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Paul

Model output discussion - winter proper underway

Paul

Please only post model discussion in this thread. 

For more general chat and banter, or moans and ramps loosely around the models, please head to the banter thread:
https://www.netweather.tv/forum/topic/86721-model-moans-ramps-and-banter/

For general weather chat including about the snow/cold chances around the country, please go to the regional threads:
https://www.netweather.tv/forum/forum/142-regional-discussions/

Thank you!

Message added by Paul

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4 hours ago, Summer Sun said:

Could you explain what is 'interesting' to some new members that chart just looks like a kid has drawn on it with crayons

Some hints of a Scandi high and a genua low which combined could make  potent easterlies 

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31 minutes ago, Danny* said:

Right - That's the snow out of the way lets get back to looking out into the mid-term with lust and hope

The models are hinting towards height rises over Scandinavia and have been doing so for a few days now.

Scandi.thumb.png.8dc6bb57297c2b289ba145a5fafaa373.png

Azores High ridging North-East towards developing heights over Scandi. No model has gone full scale with it yet because the GFS as usual revs up the Polar Vortex and pushes it all away. But, as long as continue to see the trend towards heights over Scandi as per the GFS 12z above, we've got something to look forward to. 

In the meantime, less cold towards the end of the week but certainly not what I'd call "mild".

not quite, plenty of interest for southern counties of england later on tonight and into tomorrow courtesy of storm ana which the prospects of rain, sleet and possibly heavy snow for some for a time :wink:

gfs1.thumb.png.2f6041baf86b1cfe37df86591c46f56f.png gfs2.thumb.png.de44c872c66adab0ecd8215211d7949c.png gfs3.thumb.png.ea886d1474bc22eba1b28e7eeac442be.png gfs4.thumb.png.5ba2eebc2f30f7f10428285e714f87b9.png

 

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Pretty reasonable anomalies on the 12 det run taking into account last nights

ecm_z500a_5d_nh_11.thumb.png.aed8e83629e7794754511293c1bc56ae.pngecm_t850a_5d_natl_11.thumb.png.0f4cac31ed68eae16e4091ba212d249e.png

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As much as im sure most of us would love a 62/63 style freeze for the next 3 months its highly unlikely to happen, mild spells will occur and the Atlantic will always be trying to knock at the door, but theres plenty of time yet for the cold to return this winter. 

In the short term, some very cold temperatures over the next couple of days especially Tuesday

 

Netweather GFS Image

 

 

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Finding the models for the next 10 days interesting. They look consistent for 8 days - a bit warmer, a bit wintry Thursday in the North West, high pressure, benign day or so, and then? GFS has moved to wet westerlies from ridging but now ECM is looking interesting at D9 and D10. Always interesting when options are available. 

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3 minutes ago, chionomaniac said:

I'm still not convinced that the Atlantic will come crashing in. Yes it may not be quite as cold as the last few days but there is only 1 mild day programmed on the ECM and that is at day 8. That has the possibilty to be watered down. The PV is not at full throttle yet and the jet is still showing a tendency to continue with the NW/SE axis so I wouldn't be surprised to see further cold incursions lasting longer than ant mild interludes.

No traditional zonality modelled in the reliable just yet. Just no blocking either.

I agree Chiono. It seems even from a novice like me that Nly outbreaks can happen even with subtle changes in ridging. Models seems keen to keep the jet meandering in the around the Northern hemisphere.

Ok I admit chances of a UK wide christmas snow event are slim but for certain areas maybe just possible. 

We live in the Western Isles. Supposedly on the mild atlantic. Snow is unusual close to the coast. A snow event with several inches recorded is even rarer. We have a rapidly cooling island that increases the chance of snow. 

 

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4 minutes ago, chionomaniac said:

I'm still not convinced that the Atlantic will come crashing in. Yes it may not be quite as cold as the last few days but there is only 1 mild day programmed on the ECM and that is at day 8. That has the possibilty to be watered down. The PV is not at full throttle yet and the jet is still showing a tendency to continue with the NW/SE axis so I wouldn't be surprised to see further cold incursions lasting longer than ant mild interludes.

No traditional zonality modelled in the reliable just yet. Just no blocking either.

Indeed ,just go back a few days and the models have really underplayed this cold snowy spell for southern parts of the UK ,we could see a minus 14c for the Midlands over the snow Fields by Tuesday morning something even when viewing the upcoming cold spell which I really never expected, this cold spell for me has been told to go round to some Friends for beans on toast and getting a banquet instead:D

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I'm not sure where the idea of a raging Atlantic originated. I think a zonal pattern is being indicated in the medium term but in the eastern Atlantic the energy is being spread courtesy of the HP block in the east and positive anomalies to the NW and the trough running south to our east. The key may well be if the Azones ridges a little close to the UK

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37 minutes ago, West is Best said:

Interesting scatter again on the ensembles, from a relatively short way out too. A lot of milder members from T +7 days but then most are colder than the operational further out beyond T +10 days and into Christmas:

5a2d8338a53a7_ScreenShot2017-12-10at18_55_04.thumb.png.12dda44b4b3414c52cd733d5ad3c3c0f.png

For at least 4 days we have seen a large increase in uncertainty after the 17th. So interesting times, probably even need 2 more days of uncertainty before the models can give us an answer 

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7 minutes ago, ChezWeather said:

As much as im sure most of us would love a 62/63 style freeze for the next 3 months its highly unlikely to happen, mild spells will occur and the Atlantic will always be trying to knock at the door, but theres plenty of time yet for the cold to return this winter. 

In the short term, some very cold temperatures over the next couple of days especially Tuesday

 

Netweather GFS Image

 

 

A 62/63 winter so I'm told was the coldest for 240 years which really was very freaky. There are lots of variations of winter for the UK but you can get a damn good winter without the severity of that infamous winter. As far as I'm concerned the winter has started on a high note for me......can it continue , looks very interesting viewing in the days ahead:cold:

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UKMO extended once again showing a switch to something milder next weekend

t144

ukm2.2017121612_144_lant.troplant_prp_fcst.gentracker.thumb.png.ae1129813f3439be93993f22c339b18a.png

t168

ukm2.2017121712_168_lant.troplant_prp_fcst.gentracker.thumb.png.c04d677a59c107d97a3fa29917fcb6b7.png

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32 minutes ago, chionomaniac said:

I'm still not convinced that the Atlantic will come crashing in. Yes it may not be quite as cold as the last few days but there is only 1 mild day programmed on the ECM and that is at day 8. That has the possibilty to be watered down. The PV is not at full throttle yet and the jet is still showing a tendency to continue with the NW/SE axis so I wouldn't be surprised to see further cold incursions lasting longer than ant mild interludes.

No traditional zonality modelled in the reliable just yet. Just no blocking either.

3

Indeed, I'm of the belief, the exact opposite will happen and result in a rather memorable period of weather during this December. I hinted at this in last night's post here. As for reading the stratospheric signals and such complexities, I'll leave that to others, more knowledgeable on those matters, such as your good self. With -14c projected overnight on Tuesday morning over the snowfields, travel chaos through icy roads etc. and the more snow chances yet to come as hinted at by AJ above. It's pretty memorable already, to be fair. It's as if the Express headlines have actually come true for at least a couple of days this winter, shame about the other 2,000 headlines prior. A mild blip on Wednesday with some rain and wind about once again, but aside from that six out of the seven days will be chilly for all, very cold for a few with ICE days thrown in. ENJOY!

Edited by gottolovethisweather

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There is a growing trend going into the medium term that there will be a switch to a more zonal spell of weather. Little evidence to doubt that now. The only question in my mind is what will be the duration of this zonal phase. 

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Just now, West is Best said:

Folks, my one word of advice from someone who once had their fingers frostbitten ... nothing is nailed on or certain 7 days out. A week ago someone nameless on here said that we were definitely in for a mild week. The models are not only at variance amongst themselves but there's huge ensemble scatter e.g. look at the variety of perturbations on the GFS12z:

5a2d8e6ce1745_ScreenShot2017-12-10at18_55_04.thumb.png.bf125afddbbcb89e460749a43488f807.png

 

We've all done it: been convinced of a pattern, be that cold or hot but unless I see an absolutely rock solid blocking high e.g. the Bartlett slug or a Euro high or, for us cold fans, a rock solid Greenland high or Scandi high then I would urge than anything can happen beyond T144 and nothing is nailed on. So, for those who love snow and cold why not just enjoy the present? ;) 

Yeah GP, Tamara and others touched on this when they mentioned about moving into a new MJO phase. The models will continue to make a dogs dinner of it until at least mid next week. 

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1 minute ago, CanadaAl said:

Yeah GP, Tamara and others touched on this when they mentioned about moving into a new MJO phase. The models will continue to make a dogs dinner of it until at least mid next week. 

Does anyone know the latest on the mjo. As far as I could understand, it looked as though things were looking favourable for us going forward?

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47 minutes ago, bluearmy said:

Chart of the evening for coldies is JMA day 8. 

Incidentally, ecm runs that little system along s England Thursday night which has some snowfall on its n edge 

not quite getting the concern for the outlook being flatter. Even if it verifies, we live in the UK, not Canada! 

And that JMA is very similar to the gfs op.

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1 hour ago, northwestsnow said:

Well after the frenzy eyes cast towards the models...

Not sure im as optimistic as others...growing signs of a resurgent jet stream ..this time much flatter and less emphasis on Atlantic ridging.

Ukmo looks flat at 144 and gfs-

Added to that fergies latest tweet/ musings do not inspire...

Hoping for some positives from the strat..do not want to see zonal winds increasing..!

You really are a pessimist aren't you NWS ;-)

You don't seem convinced by these apparent longer term signals then, and the fact that much of the model output at the minute (espcially the later stages) can be taken with a large pinch of salt?

I don't see Ian F's tweet at particularly concerning tbh. 

Edited by Paul_1978

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27 minutes ago, Summer Sun said:

UKMO extended once again showing a switch to something milder next weekend

t144

ukm2.2017121612_144_lant.troplant_prp_fcst.gentracker.thumb.png.ae1129813f3439be93993f22c339b18a.png

t168

ukm2.2017121712_168_lant.troplant_prp_fcst.gentracker.thumb.png.c04d677a59c107d97a3fa29917fcb6b7.png

Fingers crossed Gavin, the December daffs are struggling a bit so far:)

th.jpeg

Edited by Frosty.

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11 minutes ago, blizzard81 said:

Does anyone know the latest on the mjo. As far as I could understand, it looked as though things were looking favourable for us going forward?

Entered phase 7 yesterday according to the RMM plots, whether it motors through to P8 and 1 remains to be seen, though perhaps at low amplitude according to some plots:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

Phases 7/8/1 correlate to producing colder patterns, but there is obviously a lag of 10+ days from these phases, so may not be until later in December we may see changes, maybe in time for Xmas?

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As others have said, looking through the GEFS full on zonality looks unlikely in the medium term. 

My guess is that once next weekend is over we end up with a mid lat high, so cool but nondescript weather with a slow return to a more mobile pattern towards new year and renewed heights over southern Europe. 

Others more learned than me will no doubt have other views but I don't sense any great likelihood of HLB over the next few weeks. Fairly standard fair coming up by the look of things.

That said, based on years of experience, local knowledge etc, I thought the likelihood off settling snow here today was close to zero and yet there is a decent covering outside tonight so one never can be certain.  

 

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24 minutes ago, chionomaniac said:

And I bet that is short lived with another NWerly plunge immediately after

I can just see the (ecmwf)  plume(for the Netherlands)  but after the 17th I can see 90% of the ensemble going for mild zonal and the rest for (north) easterlies. It's not looking good for day 7 - 15

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22 minutes ago, Paul_1978 said:

You really are a pessimist aren't you NWS ;-)

You don't seem convinced by these apparent longer term signals then, and the fact that much of the model output at the minute (espcially the later stages) can be taken with a large pinch of salt?

I don't see Ian F's tweet at particularly concerning tbh. 

I don't think he's a pessimist at all, more like a realist as it does look like we are on course for a phase of positive NAO with the northern arm of the jet cranking up in the run up to christmas (week 2)...the week ahead looks generally chilly though.

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