December CET

[nigelonline]

a rather warm 6.1....

no snow south of Birmingham

[PersianPaladin]

5.7C

[tinybill]

9.9 with plemty of rain!!!!!!!!!!

[stormchaser1]

6.4c

A rainy month with hp until around the 23rd , lp towards the end of the month , think this will be a mild month

with the odd outbreak of a cold spell prob towards the middle of the month ,

nigel

[sundog]

6.4c

A rainy month with hp until around the 23rd , lp towards the end of the month , think this will be a mild month

with the odd outbreak of a cold spell prob towards the middle of the month ,

nigel

i reckon you hane hit the nail on the head there

[Duane S.]

I feel a bit guilty going for a punt so close to Dec compared to some but I think I'll still manage to live with myself as a consequence.

First week or so, nothing doing in terms of cold weather. I reckon we will see a decent cold snap, although fairly short-lived, starting around the 11th and lasting for a good week. Then after it's back to mild with maybe the last few days of the month cooling down once again.

CET 5.5

[mattneal]

cet 5.2

[Intrepid]

Il go for 4.3c

[Gavin P]

Welcome to the forum Gavin. You have not posted your location. It's not rural West Northants by any chance is it ?

LOL Ian. I've not had a chance to sort out my sig/profile.

[Glacier Point]

December, 1st leg of the CET Trophy and 1st part of the winter forecast period.

The key players this month are likely to be:-

• state of the polar air mass;
  
• a moderate strength El nino;
  
• intensifying MJO activity.
  

A persistent polar vortex parked to our north has raised some real fears for the coming winter. At an upper level, the thermal profile is very much in line with the influence of the westerly QBO with quite good match for cold air at upper layers forcing -ve height anomalies and a strong polar vortex with the AO forced +ve.

http://www.cpc.ncep.noaa.gov/products/prec...hgt.ao.cdas.gif

Were this Summer, I would have no hesitation in calling it mild all the way although these types of cold air anomalies are not unusual for winters and may indeed be integral to laying the foundations for a cold season. The key requirement is for the cold air to rapidly propagate downwards and set up over Scaidnivia and western Russia, as it did in 1963:

November 1963

December 1963

Statistically December is a favoured month for the AO and NAO to be +ve, even under westerly QBO conditions.

The weak to moderate El Nino remains in place although its impacts have been a little masked by the polar anomalies of late. I expect to see a return to a more traditional El Nino pattern for December.

The MJO has entered it's second Wave of the season and is currently slightly bogged down in Phase 3:

http://www.bom.gov.au/bmrc/clfor/cfstaff/m....Last40days.gif

With SSTAs in the Indian and Pacific Oceans remaining favourable, it is likely that the wave will re-intensify through phases 5 to 8 and re-enter phase 1 at the end of December. Phases 7,8 and 1 would be considered favourable for high latitude blocking with phases 8 and 1 being highly conducive to a Greenland / Icelandic block to develop which at this time of year would be very cold for the UK.

http://raleighwx.easternuswx.com/MJO/DecemberPhase8500mb.gif

http://raleighwx.easternuswx.com/MJO/DecemberPhase1500mb.gif

I expect this to be a major player towards the second half of the month with the 1st half being more of the current projected pattern resulting in average or just above conditions for the UK.

The Winter Forecast Constructed Analogue suggests an average or slightly below average month with +ve pressure anomalies to the north and north-west:

With the first half of the month likely to come in marginally above average, the key to December will be the magnitude of the correction thereafter. Warming of the Davis Straits during October, the underlying -ve NAO and phasing of the MJO are likely to lead to downward correction for at least 10 days and my play is for December to be below average with a CET of 4.5 C - but this could easily be lower.

Edited November 27, 2006 by Glacier Point

[SteveB]

I do hope you are right Gp. I think if we faced another mild winter, I would really start to believe cold cold periods in winters are a thing of the past.

[J10]

I'll go for 5.6c

[Wynn D Woo]

My punt for the month is 5.4C,

[TP85]

I'll go for 6.4C. Big stab in the dark.

[JohnAcc]

Quite interesting to look at the predictions above with the mean and median returning 5.1, the mode returning 4.4, the 1st quartile returning 4.4, the 3rd quartile returning 5.9 and a standard deviation of 1.33.

It would appear that the NW community favour a below average month! Anyone for a nice chilled pint of Cold Bias?

I will make my punt for a CET of 6.6 as I believe any upstream changes appear to be stalling this year therefore not affecting our shores until the first 2 weeks of Jan 2007.

Rgds, John

[derby4life]

7.3 ......

[Supercell]

I shall go with my instinct...5.2C

[reef]

I cant see anything other than a mild month, with so much warmth pumped up into the Arctic during the last week or so even a cold snap would initially be rather mild (aka mid-Feb 2005 northerly). Im going for 6.0°C - the warmest since 1994.

[Stratos Ferric]

Quite interesting to look at the predictions above with the mean and median returning 5.1, the mode returning 4.4, the 1st quartile returning 4.4, the 3rd quartile returning 5.9 and a standard deviation of 1.33.

It would appear that the NW community favour a below average month! Anyone for a nice chilled pint of Cold Bias?

I will make my punt for a CET of 6.6 as I believe any upstream changes appear to be stalling this year therefore not affecting our shores until the first 2 weeks of Jan 2007.

Rgds, John

Not unusual on here, and generally a triumph for hope over experience I think. That said, the run of warm / very warm really must break eventually. If it doesn't then the inference might well be that something fundamental and unexpectedly sudden has happened to our climate. Whilst I'm sure that day will come, I don't think it's here yet.

[tugmistress]

ok i reckon about 5.3c

[osmposm]

A depressingly mild +6.2 for me, too......though I passionately hope I turn out to be at least a couple of degrees too high.

Ossie

Edited November 27, 2006 by osmposm

[Paul Sherman]

I am going with 5.7c for December 2006.

Having looked likely to win the November CET With 7.8c, It now looks like WIB Will get that Steak

Paul Sherman

[Stratos Ferric]

This month is yet another tricky call.

December is the only month which at present is declining across its ten year average, and with January is holding its own in the last ten years when the 30 year mean is used. The value in both cases is 4.8C to Dec 2005.

It’s also one of the less volatile months in terms of big deviations from running par, but there has been a tendency over the last decade for slightly warm months, this being offset by just two markedly colder ones (1997, 2002).

The 30 year average has fallen for the past five years, a level exceeded only once in the CET series; that makes another fall this year less likely, and the value thirty-one years ago was 2.0. Not really much help because a value lower than that this year (in any month) would probably be beyond plausible anyway. Equally the 1996 value was also in the 2s, so that drop out this year tells us very little.

Nor is there a hugely discernible pattern when looking at sequences of prior months relative to their ten year running mean. This year S,O and N have all been +ve, usually this leads to Dec being +ve as well, but the ratio is only about 3:2, and amongst the 2s are several very cold (relatively) Decembers.

The one compelling trend is the one that can be traced back to 1963, with Feb 86 as the sole outlier, where no other month has fallen markedly below a line between stretching from -1.1C in Feb 63 to 4.0C last winter. December tends to be above this line, the two aforementioned examples apart, and the convergence appears to be in the high 4s.

That little lot would suggest a value this month around 4.5-5.0.

What of the fundamentals? SSTs are still high, though slightly less so now, and with more cool water to our north. Still, the suggestion is all upwards. The upper flows have been zonal, and I see nothing on the surface to buck this trend, apart from an instinct that continued very mild weather would be all but unprecedented. The Nino is also continuing to develop and there is no mass of cold air forming anywhere close. Unbroken mild would be unusual; generally mild with some brief cool interludes might be closer to the mark. The window for me moves up to around 5.2-5.7, but to go milder or cooler?

I'd like to go cooler, but I fear it's still mild, so I'll opt for ...

5.6

[Roger J Smith]

Earlier I was thinking rather mild, now I am thinking very mild. This seems to my rudimentary mind the perfect set-up for a record warm December. Very warm air is blasting in from the Atlantic day after day. New moon and southern max on the 20th, beyond the model and normal forecast horizon, usually produce very mild weather in a mild pattern, by forcing the flow just that little bit extra, like paying Wayne Rooney extra to play a little better.

As a result, 8.3 C for me. I'm expecting it to turn radically colder very soon after this all goes down, but it's a long way from Alaska to Sweden, which is about the only route that cold air can take to reach you now that Greenland is being overwhelmed by the returning mild easterly and eastern North America is saying "sorry, no service."

Edited November 28, 2006 by Roger J Smith

[Glacier Point]

With the first half of the month likely to come in marginally above average, the key to December will be the magnitude of the correction thereafter. Warming of the Davis Straits during October, the underlying -ve NAO and phasing of the MJO are likely to lead to downward correction for at least 10 days and my play is for December to be below average with a CET of 4.5 C - but this could easily be lower.

I may have under-cooked the +ve temp. anomalies for the first half of the month somewhat, certainly looks that way from GFS and ECM extended range outputs which are likely to come in +1.1 C. I'll upgrade my CET projection to 4.8 C

Edited November 28, 2006 by Glacier Point