Model Output Discussion 19th January 2014-18z onwards.

[mountain shadow]

Certainly any cold is only likely to come from the East or North West as the NAO is forecast to remain positive for a good while yet.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml

 

At least the AO forecast shows a good few member going negative indicating that at the very least cold air will be leaving the Pole for mid latitudes..

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml

 

Zonal mean temperatures over the Pole at 30hpa are at least back to average, so hopefully the PV will be packing less punch, have perhaps the models been overplaying the PV recently?

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/30mb9065.gif

[Mark Parsons]

Looking at today's text update from the met Tuesday to Thursday looks the best chance of seeing some wintry showers in the east / north east before a return to westerly winds from Friday

 

Unsettled through Tuesday and Wednesday with showers or longer spells of rain, wintry in the northeast where it will feel cold in the strong easterly winds. Elsewhere, temperatures will be near, or just below, normal and it will be windy in the southwest, risk of overnight fog and icy patches.

 

Less unsettled with sunshine and some showers on Thursday; perhaps wintry in the northeast/east.

 

However, a return to westerly winds is expected from Friday, with further outbreaks of rain, hill snow in northern Britain, and strong winds

I don't think any forecast like that one is surprising considering the intense cold in North America creating once again a strong jet that will give us possibly a repeat of what we had a few weeks back.  

[Summer Sun]

GFS 06z 8 day temperature anomaly continues to keep temperatures below normal for all but the south west, Kent, western wales, and parts of western England (more so near the coasts)

 

 

Normal 2m temps left, expected 2m temps right

 

Edited January 23, 2014 by Summer Sun

[karlos1983]

It is fascinating stuff right now watching the models and could be a lot worse IMO.

 

We are in with a chance of cold arriving from the East, A cold North West flow, or raging Zonal or all 3. This is why I enjoy watching the Models, probably to an unhealthy level tbh, but it really is gripping stuff.

 

My preference is obv to get as much cold in winter as possible, but if it doesn't happen, like this winter so far there has been plenty to keep us glued.

 

Any cold that may or may not arrive next week, looks unlikely to make it to my region, really need a full on easterly with a nice channel low for CSE and the SW to really benefit away from high ground, I'm just enjoying the ride at the moment.

[SMU]

My only comment since the overnights ( Excluding the 06z ) would be the consensus is to push the atlantic through- as per METO summary-

 

However the confidence in that outcome coming to fruition at day 8 today has weakened as already the models have swung towards a more powerful Scandi block.

 

As a result the ensembles are colder etc etc.

 

Theres 2 Scenarios here- but both are almost identical on the anomaly charts- as highlighted by Ian, Low pressure towards Southern Greenland / Iceland, Azores High, Euro trough & Scandi high.

 

Within these seemingly quasi-stationary features though is the little old island we live on & we sit right in the zone of error, so at day 9 a small model correction west by 500 miles will blanket the UK of White, while a small correction east will blanket the UK in wet....

 

Ignore the ensembles in the long term, until we see model unity around how much blocking gets North of the low at 120- The UKMO is the best solution-

with the plucky NAVGEM biting away like a little terrior as well

http://www.meteociel.fr/modeles/navgeme_cartes.php?ech=6&code=0&mode=0&carte=1&archive=0

 

S

[shedhead]

Impossible to be prescriptive. Even next week is tricky enough and no-one at UKMO will discount more wintry possibility given ongoing variance in model handling of low track/shape, entrainment of colder air etc. But that is still a few days away, so not a pressing forecast issue.

Thanks Ian...I'm sure you can understand the on going concerns here and why chasing a few wet snowflakes around 5 or 6 days hence is not exactly the main priority. Frankly I'd settled for a strong, dry cold E'erly that would just hoover the moisture out the ground but not freeze it...that however still looks like a hope rather than an expectation for now. Cheers again.

[MPG]

My only comment since the overnights ( Excluding the 06z ) would be the consensus is to push the atlantic through- as per METO summary-

 

However the confidence in that outcome coming to fruition at day 8 today has weakened as already the models have swung towards a more powerful Scandi block.

 

As a result the ensembles are colder etc etc.

 

Theres 2 Scenarios here- but both are almost identical on the anomaly charts- as highlighted by Ian, Low pressure towards Southern Greenland / Iceland, Azores High, Euro trough & Scandi high.

 

Within these seemingly quasi-stationary features though is the little old island we live on & we sit right in the zone of error, so at day 9 a small model correction west by 500 miles will blanket the UK of White, while a small correction east will blanket the UK in wet....

 

Ignore the ensembles in the long term, until we see model unity around how much blocking gets North of the low at 120- The UKMO is the best solution-

with the plucky NAVGEM biting away like a little terrior as well

http://www.meteociel.fr/modeles/navgeme_cartes.php?ech=6&code=0&mode=0&carte=1&archive=0

 

S

Exactly. People on here always moaning when FI cold charts are shown, but its OK if the METO say in 8-10 days time it will be a return X or X weather and everyone beleaves it.

Edited January 23, 2014 by MPG

[Iceaxecrampon]

06z T84

 

 

 

Snow probability only 50 - 50 is that why some members not frothing at these runs?

 

Improving - if thats what you want - for NE and Cleveland hills

 

 

......then the UK will come to a standstill on Tuesday as the LP slips

 

 

Still not impressed by any possibility of decent ppn totals - BUT if Blizzards are your thing at altitude.......

 

Yes - an interesting weekend to say the least - some excellent discussions on here making good reading - might be a late night or two?

 

Stay Safe

 

Ian

 

 

 

 

 

[Iceaxecrampon]

It is fascinating stuff right now watching the models and could be a lot worse IMO.

 

We are in with a chance of cold arriving from the East, A cold North West flow, or raging Zonal or all 3. This is why I enjoy watching the Models, probably to an unhealthy level tbh, but it really is gripping stuff.

 

My preference is obv to get as much cold in winter as possible, but if it doesn't happen, like this winter so far there has been plenty to keep us glued.

 

Any cold that may or may not arrive next week, looks unlikely to make it to my region, really need a full on easterly with a nice channel low for CSE and the SW to really benefit away from high ground, I'm just enjoying the ride at the moment.

Apologies OT

 

You have some fantastic Summers in your location which I know so well (Studland) Karlos - your right -  maybe too much to ask with these synoptics for a decent snowdrift on Ballard Down - come up here in February we dont bite!

 

 

Ian

[pip22]

According to Jay Wynne's bbc forecast just now he says ''its gonna turn colder early next week''. He does not said mid-week next week. I confused now.

Edited January 23, 2014 by pip22

[nick sussex]

Looking upstream and uncertainties re how energy gets ejected into the Atlantic next Tuesday is looking like an important factor, and then if you ally this to the differences in terms of the blocking to the ne you can see how we're seeing these different solutions later on.

 

THIS 22/12Z MODEL CYCLE...THE BIG FOUR DETERMINISTIC RUNS(UKMET...CANADIAN...ECMWF AND GFS) ALL SHOW BACKSIDE DYNAMICSSTREAKING THROUGH THE BASE OF THE TROUGH AXIS AS THIS LOW SHIFTSNORTHEASTWARD. BUT THERE IS NO CONSENSUS--FROM A LATITUDINALPERSPECTIVE ALONG THE EASTERN SEABOARD ON TUESDAY WHERE THEENERGY/JET STREAK EXITS THE EAST COAST ATOP AND BEHIND THE NEWARCTIC BOUNDARY SPREADING OUT INTO THE WESTERN ATLANTIC AND ACROSSTHE GULF COAST.

 

Those differences remain today and we need to see those resolved before pinning our hopes on a particular outcome. 

Edited January 23, 2014 by nick sussex

[ITSY]

I've seen worse ensembles in my time!

[karlos1983]

Looking upstream and uncertainties re how energy gets ejected into the Atlantic next Tuesday is looking like an important factor, and then if you ally this to the differences in terms of the blocking to the ne you can see how we're seeing these different solutions later on.

 

 

 

Those differences remain today and we need to see those resolved before pinning our hopes on a particular outcome. 

 

Hi Nick, out of interest, what is our preference? Apologies if it seems obvious, but I always struggle with the upstream pattern and how it affects us, PV aside that is.

 

Cheers

 

Karl

Edited January 23, 2014 by karlos1983

[shetland islands]

I would agree with the UKMO outlook. It is quite astonishing that I am around 100 miles west of Norway, where it has been freezing with major snowfalls. I would expect some of this cold to filter SW across NE Scotland at times bringing some wintery conditions. Looking pretty stormy on Sunday/monday too for the N and NW.

[Radiating Dendrite]

Looking upstream and uncertainties re how energy gets ejected into the Atlantic next Tuesday is looking like an important factor, and then if you ally this to the differences in terms of the blocking to the ne you can see how we're seeing these different solutions later on.

 

THIS 22/12Z MODEL CYCLE...THE BIG FOUR DETERMINISTIC RUNS(UKMET...CANADIAN...ECMWF AND GFS) ALL SHOW BACKSIDE DYNAMICSSTREAKING THROUGH THE BASE OF THE TROUGH AXIS AS THIS LOW SHIFTSNORTHEASTWARD. BUT THERE IS NO CONSENSUS--FROM A LATITUDINALPERSPECTIVE ALONG THE EASTERN SEABOARD ON TUESDAY WHERE THEENERGY/JET STREAK EXITS THE EAST COAST ATOP AND BEHIND THE NEWARCTIC BOUNDARY SPREADING OUT INTO THE WESTERN ATLANTIC AND ACROSSTHE GULF COAST.

 

Those differences remain today and we need to see those resolved before pinning our hopes on a particular outcome. 

 

Love the terminology - backside dynamics?

 

Does this mean they are talking out their a*** Nick?

 

[nick sussex]

Hi Nick, out of interest, what is our preference?

 

Cheers

 

Karl

In a nutshell the UKMO view  because that's the more amplified one and less energy will spill east off the PV, if you follow the UKMO and GFS they have a similar view upstream but the GFS is flatter, as the shortwave engages the PV some of that gets pulled nw and another piece of energy gets thrown se which heads into the troughing over the UK.

 

The UKMO also has the stronger block which of course is a big help.

[AWD]

GEFS 06z scream cold rPm/pm airflows to me in the medium range. Interesting for the north and not just to the highest ground if you don't mind it being temporary/repetitive;

Bit more iffy the further south you are, although dependant on your expectations and desire, not without interest here either;

[Summer Sun]

According to Jay Wynne's bbc forecast just now he says ''its gonna turn colder early next week''. He does not said mid-week next week. I confused now.

 

Tuesday to Thursday looks to be the current estimates before the Atlantic could break though by Friday but temperatures remain average at best lots to sort out between now and later next week

 

The main concern short term is the rain tomorrow and Sunday where an amber warning is out for Somerset some concern in Somerset for further flooding given the state of the Somerset Levels currently, yellow warnings are also out for Northern Ireland, South Wales and parts of southern England.

Edited January 23, 2014 by Summer Sun

[ribster]

Thanks Ian...I'm sure you can understand the on going concerns here and why chasing a few wet snowflakes around 5 or 6 days hence is not exactly the main priority. Frankly I'd settled for a strong, dry cold E'erly that would just hoover the moisture out the ground but not freeze it...that however still looks like a hope rather than an expectation for now. Cheers again.

I think you miss the point shed, this is a weather forum/thread for amateurs if I'm not mistaken. It's not a COBRA meeting, the authorities and emergency services receive their warnings/updates from the METO and others(as we have here) so that planning and preparation can take place. Which is best done by the professionals, what will be will be, all that can be done is to warn/prepare people. This constant jibing of those chasing snow in January god forbid is wearing a little thin!

[Frosty.]

I would agree with the UKMO outlook. It is quite astonishing that I am around 100 miles west of Norway, where it has been freezing with major snowfalls. I would expect some of this cold to filter SW across NE Scotland at times bringing some wintery conditions. Looking pretty stormy on Sunday/monday too for the N and NW.

Yes I would have thought the further north east you are, there is less chance of missing out on the cold and snow, according to the models. Whereas, the further south west you are, the less chance of anything wintry.

Edited January 23, 2014 by Frosty.

[Mucka]

I expect some will be disappointed with the latest MetO 15 day forecast with only a mention of some wintriness possible for the NE and fairly quick return to a Westerly flow with temps normal or a little below normal.

That is obviously a blended solution because the UKMO raw would likely bring the snow line further S and W  and it would also unlikely herald a quick return to a Westerly type flow with trough disruption across the W of the UK likely going forward from the 144 chart.

Given Ian's updates of the other models and ensemble suits there is no way the MetO would give a wintry forecast for that period with the evidence at hand but what they put out for public consumption and what they discuss as possibilities behind closed doors would probably give a different perspective on the likelihood of a wintry outbreak.

 

ECM London ensembles certainly look chilly with a 5 day period where the mean is around 3C or 4C which would come down a degree or two further without the scatter from around 30th Jan to 2nd Feb. Thereafter they show a gradual warm up but the ensembles will 99% of the time show a gradual warm from a point of below average temps, the further range the more toward average they will trend. I would never base a forecast outside the mid range on ensemble graphs in situations such as this - they are virtually meaningless as a one point reference and need to be used as a tool to spot trends, they are more useful for probability forecasts at closer ranges. We really need to go through the postage stamps and look at the evolution of each perturbation to get a feel for how things are shaping up.

 

 

The UKMO is obviously the best of Op runs this morning and we can see it keeps the chunk of Canadian PV out West and quietens the Atlantic while ECM and GFS want to bring the PV East toward Greenland for the same period. GFS as always is most progressive.

 

 

No way to tell which is right but the UKMO has been the most consistent so probably a blend of UKMO and ECM isn't far off. 

Things are still very much in the balance for the sort of weather type we get from the 27/28th but it will be chilly either way with some wintriness for some, especially over high ground.

It is still as you were from last night with us hoping the UKMO once again sticks to its guns and the ECM moves toward it but it is a positive that ECM ensembles are trending colder (If indeed it is a trend, we will have to wait for tonight's set) 

[nick sussex]

Just to expand on the differences upstream, heres the UKMO for T120hrs:

 

 

And now the GFS 06hrs run to T114hrs:

 

 

Now who paid attention to their geometry part of maths, not me! anyway you can see the difference in angle between shortwave and energy heading se, the UKMO is sharper and has the shortwave further west because its upstream pattern is more amplified.

 

You don't want to see that arc but more the right angle if I've got that right!

 

 

[bluearmy]

 

According to Jay Wynne's bbc forecast just now he says ''its gonna turn colder early next week''. He does not said mid-week next week. I confused now.

 in a strong wind from the wnw, it will certainly feel colder. its a forecast for the masses.

[Lynxus]

It will be nice to see some colder weather what with the models showing further wet weather.

My concern for now is tomorrows heavy rain moving in from the South West which may cause more flooding issues.

 

 

Could we also see some of the major floods that hit Cornwall a year or so ago? Even places right next to the sea were flooded..

Just no where to drain all this water away. 

[gottolovethisweather]

Nope.

UKMO assessment on 00z suites as previous. Snow NE especially Tues-Thurs etc; perhaps spell of snow W/NW later in week as westerly mobility returns. Low confidence on detail/timing with marked entropy spike d8-9. Thereafter high confidence on return to broadly zonal pattern "as seen so far this winter" albeit with around 10% EPS/MOGREPS showing varied interruptions through deep lows etc, some with easterly components. Anyway, detail Tues-Sat trickiest but UKMO not currently concerned re major snow threat for e.g. southern England (but it is too far away anyway to be given much detailed attention). In any case, all their focus on disruptive weather is tomorrow and Sunday, understandably.

 

Thanks for your updates as ever, tis good to receive a privileged viewpoint on things in here. However, part of what you state above has me confused and it's the bit I've highlighted, can you explain things further when you get a moment. 

 

How can higher confidence be ascertained after a period of lower confidence beforehand. Maybe I'm being a bit of a nitwit but I don't get your statement.

 

Aside from all that, from what you've consistently suggested I believe you forsee a right ole mixture going forward with still some sort of battleground in the meantime but with the Atlantic expected to break through eventually.

Edited January 23, 2014 by gottolovethisweather