Model Output Discussion - Heading Away From Easter

[be cause]

Awful charts IMO, I don't see the point in cold weather/great winter synoptics now, had moderate snow showers yesterday under -10 uppers yet absolutely no accumulations. And that's even with a cold low level flow undercutting.

So to get any decent snowfall now would take something truly special, even then it would probably be quickly gone.

I'm with Gavin let's have some warmth and some lower heating bills!

And although we have had a truly awesome march, I just hate seeing such beautiful synoptics going to waste, If it had of been one month/6 weeks earlier we would have probably been looking at something similar to 1947... sods law

week old snow piled high even in Belfast city center and as for the countryside ....we are looking at 1947 .. and in parts much worse .. synoptics could still produce the goods if you love snow ....

[Mucka]

It is looking very nice indeed in FI, to be fair ECM have performed very well indeed.

Well it has some support from this mornings ensemble mean but there isn't enough support across the output to take it at face value yet and there is an awful lot of uncertainty in developments between now and 144 let alone between a projected 144 and 240 chart.

Of course it may be picking up on a signal and it could be just the details that change rather than the synoptic but looking across the output at the moment it could easily flip back to blocked and cold tomorrow IMO.

BTW I switched allegiance to the mild camp some time ago so I hope it is right even though as Crew says it looks as though it would become unsettled from there though a good deal milder than now.

[mcweather]

Not bad at all from ECM towards the end of its run pressure slowly becomes lower over Greenland and high pressure builds over the UK with the coldest air heading off into eastern Europe out the way

Pressure is getting squeezed out over Greenland and the high build's over the UK

Coldest uppers build in eastern europe

And now the high has gone from Greenland with high pressure over the UK

Milder air slowly pushing in from the west

We'll be lucky on this occasion and avoid the coldest air as long everything goes to plan

I remember the darks times in the 1990's and earlier in the current century when it was the cold and snow lovers who were praying for charts at 240 to verify.

They rarely ever did lol

Edited March 28, 2013 by mcweather

[Gibby]

Good evening. Here is tonight's look at the 12z output of GFS, UKMO, GEM and ECM for tonight Thursday March 28th 2013.

All models continue to show a cold Easterly flow between High pressure to the North and Low pressure moving East across Northern France tomorrow. Little change is expected through the remainder of Easter with dry and rather cloudy conditions the most likely weather with frost at night and the odd snow flurry blowing through on the continuing NE breeze.

GFS then moves out of Easter and through next week with a strong and cold Easterly wind again across the South in particular. Though still rather cloudy a few brighter intervals would continue in the West with a few wintry showers rattling through in the South and east at times. As we move into next weekend winds back more Northerly as High pressure transfers to the NW for a time delivering fairly slack but chilly northerly winds with a few scattered wintry showers but frosts at night. late in FI the High slides South down over the UK opening the door to milder SW winds and rain at times in the final days of the run as the High slips away South.

The GFS Ensembles show very slow progress in getting 850 upper air temperatures up to the average. in fact it is not achieved until the final days of the run. The weather remains largely dry throughout the next few weeks with any precipitation spikes only shown in the far reaches of FI. The operational's track to milder weather at the end of the run is an outlier among the pack.

UKMO for next Wednesday continues to be locked in cold with High pressure centred over Northern Scotland with a ridge South through England. Light winds from between North and East remain dominant with dry weather and temperatures well below normal for early April the most likely outcome. Frosts at night would be widespread with the best of the brighter weather in the west and NW.

GEM tonight shows a cold and strong (in the South) Easterly flow carrying a lot of cloud across most areas away from the brighter NW. A lot of dry weather will be experienced across the UK while a few wintry flurries would continue to be driven in from the East in the strong breeze.

ECM tonight shows a strengthening NE flow from midweek with several days of cold and raw NE winds and cloudy skies across the UK with any brightness restricted to the far West and NW. Late in the week and more especially over the weekend a pattern change at last looks possible as the High to the NW slips steadily SE across the UK and allows the Jet to ride over the top and possibly start the process of conditions being something rather more akin to early April.

In Summary there is still a lot of cold or rather cold weather to get through before we can possibly look towards something a bit milder in 10-14 days time as a pattern change is hinted at by a rising North of the Jet stream over the Atlantic. In the meantime it's more of the same with chilly and cloudy conditions for much of the time with some bright or sunny intervals too. Frosts will persist overnight for the next week with the chance of the odd snow flurry on the cold NE flow over the next week or so.

[Guest pjl20101]

Well it has some support from this mornings ensemble mean but there isn't enough support across the output to take it at face value yet and there is an awful lot of uncertainty in developments between now and 144 let alone between a projected 144 and 240 chart.

Of course it may be picking up on a signal and it could be just the details that change rather than the synoptic but looking across the output at the moment it could easily flip back to blocked and cold tomorrow IMO.

BTW I switched allegiance to the mild camp some time ago so I hope it is right even though as Crew says it looks as though it would become unsettled from there though a good deal milder than now.

To be fair I am starting to see where CC is coming from now and makes a lot of sense, it is looking very tentative at the moment and liable to change.

[johnholmes]

I fear that optimism will be lost over the coming days. The latest output from NOAA, their 8-14 day chart below, shows total consistency in the pattern it and the other main two have shown for several days. The block to persist with the main Atlantic flow, as shown on TV forecasts today with the jet stream position, remains way south into the Med.

Until the anomaly charts start to show differences and even more so consistency for a change then I would be highly suspicious of any synoptic output, be it ECMWF or GFS or any other centre that showed an upper air pattern at 10-16 days at variance with the anomaly charts

http://www.cpc.ncep....14day/500mb.php

The synoptic long range outputs do, just now and then, give a chart that suggests changes then the anomaly patterns take this up but in watching closely over 3 years this is a pretty rare event.

Edited March 28, 2013 by johnholmes

[Snowman.]

Not bad at all from ECM towards the end of its run pressure slowly becomes lower over Greenland and high pressure builds over the UK with the coldest air heading off into eastern Europe out the way

Pressure is getting squeezed out over Greenland and the high build's over the UK

Coldest uppers build in eastern europe

And now the high has gone from Greenland with high pressure over the UK

Milder air slowly pushing in from the west

We'll be lucky on this occasion and avoid the coldest air as long everything goes to plan

Gavin honestly at those charts you know it would lead to more cold I mean look at the artic high moving into greenland.

I'm on the same side but that leads to temp warmth.

[damianslaw]

Reliable timeframe, all models showing a continuation of the conditions we have preety much been locked in for 3 weeks now, i.e. cold/very cold for the time of year under a easterly flow, but with lighter winds and heights building more over the country, we will see slightly higher maxima than recently, but conversely nightime minima will be very very low for early April with damaging harsh frosts which is certainly not going to help spring growth anytime soon, ground temperatures right now must be way below where they should be at this time of year.

It is also a very dry outlook, indeed its been a dry 6 week period especially in the NW, we haven't had much rain at all, in fact most precipitation since mid Feb has been snow.

This is not the time of year for the atlantic to suddenly fire into gear, indeed we are more likely to see blocked easterly set ups now than at any other time in the year, don't be surprised to see this pattern continue for some considerable time yet. The jet looks locked on a southerly course. There are tentative signs from ECM of lower heights moving into Greenland and therefore heights will be forced to topple across the country, but until we see more energy going into the northern arm of the polar front jet, I can't see a clear path for the atlantic to muscle its way in anytime soon. A more probable pattern would be heights settling over the country which would mean much milder conditions but still frosty at night.

March 2013 has I suspect surprised many, it has certainly surprised me, unlike Dec 2010 when the longrange forecasts in mid Nov were all painting a very cold blocked outlook and then we had the record cold snowy spell at the end of Nov, which meant I wasn't surprised to see how it panned out, there was no similiar clear signal of a very cold March back in mid-late Feb despite the second half of Feb being quite wintry cold and blocked. Indeed March 2013 started on a very average note, and I thought the very cold snowy spell 9-12 March would be shortlived.. its been a superb month for those who like the perfect winter synoptics of a dense cold pool of air to the NE and strong block stretching across scandi and into greenland, with a very southerly tracking jet, and atlantic attacks from the SW becoming unstuck and forced to retreat back south, the synoptics of last Friday are the kind that cold snow lovers dream of.

[shotski]

I fear that optimism will be lost over the coming days. The latest output from NOAA, their 8-14 day chart below, shows total consistency in the pattern it and the other main two have shown for several days. The block to persist with the main Atlantic flow, as shown on TV forecasts today with the jet stream position, remains way south into the Med.

Until the anomaly charts start to show differences and even more so consistency for a change then I would be highly suspicious of any synoptic output, be it ECMWF or GFS or any other centre that showed an upper air pattern at 10-16 days at variance with the anomaly charts

http://www.cpc.ncep....14day/500mb.php

The synoptic long range outputs do, just now and then, give a chart that suggests changes then the anomaly patterns take this up but in watching closely over 3 years this is a pretty rare event.

Post of the day so far, no point reacting to each operational run etc.

JMA long range ensembles underline what John is saying, strong anomaly even out to weeks 3-4 showing a strong

signal for northern blocking to continue.

Edited March 28, 2013 by shotski

[SE Blizzards]

ECM day 10 mean.

No real hints there of anything mild with the Zero uppers line well south.

Spring still looks an age away on that chart.

Edited March 28, 2013 by SE Blizzards

[Summer Sun]

ECM ensemble run for the final few charts

Out to a week Sunday and eastern Europe remains in the freezer whilst the UK moves into the fridge not mild but not as cold as what has just gone

Full ensemble

Edited March 28, 2013 by Gavin.

[weather_it_will]

Full ensemble

But we don't live in Debilt... You may as well show the ensembles for Bombay.

[Carlrg]

Getting there very slowly but surely.

http://www.meteociel.fr/modeles/bome_cartes.php?&ech=240&mode=8&carte=0

Even Europe and parts of Scandanavia, starting to come out of the freezer.

The really cold uppers discipating nicely.

http://www.meteociel.fr/modeles/bome_cartes.php?&ech=240&mode=1&carte=0

All in deep FI though, but giving the strength of the sun a very plausable outcome.

[bluearmy]

deep freeze - the de bilt ens are quite relevant to the uk. there are a few times when they are of little use but in general, much can be gleaned from the dutch ens, especially the other set which show wind direction.

i do begin to wonder if we are seeing a slow route out of the deep cold (relative to the norm). i note the following comments from cpc this evening

CONFIDENCE IS ALSO NOT AS HIGH TODAY ON THE MAINTENANCE OF THE HIGH LATITUDE BLOCKING

PATTERN. THERE IS HIGH SPREAD IN THE FORECAST AO INDEX AS PREDICTED BY THE GFS

ENSEMBLES WHILE MOST ENSEMBLE MEMBERS FORECAST THE NAO INDEX TO TREND TOWARD

ZERO BY THE END OF THE FORECAST PERIOD.

and

FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: MUCH BELOW AVERAGE, 1 OUT OF 5,

DUE TO POOR MODEL AGREEMENT

but then again

HOWEVER, THE ENSEMBLE MEAN SOLUTIONS FROM THE GFS, ECMWF, AND CANADIAN MODELS STILL MOSTLY MAINTAIN POSITIVE HEIGHT

ANOMALIES OVER GREENLAND.

[Guest pjl20101]

Cheers for that Nick and thanks for alerting us on the evolutions. It does indeed look like a complicated pattern indeed.

[bluearmy]

Cheers for that Nick and thanks for alerting us on the evolutions. It does indeed look like a complicated pattern indeed.

tbh, having made the post, i decided i didnt really have a clue where we were headed !!

the ridge thrown north from the azores in the early stages of fi catches my eye. currently it seems that it re inforces the blocking to our north but i wonder if it will also be successful in cutting off the train of depressions into the near continent which have been responsible for advecting the cold this far west. on a hemispheric scale.

[Purga]

Eventually it will warm up and relentlessly posting ensembles and FI charts to show this will eventually come right in much the same way as continually posting cold FI charts will also verify - eventually.

Realistically though it will be a long haul out of the cold blocked pattern as John Holmes rightly points out by referring to the 500hPa anomaly charts for guidance.

We are in a fantastic synoptic period and there is a unique beauty in the relentless cold dry weather which is so rare and different from the usually bland mediocre stuff we normally have to endure. I raise a glass to the mighty Northern Block - just hope if it does decline it will come back again fully invigorated for a 6 months stint November thru' April next winter would do nicely.

Edited March 28, 2013 by Purga

[Peejayem]

"the usually bland mediocre stuff we normally have to endure."

we just happen to be currently experiencing a different kind of bland mediocrity!

[pages]

Is the 18z correct the high is going to start sinking from t156 onwards

[Timmytour]

Looking at the recent output of the models, I must admit to being a tad disappointed to this latest thread not being subtitled - "The Hunt For Spring!"

A remarkable set of runs in what has been a remarkable winter...with the models projected easterlies in December, January, February and March all coming off with increasing amounts of success...starting from virtually nothing at all to a full scale "this is what we wanted!"

For me the aspect of the absence of very cold nights has been a feature in Herts....most probably due to the amounts of cloud that have accompanied the winds from the east. It's incredible that the "easterly" of December, the one that to all intents and purposes never really happened at all, was actually the only one that delivered the kind of successive cold nights that would have frozen ponds and lakes to a greater degree than they have been frozen hitherto. What's been great in such a relatively notably cold winter is the absence of stories of people falling through ice trying to rescue their dogs etc. instead of this being down to a greater awareness of the dangers, I would say this is more because of that lack of really cold nights.

The models are directing us to a dry and cold end to March, and it will very likely be one of the coldest. In fact I would hazard a guess and say the second half of March must rank as near the top as one of the coldest second halves of March for 100 years or more. I wonder what kind of average temperatures clearer skies would have bought, as, with these synoptics the colder nights would surely have outweighed the slightly warmer days under blue skies

[Mucka]

Forget Spring and wait for summer according to the latest JMA.

Edited March 28, 2013 by Mucka

[Chris W]

Is the 18z correct the high is going to start sinking from t156 onwards

Doesn't look like it to me:

[SE Blizzards]

Edited March 28, 2013 by SE Blizzards

[Mucka]

Even with a flatter pattern and forcing more energy NE the GFS 18z doesn't manage to free us from cold.

[pages]

Doesn't look like it to me:

More energy does go north east thou, start of a trend maybe.