Model Output Discussion - January 12th.

[shedhead]

If its a daily model discussion why not have the thread match the day ? Very confusing

Hardly confusing is it, it's just the fact no one has changed the date, I'm sure most have managed to work that one out unaided.

[snow drift]

If its a daily model discussion why not have the thread match the day ? Very confusing

If you find that confusing, good luck with model output!

[shedhead]

Regardless of what the UKMO 6-10 day outlook comes up with don't assume that its game over for either scenario.

We're not dealing with output in FI and although the UKMO take most lead from the ECM ensembles as they don't run their own past 72hrs they might still leave the door open with some uncertainty in their outlook.

I can't see this not being resolved tonight as the changes start within 96hrs so we'll know either way by then, its going to be a long day for cold and snow lovers, I'd recommend beta blockers for tonights output!

Not to overplay the importance of tonights output but this opportunity needs to be taken if you want to see some snow and cold in the next two weeks, after this we'll have to wait for the effects of the next strat warming to feed through and I'm sure patience has just about run out for most people in here.

What time is the next NOAA discussion due plz Nick?

[Zenarcher]

Review on the weather models this morning,

GFS

This morning its still not looking really all that different from last night. Looking at its latest 06z run it still seems confident on itself. It's still very keen on building high pressure up over the UK and in the Atlantic. Mild weather fans would love next week if this came off at this rate. It only gets interesting in FI when it shows things turning colder but its idea of things would mean waiting longer until the end of the month and the cold spell isn't really all that great compared to the ECM.

So whats happening to the GFS? Where does it all go wrong?

As early as 72 hours we see problems rise shown below,

As marked above,

1. Low pressure in the Atlantic positioned different. However the 06z has moved towards the ECM more so a improvement.

2. Should be lower pressure in that area. 06z run hasn't really made any move forward for this.

3. The high pressure over the UK needs to come back more and the 06z run has but just slightly.

I believe the GFS may be very very slowly moving towards the ECM we need to keep a close watch on its early developments and hope the ECM sticks to its idea as well.

ECM

It continues to be very consistent on and still shows a blocking occur in 7 days time. After this it stills brings in the colder weather but does the ECM have any support this morning? It doesn't have much support after around 144 hours but the GEM does give it some support. NOGAPS does give it support as well not much on its 00z run but I see improvements in its 06z run I believe it falls more in line with the ECM. However I see some bad news the ECM has lost its support from the UKMO over night.

GEM

Supports the ECM pretty much all the way with some different ideas in the long range it doesn't exactly lead to a blocking but overall it does show colder weather set in later.

NOGAPS

Like I said in the ECM update the 00z run isn't really too good but on its most recent update it does move towards the ECM's idea of things which is good news and means the ECM gains a bit more support.

UKMO

It's not looking to great this morning comparing the 3 main models (ECM, GFS & UKMO) at 120 hours the UKMO seems to agree more with the GFS so over night its moved to the GFS idea of things. However it does disagree with the GFS at 144 hours.

Overall it really is a mess at the moment we have the ECM being very consistent, the GFS sticking to its idea, the GEM continues to support the ECM and meanwhile the UKMO and NOGAPS don't know where to turn.

Today to Tuesday Summary: Friday and Saturday will be settled and getting much colder through the nights. Sunday is settled again and cold but windy in Western areas. Monday and Tuesday settled in the South but in the North unsettled with the risk of wet and windy weather.

Wednesday to Friday Summary: During Wednesday it will remain the same being settled in the South and unsettled in the North. A bit unsure on Thursday and Friday but I expect it to get much colder in the North and it may be unsettled for all parts of the UK at times with the far South maybe hanging on to the best of the weather.

Beyond Friday: Unsure on this at the moment but we do have 2 paths the models show. Either a mild and settled start eventually turning colder at the end of the month or as early as next weekend we go into cold weather right away.

[trisnow]

As a noob, it appears to me looking at these charts in comparison http://www.netweather.tv/index.cgi?action=modelcomp;sess= that it ECM is out on its own?

The latest image for 13th 00z seems to show the MO going the same route as the GFS @ 120hrs?

Is that what we are wondering about at the moment? As to what will happen after that time frame or have I completely misunderstood all of this conversation....

[BLAST FROM THE PAST]

This led to

then led to this

finally to this

GFS in particular at the time was bringing that Russian HP SW towards us and the mother of ALL easterlies. It signalled this as in the bag up to 72-96 hrs before it suddenly backtracked to a major miss as is shown. I remember the model watching period vividly, many of us almost had a coronary when it backtracked after seeming in the bag and I was dumbfounded by the inaccuracy of the model short term.

Two things, GFS does also get things horrendously wrong even up to close range so 144 is still very much FI at present and as far as I'm concerned we don't need GFS on board at all yet BUT we need continued progress from ECM with UKMO on board.......and I do not like t240 at all...but that is way FI.

Steve MURR....do you remember this one Steve? We all got caught out/sucked in!! Horrendous

BFTP

Edited January 13, 2012 by BLAST FROM THE PAST

[Tom Montalbano]

Have to say a very poor set of ensembles too from the GFS 06z, only seen up to t300. GFS and ECM starting to look even more polarised and they cant both be right. Must be causing major headaches with extended forecasts.

Agree with Nick on this, although METO update will be interesting, with so much disagreement short term, I wouldnt expect them to throw their weight behind either scenario. too emphatically.

Obviously hope ECM are right, who apparently have a bullish set of ensembles to back them up.

Still none the wiser, more runs needed!

Regards,

Tom

Edited January 13, 2012 by TomSE20

[jimben]

Most telling today I believe, will be what NOAA has to say regarding GFS. Let's face it cold lovers would like the PV pulled back to Canada and therefore the American modelling of this situation and how they feel regarding the GFS is, I believe, very important.

[nick sussex]

What time is the next NOAA discussion due plz Nick?

The first morning update has been done and you can find it here:

http://www.hpc.ncep.noaa.gov/preepd/preepd.html

They used the ECM ensemble mean upto day 7, the final update to that comes in around 2pm UK time.

Day 7 and on they're happy with both the ECM/GEFS ensemble means aswell as the GFS 00hrs operatonal run in relation to the placement of the polar front across the CONUS.

[BLAST FROM THE PAST]

Think MO have just updated:

UK Outlook for Wednesday 18 Jan 2012 to Friday 27 Jan 2012:

Showers or longer spells of rain on Wednesday, with rain most persistent in northern and western parts of the UK, where strong, perhaps gale force winds are possible at times. Turning colder from the northwest through Thursday, with snow becoming increasingly likely across hills. Drier, brighter spells are most likely across the south and east of the UK. Conditions late next week and through the weekend remaining unsettled with a risk of wintry showers, especially in the north and over high ground, and also a risk of overnight frosts in quieter spells. The changeable conditions are expected to continue through into the last week of January with some spells of milder, wetter weather and also spells of brighter, colder and showery weather with frosty nights.

Updated: 1129 on Fri 13 Jan 2012

That says, lets sit on the fence for a while longer

BFTP

[The Northern Ramper]

GFS has embarrassed itself further, Its now bordering on farcilce, and there remains to be almost zero support for its outcome.

I for one would bet heavily against the 06z verifying.

I expect the ecm to be nearer the final outcome however the GFS cannot embarrass itself 144 hrs before the outcome.

[Zakos]

That says, lets sit on the fence for a while longer

BFTP

Couldn't agree more. This is of no use to anyone, and virtually any outcome would end up in them technically being right....

[ITSY]

how they manage to get cold mild wet and brighter in the same sentence is hilarious! anyway, yes clearly they have no clearer indication than we do with many different pointers and models to pointing in opposite directions. the fact the the NOAA are using the ECM for 7 days out perhaps adds to its weight...still a toss up though, no higher than 50/50 and, as we approach the timeframe, the next 24 hours should tell us a lot. if there is still disagreement in 24/48 hours like there is now then i;ll be astonished - and less supportive of the ECM solution.

[P-M]

The first morning update has been done and you can find it here:

http://www.hpc.ncep....epd/preepd.html

They used the ECM ensemble mean upto day 7, the final update to that comes in around 2pm UK time.

Day 7 and on they're happy with both the ECM/GEFS ensemble means aswell as the GFS 00hrs operatonal run in relation to the placement of the polar front across the CONUS.

Sorry Nick, for someone who struggles with these particular updates, what does this mean in terms of positive or negative signals? In laymans terms for an idiot!

[trisnow]

That says, lets sit on the fence for a while longer

BFTP

I'm trying to understand a little more but would I be reading this right BFTP if I said after looking at the Model Camparison images for 120hrs and 144hrs that this update from the MO would more favour what the images from the ECM is showing rather than the GFS? The little I understand about these charts tells me that the ECM has more bars packed closer together which would fall in line with this comment from the MO? "with rain most persistent in northern and western parts of the UK, where strong, perhaps gale force winds are possible at times. Turning colder from the northwest through Thursday, with snow becoming increasingly likely across hills."

So is the MO leaning towards the ECm more?

[Paul Sherman]

Do you not feel though that "if" the Meto were going to fully back the ECM Then they would have included the words " Turning progressively Cold with Wintry Showers and Snow at Times " in the update. 12z Meto going to be crucial today or tomorrow at the latest but also feel it is trending either halfway house or more towards the GFS.

Ecmwf must feel like Louis Walsh at the moment with him backing that brazillian dude to win X-Factor with the other 3 looking in disbelief

Facinating to watch this unfold and would not like to be a forecaster for the 7-10 day period atm

Like Dave and Mr Sussex would Sit on the fence with this for at least another 24 hours

[nick sussex]

The UKMO have disregarded the GFS operational output as that wouldn't bring in colder conditions next Thursday, however until that GFS operational run at least tilts the jet nw/se through the UK then don't bank on that UKMO outlook.

The UKMO seem to go with troughing over the UK and after that they've left that part the same as in recent days.

[russ49]

hi all

i sent this e-mail to Paul Hudson about the gfs/ecm and this is his reply

Message Body

GFS is the most unstable of all the main 3 models for some reason. But they are all struggling, and its an indication of how finely balanced things are that 3 very similar models can give differing solutions.

From: ANDREW HARRISON Sent: 13 January 2012 11:05

To: Paul Hudson-LS

Subject: GFS v UKMO/ECM and the rest

hi Paul

i am an avid weather watcher (BBC/met info /Netweather/ your blog) and have been watching the potential changes that are afoot and i cant believe the difference between the gfs and the other models after as little as 72 hours (still no total agreement at gfs 6z , i am a cold lover and would like us to see an "beast from the east" further down the line but the gfs is still showing the influances from the jet and polar vortex over greenland, i just wondered what your opinion was on the current models

thanks

Russ

Edited January 13, 2012 by russ49
Removed email address to prevent spam

[johnholmes]

Some of you are quite comical a forecast is isuued which gives the day of a weather change. Fine for most of you. It then goes on to explain that its going to remain chaggeable with milder wetter spells interspersed with colder days with wintry showers and you think its a waste of time.

Why not actually look at the charts as issued by Met, GFS and ECMWF and TRY to understand what the balance is?

As an ex senior forecaster all 3 models are suggesting something similar but there are fairly large differences in emphasis. One goes for a full blooded very cold possibly snowy set up, another goes for a less full on flow from a similar source but with the upper ridge and its surface high having more effect.

I don't see the problem. There is little point in saying 5-10 days down the line THIS will happen when every part of your training tells you its far from clear which model will be nearer the truth.

How about a touch of realism in here rather than throwing toys out of prams if the ideal situation for you is not shown or predicted?

Edited January 13, 2012 by johnholmes

[Thundery wintry showers]

The models are strongly agreed on a dry, sunny and frosty spell through to Monday for the vast majority of the country, with high pressure in the perfect position (just out in the North Sea) to minimise the input of moisture from the Atlantic and the North Sea. Temperatures won't be far short of the seasonal average by day, but will fall rather below at night. The high will then retreat south-eastwards during Tuesday.

The crucial difference occurs on Wednesday/Thursday. GFS has a depression "waiting in the wings" in the eastern USA at 00Z on Wednesday:

http://cdn.nwstatic....114/h500slp.png

...and by 00Z on Thursday it has developed into a large feature which crucially heads due east, which cuts off the polar maritime flow and promotes a south-westerly type over Britain, with high pressure to the SE:

http://cdn.nwstatic....138/h500slp.png

The ECMWF has a similar feature at 00Z on Wednesday but further north/west:

http://cdn.nwstatic..../ecm500.120.png

...at 00Z on Thursday it is still well out to the west:

http://cdn.nwstatic..../ecm500.144.png

...and then it has largely fizzled out by 00Z Friday, allowing the UK its northerly followed by north-easterly outbreak as high pressure forms in the gap between "our" low and the low over the USA:

http://cdn.nwstatic..../ecm500.168.png

From where the ECMWF gets to at T+168 we should be reasonably well assured of a wintry spell, but it's a question of whether or not we will get there.

It is difficult to tell whether the UKMO sides with GFS or ECMWF at 00Z Wednesday:

http://cdn.nwstatic..../00/met.120.png

00Z Thursday is available at Wetterzentrale but it does not display the pressure charts over the USA/Canada, thus making it difficult to tell where that low is headed and how deep it is. However the polar maritime incursion stays out to the NW, suggesting that it probably won't get to where the ECMWF does, at least not as quickly, which may "buy" some time for that low to the west crashing through. Thus, it's really the T+120-168 timeframe (as often happens) that is key for whether we can get some sort of northerly outbreak that, prior to clearing away, pulls in some of that continental air as the low retreats SE.

[Zakos]

The MO does at least discount significant northern blocking until February.

There is also no model support for this even on the ECM. So were not looking at sustained deep cold just yet.

So it can be said that any outcome is possible, but I believe something like the ECM is likely to verify.

Although some mild air might get into the mix as the pattern isn't blocked, heavy and widespread snowfall is very likely.

As some mention the ECM models the jet to be in a prime position for cold reloads, making for cold and unsettled weather ; arguably better than sustained blocking in terms of snowfall.

So basically the Met expect unsettled weather, but a great deal of uncertainty as to how cold the weather will be.

[shedhead]

Compared with yesterdays 6-15 dayer they have moved more towards the ECM evolution, but in true MO style they have edged rather than jumped, leaving both options open across future updates without having to do a volte face. Given the overall set up that should come as no real surprise tho, as long as the edging continues in the right direction I'll remain fairly happy, but I've got to say GFS continues to niggle at me.

[cyclonic happiness]

_{It does seems as if the} GFS _{has changed it's mind every run for the past week, whereas the} ECM _{has beeen more or less consistant, also it was the first to pick up the possible pattern change to colder weather.}

_{So, I'm going to go for the} ECM _{and the meto update does at least seem to back up the change, although as John says the detail will never be clear until around a week before, not 10-12 days away.}

_{Why is my writing small?}

_{Sorted - I think}

[Brum Watcher]

looking at the ECM ensembles, Plenty of support for the Op. all three, Control/OP/mean tightly joined together till the end. Ukmo have tilted towards the GFS. im stuck in thinking here... looks like a second backtrack for the ECM this winter maybe...a winter to forget maybe..

[Radiating Dendrite]

_{It does seems as if the} GFS _{has changed it's mind every run for the past week, whereas the} ECM _{has beeen more or less consistant, also it was the first to pick up the possible pattern change to colder weather.}

_{So, I'm going to go for the} ECM _{and the meto update does at least seem to back up the change, although as John says the detail will never be clear until around a week before, not 10-12 days away.}

_{Why is my writing small?}

_{Sorted - I think}

In the last two-three days the GFS has started to consistently show its pattern as well though.

We shall find out soon enough. As others have said, probably a blend of both. I bet the trough sinks to our west instead!