Model Output Discussions 06z 04/11/16

[Frosty.]

Next week looks rather cold, at least further south closest to the centre of the high with widespread frosts and fog patches..so a chilly late November early December for the south according to tonight's Gfs 18z, beyond next week currently shows mild but that can change.

Edited November 25, 2016 by Frosty.

[Singularity]

Regarding longer term potential, all I can recall from the EPS is Bluearmy reporting a lack of height rises to the NW to accompany the Euro low anomaly that was there until recently. That was a sign that even if we saw the jet digging south it would be hard to get a decent cold spell going; the potential was never that great, with those wild GFS runs showing a major west based negative NAO working out well for us being an extreme answer to what could possibly occur with a low anomaly in Europe ans Canadian blocking. It always looked a bit fantastical.

Trust me, what we've danced with for late Nov-early Dec potential wise is a mere shadow of what exists for mid-late Dec... and yes I do have to include 'late' because by default we tend to focus on the earliest possible realisation time for cold weather potential. 

Remember, we've hardly even got started with this silly season

[Ravelin]

3 minutes ago, chris pawsey said:

Might sound a daft question (from a long time lurker) but one I've pondered for some time. Can someone please tell me why a z is on the end of every time caption on all the models? Just curious... 

Thanks in advanced 

Zulu Time

What is "Zulu" time?

Zero Meridian Time

"Zulu" time is that which is more commonly know as "GMT" ( Greenwich Mean Time) or time at the Zero Meridian.  Our natural concept of time is linked to the rotation of the earth and we define the length of the day as the 24 hours it takes (on average) the earth to spin once on its axis.

As time pieces became more accurate and communication became global, there needed to be a point from which all other world times were based.  Since Great Britain was the world's foremost maritime power when the concept of latitude and longitude came to be, the starting point for designating longitude was the " prime meridian " which is zero degrees and runs through the Royal Greenwich Observatory, in Greenwich, England .

https://greenwichmeantime.com/info/zulu/

[weatherguy]

34 minutes ago, Frosty. said:

The Gfs 18z shows Jack frost will be busy for a while, especially further south during next week with high pressure bringing crisp bright days and frosty nights with fog patches.

It certainly shows "Jack" something 

Seriously though, hoping a brief milder spell is what we need to shake up the pattern and give us a chance at something better in the medium term - we've been stuck consistently on the mild side of amplitude across the atlantic with a series of slider lows and ridging being pretty darn consistent with placement of the cold over and again.  While the NH synoptics have been good, it was just set up badly for the UK.  We start again. 

[Summer Sun]

14 minutes ago, chris pawsey said:

Might sound a daft question (from a long time lurker) but one I've pondered for some time. Can someone please tell me why a z is on the end of every time caption on all the models? Just curious... 

Thanks in advanced 

Z is for UTC I think

[Man With Beard]

My current take based on ensemble clusters - the vortex remains weakish, but little chance of high level blocking in the first 10 days of December all the same. However, a very steep amplification at mid-latitudes means some cold is going to come down for somewhere around the Atlantic/Europe, even if just for a few days. Chances not brilliant that this will be the UK, but too soon to write off. Temps over the period probably average to slightly above, but could be a mixture of some above average days and a couple of fairly below ones.

[Frosty.]

2 minutes ago, weatherguy said:

It certainly shows "Jack" something 

 

I'm quite happy about next week, it looks settled with frosty nights, frosts are better than nothing 

[Catacol]

56 minutes ago, Barry95 said:

The 'experts' on here keep saying 'patience', and then push the forecasted time for the cold back! 

 

No - I dont think this is true. If you analyse what the real experts on here have been saying you will note that none of them stated we would have proper cold and ideal synoptics in late Nov. There was a signal from the Met long term model for a trough over the UK towards the end of Nov with temps likely a little below average. There was a suggestion of a mid atlantic high alongside too. That hasnt come to pass - instead that high has become a strong UK block which just proves the best long term models get it wrong! But those interpreting the signals have kept their ammo dry, and my reading of all the info has been a shift towards cold from mid Dec. 

What is certainly true is that we have a much different setup to last year. All the experts have stated this, and the models bear it out. We dont have a strong westerly regime, and instead we have a meandering jet, high pressure dominance and cold air already seeping out of the arctic. And we arent even in winter yet. I suggest if you need a pick me up you read Tamara's last post. Very informative, suggesting not only a shift to an even more blocked pattern, but a possible route forward seeing potential spikes in AAM and cross polar ridging. If we get a wave 2 warming as a result then the vortex may indeed fall apart. GP is also sounding pretty bullish.

Dodge the clever posts of one or two who like to stir it up even when they know most people are on here to see if we can get snow. Instead hold on to the teleconnections we have in place. We still need some luck - but there remains a realistic chance of a special winter this time around. If we got that wave 2 attack with the MJO remaining active as Nina fades and dies (and I know these are some big ifs) then we are in business. Cold from mid December was always my call (I'm not an expert I hasten to add....) and I remain very optimistic. Can we get some high lat blocking in place by mid month and then see a SSW with impacts through January? It's possible. We would then have to be very unlucky I think not to get at least one decent cold spell out of winter, and with a bit of luck we could have a rinse and repeat pattern of cold weather through much of the season. That's about as good as it gets in the UK as with most of the great 80s winters. Another 47 or 63? Unlikely. But current global conditions would certainly shorten the odds compared to most winters since the mid 90s.

Every reason therefore to be optimistic.

Edited November 25, 2016 by Catacol

[karlos1983]

ECM op right at the top side of mild in the ensembles toward the end of the run. Noticeable spread now between mild and cold from  about the 4th onward, no real middle ground 

Edited November 25, 2016 by karlos1983

[Geordiesnow]

I actually found tonight's ECM run a little bit encouraging, ignore the FI charts on the ECM and focus that today's ECM runs has actually shown a little bit of Amplification for the first time in a while in the medium term. yes, it goes wrong but too me it would make little difference if it shows something cold because its too far out to nail down any details.

Hopefully the morning runs and especially the UKMO just start showing a little more sign of amplification and we try and go from there. I'm ignoring all this mid December malarkey because there is always every chance colder air could make a return before then. Still a chance we may see something more chilly next week although all those GFS extreme Northerlies look very unlikely but a NW'ly with the UK just about on the colder side of the jet is still possible and the ECM has ironically shifted slightly on this although the UK is just on the mild side of the jet.

And yes, there was alot of hype about blocking potential a few weeks about for the end of Nov/Start of Dec and no doubt the goalposts are being moved but we get this virtually every winter though, its nothing new sadly. Because of that hype, there has been dissapointment in this thread that most of the models has never shown a set up which was cold/snowy which goes to show weather predicting will always be very difficult and its better to take it just a week at a time.

That said, it has been cold, there been limited snowfall and parts of Scotland are experiecing very low minimums for the past few nights now and for me this November has been quite an interesting one.

[Daniel*]

Quite a stark cold anomaly covering Europe on EC week 4 - Siberian express? Sidney's poor little nuts would be well and truly frozen. 

Let's hope it plays ball...

Methinks a white Christmas could be distinctly possible for parts of UK this year... long way off though festive period ought to be cold and snowy even if it isn't conventional perfect with those short days too.  

[cold snap]

Now not going to go mad crazy here ,but GFS looking different here at only 144 ,could and i say could see a different pattern 

[cold snap]

Wake up people ! GFS trying to get the cold back in.Major differences here 

-8 850s coming into Scotland at 180 hours .

Edited November 26, 2016 by cold snap

[Aiden2012]

Looking like good gfs hopefully a new trend 

[cold snap]

South westerlies ??? GFS .not on this run .major changes here 

GFS toying with a easterly here .Major cold closing in by the end of next week .

Edited November 26, 2016 by cold snap

[Aiden2012]

If that high could just move north we would bang on but still looking like a great run 

[Aiden2012]

South westerlies incoming.

[Ali1977]

18 minutes ago, Aiden2012 said:

South westerlies incoming.

Winter incoming you mean - this could be the way winter starts!! Decent FI coming!! 

Just another different run I think,  we are no closer to knowing what's happening just yet.

Edited November 26, 2016 by Ali1977

[booferking]

Torpedo in the east pacific pushing the vortex east then the Atlantic ridge build flood gates to the north open.

Edited November 26, 2016 by booferking

[cold snap]

My my ! 

Mr Murr ,Nick where are you ???

Winter returning according to GFS.

 Bitter artic winds to end this run,as the bbc where saying its even going to be very mild or very cold .

[cold snap]

17 minutes ago, Aiden2012 said:

South westerlies incoming.

Short lived ,the escape route is coming .Cold air building in behind,northerly landed 

[cold snap]

Ukmo 144 also much colder .no south westerlies look likely there either .looking North and East ,slight shift and floodgates open,

Ecm will be interesting 

[knocker]

Weather for the weekend

Cloudy, perhaps less so tomorrow, and dry with perhaps a little drizzle in the far north and south west. Temps around average.

Keeping within the ten day time frame the GFS this morning is indicating some quite major changes, Whether they are significant or just another variation will depend on sustainability and cross model support The overview is much the same initially with the usual interplay between the upstream energy sources, around the Canadian HP and from the southern States, and the Atlantic high pressure. But as the run progreeses the upstream pattern changes and the Canadian HP is removed as the GOA ridge intensifies. This could significantly increase the chances of a cold surge into the UK down the road with Atlantic amplification.

Briefly a little more detail for this run

As previously mentioned the usual upstream energy surge and we arrive at this position by 12z Wednesday. Up until then weather over the UK will remain under the influence of the high pressure so  dry but a large diurnal temp variation with some pretty cold nights and severe frosts.

After that further forcing from the south west amplifies the ridge which forces the trough(s) tracking east to the north of the UK to drop south east over eastern Europe. So essentially after a brief spell of quite strong NWs high pressure is back in charge and thus the dry spell will continue with quite a fluctuation of temps but perhaps a little below par.

It's about now that the Canadian HP disappears and the upstream energy becomes more organized with a strong jet shooting out of the southern States The $64, 000 dollar question is where to from here? Will the Azores ridge stabilize and hold the fort?

 

 

Edited November 26, 2016 by knocker

[lassie23]

John Hammond update according to the latest model output is for a mild start to December, with a possible potent cold blast  after that.

[That ECM]

Done deal is it? Hmmm I don't think so....