Model Output Discussion - 31/10/2014 and Beyond

[knocker]

The updated ECM monthy reads thus, The higher heights over the pole and Greenland gradually reducing, little amplification upstream and no retrogression vis a vis Scandinavia, Resulting in a surface analysis similar to the current pattern with low pressure in the northern Atlantic (relative to the UK) and Greenland leading to a continuation of depressions in the mainly zonal flow. Temps around average.

Edited November 7, 2014 by knocker

[WINTRY WALES]

Morning All,

I see a tad of excitment brewing with some of the more experienced model watchers in the last 24 hours. A lot of referencing to a possible hefty negative AO this winter.......can anyone please give a quick reply to what effects this will have on the weather pattern/output if this materialises??

Thanks in advance

[Captain Shortwave]

At day 8, the GEM has a reasonably large positive anomaly over the Pole

 

GFS not far behind

Same with the parallel

 

Not bad eh.

GFS mean getting there too

 

Certainly a good chance of a full on proper split in the tropospheric vortex. Awaiting the ECM with interest.

 

ECM

Could see the cold flooding south/south west in Scandinavia in the last couple of frames.

Edited November 7, 2014 by Captain shortwave

[terrier]

Think we need to take a moment here. Yes the charts are looking better than last year. But the uk met model still isn't on board. And we're still looking at a good week at least of Atlantic depressions heading towards the uk. All these tasty looking charts are out into fi and the ECM monthly update doesn't really show anything exciting for us near average about sums it up.

[pandit-scholar]

Encouraging from the models this morning regarding possiblity of future cold, with a possible split of the polar vortex, that could leave very little of it left, which is astonishing at this stage.

But Terrier is right, we shouldn't get too far ahead of ourselves just yet, as this is still being modelled in FI, and we have seen this sort of thing disappear from the models overnight. However signs are encouraging at the moment.

In our hunt for the cold, we are also missing the possibility of a storm in the meantime as modelled on the ECM.

Edited November 7, 2014 by pandit-scholar

[joggs]

Im with Terrier,the models can show snowmaggedon a few wks down the track but the latest mo update is not tying in with the outputs of the eye candy.

[Polar Maritime]

I've just had to deleted a post. Amongst all the excitement on what the charts are showing this morning, Please think before posting and only discuss what the Models are showing. There is a thread open for ramps or Meto outlooks.

 

Many Thanks, PM. 

Edited November 7, 2014 by Polar Maritime

[Polar Maritime]

Although there are some wonderfully Wintry looking charts on offer this morning, The Models continue to be extremely volatile with changes in the N/Hemisphere continuing. So expect many many more runs with chopping/changing before any sort of resolvent, In the broad theme of things we are certainly heading in the right direction. But as we have seen in the past with these fickle set-ups and at this time-scale, These signals can be dropped like a hat so beware! Amongst all this the interest grows and continues with fantastic Model watching on offer again today.

 

Edited November 7, 2014 by Polar Maritime

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY FRIDAY NOVEMBER 7TH 2014.

NEXT UPDATE SATURDAY NOVEMBER 8TH 08:00

THE CURRENT GENERAL SITUATION. Fronts will clear NE over the UK today with a showery westerly flow following. A wave depression will move NE over Southern Britain tomorrow.

MODELS-2 WEEK HEADLINE  Unsettled with rain at times across the British Isles with strong winds too and temperatures near to normal.

THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows the flow at around 50 deg North or a little less which takes it across France for much of the period in varying strengths having crossed the Atlantic. This general pattern remains in situ over the entire period.

GFS OPERATIONAL Today's operational run shows the UK continue to see areas of Low pressure crossing the Atlantic and into the UK from the West where they become slow moving and fill slowly before being reignited by new features coming in from the West. This means little change from the current pattern of wind and rain occurring on frequent occasions for all areas in temperatures never far from the seasonal average. Winds will be quite strong at times with gales in places at times.

THE GFS PARALLEL RUN The GFS Parallel run suggests little difference from the operational in Week 1 with plenty of wind and rain for all before a slight change in week 2 is shown in as much as some colder air becomes entrained across Northern Britain for a time with some snow over the hills and mountains for a time.

THE GFS ENSEMBLES.  The GFS Ensembles paint a very active Atlantic feeding low pressure after Low pressure towards and over the UK for the first week to 10 days with rain and showers all too frequent for many in average temperatures. Later on the trend shifts Low pressure more towards the NW while maintaining a windy and westerly flow to the airflow with spells of rain and showers for all in still close to average temperatures.

UKMO. UKMO today shows Low pressure well established over the Atlantic and close to Western Britain with strong and cyclonic winds maintained over the UK through the middle days of next week with rain and showers, heavy at times in temperatures close to average.

THE FAX CHARTS  The Fax Charts continue to show a cyclonic airflow over the UK with Low pressure centred to the West and NW with occasional decelerating Eastward moving troughs crossing the UK each bringing their own version of wind and rain affecting all areas at times.

GEM  GEM continues to look very disturbed with Low pressure after Low pressure moving ESE towards the UK each bringing rain and strong winds at times with average temperatures as a result. Pressure is shown to be High to the North and colder air in association with this could flirt with the North and NE at times later.

NAVGEM NAVGEM keeps the UK locked under Low pressure over the next week, moving in from the WNW and filling slowly in situ across Britain later. Rain and showers will continue to affect all areas at times in blustery winds and average temperatures.

ECM  ECM feeds Low pressure down across the UK over the next 10 days with much rain and strong winds especially towards the South and West. Temperatures should remain close to average though with pressure high to the North later some far Northern areas could see colder air filter in here at times with somewhat drier conditions as a result.
 

THE ECM ENSEMBLES  The ECM Ensembles are rock solid this morning in maintaining a Low pressure belt stretching from Southern Greenland to the UK and down towards Italy on a Jet flow remaining South of the UK and maintaining wind, rain and showers at times in temperatures close to average.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend today has reversed from yesterday morning in as much as any rise in pressure is now shown to more likely edge down from the North later rather than the South meaning the far North could tap into somewhat colder and drier conditions in 10-14 days.

MY THOUGHTS  The synoptic pattern over the Atlantic and the UK is very volatile at the moment and this looks like being maintained over the next few weeks. The Jet flow is quite strong and expected to remain so over the upcoming period and with it's location quite well South Low pressure areas are directed down across the UK spreading their deeply unsettled conditions to all areas. With time there is an interesting and strong trend for Northern blocking to occur up near the Arctic Circle and given the season and the rapidly cooling Northern hemisphere at this time of year colder air over Iceland and Scandinavia later in the period could begin to make inroads South towards the far North and NE of Britain later. At the moment all models show this well bottled in situ as the Atlantic feed of depressions from the States remains strong at the end of the run keeping many areas unsettled and sometimes wet but it is something which will need to be watched ver coming days outputs as there is a fighting chance that this could edge South over Britain later in the month. Probably of more concern though is the cumulative effect of the amounts of rain that are likely to be falling across parts of Britain inparticularly across the South and West and unfortunately a surface flooding risk is likely to grow with time over the period. Interestingly as well if there is any engagement with the aforementioned colder air to the North late in the period we could enhance this risk still more as cyclogenesis would be exacerbated further. So interesting times ahead weather-wise with plenty of active weather events likely over the coming weeks and while there is no sign of a quick dip into winter for the UK there are enough interesting synoptics later in the period to keep the cold fans interested.

[shaky]

With the ecm monthly showing no blocking and continuation of the current spell of weather one has gota wonder which of the models are gona have egg on its face!!!the ecm this morning has picked up on the huge blocking the gfs picked up on just yesterday so maybe the ecm monthly has not picked up on it and it may in the next update!!

[radiohead]

0Z ECM and 0Z GFS ensemble mean at 240 hours. Broadly speaking the NH profile is almost identical on both. Seeing that level of cross-model consistency, on an ensemble mean at day 10, then this is starting to look very likely indeed.

 

Edited November 7, 2014 by radiohead

[IDO]

Looking at the ECM D10 mean to our north and it is clear that the op is again at the top end of it's ensemble suite for a positive heights anomaly in that region:

 

 

 

The mean is 20mb lower so although the mean is not bad in itself it needs to move towards the op in the next few days otherwise it maybe the ECM op  over doing things again. I know the GEM op is showing support for the ECM but again if you compare last night's GEM op with its mean at D10 there is again little support:

 

 

 

Its a case whether the hi res are picking up on some background signal or they are just over doing it. The GEFS mean at D10 has been very consistent with the maintenance of the current pattern and no sign of height rises to the north:

 

 

The AO continues to be forecast to recover towards neutral and this has been consistent: 

 

Embryonic signs of from the D16 GEFS for the PV in the NH to become more organised is now looking like a trend, though again the clusters are relatively even spread so I could not call it in either of three directions yet.

 

So whats for sure are at least another 10 days of Autumnal weather, wind and rain with seasonal temps. After that a degree of uncertainty but more than likely more of the same. Though synoptics continue to work in the background for possible changes in December.

Edited November 7, 2014 by i'm dreaming of...

[Mucka]

With the ecm monthly showing no blocking and continuation of the current spell of weather one has gota wonder which of the models are gona have egg on its face!!!the ecm this morning has picked up on the huge blocking the gfs picked up on just yesterday so maybe the ecm monthly has not picked up on it and it may in the next update!!

 

 

That is an odd post. ECM has picked up on blocking GFS jas shown? You can't have been following this thread or model output very closely but GFS has been playing catchup.

Here are the 12z output from the 5th ECM sniffing the air, GFS nowhere.

 

 

May be better to follow 7/10 anomaly charts for guidance though.

 

 

 

 

 

GFS much better than yesterday and more in line with ECM. Both showing strong positive anomalies to the N/NW which bodes very well.

Edited November 7, 2014 by Mucka

[MR EXTREMES]

Well Well Well -

 

Its doesn't get ANY more extreme from the models tonight..It has been duly noted that the parallel seems to have been performing well so I will include it in the thought process -

 

Remember the 2013 Analogue I posted this morning.

 

From this

March20137th.jpg

 

to this in 3 days

March201311th.png

 

 

Now look at day 7 Parallel chart

GFS07thNov.jpg

 

& 4 days Later

Parallel.png

 

The trending of today has been 3 fold.

 

* ALL models catching up on this high pressure forcing driving NW out of Central Europe - heading for Greenland.

* The Cross polar flow that was predicted to continue Eurasia to the US - the orientation has change to become a cross polar flow from Eastern Siberia around towards Svalbard in the day 8 Means, with possibly further west after-

 

this is illustrated here:

 

ECMday8 Mean.jpg

 

As you can see that's a real good solid swing in the right direction.

 

'Some' of us have been talking about extreme Indices this Winter & the next 10 days after a slight knock yesterday have come on very strong today after beginning to find the right solution for Week 3 of November.

 

In terms of extreme this seems to be the best of the night ( just for fun)

http://modeles.meteociel.fr/modeles/gem/runs/2014110612/gemnh-0-240.png?12

 

But in among the Fantasy runs there is some embedded reasoning for the extreme indexes which we should remingd ourselves

* Deep Negative OPI metric for Oct- Second lowest since 76 only beaten by 2009

* Second best SAI cover on record

* Extreme positive stratospheric temp anomaly already in place over Eurasia (current) even before we get a warming

* Extreme positive height anomaly feedback over the Taymyr region driven by the ice deficiency in October...

 

If there EVER was a slam dunk winter for an extreme -AO setting up this is it, The wave1 activity is driving this change for exactly mid month for the Northern part of Europe & 7 days before this in America.

 

I will leave you with the 00z AO ensembles from today-

 

NOAA AO.gif

 

As you can see a sharp decline, however the GFS wants to lift that pattern out straight away.

I keenly await tomorrows update where I expect an extended low AO & a few -5 runs. Remember the target is -4 index from the analoges as all the negative CET months in the last 50 years have had -4 values appear in Nov....

Cheers

s

indeed steve the models one run after my pessimistic post throw out stunning charts.

last time i see the ao index at neg 4 was 09/10.

 

then this morning we have meat on the bones with even more interest with cold into scandi area and not chilly i mean cold how watered down this becomes in future runs is up for debate.

 

but the retrogression that was thrown out yesterday morning was back last night and is back this morning and getting close to a more relaxed time frame.

 

i notice kayro posted in the strat thread about the vortex re formation but i dont see this happening and its only the gefs in it very latest charts that suggest this but ive not looked at this so wondered if anyone else feels this is the case?.

 

so its getting better and better and nice to see the models forming a chorus and singing from the same song sheet.

 

the gefs does not look like re forming the vortex still the other side of the pole.

the jma dont want to party though its the odd one out but is regarded and used at times by the ukmo

now for eye candy look northeast 09/10 still possible we had lots of northeast flows during this winter.

the 850pha charts fi.

gfs control 

gfs para

and finally the ao

nao looks to go neg then rises again then drops.

once cold establishes itself then its a tough cookie to remove.

fingers crossed this continues but i be happy once retrogression has established a block into greenland.

and futher drops of heights into europe with more activity to our east or northeast.

[bluearmy]

The ECM monthly is a difficult animal to follow post week 2 as 51 members are smoothed out into a mean. Unless you see the clusters then there isn't much to be gleaned unless there is an ultra strong signal through weeks 3 and 4

[mushymanrob]

I know 1 or 2 well respected members don't believe in the use of 500mb anomaly charts and at the most one can only take the 8-14 day NOAA chart as the main guidance, although there is an output with NAEFS further out, but until they show at 8-14 and 3-4 days later still show and so does the 6-10 the trough working east of the UK then it is not likely to happen.

link to NOAA is below and the charts from EC-GFS are very similar.

If 3-4 days down the line and the trough is moved (on the 8-14 day chart) east of the UK with marked ridging as well as large +ve heights showing to fit this idea we can then pretty confidently believe this will happen. I believe 1 or 2 are suggesting something along that time scale for the synoptic models to start to show this in the same time frame.

We just have to wait and see. 2010 is being mentioned, it was only the last 6-8 days in that month that went really persistently cold with snow becoming fairly widespread, at least over central and eastern UK. That was well predicted by UK Met and fairly well 2 weeks ahead on the anomaly charts. Patience is needed with some of you IF a cold end to the month occurs. One thing to look for on the anomaly charts is for NO sign of marked +ve heights in the Aleutians area!

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

 

 

 

wise words john. ive been following these charts ever since you championed doing so and have found them to be pretty accurate. its all well and good seeing fi charts that get hopes up (and this happened in summer too) but the anomaly charts are the ones to watch to get an idea of what might lie ahead. and currently they do suggest northern blocking.

looking at these charts ..

 

and

 

 

clearly suggests alot of northern blocking forming, cold pooling, but both charts clearly show the scandinavian high not retrogressing being sucked up to join with the greenland high. itll be interesting to see whether the models change or not, because itll be a bloody good call if the models are proven wrong.

Edited November 7, 2014 by mushymanrob

[Blessed Weather]

Although there are some wonderfully Wintry looking charts on offer this morning, The Models continue to be extremely volatile with changes in the N/Hemisphere continuing. So expect many many more runs with chopping/changing before any sort of resolve....

 

Unfortunately (for coldies) you are absolutely right PM. This mornings charts from ECM and GFS at Day 10 are similar and both look terrific. Bitter cold heading down towards us...

 

ECM 17th Nov GFS P 17th

 

But as the GFS P continues with this run, the incoming cold to the NE retreats and instead we have to look to the NW again:

 

GFS P 23rd Nov

 

But the 23rd is so far out in FI, and with such volatility in the Nth Hem, I think I'm convincing myself to look no further than the potential at Day 10 and not worry about later output! 

[Polar Maritime]

If you find your post missing, It's because it's been moved to the Winter/ramp/hopes thread, Please think before posting.

 

Many Thanks, PM.

Edited November 7, 2014 by Polar Maritime

[chionomaniac]

 I feel that unless we get tropospheric led wave 2 activity breaking significantly into the strat from Greenland area with the corresponding tropospheric WAA, then we will not get the major early season cold outbreak that is potentially being touted. The anomalies are great to look at, but as of yet they are not going to lead to major cold coming from the east for a number of reasons. The background state is wonderful for later in the winter when cold will be deeper, but not now. I am probably one of the few who doesn't want to see a disturbance in the upper strat that is too strong this early in the season because I think that the ebb and flow of the subsequent recovery will delay the next wave hitting. 

 

Other factors such as the MJO phasing and Cohen background anomaly match, tend to reinforce these thoughts. All is good, but unless we get that wave 2 activity to our NW then the cold will remain just out of reach. Any splits modeled so far have not been in the right area for us.

[Summer Sun]

Once again this morning the PV is really struggling to form even into the depths of FI, could be a very interesting winter coming up if this keeps up...........

 

GFS P

 

 

 

ECM

 

 

Edited November 7, 2014 by Summer Sun

[heath]

The ECM has clearly been leading the way re the high to our north, but its last 2 t240 charts do not have the UK in the firing line.  The 12z had the cold starting to move into NW Russia (and would then need to head east) and the 0z has it heading through Scandinavia and potentially to our north.  This would seem to mean that the UK stays in a cool, wet Atlantic pm flow into the third week of November, while cold gathers all around.

[BlueHedgehog074]

Morning All,

I see a tad of excitment brewing with some of the more experienced model watchers in the last 24 hours. A lot of referencing to a possible hefty negative AO this winter.......can anyone please give a quick reply to what effects this will have on the weather pattern/output if this materialises??

Thanks in advance

I admit I'm not the best person to ask about this, but a negative AO (Arctic Oscillation) relates to a strong blocking High Pressure system over the Arctic and Pole area. It displaces cold air from the Arctic down to lower latitudes with a fragmented Polar Vortex - sections of it become scattered all over the Northern Hemisphere. This can lead to a more sluggish pattern across the Northern Hemisphere with the pattern rather amplified in places. All of this can, but not always, significantly increase the chances of colder Winters for the UK.

In the chart below - the 00Z GEM Northern Hemisphere Sea Level Pressure and 500 hPa chart for 14th November, shows the idea of a strong negative AO - strong heights over the pole region (lots of yellows, green-yellows occupying it) with a disorganised Polar Vortex. The blocking to the North (circled in black) is strong enough (and also in a favourable place) to help steer the Jet Stream to our South with Lows sliding underneath the block. We then get cooler air feeding in from the East.

If something like this was to keep occurring, it could contribute to a cold, blocked Winter this year. Not a complete guarantee, mind you, as sometimes these patterns can break down unexpectedly with the Polar Vortex becoming more organised. Also, it's possible to have a negative AO signature combined with a positive NAO (North Atlantic Oscillation) with cyclonic-mess to the North-West, which could lead to unfavourable conditions for cold for the UK. However, as longs as you've got some kind of persistent block to the North with a negative AO, then even if the pattern tries to breakdown somewhat and/or becomes unfavourable for cold for the UK, then it's possible for a cold, blocked set-up to re-establish.

This is different when compared to the chart below with its positive AO signature. Low heights to the North with a rather organised Polar Vortex.

While there is some ridging of High Pressure around the Pacific area (near the Western North American Coast), this is a setup cold and snow fans despise as it usually helps maintain a generally flat Westerly pattern across the Hemisphere with a raging Jet Stream. Unless notable disruption to the Vortex occurs via a Sudden Stratospheric Warming event, for example (and even then it would have to be in the right place to help bring cold to the UK), then we can become locked in a mild Westerly pattern with High Pressure staying stubborn to our South or South-East with Lows to our North or North-West. Not often good for significant cold for the UK.

Sorry for the long reply (I know you wanted a quick one), but hope it's still of some help.

Edited November 7, 2014 by DiagonalRedLine
Post had appeared twice

[SMU]

Morning -

Certainly great model outputs today and cause for optimism whilst stepping back & ensuring we dont go to overboard with expectations-

I cant post to many details this morning as typing from iphone -

Some things to observe today-

Ensemble mean V operationals ALWAYS 24 - 36 hours beind the pattern change so discard muted signals for blocking past day 8-

Watch for corrections of the vortex allignment over russia at 168, the less cold runs have the cold flow alligned south south east creating a bow of higher pressure across scandi & as a result whilst the flow trends easterly the upper cold cant make sharp turns around that high-

Watch for the allignment to move to south south west - then the cold air moved quicker sw through scandi

Finally ECM monthlies are volatile & poor, however because the met office do release a monthly view thats the model in conjunction with MOGREPS they will use, unfortunatley when these landed this werk they had already missed the boat.

ECM monthly = already out of date.

S

[Winter Frost]

Steve I think what you say about the vortex alignment is happening on the 6z as cold is stuck up at Norway. Nothing to worry about then?

[shaky]

Morning -

Certainly great model outputs today and cause for optimism whilst stepping back & ensuring we dont go to overboard with expectations-

I cant post to many details this morning as typing from iphone -

Some things to observe today-

Ensemble mean V operationals ALWAYS 24 - 36 hours beind the pattern change so discard muted signals for blocking past day 8-

Watch for corrections of the vortex allignment over russia at 168, the less cold runs have the cold flow alligned south south east creating a bow of higher pressure across scandi & as a result whilst the flow trends easterly the upper cold cant make sharp turns around that high-

Watch for the allignment to move to south south west - then the cold air moved quicker sw through scandi

Finally ECM monthlies are volatile & poor, however because the met office do release a monthly view thats the model in conjunction with MOGREPS they will use, unfortunatley when these landed this werk they had already missed the boat.

ECM monthly = already out of date.

S

that's pretty similar to what I posted earlier regarding ecm monthly maybe missing the pattern change this time and will pick it up in the next update!!anyway 06z gfs not as good but not bad!!hopefully the 12zs will have stronger heights across the arctic again!!