Model Output Discussion - Into November 2019

[northwestsnow]

1 minute ago, bluearmy said:

Fwiw, the Icelandic snapshots of the latest EC46 show a pretty standard dec with pos NAO and euro heights to our south to add to those further east 

Sounds dire.

[Don]

6 minutes ago, northwestsnow said:

Sounds dire.

We can only hope they are wrong.

[bluearmy]

8 minutes ago, northwestsnow said:

Sounds dire.

Well ec46 weeks 4 to 6 haven’t proved particularly reliable for ages .... when was the last time that the meto 30 dayer didn’t mention ‘uncertain’ in the first sentence! ( or a phrase to that effect) 

Edited November 7, 2019 by bluearmy

[swfc]

Positives from the 18z,it's a dry or drier spell of weather.other than that???had 118 mm today in my area

Edited November 7, 2019 by swfc

[feb1991blizzard]

1 minute ago, bluearmy said:

Well ec46 weeks 4 to 6 haven’t proved particularly reliable for ages .... when was the last time that the meto 30 dayer didn’t mention ‘uncertain’ in the first sentence! ( or a phrase to that effect) 

Also, the anomalies are not huge, it doesn't scream of a coherent signal in the second half of the run, although i don't have the detail you may have on your subscription.

[northwestsnow]

2 minutes ago, bluearmy said:

Well ec46 weeks 4 to 6 haven’t proved particularly reliable for ages .... when was the last time that the meto 30 dayer didn’t mention ‘uncertain’ in the first sentence! ( or a phrase to that effect) 

Agreed.

You watch it be spot on now its suggesting a +NAO..

[blizzard81]

4 minutes ago, bluearmy said:

Well ec46 weeks 4 to 6 haven’t proved particularly reliable for ages .... when was the last time that the meto 30 dayer didn’t mention ‘uncertain’ in the first sentence! ( or a phrase to that effect) 

Plus, doesn't it only go to the middle of December? 

[Allseasons-Si]

SCANDI ALERT!!!

just for fun.

 

[bluearmy]

2 minutes ago, blizzard81 said:

Plus, doesn't it only go to the middle of December? 

To 23rd dec

4 minutes ago, feb1991blizzard said:

Also, the anomalies are not huge, it doesn't scream of a coherent signal in the second half of the run, although i don't have the detail you may have on your subscription.

 

Wouldn’t disagree but it doesn’t show any anomolys where coldies would like to see them ...........

 

 

[feb1991blizzard]

2 minutes ago, Allseasons-si said:

SCANDI ALERT!!!

 

just for fun.

 

Its beautiful, only problem is it will stay just for fun until we get that siberian vortex chunk around the back of it.

Edited November 7, 2019 by feb1991blizzard

[blizzard81]

A very intruiging battle seems to have commenced. We have some very positive (from a cold perspective) developments in the short to mid term. However, the long term seasonal models are seemingly digging their heels in with their positive nao outlook. I feel a mix of tension and excitement! 

[Allseasons-Si]

15 minutes ago, feb1991blizzard said:

Its beautiful, only problem is it will stay just for fun until we get that siberian vortex chunk around the back of it.

All swings at the moment as regards to placements of the hp cells,the nwp's are still toying around with northern heights but until we get to some agreement on this then  it's a waiting game and hopefully not a long one

if that Canadian pv chunk is displaced west in a favorable position ie further west than is currently shown then it's game on as it would send WAA into Greenland,the early part of the run showed it slightly further west so baby steps

what i am looking for is amp in the Atlantic towards Greenland,that is a possibility. 

it's not a usual zonal affair from what i am seeing.

Edited November 7, 2019 by Allseasons-si

[markw2680]

My first post in here in quite a while, but have to say I’m quite excited with the look of things of late, looks to me like something pretty decent could be setting up for the end of the month if we keep seeing these kind of charts. Just hope they verify and set us up for a memorable winter. Have to say I think we are due one.

keep up the excellent posts in here it’s always the first place to visit in a morning

[swfc]

I'd be happy to see the back of that insipid high to the east and get some fronts and decent 850s to the east.it has been said the high is helping forcing on our side of Europe which it is.scandi highs are great but the temps and set up isn't for me.just how I see it

[BlueHedgehog074]

A summary of the models:

The next few days looks as though it will continue rather chilly and unsettled, especially for Northern areas of the UK. Various models showing the continuation of Low Pressure systems from our West in the Atlantic squeezing East/South-Eastwards through the UK against the blocking to our North and North-East and the Azores High to the South-West.

GFS 18Z used as an example:

Some brighter, drier breaks are likely between the Low Pressure systems. There is also a likelihood these Low Pressure systems will take more of a Northerly track for a time early next week, as shown in the bottom few GFS charts above. In a way, thanks to some somewhat lower heights spilling into the Atlantic area, which appears to be bringing some stronger Lows through to the North of the UK. Still looking cool with the Jet Stream seemingly angled from a North-West to South-East direction through the UK with the Lows dragging in some chilly North-Westerly Polar Maritime flows. Having the Azores High exhibiting some reasonable amplification giving a hand in this. 

The upcoming Saturday could certainly provide some wintry interest, as a front from a weakening approaching Low to the West of the UK disrupts and becomes slow moving against the cold air over us, more particularly Northern UK. Although the event is under 2 days away, it’s not totally clear how far East or North-Eastwards the front could get. But most areas away from the far North-East could see a spell of rain, sleet or snow. The sleet or snow most likely over high ground over Northern UK, but this could get to some lower levels at times. Maybe even a bit of sleet as far South as the Midlands under any heavier bursts. The slack flow would probably encourage this too.

However, when seeing what the 850 hPa temperatures are like for Saturday lunch time, you can see the GFS is being the most generous with those colder upper temperatures (first chart below) compared to the likes of the ECMWF, GEM and ICON.

Which suggests to me it might be over doing how widespread those -5*C 850 hPa temperatures are for mid day Saturday. It would, however, likely paint the wintriest scenario for Saturday. May be a day which churns out a few surprises for the snow weather fans. Again, snow likely to fall on higher ground and over hills to the North and over the Welsh mountains. But still wouldn’t rule out some sleet/sleety rain over some areas of the Midlands, perhaps Eastern Wales, and some wet snow over lowish ground in Northern England and Scotland. 

Later into next week, there could be a tendency for the South-Easterly, or Easterly, tracking Lows to drop to the South/South East of the UK into mainland Europe again bringing in a chilly flow from the East or North-East through the UK.

Examples from the 12Z ECMWF, 12Z GEM and 12Z GFS at 192 hours:

 

The GEM having the deepest Low over and to the South-West of the UK. Consequently the only model at the time-frame of the 3, which doesn’t drop the Low as far East to the South of the UK when looking at both the GFS and the ECMWF. It’s not certain how far South or East these Lows next week could get - they could become slow moving and stay as still as a statue over the UK, or take a more Northerly route.

The ICON 12Z, while not going any further than 180 hours, does drop Low Pressure to the South of the UK with upper and surface heights building over the top. Therefore, similar to the charts above:

(Edit: not sure how it happened, but apologies for the underlining): It’s another model that has a deepish Low that drops more to the South-West of the UK to pull in more of a South-Easterly/Easterly-South-Easterly flow. Really, for those after some deeper, cold, conditions, it’s best if the Lows dropped more directly to the South-East of the UK towards that Northern or Western Italy spot. This can assist in pulling in a cold flow from the North-East, but it does help to have High Pressure to the North or North-East orientated favourably to squeeze some very, cold, air towards the UK from the Scandinavia or Russia areas. I feel there is a pretty good chance of Low Pressure next week dropping far enough South to pull in a chilly feed from the East. It’s not a definite scenario being a fair few days away. Also uncertain exactly where Low Pressure could drop over to our South (if it gets there at all not filling too quickly). As some illustrated yesterday, this would, in some ways, depend how much amplification develops upstream in the Atlantic. This could help as forcing to get Low Pressure to drop to the South or East of us. Though it does help to have some Low Pressure and upper low heights in Europe for Low Pressure to run into.

I would also be happier had the 12Z ECMWF ensemble mean below showed a slightly stronger signal for some ridging in the Atlantic at 192 hours...

...as the pattern in that area could turn out a bit flatter than what some operational models are dishing out. These means aren’t always the best to use to draw up an accurate picture of what may happen, mind. It does suggest a continuation of North-West to South-East tracking Lows with a Southerly tracking Jet Stream. But nothing really cold or snowy at the moment. 

Seems quite likely that the Azores High could remain held out to the South-West of the UK. I remember Phil Nw mentioning having this pushed out to our West/South-West without its ridging getting dragged Eastwards towards our South-East (or East) was one of the important aspects to prevent a South-West to North-Easterly tracking Jet Stream from reoccurring. This of which would bring up milder weather from the South-West. Admittedly, for some, that would be preferable. 

Tonight’s NOAA 8 to 14 day 500mb chart chart continues to maintain Low heights over and to the South of the UK, so probably staying on the cool side. The position of the ridging and higher than average heights to the East and North-East over Europe and Scandinavia would likely mean nothing too cold seems likely, especially from the North-East. Any colder shots from the North-East would likely to be brief to be honest.

 
Worth staying that these anomaly charts are never a 100% guarantee. And I know those such as knocker, John etc, have more experience with these type of charts.

Don’t think I’ve been the only one to mention it, but there has been some enjoyable model discussion in here in the last few or so days. Would be good to keep up this sort of thing up throughout Winter (but some odd funny pictures and odd one or two liners are fine as longs as they still describe the chart(s). We appreciate  people get really excited by windy, mild, cold and snowy weather and the like) 

Edited November 8, 2019 by DiagonalRedLine
Fixing some glitchy stuff

[Ali1977]

A pretty boring GFS 00z, especially after day 8 when signs of NH blocking disappear. Just one run though, but it’s runs like these that have me wanting the Atlantic in , reset , and start the hunt again. Let’s see if the ENS agree with the Op. I haven’t missed the fact the strat is on the warm up again though

[tinybill]

looking at the  gfs  from now to deep famtasy world cant see any let up with the rain   ex up north with all the problems they got now  .

[Jordan S]

This time next week we are really getting a soaking according to the latest GFS not good news if you have flooding atm.. it shows the pattern which has dominated our weather for several weeks now.. Low pressure systems dumbelling around us one after the other I guess just like us they need a break to sit and relax for a bit.. But just a lot of them have done it in a very similar place! 

Edited November 8, 2019 by jordan smith

[knocker]

Outlook - unsettled and rather cold

The North atlantic 500mb and surface analysis for midnight and the 0400 UK chart

A chilly start to the day in the north, misty/fog patches in the south and at last the persistent rain, now across the Midlands will continue to move south through the morning and fizzle out.albeit cloud and patchy stuff hanging around in the south east. So a dry day with a fair amount of sunshine albeit on the cool side

Once the cloud and patchy rain finally clears the south east a clear and cold night with a widespread frost by morning. but by then rain from the approaching occlusion will have reached far western regions

The rain will continue to track east during Saturday and will be quite heavy in central areas and will fall as snow over the higher ground north of N. Wales/Derbyshire. But as we know any eastward movement runs up against the block to the east and the front tends to fragment through the day and re-orientate  NW/SE which concentrates the rain into a south west corridor Still a little uncertainty on how far east the front will get.

The rain will persist over southern and central areas over Saturday night but clearing Sunday morning leaving everywhere with a dry and quite sunny day, albeit a bit nippy. But as can be seen another intense trough has arrived on the scene over the tip of Greenland and the associated surface fronts are approaching Ireland

By Monday the trough has moved east over Iceland but once again the movement is restricted by the ridge to the east and the surface front struggles to traverse the country. Never-the-less it manages it so a cold day of sunshine and showers, wintry over the high ground

A sense of deja vu by Tuesday as the battle between the eastbound energy and the block re-orientates the trough with much of the north of the UK is in a fresh W/NW wind and with fronts/troughs running around in the circulation some heavy and squally showers resulting which could well be of hail with snow on the higher ground

Edited November 8, 2019 by knocker

[knocker]

The midweek developments have been discussed previously. Essentially the cold trough down eastern N. America promotes mid Atlantic ridging and peps up the jet which pushes our trough, trapped between a rock and and a hard place, south. The surface charts are not to be taken as definitive

The GEFS ext anomaly is pretty much in the ball park as discussed last evening

[ItNeverSnowsInWindsor]

Quite unusual synoptics on the GFS 0z run with the southerly running jet and even the chances for snow are increasing for London
 

[jules216]

10 hours ago, daz_4 said:

Another year has passed and it is still the same old story, isn't it jules? The switch has been flipped in April 2013 and we have been stuck since then. 

Yes Daz a tale tale story of last 6 decembers(winters) is perhaps this anomaly. You can copy paste that in to summer months more less since 2015.Honorable exceptions being Jan17,Feb18 thats it

[SLEETY]

7 hours ago, blizzard81 said:

A very intruiging battle seems to have commenced. We have some very positive (from a cold perspective) developments in the short to mid term. However, the long term seasonal models are seemingly digging their heels in with their positive nao outlook. I feel a mix of tension and excitement! 

Well the seasonal models were poor last winter consistently forecasting HLB but it never happened,so I would take what they show with a large pinch of salt

[ItNeverSnowsInWindsor]

3 minutes ago, SLEETY said:

Well the seasonal models were poor last winter consistently forecasting HLB but it never happened,so I would take what they show with a large pinch of salt

They were shocking this year too with a mild autumn predicted but turning out comfortably colder than average.

[ArHu3]

1 minute ago, SLEETY said:

Well the seasonal models were poor last winter consistently forecasting HLB but it never happened,so I would take what they show with a large pinch of salt

When the models are  forcasting hlb you can seem to trust them 48-72h out but on the other when they forecas zonal 384h out it is almost always sure to verify