DH reckons its going to be a very cold Jan/Feb

[LillethTheCat]

Is it true?

I dont know where he's read that, but he reckons we are in for a big freeze in a couple of weeks or so.

I dont know why Im particularly bothered, but I would just like to know.

[PersonalClown]

Part of me thinks Yay I have a nice new coat that I want to wear and part of me goes Fuck off..my bills will be nice and low!!

[ImperialSantaKnickers]

I've heard this too. Not sure if I prefer warm but waterproofs dripping all over the place to dry but thermal underwear all day every day.

[ILoveOnionRings]

Just looked at Metcheck.com and they say next week will be ok but from Monday 14th Jan it looks like the temperatures are going to plummet

[LillethTheCat]

Thanks OnionRings

I have a new hat so I get to wear it.

[ILoveOnionRings]

I had several new scarves so I am quite pleased too, I like crisp cold days but without the rain

[OhyouMerryLittleKitten]

Was it the Metcheck map?

Certainly the first half of Jan is going to be pretty mild, but then there are a few indications that there might be a cool down. However it really does hang in the balance at the moment I'm afraid.

[LillethTheCat]

Thanks kitten

It will be nice to be able to walk the dog round a frozen field rather than a swamp

[OhyouMerryLittleKitten]

GFS ensembles don't show a plummet but a gradual drift down in temps (don't look at the 850 temps, they are the temperature at the height where the pressure is 850hpa!) and no real certainty, with a widespread in the solutions.

[OhyouMerryLittleKitten]

Well, staying mildish up until the 19th according to GFS (which is as far as the model goes)

[GloriaSnow]

no sign of snow? I was hoping for at least something over Christmas/New Year. I want something to alleviate this post~Christmas glumness!

[Yakshemash]

I thought long-range (ie more than five days) forecasting had been completedly discredited, which is why the Met Office don't do it any more.

That said, I would love a cold snap. Kill off the germs. [glares at office full of sniffers]

[LillethTheCat]

Thanks for the update Kitten. Guess we'll just have to wait and see.

[OhyouMerryLittleKitten]

Yakshe, yes it does get increasingly unreliable as you go in to the future.
One way to look at how likely a model is to be vaguely accurate is to look at the ensembles which is a collection of the same model with slightly different starting conditions. You can see looking at the 850 temps (the temperature at the point in the atmosphere where the pressure is 850hpa) that there is a wide scatter of solutions. In fact, the scatter has increased over the last couple of days, which means that moving into cold is becoming more of a possibility.

However, when looking at cold weather forecasting, one of the parameters to look for is where is the cold going to come from. If there isn't a good supply of cold air then you can move onto looking at whether there may be a SSW (sudden statrospheric warming) event. If that occurs then a cool down can occur very quickly from the north (it disrupts the pressure differential between the Icelandic low and the Azores high). There are indications that a SSW may be about to occur, but even if it does, it doesn't necessarily bring the UK severe cold, it's just one of the ingredients!

[GloriaSnow]

Ah, that's how you read those ensemble things!
Netweather has a tutorial on the stratosphere and SSW here. A few more reads and I might understand it!

Yakshemash ~ yes, a cold snap would be good to kill off some germs

[OhYouBadBadKitten]

nice link there Gloria!

[mumat39]

Hi Kitten.

With the ensembles, is it a particular coloured line that you look at or the general trend across all lines? There are 2lines that spike toward 12ish and -12ish between the 11th and the 15th, so are those treated as anomalies, or are they still possible.

I'm also hoping for a properly cold winter, or just a 'normal' season for a change as it's felt more like autumn for the last few.

Happy New Year by the way and I hope you're keeping well.

Take care. xxx

[mumat39]

Hi Gloria

That is a really good link. I think it'll take me a few good reads before I remember the differences between stratosphere and troposphere

Happy New Year to you too.
xxx

[OhYouBadBadKitten]

The operational run is the thick green line. This is the high resolution model. It starts off with the atmosphere modelled as closely as it can and has a relatively fine grid. hi res models take lots of computing power and/or more time to run. As a single model run it is likely to be the more accurate.


The control run is the thick blue line. This is a low resolution model run which is quicker to run, but it uses a coarser grid, so it is a comparatively a rough and ready model run

The other runs with thin lines are the runs where the starting points are slightly changed relative to the control run. Watch how these diverge, the tighter packed they are, the greater the confidence in the result.

Now, when the control run and the operational run diverge quickly confidence is really low!

The thick red line is an average result which of course isn't the most likeliest outcome, but it does help you see which of the runs is going off on a limb.

Run is starting to look like a very strange word now!

[OhYouBadBadKitten]

Mumat, those temps you looked at were the 850 temps, so higher up in the atmosphere. Those lines are known as outliers, and can probably be discarded as possible solutions.

[OhYouBadBadKitten]

Well......

:)
Proper cold appears on the chart Jan 19th. With snow showing.

Now of course as Yakshemash says, we can't really forecast that far in advance, but it does at least give an indication of where the weather may be going. It looks like a proper winter chart with real cold showing over us.

[Meglet]

It's lovely out there today, just put some washing on the line. If we can have a mild few days then a proper cold winter that'll do me.

[mankyscotslass]

It's horrible here today, grey and wet, a persistent drizzle that has everything dripping. Yuck!

[mumat39]

Thanks for the explanation Kitten. Fingers crossed for the 19th.

I'm going to read your reply again now and again until I understand the ensembles.

Hope you have a lovely weekend. xxx

[Labradorlover]

Thoroughly bored of this dull warm weather. It's 10C in Scotland in January FFS.
The grass is growing!

[AmberLeaf]

I have been wondering about this too, I have a lovely new scarf I was hoping to wear!

In truth Id like it to remain mild so I don't go bankrupt with the gas bill!

So cold and possible snow from 19th jan-ish?