Model Output Discussion 12z 03/04/13

[Frosty.]

Frosty if anywhere in the UK gets into the 70's next week as you suggested I will eat my socks.

The only parts of the UK which will see any decent temps are the South and East of England next week. Even this weekend with plenty of fine weather about (Saturday mostly) the North is looking at 12 degrees max and the South 15 degrees max. Hardly anything to get excited about in normal circumstances. (The long run of cold months has everyone chasing a sniff of warmer weather)

The ECM has this nailed, cooler and unsettled is the way ahead.

The ens mean for the beloved GFS in here shows it.

I enjoy reading what you post but I think the orange and reds on the maps are CLOUDING your judgement.

More HIGHS and LOWS to come in this thread over the next month I feel, SUN would say we are DEW a early heatwave. But as you know it never rains but it pours when we wish for something different.

Have you read the recent Met Office outlook?

UK Outlook for Tuesday 23 Apr 2013 to Thursday 2 May 2013:

Largely unsettled with showers or longer spells of rain across the UK. Initially the rain will be heaviest and most persistent across the north and west, and showers may turn wintry at times across northwestern hills. The south and east of the country will see the best of the dry and bright weather with some spells of sunshine. At first temperatures will generally be near or just below normal across the north and west but perhaps rather warm in brighter interludes in the south and east. Later next week and into the following week, the unsettled weather in the northwest will probably spread southeast to all parts. Temperatures will become rather cold or cold in all areas with overnight frosts probably becoming more widespread.

get ready to eat your socks then

 

I have seen more than enough model support for a warm/very warm spell across at least southern britain next week after monday, I have also posted lots of charts to support my view. I have also balanced this out by posting the ens mean charts and realise that the warm and fine spell may not last long but taking a balanced view of next week, there is warm weather likely and temps will hit the low to mid 70's if the current trend continues, kent had 72f recently so 70f plus would be easily achieved next week if the gfs, ukmo, gem, and even the ecm 12z verified.

[Gibby]

Good evening folks. Here is the report on the 12 noon output from GFS, UKMO, GEM, NAVGEM and ECM for tonight Thursday April 18th 2013.

All models show a cool NW flow over the UK as a deep Low moves away NE from the far North. A high pressure area is shown to extend NE across Southern Britain later tomorrow before it becomes eroded from the NW through the weekend by a cold front moving slowly SE over the UK overnight Saturday and Sunday. By Monday all areas lie under a Westerly flow with some rain at times in the North with the remains of the cold front bringing Sundays rain leaves the Se later in the day with Tuesday seeing north/South conditions developing with England and Wales largely dry, bright and becoming warmer while Scotland and Northern Ireland continue to see more cloud with rain at times.

GFS shows the South having a taste of some very warm air by midweek but with pressure falling and humidity rising showers would be breaking out by the end of the week with temperatures remaining well above average especially in the South. In FI tonight a complex pressure pattern develops with High pressure ridges close to the North and an ESE flow over the South in association with Low pressure to the SW. A lot of dry weather seems likely though some thundery rain at times in the South is a distinct possibility.

The GFS Ensembles show the very warm operational described above is a raindrop in a desert as it has no support from any other member. Instead nearly all other options see the weather turning quite fresh and cool as more showery conditions develop across the UK though with no great quantities of rainfall expected.

The Jet Stream continues to flow Eastwards across the UK over the coming week or so.

UKMO shows High pressure moving East over Germany with warm south winds wafting up across England. Pressure will be gently falling though and with High pressure centred in mid Atlantic and Low pressure over Iceland the path is being formed for an attack from the North of cooler and more unsettled weather by next weekend.

GEM tonight continues to show a warmer spell midweek in association with high pressure migrating slowly East over the near Continent with a warm Southerly feed across England and Wales.

NAVGEM  shows a slow progression towards cooler weather later next week as winds strengthen and veer more towards a North-westerly quarter with occasional showers by the weekend, especially in the North and East.

ECM shows the warm conditions leaking away as we move through the second half of next week with progressively colder conditions giving way to showery and eventually rather cold conditions with showers turning wintry over Northern high ground and hail and thunder probably inland each day in the slack NNE flow. There would be some sunshine in between showers but clear skies following decaying showers each day's end would promote some damaging frosts for the time of year possible almost anywhere. the unsettled and rather cold theme looks like continuing through Day 10 and beyond as new cold low pressure feeds down from the NW.

In Summary the weather looks like being a tale of two halves next week with the first half of the week looking increasingly warm and dry, especially in the South with some warm sunshine. The second half of the week looks far less certain as the synoptics are in prime position over the Atlantic for a change to colder and more unsettled conditions towards next weekend with some cold nights and frost with daytime's likely to see plenty of heavy and thundery April showery conditions with even some snow over Northern heights. Conversely an interesting GFS operational tonight would probably give us our first thundery spell under warm and humid conditions but it's very isolated within it's own ensembles and the other models for that matter.

[weather_it_will]

When you zoom out on the ECM, you can clearly see how grim it looks for northern Europe at the end of next week.

[snowking]

Yes looking nice upto Thursday (GFS was a milder outlier again so I'd expect temps around the mid teens which is very respectable for April) but it goes down hill just in time for the weekend (now there's a surprise......... not) as we await the next area of high pressure to try and push in from the west

Unfortunately for those of us looking for a bit of warm, settled weather, the Sceuro type trough setup is the overwhelming signal for the summer as a whole from as early as May, and as such, the closer we move towards the new month, the more likely we are IMO to see something more akin to the ECM offering as opposed to the GFS (not to mention that 9 times of out of 10 you would trust the ECM more than the GFS in the extended range)

A fairly pleasant weekend to come but it looks increasingly cool and unsettled towards the end of the month

SK

Edited April 18, 2013 by snowking

[Summer Sun]

The GFS ensemble tonight supports a decent start to next week before it becomes more unsettled as we approach next weekend

 

 

That pattern persists through the remaining days of April and into May

 

 

But during the first weekend of May there is a signal for pressure to rebuild over the UK

 

 

The ECM ensemble supports an unsettled cooler picture as we leave April

 

[SP1986]

the GFS has now fallen more into line with the euro models such as the ECM, with a much colder longer term outlook. I suspect if it happens it could be a 'locked in' pattern too, like many of the similar blocked patterns we have seen this year so far - we'll have to keep an eye on the outputs following these, but it's hard to argue with the ECM and its consistent ensembles (though the GFS ensembles have been remarkably consistent in agreement too, despite the operational outliers.

 

By now it does seem to be that blocking is the new pattern for the future?, this could result in some interesting winters (and summers), but that is wandering off topic a little.

[IDO]

Looking like the GFS op is now coming in line with the 500 hPa anomaly charts for later next week onwards, D10 GFS 0z mean:

Bringing a trough close to the UK with its associated cooler and wetter regimes. The ensembles have been on to this for some days, despite some milder Op runs. Todays GEFS: A clear trend for a week or so of cooler weather from D8.

This now aligning to the ECM ensemble mean (12z yesterday):

A cool spell coming for London from late next week so I would expect temps further north to remain well below average for late April there.

The next seven days are more promising for the south with seasonal highs at times, and little wind to take the edge off. It is however a SW to NE split:

Sunday appears to be the only un-settled day in the next seven for the south, as a weakening trough edges east.

Edited April 19, 2013 by i'm dreaming of...

[mushymanrob]

Finally some light at the end of a very long tunnel then? 

 

not sure to what you refer... yes theres a good chance of a few very pleasant, war, dys next week, but that doesnt look like lasting (of course) before a cooler regime takes over later on.

 

a cooler period doesnt bother me now, in fact in any sun itll still feel pleasant and the air quality associated with pm air is usually good.

[mountain shadow]

It maybe quiet on this thread poster wise, but plenty are tuning in looking for accurate model appraisal as we search for warmth.

So thanks to those sticking to the moderator brief.

[Purga]

Cooling off to somewhat below average temps and wetter conditions as we get past the St Georges Day warm blip.

 

Interesting to see how the CET comes out for April? I guess it feels a lot warmer because of the exceptional March but I wouldn't be that surprised if it turn out to be another below normal month.

[johnholmes]

a plea

PLEASE stop the personal digs-we have enough of that during the winter months.

simply post your views with charts to back it up then the rest of us can make our own minds up who is cherry picking and who is trying to give an objective view of any model

thanks

[SomeLikeItHot]

Mean CET needs to average around just below 10 for the rest of the month, to get average 61-90 CET for April., Based on the model ensembles it looks to me like the average for the next 6 days will be close to this or slightly more, but then turning cooler at the end probably ending the month at or slightly below average. Certainly though the last almost 3 weeks are warmer than average April weather, but a first week and a bit were much colder than average resulting in a near average month.

AS to the model output, I am less concerned about the temperature but more pleased to see that there hopefully looks to be some breaks from the wind over the next few days.

[Summer Sun]

UKMO shows a good settled spell this coming week very nicely this morning for the bulk of England, Wales and Southern Ireland

 

 

ECM has pressure higher and further north at t144 compared to UKMO

 

 

Into next weekend and the settled weather starts to leave

 

 

 

[Gibby]

Hi folks. Here is the midnight output report from GFS, UKMO, GEM, NAVGEM and ECM for today Friday April 19th 2013.

All models show a cool NW flow over the UK today with pressure rising strongly from the SW. An anticyclone builds across Southern Britain tonight and tomorrow followed by it being squeezed away SE on Sunday as a cold front crosses SE over the UK bringing rain with it, first to the NW later Saturday and the far SE by Sunday night. Thereafter, a Westerly flow develops with a mix of cloud and patchy rainfall mostly in the North and West while Southern Britain gradually becomes brighter and warmer by midweek as High pressure drifts East close to the South, feeding warmer Southerlies up across England and wales for a time by Wednesday.

GFS then shows colder uppers slowly filtering down from the NW along with falling pressure increasing the risk of showers across the UK in temperatures falling back by several degrees day by day most noticeable in the South. By the weekend the weather has settled into a rather cool and unsettled NW type with Low pressure continue to feed South over Britain as the Jet Stream floods South over the Eastern Atlantic bringing us back into the cold side of the flow with increasingly deep Low pressure eventually winding up to be South of the UK with the very showery conditions continuing with temperatures below average with a chill East wind to end the run around High pressure over Scandinavia.

The GFS Ensembles support a sustained period of average uppers at best in association with eventually rather lower pressure with rain at times filtering down from the North.

The Jet Stream shows the flow over the UK weakening this weekend. Next week the flow ridges High over an Atlantic high and then dives SE to the west of the UK eventually bringing the UK under colder uppers on the Eastern flank of the flow later next week.

UKMO for Thursday shows High pressure receding away East over Europe with another one centred out in the Atlantic. Low pressure developing near Iceland would likely become influential in the days that follow. However, on Thursday itself a dry and bright day would be likely for many with warm conditions over Southern Britain closest to the warm air over the near Continent.

GEM today is very similar at the Thursday time point moving on to show low pressure to the North sinking SE tilting the winds over the UK to the NW at the same time as they become more unstable with showers and eventually rather cold conditions developing over next weekend.

NAVGEM is much the same today putting the UK under a cold showery pool from the North by next weekend.

ECM finally shows High pressure becoming influential out in mid Atlantic encouraging SE moving depressions on it's Eastern flank over or to the East of the UK setting up a rather chilly and unsettled pattern as we move towards next weekend with rain and showers becoming dominant for all in rather cold conditions for late April.

In Summary today the pattern seems well agreed upon by all the main models. After a useable weekend for many rain will spoil the end of the weekend for many by Sunday evening. Then things improve for several days, especially in the South where a warm and bright interlude midweek could bring our highest spring temperatures to date before a stark reminder of how April can contrast sets up later in the week. All the big models indicate a large mid Atlantic high by then which will send the Jet South on it's Eastern flank pulling cold Low pressure down from the NW our way and setting us up for what looks to be a cold and showery next weekend with the risk of frost and longer spells of rain too later with snow possible on northern high ground.

[snowking]

Ensemble means today show pretty good continuity to day 10, with a Sceuro type trough setup, though HP never too far away to the SW, so some hope for those further S and W that we may see influence from this from time to time

 

 

(Ensemble mean height projections for days 6-10 added for comparison to overall summer 'baseline' prediction)

 

 

Interestingly, this sort of setup corresponds pretty well to the overall H500 mean anomaly projection for this summer based around similar QBO/ENSO index years:

 

 

If we focus this in a little more, and take a look at May based upon the two strongest composite years (1978 and 1962), we see a similar result:

 

 

So, we should be looking at those ensemble means as the likely baseline conditions for the period through May-August.

 

Summer 2013 will likely be nowhere near the record levels of rainfall experienced through summer 2012 (generally expected to be around average overall), but the cooler than average temperature theme is likely to persist

 

SK

Edited April 19, 2013 by snowking

[Frosty.]

We have cross model agreement for an increasingly warm and settled spell to develop next week, potentially becoming very warm in the southeast during the second half of next week, so a summery spell is likely with lots of strong sunshine and temps into the 70's f, maybe reaching the mid 70's in the southeast for a time, beyond that, there are signs that the weather will be turning cooler and more unsettled but the reliable timeframe is looking very good. The exception to the above will be the northwest corner of the uk where it will be generally more changeable/unsettled and cooler than elsewhere.

[SP1986]

There are a fair few pessimists on this forum but I think you're number one at the moment SP, that's unless you're actually wishing for these 'much colder' conditions you talk about. In the reliable time frame GFS remains fairly warm for next week and until I see these cold conditions you mention in the reliable time frame I won't be making any more judgements on it. Of course it could turn colder and the pattern could become 'locked in', but I'm not going to make sweeping judgements based on one run from GFS. The ECM 12Z is hardly disastrous anyway, certainly not to the extent you make out in your post.

 

Is it just me or is this thread quite a depressing read at times?

hmm

 

Pessimism and Optimism should have nothing to do with the model output thread, and the fact you're thinking that suggests it shouldn't be on this thread. Model output isn't about optimism/pessimism, it's about analysing the models and possible future evolutions that may occur with the synoptics shown, so how optimism and pessimism should come into it baffles me. As far as I know the model output isn't here to fulfill desires about the weather type (but correct me if I'm wrong?)

 

This morning the models show a familiar pattern to one's we have seen the past few days, with GFS more in line with the ECM (rather than a few days ago where it was showing an extension of high pressure and warmth), so as it stands in the models, the week looks like a split of two halves with the first week looking Atlantic orientated with some warm sunshine at times, mixed with rain in the northern areas, then a trend towards a cooler weather (wetter too) with Northerly winds, shown on the GFS/ECM.

Edited April 19, 2013 by SP1986

[phil nw.]

Some posts have been moved to here

http://forum.netweather.tv/topic/76235-model-banter-moans-and-ramps/

Please keep your posts friendly and comments on the model outputs only please.

Any wider discussions about preferences etc should go in the other thread as linked above.

[Frosty.]

The Gfs 06z operational run shows a warm and settled spell for much of next week with tues/wed being the best days next week where temps should reach a comfortable 18-19c 65f, some favoured spots could reach the low 70's F but then from thursday onwards it becomes cooler (much cooler everywhere by next friday on 6z) and more generally unsettled from the northwest, the far northwest will have been cooler and more unsettled throughout. The southeast corner of england hanging on to the fine and warm weather for longest but thursday not as warm as earlier in the week. The cool and unsettled spell towards the end of next week is just the opening salvo to an even cooler/cold and unsettled spell by the end of next week into the following week with arctic air flooding south with wintry showers and widespread frosts, the north and east becoming the coldest and most unsettled during that period, the south and especially the southwest becoming a little milder but synoptically the outlook is showing high pressure building in mid atlantic and a dominant scandi trough influencing our weather with a cold & showery further outlook, so the message from the 6z and other output is enjoy the fine and warm benign conditions next week because it currently looks like turning much cooler and unsettled by next friday onwards. 

[mushymanrob]

there are some very good posts here, thanks to those posting im sure many reading benefit from them as i do.

 

 cooler then average doesnt bother me much, as long as we have brightness/sun. temps arent the be all and end all. so if the end of april/early may end up in a cooler pm airmass, northwesterly then so be it. i like the variety our weather brings (as long as it doesnt effect my pocket :lol: ) an overcast cool spell though wouldnt be very welcome by many i suspect, so just what form a possible cool spell will take will of course be crucial. however thats in fi, for now theres a very nice day tomorrow after a cool start and sunday will be great too in the southeast (longest). several really pleasant, sunny, dry days look pretty certain midweek.

[phil nw.]

Yes the next 2 weeks are a typical changeable Spring outlook .

Some warm and dry days to come through the next week, especially further south, but it does look like the week after goes downhill as the high pressure relocates further west into the Atlantic with low pressure dropping down from the NW into Scandinavia.

This will turn the flow to north of west bringing cooler and more unsettled conditions across the UK.

The warmer few days ahead followed by a wetter ,cooler spell is appararent on the ens graphs for London

http://www.weathercast.co.uk/services/ensemble-forecast.html

In the meantime though some fine and warmer days to come to enjoy outdoor activities.

[SP1986]

GFS 12z shows the split too, I think the outlook is pretty much settled (no pun intended) now in broad terms, which is fairly nice to see, none of the ups and downs, and disagreements that we often get from model outputs. The nearer time looks fairly average with a few warm days, a few cool days, fairly typical before 168 hours. Post 168 hours however looks on the borderline of fairly notable cold to me, maybe people don't share that view, but frequent frosts from a synoptics situation like that. Part of me wants to see it materialise to test some fairly long standing records.

Edited April 19, 2013 by SP1986

[Frosty.]

The Gfs 12z shows a couple of warm and sunny days next week (tues & wed) but then gradually turning cooler and unsettled from the northwest, then the atlantic high extends a ridge southeastwards across the uk with a window of fine but cool weather and an overnight frost but as the ridge subsides, it becomes more unsettled with cold nw'ly to n'ly winds and showers which would be turning wintry on hills and widespread frosts, the gfs also shows a trough sliding down the north sea which would enhance the wintry showers at the end of next week with longer spells of rain and sleet with hill snow possible, beyond that, the atlantic high has another go and pushes a ridge southeast yet again which reduces the showers risk but not for long because another trough over iceland slides south to the west of the uk and eventually moves slowly over the uk with a cool unsettled pattern although not as cold as the previous weekend due to the main thrust of cold air being ejected south but over the atlantic rather than over the uk.

The ukmo 12z also shows a very nice midweek period and even holds off the unsettled weather by T+144 hours, the feeling I get is that the further southeast you are, the better next week will be with the warmest and sunniest weather for the east midlands, lincs, east anglia and southeast england with temps edging into the 70's, it may actually end up warmer than the models are currently showing as i've seen this occur many times before with temps being underestimated by a few degrees.

Edited April 19, 2013 by Frosty039

[Summer Sun]

ECM remains pleasantly warm and settled up-to mid next week 20c to 23c could be hit in the south on Wednesday

 

 

Thursday sees the cooler air starting to move in from the north west though we do remain settled

 

 

By Friday and its all change as Northerly winds take over bringing cooler air to us all though given its a northerly we should see plenty of sunshine

 

 

If it follows previous runs the high in the Atlantic won't get in whether that remains the case tonight remains to be seen

 

12z is indeed following the 00z run with the high getting blocked off in the Atlantic

 

 

The 12z ends very unsettled with a deep low over the UK and the Atlantic looks well and truly blocked off been here before aint we luckily its still at the t168+ range yet so ample time for changes to occur between now and this time next week

Edited April 19, 2013 by Gavin.

[Frank Trough]

GFS 12z shows the split too, I think the outlook is pretty much settled (no pun intended) now in broad terms, which is fairly nice to see, none of the ups and downs, and disagreements that we often get from model outputs. The nearer time looks fairly average with a few warm days, a few cool days, fairly typical before 168 hours. Post 168 hours however looks on the borderline of fairly notable cold to me, maybe people don't share that view, but frequent frosts from a synoptics situation like that. Part of me wants to see it materialise to test some fairly long standing records.

why don't you post much in the winter? i think it would be more your scene.

No doubt now that things are going nosedive as we progress through next week, hence the fumbling in the trousers of all the coldies. I'm not quite sure what they expect though - probably ice days and lying snow.

Still, i'm glad i'm out of the country. The Ecm looks horrible in its later stages:

http://www.wetterzentrale.de/pics/Recm2401.gif

that's a chart i don't want to see repeated very often once we get beyond May. The met office longer range indicates some kind of easterly flow setting up after that and the GFS had showed this regulalrly in the last couple of days in its later output:

http://www.wetterzentrale.de/pics/Rtavn3841.png

Of course, we'll have to wade through the posts about "locked in" cold before that can happen.