Model Output Discussion - 18z 31/10/15 onwards

[Geordiesnow]

It does seem we may see temperatures finally dropping more down to average as the models are indicating more in the way of cooler Atlantic weather as we head into next week. 

 

Got too keep a close eye on the weekend though, could be a lot of rainfall in areas which have experienced quite a lot of rain recently and the small potential of that ex hurricane Kate producing severe gales for the more southern areas. 

[ItNeverSnowsInWindsor]

Parts of Scandinavia going in the freezer by T144 on the latest 12Z run. The siberian high seems to be stronger and having more of an impact there as the shortwave over South Finland in 6Z is absent on the latest 12Z.

 

 

[Duane S.]

Some interesting variations on far FI on the 12z run including this peach...

 

Unlikely of course as there is little support for what causes it, aka trough disruption central Canda which throws up strong ridging ahead from the Eastern Seaboard into the Arctic, however  there is undoubtably a continued trend to set up the growing vortex away from Greenland. That in itself increases our chances of a cold spell 3 fold than if the vortex sets up residence over Greenland (may well still occur of course). Plenty of fun weather watching ahead as we near winter proper I feel!

[Polar Maritime]

The GFS shows an unsettled/stormy picture next week, Vastly different to the pattern we have been stuck in with winds turning more a cool N/Wly Pm flow. With deep Lows circulating over or close to the UK through-out the run, Bringing some very windy/wet conditions for most at times, And it will feel raw as it should do at this time of year.. Of interest these sorts of conditions can bring some very heavy falls of snow for the Scottish Mountains, An 'interesting' week coming up for once in a long while.

Edited November 11, 2015 by Polar Maritime

[phil nw.]

The GFS shows an unsettled/stormy picture next week, Vastly different to the pattern we have been stuck in with winds turning more a cool N/Wly Pm flow. With deep Lows circulating over or close to the UK through-out the run, Bringing some very windy/wet conditions for most at times, And it will feel raw as it should do at this time of year.. Of interest these sorts of conditions can bring some very heavy falls of snow for the Scottish Mountains, An 'interesting' week coming up for once in a long while.

Yes PM it will feel quite different next week with the relentless mild finally giving way to more typical November temperatures.

GFS T120hrs shows the jet wavering across the UK which looks like the ongoign pattern with frequent changes of airmasses as wave depressions run across from the Atlantic.

 

ECM showing the polar air coming further south 

 

a look at the 2mtr temp graph also underlines the decline from the current high values.

 

Gale and rain warnings are already out for the next deep low named Abigail heading towards Scotland.

 

We are now into a much more more mobile pattern so although there are no indications of any cold blocking there will be plenty of movement in the charts to give interest.

This setup  will certainly have a much more unsettled and colder feel going into the second part of November as the Euro high looks like being squeezed further south.

[Captain Shortwave]

Both the ECM and GEM try to develop a properly northerly spell, but that classic El-nino upstream pattern seems to thwart every attempt coming as heights remain low to our west seemingly extending the lifespan of the Euro ridge.

 

That Siberian high is another seemingly never ending anomaly at the moment which seems to be helping to block the normal propagation of the polar vortex at lower levels. So I would call a mixed westerly pattern, but perhaps with rainfall being the key talking point as opposed to wind as low pressure I suspect will be less vigorous than we would normally expect at this time of year.

[Blessed Weather]

Good to see the ECM and GFS 8 – 10 Day Height Anomalies confirming the trend of recent Op runs, with lowering of heights over the UK and northern Europe and the Euro High easing away. The direction of contour lines supporting the likelihood of PM incursions.

 

An animation of the Height Anomaly chart for this time last week versus today highlights the welcome change.

 

 

I sense hope here and in the Alpine ski resorts!  

[Summer Sun]

So close to a decent northerly only the euro high stopping it

 

[bluearmy]

So close to a decent northerly only the euro high stopping it

 

'only the euro high stopping it'

indeed gavin

[Newberryone]

Until the demise of the Euro high comes within T168hrs then I'd be wary of viewing it as a done deal. The outputs for the last few days have suggested its demise and have backtracked. What we've seen is outputs at days 8 to 10 never verifying and any Euro high demise constantly put back.

 

I'm not sure the ski resorts are hitting the total panic button yet but if these constant backtracks continue for much longer then it will really be alarm bells ringing.

 

The actual warmth in Europe is  unprecedented for the time of year with records being broken since the start of November and if this continues we won't see monthly records being broken by a degree or two but by huge amounts.

Judging by the latter stages of the Ecm 12z, good call from Nick Sussex earlier today re the by now relentless Euro high.

[Singularity]

 

See here how GFS cuts off a trough in the jet between +192 and +228 hours. This is what serves to 'prop up' a ridge off the Eastern Seaboard while the main Atlantic trough shifts east to locate across the UK, bringing a more mixed regime with quite a bit of PM air getting into the mix.

 

ECM and GEM create problems by maintaining that extended trough as a feature of the polar jet rather than cutting it off. There's then no real support for high pressure to build east from the U.S. and a mid-Atlantic trough continues to be the major theme, with a Euro High as a downstream consequence:

 

 

This particular run is very amplified Canada/Greenland due to an insanely powerful storm being developed there. That's what brings an impressive northerly blast to areas north of the UK and if the Atlantic pattern had been further west... need I say more?

 

No interest in that bomb from the past two GFS det. runs, and only a couple of 12z GEFS members get even close, so perhaps that's one from ECM to view with a lot of skepticism at this point in time, depending on how the ECM ensembles are looking in that respect. The risk that the mid-Atlantic trough persists, though, is definitely something to keep an eye on, given how well it fits with the El Nino background.

 

Or does it?

 

 

Out of interest I've had a look at how the two 'Super' El Nino events shaped up in Oct-Nov, Nov-Dec, Dec-Jan and Jan-Feb (bottom four charts) in comparison for 1st Oct to 9th Nov 2015 (top chart).

 

The configuration across the North Atlantic seems to match quite well with the Nov-Dec and Dec-Jan patterns of 1982 and 1997, implying (irrespective of other driving forces) that we're about a month or so ahead of those two years in terms of the atmospheric response to El Nino. Yet the magnitude of the positive height anomaly over Europe this year has been well beyond anything seen in the two case studies when occurring alongside that N. Atlantic pattern.

 

The 2015 pattern is a little west of the 1982 and 1997 patterns and looks to be about halfway between the classic strong El Nino pattern and the sort of thing seen for El Nino Modoki (i.e. Central Pacific) events - driving a more amplified N. Atlantic pattern.

 

If the GFS det. and majority of GEFS have their way, then we'll soon be moving to more of a 'super El Nino Nov-Dec' type pattern based on the two past years looked at. This is in large part where the long-range model projections of Sep-Oct got their idea of a very unsettled November from.

 

ECM's det. is trumpeting the halfway house (hybrid?) type pattern this evening, but was very much on GFS' road this morning so it can't really be said to be backing either outcome at this point in time.

 

 

I have my suspicions that the hybrid pattern is better for messing with the tropospheric polar vortex, though I'm not sure it will matter much once the strat vortex works it way down. To take that down we'll most likely be looking elsewhere, and later on in the winter.

 

 

p.s. I'm aware that just using the super El Nino years isn't necessarily using the best analogues given differences in the distribution of SSTs in the Pacific (particularly relative to the 1997-98 event) along with differences in other basins. As far as I can tell the widely +1*C or so Indian Ocean anomalies are unique among strong El Nino years.

Edited November 11, 2015 by Singularity

[damianslaw]

It's been preety quiet in this thread for a while now - normally at this stage in the year we see the winter forum watchers awakening, but alas I suspect the exceptionally mild set of synoptics we have been locked into recently is keeping many still in summer hibernation mode...

 

However, the models have become somewhat more interesting if you are after more seasonal conditions and changeable weather rather than a stuck pattern. The atlantic is firing into full winter strength mode, and is going to change the pattern of recent weeks to some degree ushering in the first stormy spell of the season and colder spell of the season (relatively speaking and only about 24 hours) - but for the first time this season we will see the sub 528 air thicknesses invading the country with snow for northern high ground, something for cold lovers to cheer about at long last.

 

We will quickly see this shot of polar air cut off once again by ridge developments from the SW which will pull in very mild air again by Sunday with the longwave trough lying limpet to the west, but unlike the past 3 weeks this will kicked into touch very quickly by lowering of heights from the NW which look like pulling down every cooler air next week, with temps back down to near average.

 

 

[pyrotech]

I am surprised that there is no mention  on here about possible rainfall totals over the next 4 days and again into next week.

Some very large totals are possible for some western areas.

The winds are of obvious concern as its in next 24 hours, but rainfall totals in North West Wales , Western Scotland and North West England look a concern for flooding.

I would think warnings will be issued during tomorrow for this risk.

Major cold looks unlikely for November and Historically El Nino gives the opportunity for snow in second half of winter, however the Moisture presented by El Nino can make any snow events quite significant.

I see stormy until mid December completely Zonal with flooding remaining a risk. 

[peborant]

I am surprised that there is no mention  on here about possible rainfall totals over the next 4 days and again into next week.

Some very large totals are possible for some western areas.

The winds are of obvious concern as its in next 24 hours, but rainfall totals in North West Wales , Western Scotland and North West England look a concern for flooding.

I would think warnings will be issued during tomorrow for this risk.

Major cold looks unlikely for November and Historically El Nino gives the opportunity for snow in second half of winter, however the Moisture presented by El Nino can make any snow events quite significant.

I see stormy until mid December completely Zonal with flooding remaining a risk. 

 

Well thankfully I wasn't the only one thinking that! Up here in central Scotland we have had rain every day for the last 8 days and everything is saturated. Monday morning is a cause of concern after the washout next weekend and we are not even in the west side of things...

[bluearmy]

The op GEM continues to fiddle around with high anomoly solutions in interesting locales. the 00z certainly bringing the Siberian high into play much earlier than might be expected. Generally, a run that would wet the appetite of coldies with a swathe a high anomolys to our North.

not many gefs members seem to be on this page though so probably just one of the GEM's more variable outputs.

[cheshire snow]

This Mornings ECM at T240 (FI) would certainly be a shock to the system with -5uppers into Southern England

-7 Uppers cover the rest of the UK.

 

C.S

[Polar Maritime]

In the short term there's some very stormy weather to come for Scotland and the far North over the next 48hrs or so to keep tabs on, As storm Abigaile whips in from the N/W with cooler -3/-4 850's being dragged in bringing blizzard conditions for parts of the Highlands down to 4/500m, And some very heavy rain with severe gales especially for the Shetland/Hebrides Islands. 

Edited November 12, 2015 by Polar Maritime

[Frosty.]

The Ecm 00z draws Arctic air south towards the end of the run with potential for further cold reloads beyond T+240 hours, some of us would see some snow from that day 10 chart. I'm hoping the last few weeks of autumn bring an early taste of winter, the majority of us on here want that and we sure deserve it!  

[fergieweather]

The Ecm 00z draws Arctic air south towards the end of the run with potential for further cold reloads beyond T+240 hours, some of us would see some snow from that day 10 chart. I'm hoping the last few weeks of autumn bring an early taste of winter, the majority of us on here want that and we sure deserve it!  

Yes, but wide spread from even next Tuesday onwards in individual stamps and this reflected well in plumes. E.g as here:

[Paul]

The Ecm 00z draws Arctic air south towards the end of the run with potential for further cold reloads beyond T+240 hours, some of us would see some snow from that day 10 chart. I'm hoping the last few weeks of autumn bring an early taste of winter, the majority of us on here want that and we sure deserve it!  

 

And in the meantime, there's just a few storms, an ex-hurricane the risk of floods, damaging winds and the like!

 

Rain totals next 5 days make for fairly grim reading:

 

 

Lows aplenty

 

I get the hunt for cold thing, but plenty to look at besides the odd FI glimmer right now, and plenty of time for more realistic cold chances too. 

[Summer Sun]

Could be looking at some flooding issues in Cumbria and parts of Western Scotland with some torrential rain over the weekend and again next week as the rainfall totals show

 

 

By day 10 large parts of the UK have some fairly high totals

 

[cheshire snow]

Little bit for everyone on the 06z,Heavey Rain,Gales,Heavey snow,and even a channel low giving snow in the South

Pick the bones out of all that.

 

C.S

[MPG]

Little bit for everyone on the 06z,Heavey Rain,Gales,Heavey snow,and even a channel low giving snow in the South

Pick the bones out of all that.

 

C.S

Can't see the channel low producing any snow from the 06z output.

[Polar Maritime]

Can't see the channel low producing any snow from the 06z output.

 

Here you go MPG, Yes C.S the GFS 6z shows a very disturbed Wintry/Stormy outlook with deep Lows heading further South dragging in colder air with it from the N/W. Certainly an interesting outlook with lots of features to keep tabs on.. A very 'active' period of weather coming up. 

Edited November 12, 2015 by Polar Maritime

[Liam J]

Can't see the channel low producing any snow from the 06z output.

It would for the Pennines and southern uplands & poss Welsh mountians, away from there it's only about 30% risk on the GFS snow risk map, also it's 10 days away so don't expect it to verify like that (not that you would)...