The annual Christmas day count down from T+384

[chionomaniac]

Thanks John,

I guess if you were going to make a forecast based on average conditions without the use of models for Christmas the two would be pretty similar do you think? Still time for change but I wouldn't bet against your first forecast proper being quite accurate.

c

[johnholmes]

Day 9 T+192 hours

comparing GFS and ECMWF

GFS first

now ECMWF

well both have low pressure in charge but they are not that similar.

GFS with its westerly and ECMWF has a closed circulation LP over the country with a fairly slack flow around it.

One comment about them both, neither are all that similar to their 24 hour earlier forecast chart!

So maybe we should wait for another days run?

final ps and the 18z has an even more different slant on it with a deep low tracking across the UK between 24-26 December!

The next one I will be able to do will be Day 11 T+144 as I'm away tomorrow.

Edited December 17, 2007 by johnholmes

[johnholmes]

update will follow later this evening

[johnholmes]

Day 11 or T+144

GFS version at 12z today

ECMWF version

Well both have a westerly but the major centres are not that similar, especially in their positions.

If we just use the data from GFS, it's the only one we have detail on,

T12 suggests

This

Not all that far from about normal which is what one should expect with a PM westerly airmass.

Ppn shows this

so for most its looking like a dry day with a moderate westerly wind away from the exposed north western parts of the country. Just right for walking the turkey and 'sprouts off!

Dawn temperatures may give a whitish appearance to some lawns with a ground frost for quite a few areas, IF the wind drops out enough and even a touch of air frost for very sheltered valleys, RR in the Lakes perhaps!

I wonder what Day 12 will bring, apart from the Met O joining the other two models.

A look at their T+132 Fax shows this at the moment, its only for Xmas Eve, they seem about 24 hours behind the other two models at the moment, GFS and ECMWF have that frontal area over/east of the UK during the 24th.

Edited December 19, 2007 by johnholmes

[Zerouali lives]

It's looking like a white Christmas for Aviemore, Carrbridge and Tomintoul.

Nothing for the rest of us.

[johnholmes]

cue for all B&B, hotels etc in the area to get a lot of calls!

[damianslaw]

Day 11 or T+144

GFS version at 12z today

ECMWF version

Well both have a westerly but the major centres are not that similar, especially in their positions.

If we just use the data from GFS, it's the only one we have detail on,

T12 suggests

This

Not all that far from about normal which is what one should expect with a PM westerly airmass.

Ppn shows this

so for most its looking like a dry day with a moderate westerly wind away from the exposed north western parts of the country. Just right for walking the turkey and 'sprouts off!

Dawn temperatures may give a whitish appearance to some lawns with a ground frost for quite a few areas, IF the wind drops out enough and even a touch of air frost for very sheltered valleys, RR in the Lakes perhaps!

I wonder what Day 12 will bring, apart from the Met O joining the other two models.

A look at their T+132 Fax shows this at the moment, its only for Xmas Eve, they seem about 24 hours behind the other two models at the moment, GFS and ECMWF have that frontal area over/east of the UK during the 24th.

I'll take a west/north west polar maritime airstream for christmas day anything but a mild horrid south westerly tropical airstream. I'll be in Windermere for the christmas period so I like your suggestion of some frostiness first thing although quite quickly will clear.

Having said that though, christmas is certainly looking 'unseasonal' in my book with no snow not even for the hills so nothing to look at! All in all i'm dissapointed however my head has has a 'sinking' feeling for much of the last week with my inkling that this high was always going to kill the chance of snow on the day or even christmas eve and boxing day! My thoughts are quickly turning to the new year now.

[johnholmes]

T+96 hours

The final post from me into this thread this year; apologies for it not being done every day.

Just 96 hours to go so what is in store. I suspect you all know the answer but never mind.

The 1000-500mb chart shows the 528 line briefly over some parts

with its partner the 1000-850mb below

and now the zero C

and finally the msl and ppn chart

perhaps just a look at the minimum temperature chart for 06Z

and finally finally!

the Met O Fax chart for 12z Xmas Day

Looking at those charts and I think anyone would be hard pushed to get a White Christmas out of any of them! No ppn where the zero C is low enough to give hill snow. Only parts of the Highlands likely to get anything in the way of any frost that mostly ground rather than air frost.

Once the rain clears away from the south east then a dry, and in places, a rather breezy day with sunny intervals, quite prolonged away from the west.

In the far north west some showery outbreaks later in the day, generally of rain but some snow possible for the higher parts of the Highland region. Say above about 2,500ft.

Anyway have a Very Happy Christmas everyone even if its mostly green.