From what I could tell from the MetO updates a week or so ago, the chance of a change to generally colder conditions before the end of December was only an outside one and there was never really any consistent signal for this from the models we have access to. It has seemed to me that any change is and always was more likely to be sometime in the New Year.

Correct, David.  The Met Office forecast referred to high pressure becoming more influential and it possibly turning colder at the end of the month but the references to wintry weather and snow were for January.

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However the GFS operational predicting a #PolarVortex split of relatively short duration with sister vortices merging over Eurasia. Will discuss the implication for Northern Hemispheric #weather for January and possibly into February in tomorrow's blog. pic.twitter.com/e48gmSVGVf

— Judah Cohen (@judah47) December 23, 2018

Think we could get some Jan 87 style Synoptics showing in the models given the warming being modelled

Would a Jan '87 event even be possible nowadays, given we've had thirty years GW inbetween times?

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Would a Jan '87 event even be possible nowadays, given we've had thirty years GW inbetween times?

Yes. If we can get -3C daytime highs at the end of February in an easterly, albeit due to record-breakingly low thickness for the time of year, we could just as well have a Jan 1987 type event again. It will take even longer than the 20+ years it took to get that -3 though!

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Would a Jan '87 event even be possible nowadays, given we've had thirty years GW inbetween times?

If what had happened back on March had happened mid January then we would potentially have been looking at something even colder then January 87. 

The fact is  large areas of southern England saw sub zero day maxes in March with the sea freezing on the isle of white. For this kind of cold to happen in March in the far south (never mind the rest of uk) it took something extreme, and had this extreme happened mid January when the sun is significantly weaker, and the days are shorter then I suspect  widespread minus double day time highs would have been possible. 

Would a Jan '87 event even be possible nowadays, given we've had thirty years GW inbetween times?

That's an odd question, given what we got in 2010 at the end of Nov early Dec that year.

I should think a 63/ 47/78 blah blah are all possible given the right synoptics 

 

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If what had happened back on March had happened mid January then we would potentially have been looking at something even colder then January 87. 

The fact is  large areas of southern England saw sub zero day maxes in March with the sea freezing on the isle of white. For this kind of cold to happen in March in the far south (never mind the rest of uk) it took something extreme, and had this extreme happened mid January when the sun is significantly weaker, and the days are shorter then I suspect  widespread minus double day time highs would have been possible. 

I think anything is still possible, but still less likely given the current climate state of the Arctic and the Atlantic. When we look back at when the Arctic and Atlantic were cooler, intense winter weather had a higher probability of occurring. 78/79, 81/82, 84, 85, 86, 87 to name just a few winter events well documented in history. 

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That's an odd question, given what we got in 2010 at the end of Nov early Dec that year.

I should think a 63/ 47/78 blah blah are all possible given the right synoptics 

 

There was also the month-long freeze of winter 2009/10, which IIRC commenced about a week before Christmas 2009.

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If what had happened back on March had happened mid January then we would potentially have been looking at something even colder then January 87. 

The fact is  large areas of southern England saw sub zero day maxes in March with the sea freezing on the isle of white. For this kind of cold to happen in March in the far south (never mind the rest of uk) it took something extreme, and had this extreme happened mid January when the sun is significantly weaker, and the days are shorter then I suspect  widespread minus double day time highs would have been possible. 

"..had this extreme happened mid January when the sun is significantly weaker, and the days are shorter then I suspect  widespread minus double day time highs would have been possible. "

Think that's probably pushing it a bit. That's once a century stuff and probably never been widespread.

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"..had this extreme happened mid January when the sun is significantly weaker, and the days are shorter then I suspect  widespread minus double day time highs would have been possible. "

Think that's probably pushing it a bit. That's once a century stuff and probably never been widespread.

I was referring to central southern England with regards to minus double day time highs. But I believe it would have been likely had such cold arrived a month & half earlier. As it was widespread -2C to -4C still happened.

 

There was also the month-long freeze of winter 2009/10, which IIRC commenced about a week before Christmas 2009.

Probably a S.E centric post   and certainly very cold compared to many preceding Decembers and Januarys  but couldn't hold a candle to most of the others mentioned in the list of extremes in the South East.

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Not an inspiring op run from GFS

More uncertainty into the mix at an earlier stage. Still not cold though. 

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Not an inspiring op run from GFS

GFSP 12z brings colder conditions from the east for a time.

https://www.theweatheroutlook.com/twodata/gfsp.aspx?run=12&charthour=312&chartname=mslp500&chartregion=na-region&charttag=500hPa%20GPDM

 

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More uncertainty into the mix at an earlier stage. Still not cold though. 

We won’t see much in the way of Stella charts in FI until the reversal due 25th.

The fact we’re seeing interest and scatter now is a bonus IMO. Watch out for a significant uptick in sub -10 options post 300hrs from charts Tues onwards.

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We won’t see much in the way of Stella charts in FI until the reversal due 25th.

The fact we’re seeing interest and scatter now is a bonus IMO. Watch out for a significant uptick in sub -10 options post 300hrs from charts Tues onwards.

Agreed - any current FI candy is just gravy (hmmmm... candy and gravy).

Ironically I would expect the juicy charts to start to appear on the horizon just when the aircraft data takes a dip. So will the models resort to "climate" in the absence of data?

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I was referring to central southern England with regards to minus double day time highs. But I believe it would have been likely had such cold arrived a month & half earlier. As it was widespread -2C to -4C still happened.

There wasn't much solar heating then but I would agree it could have been a couple of degrees lower. I don't think - double digit maxes  would have been "likely" though. I can only find one -11C last century in England  and that wouldn't have been widespread. Maybe there were more that I've missed.

 

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Very uninspiring output at the moment, perhaps some frost and fog if skies clear. With Southerly toppling HP it could be a long route to anything of interest. Let’s see what tomorrow’s runs bring.

Very uninspiring output at the moment, perhaps some frost and fog if skies clear. With Southerly toppling HP it could be a long route to anything of interest. Let’s see what tomorrow’s runs bring.

I think it would be a longer route back to having anything of interest if it wasn't for the SSW which I think has now commenced or is about to commence. Given this, I think the chances of notable changes in the model output in the days ahead, whether they be for better or worse, are higher than they would have been without the SSW.

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