Model Output Discussion 18th Nov.2013-12z onwards.

[Grimsby Snow Lover]

Brian Gaze going for a gradual warm up as we head into December.

 

although a split ENS the majority are heading mild

 

Will 18z be another downgrade??

...as is the further outlook from the met office. That said, temperatures are forecast to remain on the colder side of average for next week with a gradual return to average as we head into December. Could be a lot worse.

[Catacol]

I couldnt get that GP thumbnail to be big enough, so did some jiggery pokery and got it working in a fresh post. Quite a good, basic way of understanding what the GWO plots mean for us.

 

 

 

 

 

Edited November 19, 2013 by Catacol_Highlander

[Geordiesnow]

Regarding the upcoming high pressure potential spell, my only question would be how much cloud will there be and this will determine how much frost and fog there actually be but its nice too see we are heading into a settled spell of weather though. One is hoping cloud amounts won't be huge but I do feel in Eastern areas, it could be quite a cloudy weekend overall with limited frost and fog. 

[NorthernRab]

Not exactly a raging polar vortex, quite the opposite in fact. Based on such charts, the general trend for high latitude blocking on the CFS etc I'd say we're in quite a comfortable position as we head into winter, whether we're under fog, frost, snow, rain or hail come the end of the month. 

 

[Cloud 10]

 

I couldnt get that GP thumbnail to be big enough, so did some jiggery pokery and got it working in a fresh post. Quite a good, basic way of understanding what the GWO plots mean for us.

 

 

gwo_40d.JPG

 

 

 

 

 

 

Good thread here from 2008:

 

Gwo And Global Angular Momentum - The netweather guides... - Netweather Community Forums

[Ali1977]

Heights pushing back up towards Greenland in deep FI. T330

[nick sussex]

Sadly the GFS 18hrs run continues the trend of less amplification upstream so no shortwave ejected se and the PV starts gathering to the north in the latter stages of the higher resolution output.

 

The lower resolution is a horror show for cold lovers and thankfully well into the future, before then after this initial shortwave has cleared se it looks to dry up with some frost and fog.

[nick sussex]

Yep, I think I need a drink to forget that run 

Hopefully tomorrow will be better.

Yes that GFS lower resolution is dreadful, if the horror show started at the twilight zone part of the output then you could just dismiss it as the typical GFS post 240hrs nonsense but the buzzards begin to circle earlier. Lets hope for better tomorrow.

[johnholmes]

this type of post is simply silly in my view, you are of course entitled to that view but can we please have some factual evidence that you have based this comment on please?

 

Anyway I've seen enough to convince me that and colder spell is not likely this side of Christmas got an awfully bad feeling about this winter full stop.

 

And I would make the same comment had it been that winter was going to be mild throughout.

 

NO ONE knows beyond mid December to any real degree of certainty, maybe 50-60% that far. Beyond that and we are into using very complex seasonal model outputs which are still very much in their infancy.

[phil nw.]

Can we avoid speculation and crystal ball gazing and stick to what the models are actually showing please folks.

 

A few recent posts are more suited to the moans and ramps threads thread and are not for here.They have been removed.

 

Thanks all.

[johnholmes]

To those who suggest/hope that the runs tomorrow might be better=why, and even if they do will they likely be more accurate?

 

For what it is worth, perhaps not much for some of you, the anomaly charts are pretty clear on what is going to happen for about 2 weeks. That is for an upper ridge to dominate for most of the time, but with still some doubt over how much of the time it will dominate. There is still a small, perhaps very small probability, of a short lived polar outbreak. Then after 14-maybe 18 days the Atlantic 500mb flow seems likely to take over? Or so it seems based on the last 2-3 days output. Who knows they may start to show this as just a blip 3-4 days down the line. I have never seen the AO and NAO so variable as they show today and have no idea why they are so variable. Anyone any suggestions as to why? The MJO continues to show no guidance at either the actual or forecast level with it close to the zero area throughout. Hence my question about the AO and NAO. Or are they simply showing what the synoptic models are-uncertainty? I am not a great believer in them beyond about day 7 even for guidance but their variability as I've just said is unusual or at least the degree of it shown today.

Edited November 19, 2013 by johnholmes

[Purga]

_{An atrocious chart for cold lovers in FI}

 

 

 

_{Maybe a brief toppler at the end}

 

 

[Mucka]

_{An atrocious chart for cold lovers in FI}

 

 

 

_{Maybe a brief toppler at the end}

 

 

 

 

It is but it isn't worth worrying about really. 

I still think there is enough uncertainty in the ensembles from the mid range to just about hold our interest.

 

Pure speculation here but it is based on ensemble data.

 

All the odds are against any deep cold and snow chances turning up for start of December and there is no signal for it but I'm not giving up until the ensembles predominantly show a more zonal flow in hi res.

There is still a very small chance of something turning up between day 6 and 9 but if not I think GFS may be starting to find a pattern change around day 10/11 from the mid latitude blocking around the UK.

At the moment it seems to be split as to whether to try and build heights over Scandinavia or a dig a trough down either through the UK or just West of the UK with a more amplified pattern behind so the waters are very muddied.

Since patterns tend to repeat themselves though I wouldn't be surprised if we were looking at another mid Atlantic ridge early December.

 

If that very weak signal disappears over the next couple of days rather than strengthens I will take a break and recharge my batteries but until then the outpput will hold my interest.

Edited November 19, 2013 by Mucka

[Panayiotis]

Hmmm I know its the GFS, the 18z and im looking at FI but there are some trends appearing at +360hrs. Some of the members want to rebuild pressure in the Atlantic with a N/NW developing for the UK.
http://176.31.229.228/modeles/gens/run/gens-0-1-360.png
http://176.31.229.228/modeles/gens/run/gens-2-1-360.png
http://176.31.229.228/modeles/gens/run/gens-6-1-360.png
http://176.31.229.228/modeles/gens/run/gens-11-1-360.png
http://176.31.229.228/modeles/gens/run/gens-15-1-360.png
http://176.31.229.228/modeles/gens/run/gens-16-1-360.png
http://176.31.229.228/modeles/gens/run/gens-17-1-360.png
http://176.31.229.228/modeles/gens/run/gens-18-1-360.png
http://176.31.229.228/modeles/gens/run/gens-19-1-360.png
http://176.31.229.228/modeles/gfs/run/gfs-0-360.png

Ensemble at 384hrs:

 

Notice some of the heights heading towards Greenland and the trough still present over Europe? I think its definitely worth watching for the next 'potential' as the next couple of weeks will see HP dominate with frost,fog,sunshine and crisp days.

Edited November 20, 2013 by Panayiotis

[ARNOTT ad]

Oh dear. Like I thought. The models/atmosphere aren't providing us with much hope that's why I said we needed these charts to fulfil quiet side if Christmas on here.

Just to think back to 2010 at what we were looking at...... If only again

[Timmytour]

There are no guarantees of what's coming, but I think that what we've had so far this month and how the models are shaping up the rest of it to be is not so far removed from what November 1962 was.That's not to say we've got a December like it to follow, but i don't think anyone who was privy to the information we have at our disposal nowadays would have seen what was in store back then...just as no one can know now. 

[BlueHedgehog074]

The 8 to 14 day 500mb anomaly chart from the NOAA does show that we're likely to see some sort of blocking High Pressure around, or over, the UK, with the higher than average heights (represented by the red dashed lines) mostly concentrated in that area. This looks to link up with an area of higher than average heights to the West/South-West of us. So perhaps a scenario of a UK high linking up with an Azores high, with the likelihood of Low Pressure systems mostly running over the top of the High (with those areas of lower than average heights to the North/North-West of the UK - marked by the blue(ish) dashed lines on the chart), which could eventually start to knock the UK blocking high Southwards....

 

NOAA 500mb 8 to 14 day anomaly chart (19th November)

 

....However, if some of the lower heights around the Italy/South-East Europe area really do have enough strength to continue propping up the high, the idea of it sinking may not be the route to head in at all. I think specifically, though, more runs from numerous models, especially the GFS (because of it seemingly being keen for the possible mobile, Atlantic, pattern to return in deepish FI on some of its last few updates) will be needed to see where we continue to trend in. But a UK setting itself up close, or over, the UK island for a while seems like the most possible outcome for now, but perhaps trending a little bit further South within time. The ECMWF 12Z ensemble mean goes for something similar, but with the idea of the High Pressure possibility getting put more towards the Southern UK.

 

An example from the ECMWF mean at 240 hours - High Pressure over the southern/South-Eastern UK with a fairly flat Westerly pattern over our area of the World.

 

This follows the ECMWF 12Z operational run in that it also shows a fairly, flat, Westerly, pattern over us with High Pressure to our South, and areas of Low Pressure to our North.

 

It perhaps should be noted that the NOAA anomaly chart does show some fairly amplified area of heights over Western America, which could probably help to put us back into a more amplified and/or blocked pattern if we get to that scenario of High Pressure ending up being knocked Southwards/South-Eastwards over us beforehand. Plus, those ECMWF Hemisphere charts show some ridge(s) of High Pressure over America, with another quite notable ridge directly to the other side of the UK.

 

(The same 240 hours ECMWF ensemble mean chart, with the black circles showing the areas and ridges of High Pressure I spoke of. The ridge on the other side of the world, especially, is helping to give the Polar Vortex and those areas of dark blues a bit of a beating)

 

I must admit, some of this is still just estimations, but I would probably suspect from reading posts in the past that amplified highs in other areas of the world can help to make the pattern in our area of the world more amplified with the Jet Stream becoming less flatter. This can then lead to longer term blocking in places if Low Pressure systems/troughs can angle themselves favourably against the amplified High Pressure systems to send Warm Air Advection Northwards to disrupt areas of the Polar Vortex above. But if the High Pressure systems don't amplify enough, the Jet Stream can blast over the top of them and flatten the ridges out like pancakes!

 

But on the whole, the Atlantic, at least for now, looks like it will likely be 'asleep' for the next 7 days or so with High Pressure likely to take its nap over the UK. A continuation of cool/cold days likely, and perhaps especially towards the South where they could be most exposed to the cold, slack, Easterly/North-Easterly flow on the High Pressure system's Southern flank (although their probably won't be much difference really. Plus orientations to the modelling of the high will likely to keeping changing at times). And then perhaps signs for the High Pressure to gradually sink Southwards (albeit maybe not completely) as some models show the pinks and blues from the areas of the Polar Vortex to become more invasive to the North putting pressure on the High over us. I would certainly say that even this High Pressure sinking idea is not definite and their is the possibility of further Polar Vortex disruption occurring further down the line. Some of the adjustments made by the models this week demonstrates how easily things can change. (Even though I confess sometimes, it can still be easy to become sucked into the dreamland stuff the charts spit out at you, he hee).

Edited November 20, 2013 by DiagonalRedLine

[IDO]

Amazing how we were sucked into the ECM FI. In fact a 180 turn from the model showing above average uppers in that range now:

Compared to the 18th!!! For around the same time:

The 0z at T240:

GFS: ECM:

The GFS mean at T240 backs the op:

So the sinking high trend showing yesterday continues. The ECM op has less zonal but on recent adjustments I suspect they will follow the GFS route in due course.

Gem at T240 (same synoptics): UKMO:

Of course anything can happen with our weather but looking solid from the models for average/cool dry 7-10 days followed by a trend for lower heights to edge in from the north and a more westerly flow setting in.

[Tim Bland]

Maybe some members will stop bashing the GFS now? ECM has been awful recently and the UKMO not much better.

[MR EXTREMES]

as matt hugo said in the strat thread looks likely that a more alantic dominated outlook this side of Christmas so temps returning to more normal values after a pretty settled spell I suspect we will start to see heights start slipping away to our south in future model runs.

 

but for now for several days atleast dry cool and settled.

[stratty]

Maybe some members will stop bashing the GFS now? ECM has been awful recently and the UKMO not much better.

...........certainly reminds me of a football match where a team has scored two quick goals......"It's all gone quiet over there!!!"

[Frosty.]

The GEFS 00z mean shows a prolonged spell of settled weather on the way as high pressure builds in across the uk, there will be widespread frosts and fog will become the main hazard, the fine spell should last until at least the end of next week for most of the uk but as the high begins to slip south, the far northwest / north are likely to turn more unsettled, windier and milder with atlantic weather piling in but the fine, benign and chilly spell looks like persisting longest towards the south / se...probably into early Dec, high pressure remaining close to the south.

[Frosty.]

The Ecm 00z op run shows a prolonged spell of rather chilly anticyclonic weather but the high eventually pulls back further into the atlantic to the west/sw of the uk with lowering heights to the nw/n and even before the end of the run, northern britain is turning windier and more unsettled as atlantic weather invades..the Ecm has been a disaster.

Edited November 20, 2013 by Frosty.

[SMU]

Morning All

A decidedly poor outlook from the models overnight with a tight circulation building up over the pole signalling the end to any thoughts of polar blocking -

Looks like on this occasion the ECMs long term vision was wrong and the MOGREPS / DECIDER models were correct-

You win some. You lose some. The ensemble

Mean is going to look horrid today and wont msje comfortable viewing if its cold your looking for ....

S

[Cecil Hogmanay Melchett]

Agreed Steve,

You never know whats around the corner but i think we can write off any hope of HLB for a good week to 10 days minimum.