The Run Up To Christmas Based On The 12z Gfs

[TEITS]

General synopsis.

A large area of high pressure will be centred over the UK during this period.

General description of the actual weather.

All 3 days are very similiar during this period. The temperatures will be around average although dropping to slightly below on Boxing day. Fog and frost seem likely with the chances of fog persisting all day.

GEFS ensembles.

Very similiar to previous nights as high pressure continues to be the theme. Very difficult to be precise on the exact location as this could make a huge difference to the actual weather experienced. At the moment I would say more likely to be centred over the UK rather than to the NE.

1. very cold 4.

2. Cold 6.

3. Average 6.

4. Mild 4.

[Michael Fishermans Friend]

Well it looks odds on to be a dry Christmas. but after the last few 12z runs it's put the HP practically everywhere but not sure to the south west? - It looks like we'll have to wait until after xmas for what happens next.

All the same this is a good experiment at seeing how well the GFS performs at FI and then closer to the time, perhaps this could be done for other times in the winter too!

Good work TEITS!

[Nick L]

I would take a frosty and foggy Christmas. Might not be snowy but it's better than rain.

[maidstone weather]

I would take a frosty and foggy Christmas. Might not be snowy but it's better than rain.

Similar to 2005, that was quite foggy and frosty - followed by an easterly :winky:

[TEITS]

Have to admit im not very motivated to do it tonight but here goes!!

General synopsis.

High pressure to the S and low pressure to the N with very mild SW,lys across the country as the polar jet runs SW-NE.

Christmas Eve/Day will be mainly unsettled with spells of rain. It will be very mild on Christmas eve although northerrn areas will be cooler. The temps on christmas day will be exceptionally mild for many areas although slightly cooler in the far N. During Boxing day the unsettled trend continues but the temps will be cooler, around average in the N, slightly above in the S.

GEFS ensembles.

A real spread in the ensembles tonight with some continuing the trend of high pressure over the UK whereas others show similiar to the chart above. The only difference tonight compared to previous nights is the scenario of high pressure over the UK isn't as prevalant as recent ensembles.

1. Very cold 0

2. Cold 8

3. Average 5

4. Mild 7

[Nick L]

Bet that was painful to type TEITS! Thanks anyway.

[ukmoose]

Very brave of you to put that chart in Teits.

Not looking great at this distance it has to be said. I hate to see HP in that location at any stage of the winter, let alone Christmas Day!

[Andy Bown]

Very brave of you to put that chart in Teits.

Brave : having or showing courage, resolution and daring.

There's nothing brave about TEITS posting that chart, he's doing what he said he would throughout the run up to Christmas using the 12z GFS.

Thanks for doing this thread TEITS .

[ukmoose]

Brave : having or showing courage, resolution and daring.

There's nothing brave about TEITS posting that chart, he's doing what he said he would throughout the run up to Christmas using the 12z GFS.

Thanks for doing this thread TEITS .

Brave in the sense of showing resolve and determination against the odds knowing Teits' (and others') preference for cold and not wanting to disappoint!!

I could sense his resolve was wavering but he still made the call! Brave I'd say.

Edited December 14, 2008 by ukmoose

[J10]

Hope TEITS doesn't mind me doing this, but is the ensemble man average for Christmas Day.

IUt will be intersesting to show how this cahnges ona daily basis.

[TEITS]

Before I begin tonight I just want to add that I feel the charts im posting below are complete rubbish and not representative of the actual model output. Im adding this so in a few days we can look back and laugh at these charts!

General synopsis.

Large area of high pressure over France with deep low pressure systems to the north bring W/SW,lys to the UK.

General description of the weather.

Very mild on christmas eve, day with rain at times in the North. Boxing day will be cooler although further rain in the North.

GEFS ensembles.

The ensembles continue to indicate high pressure over the UK. The chart above isn't representative of the GEFS ensembles.

1. Very cold 3.

2. Cold 6.

3. Average 7

4. Mild 4

Due to the difference with the ECM I am posting the chart for christmas day.

Edited December 15, 2008 by THE EYE IN THE SKY

[J10]

Ensemble mean as per the 12Hz on the 15th December 2008. this completely confirms what TEITS said about the operational run not being representative of the ensembles.

[Nick L]

God knows what tomorrow will throw out of the rubbish tip!

[TEITS]

Ensemble mean as per the 12Hz on the 15th December 2008. this completely confirms what TEITS said about the operational run not being representative of the ensembles.

Thanks for adding these on this thread.

Certainly a great example of what the ensembles are representing.

[TEITS]

General Synopsis

Large area of high pressure which is centred over Germany is expected to dominate this period bringing a light SSE,ly flow.

General descrition of the weather.

Very similiar weather is expected during this period with very little difference between each day. Dry, settled, with frost & fog at night describes this period perfectly. The temperatures are likely to be slightly below normal and cold where fog persists. The only exception is Ireland where it will be slightly milder with less of a risk from frost & fog.

GEFS ensembles.

Very difficult to really put these into a category due to not knowing the exact positioning of the high pressure system and also the fact that temperatures could vary significantly with your location. Also if Fog does persist this will make a big difference to your max temperature.

1. Very cold 0

2. Cold 13

3. Average 7

4. Mild 0

[azores92]

we all know who the favoured ones are(midlands, vale of york etc...)

Edited December 16, 2008 by azores92

[J10]

Here is the Ensemble Mean from the 16th Dec.

[Eugene]

Yes i can't see anything but a dry and rather cold christmas day this year, not sure where the daily express got their wettest christmas on record from, maybe ian brown is now advising them

[TEITS]

Yes i can't see anything but a dry and rather cold christmas day this year, not sure where the daily express got their wettest christmas on record from, maybe ian brown is now advising them

I can't believe they are saying this Eugene. Looking back on this thread rainfall has never been a feature.

[Richard Taylor]

Well we have had 2/3rds of our monthly rainfall over one weekend last week, so it has rained oop north!

But fascinating reading nevertheless.

[TEITS]

Before I begin tonight I just want to say there has been a significant change in the model output today with a slightly different trend emerging. When a new trend emerges this is prone to errors at first which is why I would strongly suggest you follow this thread over the coming days.

General Synopsis.

High pressure centred over Holland is expected to ridge NE during this period and merge with an existing cell bringing a flow from the E. During Christmas day and Boxing day the high pressure centred over Scandinavia will reach 1055mb bringing a progressively colder flow from the E.

General description of the weather.

Christmas Eve will be settled, dry with spells of sunshine. The temperatures will be around average or slightly below. During the evening frost is expected to develop with the chance of freezing fog developing.

Christmas Day will continue with the dry, settled theme although temperatures will be colder. The temperatures will be below normal with max temps ranging from 3-5C. During the evening cloud is expected to increase from the East.

Boxing Day will start fairly cloudy and cold with a few showers possible especially towards the E. These showers are likely to turn to snow during the afternoon bringing a light covering especially towards E Anglia/SE, although I wouldn't rule out snowfall anywhere based on the current charts.

GEFS ensembles.

Unfortunately I haven't had much time to view the ensembles tonight so I shall just post what I think are relavant diagrams.

As you can see the theme is generally high pressure. However due to the new pattern emerging the exact location is very uncertain which is the other reason why my ensembles analysis is brief tonight.

[J10]

The Ensembles mean now showing a dominant HP over the UK on Christmas Day.

[maidstone weather]

Christmas Eve will be settled, dry with spells of sunshine. The temperatures will be around average or slightly below. During the evening frost is expected to develop with the chance of freezing fog developing.

Christmas Day will continue with the dry, settled theme although temperatures will be colder. The temperatures will be below normal with max temps ranging from 3-5C. During the evening cloud is expected to increase from the East.

Boxing Day will start fairly cloudy and cold with a few showers possible especially towards the E. These showers are likely to turn to snow during the afternoon bringing a light covering especially towards E Anglia/SE, although I wouldn't rule out snowfall anywhere based on the current charts.

That appears to be very similar to 2005, where we had an easterly from Boxing Day night until the end of the month. Certainly some interesting synoptics

[TEITS]

Very brief one from me tonight as I have guests coming shortly.

General synopsis.

Large area of Hp covers all of the UK during this period.

General description of the weather.

Settled, dry, over all 3 days with frost and fog likely especially during the evening onwards.

GEFS ensembles.

[Nick L]

I think that's all that needed saying anyway TEITS! Thanks again.