mcweather
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GFS 12Z has England and Wales bathed in minus 6 uppers at the end, picking up on that trend for the final third of the month perhaps.
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4 hours ago, iapennell said:
In which case, why would one try to make predictions for the season ahead?!! The fact remains, that there are several macro-scale pointers (that are very unlikely to change in the space of a few months), like the El Nino Cycle, the wind-pattern high over the Equator (Quasi Biennial Oscillation), pronounced sea-surface temperature anomalies north and west of Britain (and where these are) along with marked seasonal Arctic sea-ice anomalies not to mention where we are in the Sunspot Cycle that tend to hold true over longer periods of time that one can use to make a prediction. That is not to say unforeseen events cant or wont knock the prediction off course, but using the macro-scale variables to make predictions for the season ahead (particularly for a season in which the Circumpolar Vortex is liable to settle into a particular pattern and stay there- and one can ascertain where the likely baroclinic zones affecting it, and therefore the storm-tracks will be) is likely to produce more accurate forecasts over the long term than going by more transient features like blocks on weather charts.
That's not to say weather charts and model runs up to three weeks out are not valuable, particularly on approaching the beginning of our predicted season, but they tend to show up to three weeks ahead at most. Blocking highs over Scandinavia in themselves can encourage cold and snow-cover over Europe that might lead to a tweaking of the early part of a seasonal prediction in a colder direction; but both the block and European snow-cover are transient features that can be swept away should the Circumpolar Vortex strengthen, the Rossby Wave pattern shift east to place an upper trough just west of Norway and milder south-westerlies remove the European snow-cover! Even the forecast models can get these wrong! However, strong sea-surface temperature anomalies, El Nino Oscillations and high-latitude sea-ice anomalies almost never change that quickly (owing to the very large specific heat capacity of oceans) so they can be relied upon more in making seasonal predictions.
Hi Ian I always take time to read your forecasts and admire the effort you put in and the fact that you attempt to back it up with some science.
I do have to say that I feel you offer some hostages to fortune with some of the detail that you try to give so far ahead.
I wonder have you applied your system to hindcasting some of our colder winters like 2008/9 2009/10 to see what you would have forecast, and bearing in mind the detail that you tend to put in wwhether you would have picked up the severe cold spell of late November/December of 2010 for instance.
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Always an enjoyable read as this thread gets going each Autumn and the hopes and fears of cold and snow enthusiasts are aired.
Very interesting post from Steve Murr earlier in the thread, will be interesting to see how things pan out in that regard.
My gut feeling this year is that High pressure will play a significantly bigger roll than the last three winters, The exact positioning of course will be the crucial thing.
The ECM seasonal is certainly hopefull at the moment the Glosea not quite as cheery for coldies but lets face it a half way house between the those two would be better than anything we have seen
since 2012/13 so in that sense quite a bit to be positive about really.
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Having seen my first falling snow this morning since Feb 2015
, I can't help but notice that todays 12z gefs ensemble members seem to be showing an increasing number of cold or very cold options late in the run. Only one model I know but these very cold runs seem to be to be gradually increasing in number with time. Possibly a trend to keep an eye on.
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Thankfully saw some falling snow this morning in the Blandford area around 8am It was quite blizzard like with the very gusty winds.
First I have seen since Feb 3rd last year.
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1 hour ago, nick sussex said:
It's funny when you look back at some previous March snow events they didn't have deep cold. Take this from March 2/3 1995. A little low runs quickly eastwards from the Atlantic, this delivered some significant snow to the Midlands/E/Anglia/Home Counties north of London.
I remember this vividly because I was at University and of course the snow didn't really do much in London. A lot of students couldn't get in from areas to the north and nw of London.
This winter for the UK has almost been like trying to get the stars to align perfectly, every marginal set up has gone pearshaped and its almost like you'd need to see the -15 850 temp line to have a decent chance! These snow events in March are not that rare and you'll often see more snow in March than December.
I agree Nick. an awful lot said in these threads about the requirement for uppers between minus 5 and minus 10 to get a worthwhile snowfall yet in reality the deepest snow I have ever seen ie 12- 18in general covering with drifts 10-20 feet deep occurred 18tH/19TH FEB 1978 with uppers of -2 to - 3.
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Don't forget as per Ian F'S post earlier that the operational models are behind the curve on this change to cold and are playing catch up, so I wouldn't be surprised to see some quite stellar charts coming out over the coming days. Especially with ( again as per Ian post) the projected storm tracking moving south of the UK.
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3 minutes ago, nick sussex said:
Frustratingly the ECM whilst good synoptically doesn't have enough cold air to the east. We really need to see some sub -10 850s that can be advected west. Theres still time for changes because that set up with sufficient cold is a convective snow machine.
Yes Nick I would be calling this another ECM240 up the garden path job were it not for the fact that it is almost identical to the latest GFS 12Z AT 252.
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Just shifting the topic a little. There has been much talk of Channel lows over the past few days and why said systems look like producing very little of the white stuff this weekend The answer is quite simple non of the lows shown have been classic Channel lows.
A real channel low is not a slider from the northwest that happens to end up in the channel.
A proper channel low is one that moves up along the channel from the west or southwest and scrapes along the bottom of an already entrenched area of high pressure pulling air from the east out of Scandinavia or Russia. The advantage of this in producing snow is that it sucks in a dry cold feed off the near continent . Real channel lows are incredibly rare Jan 1881 and March 1891 being the best examples.
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Well certainly a very interesting ECM tonight and also showing some consistency from this mornings run, but we have seen this sort of thing from the ECM already this winter with two consecutive runs consistently going for a cold and snowy set up only for them to disappear the following morning. If the ECM is showing something similar or even better come Saturday 12z run then I might start to take it seriously otherwise I,m afraid it might just be another case of up the garden path.
On the other hand with a few a few minor tweaks it could become an absolute classic
We shall just have to wait and see.
I do hope for all the snow lovers on this forum that it is the latter
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Lots of ups and downs from those viewing individual model runs. However even now we are only at the very edge of beginning to view the period that the Meto
have marked out as a period for colder than average weather. So nothing unusual in seeing a mainly westerly outlook for the time being. For now there is simply to much west to east motion energy in the northern hemisphere set up for anything other than transient cold tucking in behind the passing depressions.
It will change as the seasonal wavelengths start to take effect hence the Meto's continuing confidence in the mid month change to colder than average.
Don't forget even average conditions allow some snow to fall ( even in the south) so even slightly below average conditions would see an increase in that potential.
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45 minutes ago, snowking said:I think this is a fair point, but for me the last 7 or so years have proven two things that many members on here thought true to be quite the opposite
1) The whole idea that even given our changing climate that the UK can't experience substantial cold (December 2010 the main candidate for this amongst others). Dare I mention the crackpot 'M.W' theory?!
2) The idea that beyond about February 10th any chance of a major cold spell for the UK is gone. I suspect this idea was formed following the late February 2005 cold spell where we saw almost perfect synoptics (and indeed in my part of Essex at the time we saw 17 consecutive days of snowfall) but some less impressive conditions ultimately on the ground. If anyone wanted proof that this is not the case, March 2013 should hopefully shine through here.
What we're experiencing right now appears to be what many expected all along from a 'typical' El-Nino winter - a stormy start, some moderate (albeit short) cold spells in Jan and the majority of any cold potential really backloaded. This was what the majority of winter forecasts I've seen have suggested, these were my own thoughts, these were the suggestions from the GloSea5 seasonal output we get to see via the Planners Forecast and from what I can see happening about 10km above our heads in the coming weeks this would seem the most likely direction of travel.
Of course none of this guarantees something much colder for the UK. We're a tiny little island in the middle of a big ocean. But the notion that time is running out just because we're heading into February is not one we should let concern us
SK
Thanks SK
One of the best posts I have ever read in this forum re late winter cold and snow prospects. There is an awful lot of tosh talked about the sun being too high etc to get decent cold and snow in late feb and early March. The height of the sun didn't have much effect in the second half of feb 1978 when I had three blizzards in four days on the south culminating in 20 foot drifts on the 19th Feb. Nor did the height of the sun or the day length make any difference to the poor farmers pulling dead sheep out from under the immense drifts in March 2013.
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2 hours ago, West is Best said:
This is the same GloSea5 that completely missed the last and only cold spell of the winter, telling us that the signals were for continuation of rampant Atlantic?
The models are zonal with a whopping great Bartlett high to our south, which is THE dominant signal right now and for the immediately foreseeable future. Unfortunately.
With respect WIB. I think you,re getting things a bit mixed up here. GLOSEA 5 is a broad scale atmospheric model. Last week s colds spell was brought about by a high pressure area that simply took a couple of days longer than usual to move over the UK and as such to my mind at least was a minor perturbation in the west to east pattern that had been well forecast to exist through most of January. A bit of wintry good fortune if you like. GLOSEA is there to paint an overall atmospheric picture not to decide if its going to snow on a certain day in the eastern or western half of England
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From some of the posts today I was expecting the 06z GFS to have all twenty ensemble members up around 10C yet beyond the coming week which we have known for a while was likely to be zonal there are plenty of cold perturbations. Funnily enough the mildish clustering breaks up on feb 1st so plenty of time for Feb and march for that matter to deliver the cold and snow that many of us crave. I know that the sun is getting higher in Feb. and March but I have had 20 foot snowdrifts in the second half of Feb even down here on the south coast.
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8 minutes ago, Steve Murr said:
Dont hate the azores low - love it ( dont hate it )
- as long as it doesnt get to far north ...
its a snow bringer ....
These 2 charts never get a mention in the archives but the second one had the most fierce easterly ever..
its what happens when you spike the subtropical jet north out of spain against high pressure over greenland -
s
or the daddy of them all Steve
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6 minutes ago, northwestsnow said:
Are you impying a toppler Blue?
No he isn't . I think Blue Army might be suggesting the possibility of the fabled channel low or lows brushing past the embedded cold the UKleading to a snowfest for the south and southeast.Of course I might be wrong.
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The great thing about Greenland highs is they can lead to charts like this
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It might seem churlish but I preferred last nights ECM cross polar flow, in terms of getting the cold here and more importantly keeping it going.
However after the crap we have had to put up with for the past two months then I,d take four days of sub -5 850's and a possible reload as a start.
Just imagine if this progged cold snap could hold on until GP,s torpedoed vortex towards the end of the month
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I,m sure this community awaits your unbiased and level headed views of the models with great anticipation Gibby.
I for one will very much welcome the day of your return to posting your excellent analysis.
Your contributions are very much missed.
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As may have come across in my sparse postings I,m of the opinion that developments into January will be a slow chiller ( I can't bring myself to use the phrase slow burner what with the blowtorch crap we've been enduring) and this mornings gfs 06z FI is the sort of thing I mean with a trough over us that becomes colder over time as the high latitude blocking starts to feed colder sourced air into the mix. I.m still of the opinion that it will be well into January or early Feb before real nationwide deep cold arrives and with it the risk of more widespread snowfall away from the usual prime spots.
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6 minutes ago, winterof79 said:
Ahh the memories.How quickly things can change
http://modeles.meteociel.fr/modeles/reana/1978/archives-1978-1-1-0-0.png
yes great memories WO79 and that chart was just the start of it.
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Some excellent posts in here today. As Man with beard has shown a few posts back the gfs is all over the place with its possible outcomes.
Nick Sussex as always keeping us informed of thoughts from across the pond on the all important developments there
and of course Tamara's superbly written piece looking at the global picture explaining in detail why we,ve had what we,ve had so far and how that may well be about to change.
I would caution about getting to hung up about trying to get this first attempt at an easterly to deliver the goods. (Much though some cold, frost and snow would be more than welcome after the dismal grey and wet rubbish we have had to endure for nigh on two months) From what I can glean from those far more expert than myself this is just the start of the process that may at some point down the line deliver a genuine extended cold and /or snowy spell to the UK.
In some ways I am starting to get a feel of January 1978 about the upcoming month with GP suggesting that we should initially look North west for the change to more seasonal conditions. During January 1978 a general west to south-westerly regime started to become more north westerly as lows started to move southeastwards across the UK. There was one memorable exception where a depression moved more west to east and produced an exceptional blizzard that buried much of Highland Scotland around the 28th Jan. Thereafter a more nw/se line resumed and I remember moving house on the 31st Jan with heavy sleet falling even down here in coastal Dorset. This of course being brought about by the subtle but increasing influence of high latitude blocking.
A week into Feb and the high latitude blocking really took over and the middle two weeks of February brought and extended cold a very snowy spell to Scotland and much of eastern and southwestern England a spell which culminated in the great southwestern Blizzard on the 18/19Feb ( the third deepest snowfall of the last 150 odd years).
Here's hoping that the the changes now happening will go on to lead to something similar.
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1 hour ago, bluearmy said:
the gfs is certainly trending away from what coldies want to see. Generally, the pendulum needs to swing back and forth rather than heading in one direction.
As far as the meto updates telling you where we are headed in the longer term, I can remember only a handful where they publically commented on wintry weather coming before we were fairly confident on here. of course, given our propensity to be not wintry, they are generally right to keep their counsel, especially with the express ready to proclaim the next ice age at the drop of a hat.
I certainly agree with you BA regarding the Meto updates, It has been said on here before but it bears repeating that when push comes to shove the Meto are a specialist short to medium term forecasting organisation and as the national forecaster with a reputation to protect (and a very anti meto media to deal with) they will rarely jump for a cold weather scenario way ahead unless it is hitting them over the had with a hammer like Nov2010.
2013 was a classic in terms of this guarded approach. Most of the experienced posters on this forum could see that the cold was coming and that trough disruption was very likely but the Meto updates were if I recall correctly very guarded. I seem to recall Fergie posting a lot about Shannon entropy lol.
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Much as I hate this awful mild muck that we have been stuck in for the last six weeks. I think we may have to get through just a bit more of it yet
before we see a real pattern change ( as opposed to a sceuro ridge that flatters to deceive while maintaining the mild flow).
Most of the sensible long term forecasts ( as opposed to Excreta weather) have spoken about a mid Jan/late Jan change to a colder pattern and that still seems the most realistic outcome for me.
If we are going to see a mid Jan change to cold then it won't be until perhaps just into the newyear that a consistent shift ( that gathers pace and ensemble members with time) might begin to appear in the gfs FI output. So for the moment its a case of sitting tight.
Interestingly Adam Scaife. One of the met office head honcho's was quoted yesterday in article about the current exceptional mildness. He mentioned that El Nino winters are often frontloaded with mild and backloaded with cold and suggested that this winter colder than average temperature would be more likely occur in February and March. This would tie in with a gradual pattern change via ssw starting mid/late Jan.
Now let me see when was that famous winter that saw a pattern change mid/late Jan and then the coldest temperatures occurring in Feb and March?.............
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, I can't help but notice that todays 12z gefs ensemble members seem to be showing an increasing number of cold or very cold options late in the run. Only one model I know but these very cold runs seem to be to be gradually increasing in number with time. Possibly a trend to keep an eye on.
Model Output Discussions 06z 04/11/16
in Forecast Model Discussion
Posted
Good post Itsy. The basic facts have been that Fergies updates and the Glosea and ECM long rangers have all pointed to the end of the month as being the time when things could get interesting and if that's the case one wouldn't expect to any spectacular winter charts showing up until after mid month really. So its case of sit tight and wait for the start of hopefully good things to show up on the medium range charts probably in about 7-10 days time.
There are lots of things in our favour for cold. What would be great to see would be an ensemble graph like the ones that appeared in mid November 2010 which showed the 850 hpa temps falling of a cliff. That's when we knew it was game on for that amazing December.