Winter 2017/2018-Stormy December, Two Severe Wintry Spells January/February.

[iapennell]

@karyo, I'm glad you found the forecast.  I do indeed remain confident that there will be high-latitude blocking during late January and in February, which will result in a spell of much colder weather across the country courtesy of east or north-easterly winds from Russia. 

It's not just that we have a La Nina episode in the Equatorial Pacific but the equatorial waters across much of the Atlantic and Indian Oceans are also cooler than normal, whilst sea surface temperatures are a little above normal over the Northern Hemisphere subtropical oceans- cue a weaker Hadley Circulation and slacker NE'ly Trades that add less Westerly Atmospheric Angular Momentum to the Northern Hemisphere circulation than normal for the time of year. 

The QBO is now firmly Easterly, the Sun is very quiet and snow-cover is well-established over the Eurasian landmass: All of which point to a strong likelihood of high-latitude blocking, particularly when the Julian Madden Oscillation gets into the right phase to enhance that possibility (which it will in late January and early February). 

[iapennell]

It remains for me to wish all on this Forum a happy Christmas and all the best for the New Year. 

Ian Pennell 

[Katrine Basso]

Thank you Ian for your excellent forecast. Have a very Merry Christmas and a Happy New

[lassie23]

On 12/9/2017 at 16:57, iapennell said:

@lassie23 My prediction for December is for stormy conditions, particularly across Scotland and Northern England, but with winds from the west rather than south-west and for colder sub-Arctic incursions getting into the mix in the North.

We have just had Storm Caroline that has brought very strong winds to Scotland and North West England. As this deep depression moved east towards Norway much colder (and strong) north-westerly winds have brought snow to parts of Scotland, North West England and, in particular, the Isle of Man (where roads have been rendered impassable and ferry services to the island from Heysham and Liverpool suspended).

I expect much of the same weather for the rest of December, probably stormier than what it has been like to date. Strong westerly winds will bring rain along with mild temperatures: Following the passage of depressions there will be further cold snaps with north-westerly winds bringing snow showers and night frosts (with snow more likely in Scotland and the North). 

There is, of course, another Arctic snap predicted for next weekend that will, in turn, be followed by milder Westerlies: However we do not have the sustained high-latitude blocking anticyclones that would bring severe and long-lasting cold at present. For that to occur you would need a strong anticyclone of 1040mb or more persisting over Scandinavia (or over Greenland and Iceland for northerlies) and remaining resolutely in place.

  I do remain confident that such high-pressure will set in over the European Arctic in late January and February: This is what will help to deliver our coldest and most severe wintry spells for five years. 

 

The models were hinting at an easterly for mid  January, not sure if they have ditched it.

[stubbys]

If this comes off, only 11 days away, would this mean potential snow and Gale force winds?

[Don]

Hi Ian

What are your latest thought on the mid to late January period?  Do you still expect a cold spell to occur?

Thanks

Don

[I remember Atlantic 252]

8 hours ago, stubbys said:

If this comes off, only 11 days away, would this mean potential snow and Gale force winds?

yes, but transient, and not a chance of coming off, 11 days miles ahead, deepest FI, or F1 as norman closs says

[stubbys]

1 hour ago, I remember Atlantic 252 said:

yes, but transient, and not a chance of coming off, 11 days miles ahead, deepest FI, or F1 as norman closs says

Excuse my ignorance but why no chance in this scenario happening If the charts show it? I'm well aware a chart 2 days or even a day away changes, but to say No chance? Thanks

[iapennell]

17 hours ago, Don said:

Hi Ian

What are your latest thought on the mid to late January period?  Do you still expect a cold spell to occur?

Thanks

Don

Hello Don, and Happy New Year. 

Looking at the next couple of weeks the Circumpolar Vortex looks like it will remain fairly robust, and certainly the weather charts from the Met Office, the Met. Check 384 hour outlook suggest a blustery outlook with deep depressions passing close to Scotland with strong Westerlies affecting the UK. This is certainly in keeping with what I predicted through Mid-January. 

Looking further ahead - into late January,  there is now consensus for mean wind-speeds from the West to weaken substantially at the 10 mb and 30 mb levels at 60N (http://www.weatheriscool.com). The QBO is in an Easterly Phase high over the Equator and the Sun is quiet. The change to a weaker Circumpolar Vortex will follow the return of the Sun to warm the Arctic Stratosphere in late January and, consequent upon a greater pre-disposition to disruption of the Stratospheric Arctic Westerlies, I am certain that much weaker Stratospheric Westerlies (and possibly even a Sudden Stratospheric Warming) will happen after the 28th January.  This will (ultimately) lead to strong high-pressure over northern Scandinavia and a spell of bitterly cold east or north-easterly winds over the UK. 

I remain confident that we will see the synoptic outlook changing to favour much colder conditions towards the end of January.  I did ( of course)  predict two very cold spells, each lasting about ten Days: I still expect these to happen but (looking at current outlooks) I am not expecting these to manifest before the 25th January; it is entirely possible that these two cold spells merge to give one three-week spell of bitterly cold easterly or north-easterly winds bringing local snowfalls and hard night frosts nationwide that will dominate much of February. 

The Circumpolar Vortex does weaken in February in most years, allowing either a dry fine spell with frosty nights or high-latitude blocking leading to a spell of bitterly cold easterly winds. The weak La Nina, easterly QBO and quiet Sun this winter will combine with the Return of the Sun to the Arctic Stratosphere in their effects to weaken the Circumpolar Vortex much more and this will result in blocking high-pressure systems getting established over northern Europe. 

This will lead to much colder weather reaching Britain. If you want a date by which this very cold weather will have arrived at the latest I would suggest 1st February. 

 

 

[Don]

2 hours ago, iapennell said:

Hello Don, and Happy New Year. 

Looking at the next couple of weeks the Circumpolar Vortex looks like it will remain fairly robust, and certainly the weather charts from the Met Office, the Met. Check 384 hour outlook suggest a blustery outlook with deep depressions passing close to Scotland with strong Westerlies affecting the UK. This is certainly in keeping with what I predicted through Mid-January. 

Looking further ahead - into late January,  there is now consensus for mean wind-speeds from the West to weaken substantially at the 10 mb and 30 mb levels at 60N (http://www.weatheriscool.com). The QBO is in an Easterly Phase high over the Equator and the Sun is quiet. The change to a weaker Circumpolar Vortex will follow the return of the Sun to warm the Arctic Stratosphere in late January and, consequent upon a greater pre-disposition to disruption of the Stratospheric Arctic Westerlies, I am certain that much weaker Stratospheric Westerlies (and possibly even a Sudden Stratospheric Warming) will happen after the 28th January.  This will (ultimately) lead to strong high-pressure over northern Scandinavia and a spell of bitterly cold east or north-easterly winds over the UK. 

I remain confident that we will see the synoptic outlook changing to favour much colder conditions towards the end of January.  I did ( of course)  predict two very cold spells, each lasting about ten Days: I still expect these to happen but (looking at current outlooks) I am not expecting these to manifest before the 25th January; it is entirely possible that these two cold spells merge to give one three-week spell of bitterly cold easterly or north-easterly winds bringing local snowfalls and hard night frosts nationwide that will dominate much of February. 

The Circumpolar Vortex does weaken in February in most years, allowing either a dry fine spell with frosty nights or high-latitude blocking leading to a spell of bitterly cold easterly winds. The weak La Nina, easterly QBO and quiet Sun this winter will combine with the Return of the Sun to the Arctic Stratosphere in their effects to weaken the Circumpolar Vortex much more and this will result in blocking high-pressure systems getting established over northern Europe. 

This will lead to much colder weather reaching Britain. If you want a date by which this very cold weather will have arrived at the latest I would suggest 1st February. 

 

 

Thanks very much for the reply Ian and Happy New Year to you too.  I'm glad you're still confident about the cold spell(s) materializing.  A three week spell of bitter easterlies would do me!

Edited January 7, 2018 by Don

[karyo]

Thanks for the update Ian. Sounds good to me too. 

[Yarmy]

4 minutes ago, karyo said:

Here it is: 

 

What happened to stormy December?

[karyo]

1 minute ago, Yarmy said:

What happened to stormy December?

It happened! But I suggest you post in the relevant thread if you wish so rather than here. The moderators won't be happy. 

[Yarmy]

4 minutes ago, karyo said:

It happened! But I suggest you post in the relevant thread if you wish so rather than here. The moderators won't be happy. 

Did this happen?

"The month will be dominated by deep depressions racing east-north-east from Newfoundland towards Iceland.  These strong westerlies will bring rain, gales and relatively mild temperatures across the UK with regularity and daytime temperatures of 10˚C or even higher will be common across the English and Welsh lowlands during the month"

 

[Nick L]

18 minutes ago, karyo said:

It happened! But I suggest you post in the relevant thread if you wish so rather than here. The moderators won't be happy. 

It was unsettled but I wouldn't say it was particularly or unusually stormy. Temperatures nearly bang on average for England too with a widespread superb snow event for many. Rainfall was above average, not average, too.

I'm all for praising long range forecasts when they're correct, and appreciate the effort iapennell has gone to, but let's be objective in praise and criticism.

Edited January 8, 2018 by Nick L

[MP-R]

32 minutes ago, Yarmy said:

What happened to stormy December?

It wasn't a stormy one but there were two periods of strong winds here. Indeed on the 10th, before the snow arrived, it was temporarily very windy at my location with a gust nearly touching 60mph, higher than anything else in 2017. The closing days were also windy.

[karyo]

23 minutes ago, Nick L said:

It was unsettled but I wouldn't say it was particularly or unusually stormy. Temperatures nearly bang on average for England too with a widespread superb snow event for many. Rainfall was above average, not average, too.

I'm all for praising long range forecasts when they're correct, and appreciate the effort iapennell has gone to, but let's be objective in praise and criticism.

Nick, Caroline and Dylan say hello! I guess two storms and numerous depressions are not enough...

Also, temperatures were slightly above average overall and there were some notable mild spells with 10c exceeded for several days. Ian's forecast didn't go for blowtorch anyway.

Here is the link from the Met Office: https://www.metoffice.gov.uk/climate/uk/summaries Rainfall was 99% of average.

Pretty good for a forecast issued on the 11th November don't you think? The general theme is correct.

Edited January 8, 2018 by karyo

[bluearmy]

6 minutes ago, Nick L said:

It was unsettled but I wouldn't say it was particularly or unusually stormy. Temperatures nearly bang on average for England too with a widespread superb snow event for many. 

We can’t expect a lrf to pick out a single slider event though it was part of a general countrywide cold spell which wasn’t really picked and Scotland,  in particular, had a cold month.  it’s not a terrible lrf but neither is it overly accurate against climatology.

[Nick L]

Just now, karyo said:

Nick, have Caroline and Dylan say hello! I guess two storms and numerous depressions are not enough...

Also, temperatures were slightly above average overall and there were some notable mild spells with 10c exceeded for several days. Ian's forecast didn't go for blowtorch anyway.

Here is the link from the Met Office: https://www.metoffice.gov.uk/climate/uk/summaries

Pretty good for a forecast issued on the 11th November don't you think? The general theme is correct.

Two storms in December does not make a stormy December in my book. I find it peculiar how the forecast went for stormy but with normal rainfall, perhaps that could be explained?

To me it was a normal December generally aside from the rainfall. Unsettled, yes. Stormy, no. Caroline only affected the far north of Scotland too! For England and Wales it was far from a stormy month. 

[Nick L]

Just now, bluearmy said:

We can’t expect a lrf to pick out a single slider event though it was part of a general countrywide cold spell which wasn’t really picked and Scotland,  in particular, had a cold month.  it’s not a terrible lrf but neither is it overly accurate against climatology.

Considering the forecast pin points a potential freezing rain event in January (which is incredibly rare in this country) I think it's fair game, personally.

[karyo]

2 minutes ago, Nick L said:

Two storms in December does not make a stormy December in my book. I find it peculiar how the forecast went for stormy but with normal rainfall, perhaps that could be explained?

To me it was a normal December generally aside from the rainfall. Unsettled, yes. Stormy, no. Caroline only affected the far north of Scotland too! For England and Wales it was far from a stormy month. 

Caroline affected a good part of the country. Maybe not Buckinghamshire and the more southern areas. Normal rainfall proved to be correct. Look at my last post.

[Nick L]

Again, none of this is a dig at the author of the forecast. I'm sure iapennell will be happy to go through things that went right and things that didn't, and why. It's what separates genuine forecasters from charlatans like Madden and co. I just don't agree with blind criticism or praise when it's unwarranted, that's plain anti science.

[Nick L]

2 minutes ago, karyo said:

Caroline affected a good part of the country. Maybe not Buckinghamshire and the more southern areas. Normal rainfall proved to be correct. Look at my last post.

 Fair enough, misread the rainfall figures. A bit above normal for England, generally near normal elsewhere. 

[karyo]

Just now, Nick L said:

Again, none of this is a dig at the author of the forecast. I'm sure iapennell will be happy to go through things that went right and things that didn't, and why. It's what separates genuine forecasters from charlatans like Madden and co. I just don't agree with blind criticism or praise when it's unwarranted, that's plain anti science.

Fair enough but where exactly did you see the blind praise? I have given facts as to why I think that Ian did well so far with his forecast.

On the other hand, a member in the MO discussion said where is the stormy December?  That was an one liner comment that you supported by saying he is correct. That surprised me as you are part of the forum team. Yes, point any weak points of the forecast but also give credit where it is due. His forecast so far is more right than wrong and I repeat I don't give blind praise.

[Nick L]

6 minutes ago, karyo said:

Fair enough but where exactly did you see the blind praise? I have given facts as to why I think that Ian did well so far with his forecast.

On the other hand, a member in the MO discussion said where is the stormy December?  That was an one liner comment that you supported by saying he is correct. That surprised me as you are part of the forum team. Yes, point any weak points of the forecast but also give credit where it is due. His forecast so far is more right than wrong and I repeat I don't give blind praise.

I guess we differ on the definition of a stormy December!