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Paul

Focussed Model Discussion

Paul

This is the focused model discussion - please only post about the model output. 

For a more laid back, bantery model discussion please use the Cold hunt - models and banter thread.

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Eps extended are less flatter jet again to our west with more of a mean ridge again .... nothing spectacular..... need the clusters to show how the probabilities sit 

just a wonder that now the downwelling wave is approaching the trop, is the modelling going to be prone to even less reliability  ?. Not that it’s been great for the past week or so but at least we know what went wrong with the east American low not behaving .....

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i dont want to take the thread off course of will it wont it in 10 days time, but is the rain band moving in quicker that first thought?? 

im in somerset, the last forecast i saw this morning had it clearing in the early hours then showers from late morning onwards, looking at it now if it keeps going at its present speed it will clear here in a couple of hours, showers already packing in the Ireland as i type. 

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May as well answer in here too!

It's about where it was modelled to be from what I can see. 

Radar @ 2030

radar2030.jpg

Model for 2000 and 2100

20.png21.png

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1 minute ago, Paul said:

May as well answer in here too!

It's about where it was modelled to be from what I can see. 

Radar @ 2030

radar2030.jpg

Model for 2000 and 2100

20.png21.png

Cheers

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19 minutes ago, fromey said:

i dont want to take the thread off course of will it wont it in 10 days time, but is the rain band moving in quicker that first thought?? 

im in somerset, the last forecast i saw this morning had it clearing in the early hours then showers from late morning onwards, looking at it now if it keeps going at its present speed it will clear here in a couple of hours, showers already packing in the Ireland as i type. 

This morning's forecast had the front going through somerset around 00 so it's not going to be far off

Edited by knocker
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44 minutes ago, bluearmy said:

Eps extended are less flatter jet again to our west with more of a mean ridge again .... nothing spectacular..... need the clusters to show how the probabilities sit 

just a wonder that now the downwelling wave is approaching the trop, is the modelling going to be prone to even less reliability  ?. Not that it’s been great for the past week or so but at least we know what went wrong with the east American low not behaving .....

It's a fair question and will all add to our knowledge for future events! I guess it would be too much to ask for three consecutive years with an SSW so we may have to wait a while to put the lessons from this one into practice! Will have to go through some of the older threads and take copies of the various charts from the start to compare for the future.

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ECM ensembles are certainly not as good down the line with more and more Atlantic lows powering up in the central Atlantic in early Feb. I'm not convinced about that trend but we will see. I've not seen what the Arctic is doing yet so I won't comment on that. Also still a very wide range of options on the table to be fair!

The other more positive thing is there does seem to be strengthening agreement for a possible larger snow event around the 29-31st, indeed that is reflected in the ECM ensemble mean having an area of lower heights over the UK for the 31st. There is going to be a fair amount of uncertainty with locations, some give just a small load locally, others give a country wide snow set-up.

So in terms of the ECM, a mixed bag, potential in the medium term but not as good further on.

Edited by kold weather
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So, the big three at 96 (GFS 90).   Clearly, there's much to be agreed and these changes will have bigger implications down the line.

GFS image.thumb.png.af60f9e814721e1102086f1e8805501d.png UKMO image.thumb.png.913271db55421be36badaf0393aec241.png ECM image.thumb.png.a160cbdf3a6de6e32e2deb696de5ce08.png

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1 minute ago, Hull snow said:

When’s ecm 46 updated again ?

About now.

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Week 2,3,4

16136367-0FB2-4E1D-B2C9-1365FEEE2EBD.thumb.png.8b92896a73fc9b039f0c7424a25c9791.png172E9D35-161E-478E-8139-0E58B9DE8392.thumb.png.713d933d3a8a1952152191a1a2f9855e.png9EB7473A-E85D-49D7-AFA0-C434F92A1C92.thumb.png.b336ae14655653807618d02ab473caca.png

Edited by karlos1983
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19 minutes ago, Hull snow said:

When’s ecm 46 updated again ?

Looks like expected weeks 3 and 4 on the Icelandic site ......growing height anoms around Greenland and low anoms Europe ....week 4 looks a bit slack re those anoms, will wait for the global charts to get a better handle but the mean looks a bit more as though there is more spread on restricted view. 

Edited by bluearmy

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The whole run out to day 46 is a continuation of what we’ve been seeing for end jan and through feb  ....I guess if we manage to get the pieces into the right places at the right time, they may well stay there! 

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Got to say the GFS is proving utterly useless when it comes to the Arctic at the moment. 4 runs today and 4 wildly different solutions. 00z has an arctic high that links to the Azores high ridge, the 06z attempts a cross polar flow from US+Russia then pumps up a strong high from Russia, the 12z doesn't even bother at all with the first arctic high, then eventually creates one at the death of the run and the 18z develops 2 highs via ridges in the Pacific.

Just about covered every possible solution in the space of 4 runs, so I'd probably suggest that alone hints at quite a highly uncertain set-up.

GFS 18z basically is an exact rerun of this weekend in FI, to the point where the storm I the US takes an identical track and this causes the ridging to collapse eastwards and we reset into the classic default GFS +ve NAO dirge.

On balance I'm still expect some more significant blocking to arise between the 5-10th Feb, though where would have a large impact of course. I did originally think Greenland area but its starting to look like the only way to get rid of that PV is to fire several nukes at it! So maybe we will have to focus further east in a hope for something to take hold strong enough to disrupt the current pattern.

Edited by kold weather

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45 minutes ago, kold weather said:

Got to say the GFS is proving utterly useless when it comes to the Arctic at the moment. 4 runs today and 4 wildly different solutions. 00z has an arctic high that links to the Azores high ridge, the 06z attempts a cross polar flow from US+Russia then pumps up a strong high from Russia, the 12z doesn't even bother at all with the first arctic high, then eventually creates one at the death of the run and the 18z develops 2 highs via ridges in the Pacific.

 

Indeed the GFS has really struggled with the Arctic setup; AO charts have swing about quite a bit and if you look at the latest set showing observed v forecast it actually sits above the spread from previous forecasts. 

If we do finally see the SSW moving down then I don't really have a lot of confidence in how it's handled by the GFS going forward. 

Screenshot_2019-01-21-23-55-41-378_com.android.browser.png

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ECM day 10 zonal wind chart on Berlin site much better this morning with net easterlies in the troposphere from 60N northwards:

image.thumb.jpg.1ef8ecbb5d5efae936d3d8a512647ce6.jpg

That will be from yesterday's 12z ECM.  Coupled with above GFS run, have we finally landed something at the 11th hour?  My despondency yesterday premature, me thinks!

Edit, my post about the GFS run is in the other thread, sorry!  

Edited by Mike Poole
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Continuing briefly from the short range with the gfs noting once again the starting position a tad different to the fax. By T150 the next trough has swung into the Iceland area and the associated front(s) have traversed the country bringing some rain, sleet and snow. From this point a familiar scenario with high pressure ridging in the west as the trough drops south east over the UK bringing with it strong winds and some very unsettled conditions with rain, sleet and not a little snow.around this time next week

gfs_z500_vort_natl_26.thumb.png.c7ec17208751b0a9928c2630c6507d09.pnggfs_z500_vort_natl_30.thumb.png.674684d186ca448327ae16cbd0323534.png850t_anom_86.thumb.png.43afffbc6f5dfff5066e967919a9bdb6.png

Edited by knocker
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The ecm has the trough in the Denmark Strait at T162, suppressing the Atlantic ridge with the UK in a showery north westerly. From this point it tracks south east over the UK as another trough is ejected from the eastern seaboard, Thus some very unsettled weather Tues/Weds next week with rain, sleet and snow and quite cold.

t162.thumb.png.57ef3dcc5dbb25e746aca9c523dd34d4.pngt192.thumb.png.f37ab615d0edbc20ef900cdc7ae8097e.png

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We have been here before, but more reason to be optimistic that around the start of Feb we should see the downwelling help more with the forcing of the pattern.

The three models at D10:

279095443_gemnh-0-240(1).thumb.png.25b118dcc99732ce6cae7328739466b6.png1592069837_gfsnh-0-240(1).thumb.png.054619d88c626b50d44894b92122aea0.png806472155_ECH1-240(8).thumb.gif.0fc483db2375d8ab78b0ff5cd700dfa1.gif

We have seen the focus of recent runs with this three-wave attack, surface Siberian High, Atlantic Ridge/High & Pacific wave so the above longwave pattern is quite believable.

Can it develop from there to give us some HLB'ing? The GFS op is getting there with wedges moving in the flow in the higher latitudes, so they may, as they shuffle around, direct some much colder air, at least temporarily to the UK. It would be a start.

Looking at the GEFS at D16 suggests they still have to pick up the op signal. At D10 there is good cluster support of the op, though the Control needs a second bite 3-4 days later to get heights into our NW. The mean at D10 shows the op is viable:

1566165314_gensnh-21-1-240(1).thumb.png.1997665952e9fd46f672dd7f792d9a7d.png

We know what the models are like with false dawns so wary as we go, though in the knowledge it is only a matter of when not if.

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A couple of forecast soundings illustrating the cold unstable air

liv.thumb.png.995668112e1a4e562ca897601702b2ba.pngbristol.thumb.png.88fe5808b932f43235254fd5e2026b03.png

convect.thumb.png.3888ba62e13d541aa082e37dd9b89762.png125962550_concec12.thumb.png.f8ae44f9b724591d8b4ee085203afcba.png

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The EPS this morning has the high cell over the western Arctic  with a rather diffuse Arctic/N. Canada vortex which seems to have facilitated the east European ridge to encourage the Atlantic one to shift a tad east. Which perhaps ties up with trough ducking down sharply south over Britain  towards day ten of the det runs. One would think this portends some unsettled weather with temps a fair bit below average

9-14.thumb.png.c8509a1a80d5b6ca4a6864caa2e66270.png

 

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3 hours ago, Mike Poole said:

ECM day 10 zonal wind chart on Berlin site much better this morning with net easterlies in the troposphere from 60N northwards:

image.thumb.jpg.1ef8ecbb5d5efae936d3d8a512647ce6.jpg

That will be from yesterday's 12z ECM.  Coupled with above GFS run, have we finally landed something at the 11th hour?  My despondency yesterday premature, me thinks!

Edit, my post about the GFS run is in the other thread, sorry!  

Mentioned yesterday back on page 7 re: reversal making its way down through the troposphere sustainably on GOES and GFS NAM plots last few days of month into start of Feb. GOES until last few days not keen on downwell into trop, like the EC, GFS on and off, now these three now showing trop reversal we might finally see trop circulation impacts showing in NWP z500/mlsp charts, but whether it works favourably for UK remains to be seen.

Strat-trop coupling help or not, MJO may give a helping hand too late month into early Feb, latest EPS z500 mean suggests ridging pinch from both Atlantic and Scrussian areas over the top of Euro trough - which could lead to more interest towards NE or E flow start of Feb.

35A6E979-D8E6-49B8-B28B-08B17D4C7B41.thumb.png.268583ce0352683d18ee0df76f7a407e.png

But the ongoing Canadian vortex imprint on the N Atlantic sector remains a conundrum.

Edited by Nick F
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35A6E979-D8E6-49B8-B28B-08B17D4C7B41.png gfs-ens_z500a_nhem_41.pnggfs_z500a_nhem_37.png nino_6_feb_mid.png

Comparing the EPS chart Nick shared with the GEFS 00z for the same date and GFS 00z for a day earlier (D10 little different) shows an impressive degree of similarity between them - and they also match pretty well to the MJO P6 +ENSO composite I discussed yesterday. The main modification being, as anticipated, the larger Canadian vortex lobe - this perhaps being what's given the models some difficulty as they need to be more accurate in order to capture the breaks in the Canadian-European low chain that the tropical forcing makes possible. It's a shame ECM produced another broad, rounded trough on the 00z - feels strange because in times past such a habit has been associated with GFS.

We'll see how it goes. I'm getting the impression that the wave-1 dominated nature of the SSW event is producing a more 'lopsided' downwell imprint than usual (hence zonal mean winds not looking all that impressive at the lowest atmospheric levels) which may cause the models some issues. Focal area for negative zonal wind anomalies should be pretty much due N of the UK so it'll be interesting to see how that interacts with the emerging tropically-forced pattern; there shouldn't be much in the way of trough activity trying to get in the way.

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