Model Output Discussion; into 2015

[nick sussex]

It has to be said a mlb is a bloody good deal considering and many many mlb has eventually lead to something wintry especially in late jan and feb.

I wrote jan of a longtime ago but in all fairness a mid latitude block can end up anywhere only take a slight weakness in vortex then the mlb ends up a Scandinavia block or even but rare Greenland block.

I do however see solar forcing really mixing up the atmosphere but at the same time there are still background drivers that are in favour for something cold I punt for at least a week in feb for something more substantial if not then a uk high pressure things settled but frosty.

It's all pretty knife edge and looking at the models in detail you can see why.

We await the ecm on its verdict but this model has been if anything more against coldies and has been performing well apart from nov with its garden path greeny heights.

I don't believe any blocking will be sustained this month around Greenland.

At this point I think theres more chance of me losing weight than a Greenland block, sadly my resolution lasted all of 3 days! I think the best we can hope for is something similar to late December with perhaps a less quick topple and if we're lucky this topples towards Scandi but that depends on whether the PV can elongate and not reform into one round blob much like my current waistline!

Edited January 5, 2015 by nick sussex

[Geordiesnow]

Still interested in how these fast moving low pressure systems are going to be modelled, still the potential for quite a deep vigirous low with severe gales possible as we head towards the weekend. 

 

The cold shot from the NW would still interest me also even though it seems PM shots from the Atlantic tend to be more modified hence if the same cold came from the East, it would look more likely snowfall would get to lower levels however if this set up does not downgrade then some lower level snowfall is certainly possible, one to watch for sure. 

 

Overall for anything more significant and longer lasting cold, the outlook is still awful, we do still look to be in a bit of a rut unfortunately but I would still not write off the whole of January by any means though. 

[Mucka]

NCEP commented in their update that the GEFS unusually might be more amplified than the ECM ensembles:

 

HEIGHTS BUILD AGAIN IN THE NORTHEAST PACIFIC AND WESTERN CANADA

DOWNSTREAM FROM A TROUGH IN THE EASTERN PACIFIC...WITH AMPLITUDE

DIFFERENCES AS THE GEFS MEMBERS BUILD THE RIDGE FURTHER NORTH THAN

THE ECMWF ENSEMBLE MEMBERS.  SINCE THIS AREA IS DOWNSTREAM FROM

PERSISTENT CYCLONIC FLOW TAPPING WARMER AIR FROM THE

SOUTH...HIGHER HEIGHTS ARE POSSIBLE...SO WE PREFERRED TO

INCORPORATE THE GEFS FCST INTO THE OVERALL BLEND TO OFFSET THE

SLIGHTLY LOWER ECMWF HEIGHTS.

 

Further on this caught my eye:

 

WITH

THE CYCLONIC FLOW OVER THE CENTRAL PACIFIC CONTINUING EARLY NEXT

WEEK...THE EAST PACIFIC RIDGE AMPLIFIES ALL OVER AGAIN.

 

Its somewhat confused because there was talk of the ridge breaking down and a zonal flow taking over the CONUS for the second half of January, maybe that's still the case but timing wise can we get some blocking before that happens and then a favourable topple towards Scandi.

 

Also is the cyclonic flow in the central Pacific a good sign re the MJO?

 

 

These updates are great and always Interesting.

One thing I have noted within GFS ensembles on some members is a tendency to try and resurrect any Atlantic ridge deeper into the runs.

That is why I suggested a messy 3rd week pattern where the rest of January's weather will be decided is quite likely with the Atlantic being favoured to win out at this point.

Even if the first attempt is overrun I can foresee another attempt coming quickly behind so even though I favour the Atlantic  at the moment I would be very reluctant to discount cold/blocked prospects for the rest of Jan.

 

At least it is nice to have the thrill of the chase again, hope coldies can get some satisfaction this time.

[Daniel*]

It does irritate me how some decide to take every run like a predecessor of what is to come, I notice this bias is increased when it comes to mild SW'lies, meanwhile once cold is shown its like how can this happen bah we've been let down before why will it be any different. Later on GFS is really rather cold on the surface, with +ve heights possibly trying to establish towards our E, this opens up interest going foward. We've had a fair share of disappointments so I understand the unease, but even teams like millwall will scrape out something from every 10 games. I genuinely think we will have at least once bite at the cherry this winter...this is nothing like last winter although the upcoming days will feel like it, certainly not a stagnant pattern, turbulent week ahead but once the tide retreats interest sprouts. I'm no expert but the final third to me seems like the ignition..

[Mucka]

Hey those charts hardly show any downgrade at all, certainly not worth pointing out with still plenty of runs showing 850 hPa temps of -5C next week.

 

They downgrade the weekends snow chances and downgrade the cold prospects in deep FI with a warm up replacing the cooling trend. If you look through the actual ensemble suite you see there is more of a tendency to quickly overrun any blocking attempts.

I think downgrade can be an emotive term but it is not meant as such in this context.

Also I am not stating it is a trend as yet, just pointing out the differences.

Edited January 5, 2015 by Mucka

[Nick F]

For what its worth im still at a loss why a rise in pressure to the west of the uk in fi is getting so much attention?I appreciate its popping up on gfs-gfs p but wheres the underlying trend for this to materialise?The 500mb charts don't hint at it altho I guess anything is possible tbh.Im the eternal optimist but its a long shot given the weather coming off the eastern seaboard a big ask at that distance!!Heres hoping anyway

 

Unlike last winter, climo this winter is more supportive towards some sort of blocking later this month or failing that, in February.

 

The ENSO, which is in a weak Nino-ish pattern atm, tends to favour a more blocked pattern in the second half of winter historically - more particularly Feb, but also late Jan. Winter 2004-05 keeps cropping up as a good analog, as it also had a weak El Nino. December that winter was fairly zonal apart from a brief northerly late in the month. January was predominantly zonal, but 22nd onwards saw a ridge build north to west of the UK, as indicated by recent GFS op/P:

 

http://www.wetterzentrale.de/archive/ra/2005/Rrea00120050123.gif

http://www.wetterzentrale.de/archive/ra/2005/Rrea00120050125.gif

 

The mid-latitude high hung around near the UK through much of February 2005, though didn't position favourably to the north of the UK until later in the month to produce a cold easterly flow (though it was a fairly marginal easterly flow):

 

http://www.wetterzentrale.de/archive/ra/2005/Rrea00120050223.gif

 

MJO movement in Jan and Feb 2005 was also favourable for blocking later in those months, going into 7/8 late Jan and 7/8/1 late February. We may see movement towards 7/8 in the next 2-3 weeks, we may not.

 

 

Furthermore, easterly QBO this winter favours a weakenening of the PV at times, so continued rossby waves propagating towards the pole in -QBO will put further pressure on it over the coming weeks/few months.

 

Now, each winter will work out different to analog years of course, but it shows that similar climo may lead to similar outcomes using them.

Edited January 5, 2015 by Nick F

[Frosty.]

I don't understand the downbeat mood about the 12z so far, there is nothing unexpected here, no different to the latest MO update, unsettled, very windy at times, milder when its wet and windy, colder when its showery. I'm fed up of looking at trashy zonal charts but what can we do about it, this sums up the winter so far, with no sign of a marked change according to the experts in Exeter.

Edited January 5, 2015 by Frosty.

[Mucka]

I don't understand the downbeat mood about the 12z so far, there is nothing unexpected here, no different to the latest MO update, unsettled, very windy at times, milder when its wet and windy, colder when its showery. I'm fed up of looking at trashy zonal charts but what can we do about it, this sums up the winter so far, with no sign of a marked change.

 

But that doesn't sound a very upbeat counter Frosty.

We need the old Frosty cheering on the blocking 2nd half of Jan.  :w00t:

[IDO]

The repeating December pattern can be seen by a comparison of ECM:

 

  WSI_Energy
History doesn't repeat but sometimes it rhymes...January evolution similar to December evolution? http://t.co/JMO5GhNXNX
05/01/2015 18:15

 

GEM is a bit better tonight in that the short waves are not as predominant on the jet as it exits the US. There is a similarity with HP escaping the Conus and blending with the Azores:

 

 

 

[Carlrg]

  I think that we are on borrowed time this year re cold for our tiny island and have 4 possible opportunities for cold before the horse bolts.

 

1. The desalination of the Atlantic ocean leading to catastrophic failure of the gulf stream.

 

2. The eruption of the super volcano under Yellowstone Park spewing millions of tonnes of dust particles into the upper atmosphere and blocking out the sun.

 

3. A giant asteroid hitting the Earth causing a tilt in the axis and sending the British Isles into a more northerly and more favourable position.

 

4. A perturbation in the mysterious and enigmatic FI actually verifying.

 

 

 

 

 

 

 

 

 

 

 

But unfortunately any 1 of the 4 above mentioned scenarios has an equal chance of coming to pass.

Edited January 5, 2015 by Carlrg

[Frosty.]

But that doesn't sound a very upbeat counter Frosty.

We need the old Frosty cheering on the blocking 2nd half of Jan.  :w00t:

How's this for positive, this winter can only get better, I still think mid or especially late january will bring a colder spell based on lots of wintry perturbations in recent days covering that period.

[Mucka]

Can somebody nuke the monster slug Eating our Winter please.

 

[Polar Maritime]

  I think that we are on borrowed time this year re cold for our tiny island.

 

Not at all, In-fact far far from it. It's the 5th of January, Were not even half way through Winter yet.. 

 

Let's continue discussing what the Models are actually showing.  

Edited January 5, 2015 by Polar Maritime

[Geordiesnow]

Interesting ECM 120 Hours with that unusual kink looking in the isobars, could be some very very strong gusts for a brief time for Scotland looking at that. I do doubt the reality will look like that mind but the potential for some stormy weather is still there. 

 

Shame it totally downgrades the polar airmass at 144 hours mind but still pretty gusty. 

[MR EXTREMES]

At this point I think theres more chance of me losing weight than a Greenland block, sadly my resolution lasted all of 3 days! I think the best we can hope for is something similar to late December with perhaps a less quick topple and if we're lucky this topples towards Scandi but that depends on whether the PV can elongate and not reform into one round blob much like my current waistline!

You and me both fella be alright if we could go play in the snow might lose some pounds maybe stone that way lol.

I agree though Nick it's all looking a bit to vortex controlled right now.

And my waistline is pretty much like last years vortex at least you lost some this winter haha.

What I find odd is there not been any substantial information about what's happened in the strat and it's all go rather messy like the models !.

I expect the big cheeses within the net weather circle must be wondering what's going on but I will say at the start of winter I felt more optimistic than 09/10 because there's no doubt that all these drivers are interconnected!.

But just goes to show the slightest changes make big differences !.

The vortex was on the ropes in early December but had managed to find some steroids for the fight back it seems it now found a can of spinach lol.

[Mucka]

Interesting ECM 120 Hours with that unusual kink looking in the isobars, could be some very very strong gusts for a brief time for Scotland looking at that. I do doubt the reality will look like that mind but the potential for some stormy weather is still there. 

 

Shame it totally downgrades the polar airmass at 144 hours mind but still pretty gusty. 

 

 

It phases the second low very quickly into the flow from 120h to 144h but it is hard to know what sort of flow is maintained because of the 24h steps. On the downside (for NW snow chances) it mixes in some milder air but on the plus side the warm sector is very limited through the transition maintaining coldish uppers for many.

I guess it is all academic as will change again the next run.

[Frosty.]

Let's continue discussing what the Models are actually showing.

Exactly, and what they show is polar maritime alternating with tropical maritime and rPm for the next few weeks, towards the end of this week looks a little more wintry, especially for Scotland but then another bout of wet & windy weather early next week followed by colder and showery weather, this is then followed by another spell of wet and windy weather...lol.. and this is followed by colder and showery weather, and this is..I think you get the picture. Edited January 5, 2015 by Frosty.

[knocker]

Which translates to above average temps in the near future.

Chart weatherbell

 

Edited January 5, 2015 by knocker

[Jason M]

Bit suprised at the comments tonight. I'd assumed the GEFS were a mildfest tonight, but actually they are okay. There is a lot of uncertainty but that's to be expected out beyond day 10. In essence the uncertainty is a good thing in this context as tbh a few days ago the pattern was absolutely nailed right out to 384 hours. This break in the pattern is also moving forward still through the timescales.

I agree with Nick :-) regarding the chances of Greenland blocking. Next to no chance IMHO given the way this winter has gone. If we get anything at all it will be via a block to our East / northeast in my view.

[mushymanrob]

Id have thought the gfs 12z is practically in line with what the noaa anomaly charts would allow... Ie not much of a ridge at all, and a feature youd pretty much expect in a mobile westerly flow.

Theres no pattern change there... Sorry.

[gottolovethisweather]

Upon viewing the GFS (P) 12z, although continuing the zonal theme there is a tendency from the 10th January onwards out into deep FI for the NH Jet axis to dive across us on a NW to SE trajectory more often. These are much preferred synoptics than those we are enduring currently and is apparently a trend over recent viewings, at least to my eye. The only snow hopes away from the NW exist on such FI charts right now but even the ECM 12z of late sticks to a similarly developing theme. Warm sectors or TM airmasses within the depression driven outputs of alternating rPM and TM incursions through the entire run, would obviously cause any melting of any transient snowfalls but at least the risk is there, unlike last Winter and a fair few that I personally detested during the 1990s. Hell, even a channel low pops up at t+288 hours which would be something to remember this Winter by down in my neck of the woods.

 

Entrenched and prolonged cold nowhere to be seen for now in the outputs and to be fair, such synoptics are very rare. However, the favoured timescales for such conditions to occur are so often from the second week of January right through to the end of February, if one should look back through the annuls of time. All of us cold Winter hearted folk simply need to remember how the UK weather can and often does change unexpectedly due to our chaotic climate dynamics and I feel that the charts may well look a whole lot different by the end of this coming week as we head nearer mid-January. 

Edited January 5, 2015 by gottolovethisweather

[nick sussex]

The ECM in terms of the weekend is very flat and any PM flow is very short, the UKMO is the coldest and keeps it going for longer. The GFS supports the ECM so for the timebeing the UKMO looks a lower probability.

 

Thereafter the ECM is flat as a pancake upstream, by T240hrs it develops a family of shortwaves which develop to the sw, its hard to know what the ECM's next step would be!

 

Perhaps the Adams family might support a lobe of high pressure working eastwards if theres a touch more amplification over the central USA.

 

Overall the ECM is pretty underwhelming but even if the MJO does go into phase 7 the ECM probably won't pick that up until tomorrow.

[chris55]

PV easing over Greenland, disruption to Azores high. ECM det FI trending slightly towards GFS idea.

 

Edited January 5, 2015 by chris55

[johnholmes]

I've just posted this in the storm thread area but in terms of short term weather it is also relevant in here, this is for any model related discussion not just GFS F1.

 

UK Met having trouble as well in sticking a pin in the chart! Unkind but obviously they are getting varying outputs from the models they use.

The latest show at 00z Thursday T+72 991mb approx 47.5N 46W and at 12Z 53.5N 31W centre 979mb, both these fixes given this morning. The 12z fix fits about what they had a day or so ago I think it was, and is different to the T+84 which showed a centre 991mb and further west.

Not sure just how it is then and in the future to what the jet will be but simple extrapolation would move it just north of the Faroe Islands. Of course if it exits at the left exit of the jet then turning more sharply and being deeper.

Turning to their Atlantic area shipping outlooks, link given below along with the Fax link I use (I prefer it as it gives the times of output for each Fax chart), the bit about the low we are talking about I have bolded.

http://www.metoffice...-seas/#?tab=map

Fax link

http://www.weatherch...rg/ukmomslp.htm

It certainly is worth watching, and was well predicted in a general sense 4-5 days, if not longer, by the anomaly charts which showed the Atlantic really showing a very strong flow with marked temperature contrasts at 500mb.

 

The general synopsis at 0800 UTC Mon 5 Jan

At 050000UTC, lows 61 north 35 west 967 and 58 north 31 west 977 merging, expected 67 north 18 west 977 by 060000UTC. Developing low near 57 north 20 west expected 73 north 15 west 967 by same time. Low 66 north 29 west 960 expected 65 north 36 west 977 by that time. at 050000UTC, low 47 north 70 west 993 expected 53 north 49 west 965 by 060000UTC

[Cloud 10]

Which translates to above average temps in the near future.

Chart weatherbell

 

.....but below average temps in the nearer,near future.