Model Output Discussion 17th Dec.2013-12z onwards.

[Geordiesnow]

Last third of January and into early February will see a dramatic change in our weather. Patience is the name of the game.

 

A change to what? Drier sunnier weather? A heatwave as we head into February?

 

Whatever this "dramatic change" is, is their any proof of this or is this more likely just a wild stab in the dark guess?

[Frosty.]

I have seen positive signs from the models for a rather colder second half to January and that is pretty much what the met office are still indicating, and staying generally unsettled for most of the month ahead. Even though there was no mention of wintry ppn, we can draw our own conclusions that rather cold weather in january would produce snow. I also have a feeling that feb and march will be colder and more blocked with snow and lots of frosts. :-)

[kumquat]

Surprised  (on 18z GFS) not to see more pronouncement of an Atlantic ridge between 120 - 180 hrs. Doesn't look right to me. Think pressure will rise faster than that around the southern tip of Greenland.

 

Edit: Still a good pattern at that stage. Wouldn't be surprised to see significant developments in this area in the coming days.

Edited December 30, 2013 by kumquat

[Jason M]

Fairly strong agreement within GEFS of a continuation of what we have. There are still a few good easterly options scattered in amongst the group but the largest signal by far is for zonality.

Worth keeping an eye on the easterly options but they have been knocking around for some days now and are not increasing in number or moving forward through the timescales. Most of the interest lies out at 10 days and beyond where it has been for the last week or so.

Still, a brand new shiny set of runs will await us in the morning :-)

[Snowman.]

Ahh.

 

 

Oh and the 18z FI is just one run and like always will be a different tomorrow.

[Catacol]

I agree, I sometimes use the zonal wind charts in here to show how they might be impacting on the models, and if people see something about the strat in here then they might become more interested to then go over to the strat thread.

 

It's a bizarre request, its model related and totally pertinent to this thread. I for one will continue to post references to the strat.

 

Have to agree. Model discussion thread... not tropospheric model discussion thread. Not sure we can treat them seperately anyway, so posts that include strat model forecasts seem perfectly in line with the purpose of this thread. The strat thread is a technical subset.

 

GFS runs include a 10hPa chart as part of their standard model output... so where is the distinction there?

Edited December 31, 2013 by Catacol_Highlander

[TSNWK]

Morning all. Not a good start to day for coldies. GFS is pretty much the same throughout, which is lobes of the vortex being sent towards the northern half of the uk every so often throughout the run and in between we have ridging of the Azores high towards us. Best I can offer on the GFS are the last two frames whereby the vortex relocates towards scandi and there are some surface heights over Greenland.

UKMO looks similar to GFS at 144, they both show the back to work storm on the 6th.

Edited December 31, 2013 by TSNWK

[Great Plum]

Morning all,

A crumb of comfort with this morning's GFS ensembles:

http://www.wetterzentrale.de/pics/MT8_London_ens.png

Whilst the OP run continues its relentless bouncing around, notice how the mean drops below average on the 8th Jan and continues in that vein for the rest of the run - more colder options appearing as well...

[That ECM]

Morning all,A crumb of comfort with this morning's GFS ensembles:http://www.wetterzentrale.de/pics/MT8_London_ens.pngWhilst the OP run continues its relentless bouncing around, notice how the mean drops below average on the 8th Jan and continues in that vein for the rest of the run - more colder options appearing as well...

I agree and forgetting the specifics in the longer term, the trend is good. The op does have some chances for cold but best not to get hung up on detail past t120 plus.http://images.meteociel.fr/im/3838/ECH1-168_pfj9.GIFA news worthy storm for America and good nh profile IMO. Edited December 31, 2013 by That ECM

[TSNWK]

ECM looks best of the bunch again this morning. Far more amplification of the mid Atlantic ridge around 168 and 192. Be nice to see that uk trough clear through south eastwards this run.

Not really sure what happened at 216 and 240' the trough kinda of evaporated in situ, leving us in a chilly flow I would have thought. Maybe a couple of days of chilly settled weather before the next bout of weather from the north west as quiet frankly I can see nothing on that ECM that is leading to a long wave pattern change.

Edited December 31, 2013 by TSNWK

[Timmytour]

One model discussion thread lasting two weeks in December.....it's probably a few years since that last happened on this forum and indicative of the relative lack of wintry potential in the models this year compared to the last few years.....

[Radiating Dendrite]

One model discussion thread lasting two weeks in December.....it's probably a few years since that last happened on this forum and indicative of the relative lack of wintry potential in the models this year compared to the last few years.....

indeed......though the mods only use to let it get to 36 or so pages before a new one.

[IDO]

I would ignore the GFS 0z this morning, it is an outlier solution on many variables, from pressure, rainfall and wind speed:

 

 

 

The ensembles are picking up what BA, Mucka and others were picking up 5-6 days ago, some sort of mean upper trough into S.Euro:

 

D10, eg:   

                   

 

Of course five days ago there was little info as to how this would play out, and it appears that the signal to introduce the AH into the mix (2-3 days ago) has meant that the trough is now further east and transitory, but this suggests we may drag in colder uppers for a while:

 

  

 

Maybe a short colder spell around D10. At the end of FI there is an eclectic mix of solutions with zonal & MLB Nr UK the main players.

 

GEM at T240 also has the upper trough to the south of the UK but the surface systems ride over.

 

So it goes from this at T198:    To T240: 

 

Similar dynamic from the ECM:

 

T216:   T240: 

 

Once the zonal pattern arrived in December it was always going to be a long haul towards cold. I said at the time, mid Jan was where it might lapse, based not on science, but on experience of previous  zonal spells, however without the help from the strat (if it helps) that may be an under-estimate. There was never any clear signal for prolonged cold (early-mid Jan) from the last week's charts just a signal that the pattern could vary enough to alter where we currently sit in this westerly regime. There still remains a chance for colder zonality from the GEFS, so January is not lost yet.

 

 

 

 

 

 

 

 

[bluearmy]

two points - the ECM flattens the ridge at day 10 so it's safe to assume this is what the spreads were indeed showing last night. Looks right to me and the obvious consequence of not getting a pocket of high heights established around iceland as the op/control did on the 12z.

EDIT: could be wrong on the spreads. There does look to be a cluster that get a block established ne of iceland by day 10 on the 00z run. Thats pretty well your only hope to avoid a continuation of the zonal train through to mid month at least. (Though on third inspection, it is probably a clustering of very low heights)

Secondly, re the ec32, I haven't checked the timings and NH profile of the control but its the only single run I can see and it did build a strong greeny block later in the run. I will double check later to see if it could tie in with a quick response to an SSW around the 18th/20th. I think it was a bit too quick from memory.

Edited December 31, 2013 by bluearmy

[Frosty.]

I like the look of these charts from the GEFS 00z mean, this shows a colder spell next week with a slightly more amplified pattern, weak mid-atlantic ridging and the trough finally making it to the north east of the uk which would enable a rush of colder polar maritime air to sweep southeast across the uk, it also shows the jet alignment tilting more wnw / ese which brings rather colder air further south for longer and that would turn the precipitation more wintry, and not just on hills and also an increase in night frosts and icy patches...so I think these are yet more encouraging signs for coldies.

Edited December 31, 2013 by Frosty.

[Gibby]

Good morning. Here is the latest report on the midnight outputs of the NWP for the final day of 2013.

 

All models show a continuing very unsettled period between now and the end of next weekend with details slightly different between the models but  all saying the same message of Low pressure over or to the NW of the UK with a strong to gale West or SW flow over all areas. The wet and very windy spell is going to persist through the first week of 2014 with strong winds and heavy rain alternating with brief drier and more showery interludes. Temperatures will remain close to average largely offset for much of the time by the strength of the wind.

 

GFS then moves into next week showing very little change with the rest of it's run typifed by continuing very strong West winds and further spells of rain with some colder periods over the North with wintry showers at times over the hills. There seems only a small chance of much in the way of anything more than very short dry interludes between the rain bands.

 

UKMO closes it's run next Monday with an intense depression under 950mbs just off Northern Ireland with gale or severe gale force WSW winds over the UK with showers or longer spells of rain rushing through on the breeze through the day in very average temperatures for early January.

 

GEM is also reluctant to show anything other than more of the same towards the end of it's run with the chance of a rather colder and less windy period later next week when wintry showers might occur almost anywhere for a time.

 

NAVGEM too shows frequent Lows crashing across the Atlantic and into the UK bringing repeated bands of wind and rain, heavy at times across all areas in average temperatures.

 

ECM today shows a slight change towards the middle of next week with a pause in the Atlantic bandwagon allowing for a quieter couple of days with a few wintry showers in colder air before I'm afraid the next system over the NW Atlantic regains supremacy with fronts crossing East over the UK by the end of the week returning wind and rain to all areas as well as returning temperatures to average values.

 

The GFS Ensembles paint all too familiar a picture again this morning with an Atlantic bias throughout carrying forward the very unsettled, wet and often windy period to which we have become accustomed right out to the far end when there are quite a few members showing an Anticyclonic end to the run biased towards the South of the UK

.

The Jet Stream remains very strong crashing over the Atlantic and into the UK or Northern France for the next week to 10 days before the High pressure based bias in the ensembles pushes the flow further North across towards Iceland at the end of the run.

 

In Summary it seems my innitial encouraging thoughts towards a break in the pattern to something more wintry last night was a tad premature as any such thoughts from this morning's output have been largely dwarfed or removed as the seemingly immovable train of Atlantic weather systems remain. There does seem some indication of a slow down of intensity of the wet and windy period later in the outputs as High pressure does show more of a hand but not necessarily in the right place for cold weather to become established.

 

[nick sussex]

Morning all

The latest installment of Indiana Jones and the Search For Snow sees shares in BDL Bitter Disappointment Ltd jumping this morning after the ECM makes yet another backtrack, it was a case of two decent operationals and then it crashed and burned!

It still has that deepish low upstream that could have delivered a semblance of interest for the UK but sadly the troughing over the UK takes too long to fill, is poorly orientated and far too deep, no energy going se but generally ne.

The GFS continues on its gritty reality path so it didn't even bother showing any interest over the last few runs, it fails to make anything of that same upstream low that the ECM has and so all the energy pours east and its dire in the lower resolution, more wind and rain and just basically a rinse and repeat of the last few weeks.

In terms of the upstream pattern NOAA for the timebeing prefer the ECM and don't think much of the GFS operationals because of the lack of that low development, said low will now be named the Hope Low, you may ask why well because its the only thing remotely interesting if you're a coldie and that would still need a backtrack from the models in terms of the low over the UK.

A few of the more palatable GEFS generally have that low, its a case of no low and zero chance of even a colder blip, so that low has to verify, without that theres little amplification ahead of it and the low heights will encroach too far east before the limpet troughing over the UK weakens.

Edited December 31, 2013 by nick sussex

[Paul_1978]

Hi All,just noticed a couple of folk liked the post above, just curious to know if its because they like this sort of weather type oris it just simply the quality of the input ?Thanks.

It's because they like the type of weather. Take Summer Sun and Ian Brown for example, both known preferrers of mild (and nothing wrong with that), and who often "like" posts that refer to milder or wet weather regardless of the 'quality'. Edited December 31, 2013 by Paul_1978

[Cecil Hogmanay Melchett]

Hum.

Another morning,another poor set of model output.The models are pretty awful out to 144h with pretty good agreement for this kind of setup

http://www.wetterzentrale.de/pics/Recm1441.html another bomb approaching the UK,just as this low hits another huge depression forming across the Atlantic to flatten the pattern once more

 

http://www.wetterzentrale.de/pics/Recm1681.html

 

First 10 days of January will be snowless for most of the UK and at day 10

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

Still a powerful PV sat like a slug over Greenland and HP stretching across Southern Europe.

[bluearmy]

the timing on the ec 32 control was pretty well spot on re the greeny ridge which goes up around the 26th.  (in conjunction with a raft of arctic ridging establishing a large area of 546 dam nw of greenland). interesting .........

[Summer Sun]

Worth keeping an eye on next Monday it has the potential for more Gales and heavy rain

 

[Summer Sun]

Once again this morning next Thursday shows potential for something less stormy to develop from ECM's ensemble thanks to high pressure building in the Atlantic those who've suffered flooding and or power cuts over the past few weeks will welcome something more settled

 

 

-5 850's starting to get closer as well by this stage

[johnholmes]

I like the look of these charts from the GEFS 00z mean, this shows a colder spell next week with a slightly more amplified pattern, weak mid-atlantic ridging and the trough finally making it to the north east of the uk which would enable a rush of colder polar maritime air to sweep southeast across the uk, it also shows the jet alignment tilting more wnw / ese which brings rather colder air further south for longer and that would turn the precipitation more wintry, and not just on hills and also an increase in night frosts and icy patches...so I think these are yet more encouraging signs for coldies.

 

hi frosty

Are you saying the chart you show indicate the jet tilting more wnw/ese?

your phrase 'a rush of colder polar air to sweep southeast across theuk...'

os also a touch OTT don't you think.

 

I am beginning to despair of new folk ever this winter having any objective assessment of what any model actually shows other than the search for cold?

For newcomers do read the output from Gibby it is as near as objective and in plain language as you are likely to get in my view.

okay folks so I know the majority of you (me included) really would like to see deep cold and snow but objectivity would really be quite welcome at times and it is not just you frosty either.

[Cecil Hogmanay Melchett]

hi frosty

Are you saying the chart you show indicate the jet tilting more wnw/ese?

your phrase 'a rush of colder polar air to sweep southeast across theuk...'

os also a touch OTT don't you think.

 

I am beginning to despair of new folk ever this winter having any objective assessment of what any model actually shows other than the search for cold?

For newcomers do read the output from Gibby it is as near as objective and in plain language as you are likely to get in my view.

okay folks so I know the majority of you (me included) really would like to see deep cold and snow but objectivity would really be quite welcome at times and it is not just you frosty either.

Yes i think i agree John.Im the first to go   when i see cold synoptics via NWP but really there is precious little to be excited or optimistic about at this time.I love Karls enthusiasm but for newbies i fear it can be a little 'Over the top' at times,while there are reasons to be cautiously optimistic regarding the stratosphere  its still going to be quite a bit 'down the line' before we can start to contemplate the ramifications for our little island.

It certainly looks to me that we can pretty confidently write off the first 10 days of Jan for snow prospects,after that who knows.

[IDO]

I was disappointed with the ECM mean at T240 last night, as the overriding signal was to flatten the ridge. The ECM mean at T216 for the 0z:

 

Promising and ties in with some of the GEFS.

 

At T240: 

 

More inclination to send energy over the top. Not a panacea for cold and snow but may lead to a better variant of the zonal theme. Of course that mean reflects just as many members, I would guess, continuing to flatten the pattern. So the favorite remains, like the GEFS, more of the same.