Model Output Discussion

[TEITS]

Well the 18Z has certainly put a smile on my face.

Like I said a few days ago these are extraordinary charts even for F.I because rarely will you see such N blocking in early Dec. The GFS might throw up these wonderful fantasy charts during the winter but I can't remember many runs like this for early Dec. You usually see these type of F.I charts in late Dec onwards.

[Thundery wintry showers]

http://www.wetterzentrale.de/archive/ra/1965/Rrea00119651121.gif

:smiliz19:

[TEITS]

http://www.wetterzentrale.de/archive/ra/1965/Rrea00119651121.gif

:winky:

I bet you can't find many more especially since the late 80's. :smiliz19:

The month of December has never really been known for its E,lys as past cold spells have often been N,lys. The frequency of E,lys always increases towards the latter part of winter and are most frequent during the months of April,May.

This is the point im trying to stress to members who keep mentioning F.I. In all my years of following the models I have seen numerous F.I charts suggesting N blocking and bitter E,lys but I haven't known many model runs like the 18Z this early in winter. This for me could be significant and I wouldn't be surprised if these charts actually become reality.

[MR EXTREMES]

This is very true NS. Winter starts in 20 mins and we're spoilt already with interesting outputs! :smiliz19:

i was thinking more on the lines of april 1st :winky:

[Cecil Hogmanay Melchett]

As predictaed its back to normal service on the 0z run! Less said the better.

UKMO is also a poor run so its over to the ecm to salvage something.

:smiliz19:

[Cal]

Aye, normal service resumes from the GFS 06hrs run, but it was a fair outlier.

http://212.100.247.145/viewimage.pl?type=ens;date=20091201;time=00;file=t2mLincolnshire

[azores92]

as has been said before, the models are really struggling to find their feet atm. it was yesterday morning when we were looking at the same picture, before the 12z ecm and gfs dream synoptics came out, and the atmosphere was incredibly different. i would not be surprised to see a couple more flips in the outlook before the models finally decide on which one itll be. thing is, there are so many conflicting signals, stratospheric conditions, state of mjo and enso, the models are almost certainly confused by the whole situation.

[Weather-history]

GFS 0z run reminds me of January 1937 somewhat. High pressure to ENE, low pressure the west. Neither one was giving way, result a mild and vert wet January for the UK. There was a short cold interlude at the back end of the month as the high gained the upper hand for a short while.

[cyclonic happiness]

Still all to play for as the models are struggling after thursday with the control run being a huge cold outlier and the operational being a huge warm outlier.

Don't worry too much, My money's on a colder longer term, as the models always do "summersaults" when something moer interesting is due.

Edited December 1, 2009 by cyclonic happiness

[phil nw.]

as has been said before, the models are really struggling to find their feet atm. it was yesterday morning when we were looking at the same picture, before the 12z ecm and gfs dream synoptics came out, and the atmosphere was incredibly different. i would not be surprised to see a couple more flips in the outlook before the models finally decide on which one itll be. thing is, there are so many conflicting signals, stratospheric conditions, state of mjo and enso, the models are almost certainly confused by the whole situation.

Yes the 00z pushes more energy off the Atlantic and keeps the blocking further away leaving us in a more Southerly/South westerly flow.

The trough aligned further North on this run,more in line with 18z parallel GFS last night.

[nick sussex]

Yes the 00z pushes more energy off the Atlantic and keeps the blocking further away leaving us in a more Southerly/South westerly flow.

The trough aligned further North on this run,more in line with 18z parallel GFS last night.

Morning Phil

This was always a risk if pressure didn't rise to the ne to deflect the jet se'wards, as soon as you get low heights to the ne with this pattern and high pressure to the east you're in trouble, personally i hope the pattern retrogresses, if its going to be mild at least let it be dry, unless the models switch back very quickly then eventually the russian high will throw a ridge sw'wards under the trough and pressure will rise over southern europe.

Anyway thats the worst case scenario and because the PV is jumping all over the place and the effects of those changes in the Pacific probably won't be accurately modelled yet I'm going to hold fire before opening the emergency prozac line!

Edited December 1, 2009 by nick sussex

[Frosty.]

Yes the 00z pushes more energy off the Atlantic and keeps the blocking further away leaving us in a more Southerly/South westerly flow.

The trough aligned further North on this run,more in line with 18z parallel GFS last night.

At least IB will be happy

Nothing has really changed overall, the cold FI shown last night was pure fantasy that only exists within a super computer so as I said yesterday, we will shortly be back to square 1.....wet and windy at times with either near average or mild temps.

[Glacier Point]

The operationals were probably too progressive last night but today's output is none-the-less very interesting.

GFS mean H5 anomaly for days 11-15 and the operational ECM and GFS are suggesting a noteworthy longwave pattern developing across the NH:

http://raleighwx.easternuswx.com/models/gfsensemble/00zENS11-15day500mbHeightAnomalyNH.gif

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html

These show three discrete major upper level vortices developing across the mid latitudes. We've not seen that for a long time.

In the medium to long term, it continues to look unsettled and close to average but with the interesting stuff building far to our north-east.

[phil nw.]

Long discussions regarding 00z runs here

http://www.hpc.ncep.noaa.gov/discussions/pmdhmd.html

No one model is favoured it seems.

Reading between the lines there are still doubts upstream over the amplitude and strength of the upper flow off the Pacific and across the U.S.

Of course this impacts on us around the T120 hrs range.

Edited December 1, 2009 by phil n.warks.

[nick sussex]

The operationals were probably too progressive last night but today's output is none-the-less very interesting.

GFS mean H5 anomaly for days 11-15 and the operational ECM and GFS are suggesting a noteworthy longwave pattern developing across the NH:

http://raleighwx.easternuswx.com/models/gfsensemble/00zENS11-15day500mbHeightAnomalyNH.gif

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html

These show three discrete major upper level vortices developing across the mid latitudes. We've not seen that for a long time.

In the medium to long term, it continues to look unsettled and close to average but with the interesting stuff building far to our north-east.

By long term do you mean the cold finally arrives at the end of February! Is there not a chance that the pattern could retrogress sufficiently with trough held further west and eventually a cut off low runs se' wards or does the pattern have to go with low pressure stuck over the uk finally slipping se wards as pressure rises over the top,?

The freebie ecm ensemble today is for Denmark, although quite away east still interesting to note the operational run was mostly at the top end of members.

http://www.ecmwf.int/products/d/sampler/epsgrams/europe/page.html

Having said that the control run does back it.

Edited December 1, 2009 by nick sussex

[phil nw.]

Morning Phil

This was always a risk if pressure didn't rise to the ne to deflect the jet se'wards, as soon as you get low heights to the ne with this pattern and high pressure to the east you're in trouble, personally i hope the pattern retrogresses, if its going to be mild at least let it be dry, unless the models switch back very quickly then eventually the russian high will throw a ridge sw'wards under the trough and pressure will rise over southern europe.

Anyway thats the worst case scenario and because the PV is jumping all over the place and the effects of those changes in the Pacific probably won't be accurately modelled yet I'm going to hold fire before opening the emergency prozac line!

Morning Nick,

Yes i think a few of us half expected a flip in the models again o/night.As i said last night`s 18z parallel,which i posted then,showed what could happen if the Atlantic didn`t play ball.

Still as you suggest it`s still finely balanced and if you refer to that link in my earlier post still much uncertainty upstream over the flow this week.

I just get the feeling that maybe we will get lucky if this pattern keeps repeating but not just yet.

Ah, i found the xmas smileys

Edited December 1, 2009 by phil n.warks.

[Severe Siberian icy blast]

Long discussions regarding 00z runs here

http://www.hpc.ncep....ons/pmdhmd.html

No one model is favoured it seems.

Reading between the lines there are still doubts upstream over the amplitude and strength of the upper flow off the Pacific and across the U.S.

Of course this impacts on us around the T120 hrs range.

Agreed , the models have absolutly no idea whats goin on , the only thing thats consistant is the high to our north east really, as for them raging south westerlies with at one point a pool of 10c uppers is about as stupid as its ever goin to get , it annoys the hell out of me to see the forecasting models throwing in such extreme predictons each day , surely there is no point in the F1 as it hasnt even been any good for trends as of late , gives ppl somethin to talk about thats all it does .

[cooling climate]

At least IB will be happy

Nothing has really changed overall, the cold FI shown last night was pure fantasy that only exists within a super computer so as I said yesterday, we will shortly be back to square 1.....wet and windy at times with either near average or mild temps.

You may well be right but at the same time I could quite easily see the models reverting back to

yesterdays outputs.

The PV is still modeled to split and the main area to fall into Canada, the difference this morning

is that the heights over the Arctic are now being modeled to fall into Russia rather than come

south over Greenland and Svalbard area.

I think this is still very much up in the air so to speak and could go either way.

[Frosty.]

You may well be right but at the same time I could quite easily see the models reverting back to

yesterdays outputs.

The PV is still modeled to split and the main area to fall into Canada, the difference this morning

is that the heights over the Arctic are now being modeled to fall into Russia rather than come

south over Greenland and Svalbard area.

I think this is still very much up in the air so to speak and could go either way.

It was no surprise to me that the stunning 18z would be followed by the lead balloon feeling that the 00z has given us, it happens so often i've lost count. I think our patience is going to be severely tested during the next few weeks.

[BLAST FROM THE PAST]

At least IB will be happy

Why? ECM maintains a southerly jet.....longterm exactly what we want, and no fear it is the form horse.

I agree wholeheartedly with GP re yesterday's outputs being 'too soon'. I believe that outputs that show southerly jet with increasing storm potential through 7-15 Dec, with direct hits over the UK and NOT to the north in GIN corridor, will be on the money for me.

I am looking at two periods that may 'set the winter up'. First is mid Decemeber but possibly more importantly is the New Year period. I think this month a few shots are going to be fired across the boughs with the stormy/peak energy period around New Year being the 'switch' to bring in that arctic weather.

Don't be downbeat about the change of outputs today, they are still very much so encouraging and 'on course'. I think it was KW [Mr AO] who mentioned the fine line between cold and mild, in these synoptic patterns that is spot on. If we were in the MEW pattern there would be no fine line.

BFTP

BFTP

[swilliam]

One thing that can be said though is that we will get the cold pooling to our East and North that we were all desperate for a few weeks ago

[johnholmes]

GFS mean H5 anomaly for days 11-15 and the operational ECM and GFS are suggesting a noteworthy longwave pattern developing across the NH:

http://www.meteo.psu...0z/hgtcomp.html

These show three discrete major upper level vortices developing across the mid latitudes. We've not seen that for a long time.

they are fairly unusual charts for sure Stewart-in fact I don't remember seeing anything like it in the past 3 years-zonal almost the whole hemisphere at our latitudes but far from zonal further north with very large +ve anomalies showing in the Arctic area. That is a pretty impressive -ve anomaly also w or sw of the UK.

Edited December 1, 2009 by johnholmes

[nick sussex]

Another freebie ecm info today is all 50 ensemble members upto 168hrs, quite a few scenarios on show.

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009120100!!/

Having looked through them all i'd say theres 8 members that could go on to develop something interesting by 240hrs, quite a few though take the trough too far north and east with ridging into southern europe. The problem i think for many is remaining patient to see if the pattern evolves over time but there would be an awful lot of rain and wind beforehand, IMO the quickest way out of this is the trough hangs back further west and disrupts with cut off low heading se'wards unfortunately this looks like a longshot.

Edited December 1, 2009 by nick sussex

[Methuselah]

One thing that can be said though is that we will get the cold pooling to our East and North that we were all desperate for a few weeks ago

I agree. That does seem to be (together with a south-tracking jet) something that's evident on most of the model runs...The constant flips between raging Easterlies and blowtorch Southerlies seems to be just detail. One indivual run/solution (IMO) cannot possibly represent probability, possibility or likelihood...

[nick sussex]

The extended ecm ensembles are out, a cooling trend after 240hrs but at this timeframe not worth reading too much into this, it would have been nice and a bit of fun to see the synoptics of that rogue ensemble member which looks like bringing the next ice age!

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html