the effects of anomalous warmth emitting from the exposed Arctic Ocean waters bordering Asia and anomalous cold associated with an early advance of snow cover across Asia.

 

In short, the surface heat input over the ocean leads to an increase in pressure above that region, which shifts the mean storm track across Asia to the south. This leads to excess snowfall and an early advance of snow cover there, which in turn creates anomalously cold surface conditions. These may produce a positive feedback through encouraging a further lowering of pressure over the continent.

 

To see what this looks like, we can actually look at current model output:

   

These charts, for two days ahead and ten days ahead respectively, show anomalously low pressure over the Asian continent, with anomalously high pressure over the adjacent area of the Arctic Ocean.

 

Encouraging signs that we're on route to a winter of blocking highs throwing cold at us from a frigid continent?

...it's not that simple I'm afraid. The relationships discussed in the paper are reportedly lacking in confidence, due in large part to relatively sparse observational data, both in spatial coverage and duration.

Not only that, but a corresponding effect on the NAO and AO - forcing them negative - appears to be even less certain. In fact I get the impression that the main thrust of this 'warm Arctic, cold continent' forcing tends to place the UK at the western limits, meaning that it takes a particularly strong response to get us in on the act - though this may not be a surprise to many who have followed the countless near misses of the past decade!

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I doubt we'll get anything close to this sort of cold this Winter or any Winter away from the top of the Scottish mountains.............-41C windchill?! my god this must have felt perishing! 

http://www.wunderground.com/history/airport/KORD/2014/1/6/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA

 

 

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Lots of comments on snow cover to the east. I have to admit I don't see the significance. One chart like the one Brian has posted in the MO thread and it melts most of it. Then what?

For me it's just as tenuous a single link as any long range indicator. It may well be important as part of a far bigger picture, but that's a picture we are not even remotely close to understanding yet, and to take anything from it in isolation is sheer folly. 

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Totally agree Matthew , Snow to our East means naff all for us, it is one of 68 links IMO

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You missed at least ten dozen numbers in front of that 68 

But yeah, probably does play some part, but not THE part. Nothing plays THE part. 

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You need to look at it the other way round.

The rate of increase of south Siberian snow cover in October is a symptom of certain atmospheric patterns and motions which have a bearing on the extent of northern blocking and the strength of the polar vortex weeks later during winter. The idea is that some of the movements of warm air northwards towards the Pole and upwards into the stratosphere which get us all excited in winter need to begin their journeys now.

You can pore over the charts and model output to determine how far south low pressure is over Siberia in October, how far into the month it persists, the angle and timing of the polar vortex as it begins to form, etc. Or, if you're pushed for time, you can watch how quickly Eurasian snow cover spreads south and use this as a proxy.

It's irrelevant whether or not it melts away in November. It's a symptom of the October atmosphere and the ways the atmosphere may develop in the months ahead; it's not in itself a cause of anything in the future.

If you think that's a load of hokum, fair enough, but don't dismiss the idea because the snow melts away in November. By that time the state of the atmosphere which caused the snow to increase or otherwise in October has been and gone, and it's that state of the atmosphere in October which we're interested in, along with the movements of energy that continue to develop in the weeks ahead.

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Good post SFB.

So if and when we get an Easterly it will bring colder air in from the East? Correct?

 

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