Model Output Discussions 12z 01/09/2016

[carinthian]

Just been issued by our snow portal service of advanced warning of significant snowfall for Sunday. Preliminary forecast of 50cm at height location 2000m . All due to sinking of a polar trough into the Alpine region by the end of next weekend. As the weekend approaches I will update with the information provided  by our fine mesh model numericals as to the exact amount of snowfall with timings to with-in a few square Km. Usually not far of the mark. Meanwhile, nice mild Autumn sunshine continues in the Eastern Alps.

 C

Edited October 31, 2016 by carinthian

[karlos1983]

17 minutes ago, abbie123 said:

Turning much colder as we go through the week..

Nice one abbie, I saw this on Twitter, great visual representation from the Met O of how cold the Continent is, and the blues spreading over to almost all parts of North West Europe. 

 

[Ravelin]

30 minutes ago, weirpig said:

Difference again at 144  compared to the last run  with so much difference at a short term range  impossible to know what the pattern will be like going forward

D10 GFS 0z on the left and 6Z on the right....

A fair difference, but not massively so, except across N.Europe (as usual).

[karlos1983]

Deep deep lala land but two things I don't really want to see, PV location and an increasingly strong Jet stream flying out of NE Canada. Hopefully this is just a brief beef up.

 

[Ravelin]

Which then leads to a massive injection of warm air towards the pole from the North Pacific at the very end of the run, whacking the deep PV lobe across to our immediate North. 

Edited October 31, 2016 by Ravelin

[karlos1983]

however....... I do like where the PV is headed 

The Strat Vortex not loving life either at the end of the run, displaced.

Edited October 31, 2016 by karlos1983

[West is Best]

Gosh, the 6 is a cold run. Loving some of these charts. There's a sustained period of low to very low 850hPa upper air temps. 

 

I'm wondering if this might vie as one of the coldest runs for the time of year in recent memory?

[feb1991blizzard]

5 minutes ago, West is Best said:

Gosh, the 6 is a cold run. Loving some of these charts. There's a sustained period of low to very low 850hPa upper air temps. 

 

I'm wondering if this might vie as one of the coldest runs for the time of year in recent memory?

Depends how far back your going and whether your talking about the UK or the continent / scandi, I'm sure the -8c isotherm has been over UK around bonfire night in the past but further East it does look brutal, don't forget we had lying snow quite far south in 2008 even earlier.

[Scandinavian High.]

Is there a hint that high pressure is  trying to pull up to Scandinavia there ???

[karlos1983]

GFS Control Run isn't warm either

 

With better ridging in the Atlantic in deep Fl keeping us on the cold side. Not too shabby

Edited October 31, 2016 by karlos1983

[tight isobar]

As others have 'highlighted' on a grander scale the large lobe pv is very much shying away from its usual stomping ground. 

And eastern seaboard usa' needs an eye' as waa willl aid both pv split and migration of any poloar vortex' to more of an easterly/ southern easterly migration. ...

 

[bluearmy]

Evidence on the 00z ecm spreads that the diving depression may be further west in a similar way to the 06z

[feb1991blizzard]

ECM Ens trendeing slightly colder d-11-15 than recent runs.

[Ali1977]

4 minutes ago, bluearmy said:

Evidence on the 00z ecm spreads that the diving depression may be further west in a similar way to the 06z

Is this a good thing, does this set up a more potent Easterly?

[Mark Neal.]

4 minutes ago, Ali1977 said:

Is this a good thing, does this set up a more potent Easterly?

The further the low is held back to the West better chance of us seeing colder air to the East closer to our shores and on the colder air side of the low. Sliding Low even better as Mr Murr has been alluding too.

[Summer Sun]

Bonfire night could be a bit windy

[northwestsnow]

BBc monthly suggesting quite a benign pattern as we move through November with temps a little below the norm generally, looking at all the NWP to hand i'd suggest thats a good shout at present.

Things can and do change unexpectedly but there is little apetite for any westerly regime that i can see in the outlook.

[carinthian]

This chart from GEM is my favourite route towards early seasonal snowfall. Would eventually produce a sharp upper trough over the UK in the 10 day time span prolonging much of Europe in the colder air mass. Has been discussed over here with the other models and certainly not out of the question as could lead to some significant snowfall in places. One for our snow portal providers to get excited about.

 C

[Frosty.]

27 minutes ago, northwestsnow said:

BBc monthly suggesting quite a benign pattern as we move through November 

Benign? 

The GEFS mean suggests unsettled and quite windy at times with a wnw / ese aligned jet. The outlook doesn't look gentle and kind to me

Edited October 31, 2016 by Frosty.

[bradymk]

Arctic temperatures were close to average throughout the summer but are now way above ECMWF reanalysis averages from 1958 to 2002. Arctic sea ice also very low for time of year, even below 2012. 

With good advancing snow cover too then these particular factors are looking pretty good for us and a -NAO/-AO. The record low arctic sea ice is particularly eye catching and is clearly going to have a large part to play. 

Arctic sea ice is now around 450,000 sq km behind the record-low extent for Oct, unprecedented and with the current state of the stratosphere and Eurasian snow cover, I'm feeling quietly confident going into this winter.

Some charts below just to show the unprecedented arctic situation.

 

 

[Ali1977]

1 minute ago, Frosty. said:

Benign? 

The GEFS mean suggests unsettled and quite windy at times with a wnw / ese aligned jet.

I agree, beyond the cold spell next weekend it looks like we could see weather fronts sweeping through from the NW with brighter days between them. I have a feeling the aligned jet you mention WNW/ESE may swing more NW/SE as time goes on as it looks like WAA may push up from Canada in a few weeks time.  The next EC46 and seasonal GLOSEA out this week may give us more of an idea what we "could" expect mid to late Nov.

[jvenge]

2 minutes ago, bradythemole said:

Arctic temperatures were close to average throughout the summer but are now way above ECMWF reanalysis averages from 1958 to 2002. Arctic sea ice also very low for time of year, even below 2012. 

With good advancing snow cover too then these particular factors are looking pretty good for us and a -NAO/-AO. The record low arctic sea ice is particularly eye catching and is clearly going to have a large part to play. 

Arctic sea ice is now around 450,000 sq km behind the record-low extent for Oct, unprecedented and with the current state of the stratosphere and Eurasian snow cover, I'm feeling quietly confident going into this winter.

Some charts below just to show the unprecedented arctic situation.

 

 

Just keep in mind that Sea Ice will likely to start an acceleration after November 10th or so and things can freeze fast up there. That said, I'm not sure how much the sea ice will come into play come the start of winter, or if the lack of sea ice now can influence the setup we have in December. Perhaps someone can clarify, but I suspect it would be for a different thread.

[northwestsnow]

1 minute ago, Ali1977 said:

I agree, beyond the cold spell next weekend it looks like we could see weather fronts sweeping through from the NW with brighter days between them. I have a feeling the aligned jet you mention WNW/ESE may swing more NW/SE as time goes on as it looks like WAA may push up from Canada in a few weeks time.  The next EC46 and seasonal GLOSEA out this week may give us more of an idea what we "could" expect mid to late Nov.

The BBC monthly is online and looks and sounds generally benign, of course there will be unsettled interludes but on the whole, and i quote directly -

'As we head into the second week of November the pattern of fairly quiet autumn weather continues. Pressure will always remain high to the south and west of the British Isles maintaining a good deal of dry weather. Winds will mostly come in from a north or northwesterly direction bringing troughs of low pressure containing showers or even some longer spells of rain and stronger winds. The air will be cold enough for this to fall as snow over the hills of Scotland. This is not unusual for this time of year, what is more unusual is the fact we have not seen more snow on the hills so far the autumn. The driest conditions and best of any sunshine will be over the southern half of England and Wales. It will be a cold week more widespread frosts and also patchy fog, most likely in the south where winds will continue to be lightest.'

 

[Ali1977]

1 minute ago, northwestsnow said:

The BBC monthly is online and looks and sounds generally benign, of course there will be unsettled interludes but on the whole, and i quote directly -

'As we head into the second week of November the pattern of fairly quiet autumn weather continues. Pressure will always remain high to the south and west of the British Isles maintaining a good deal of dry weather. Winds will mostly come in from a north or northwesterly direction bringing troughs of low pressure containing showers or even some longer spells of rain and stronger winds. The air will be cold enough for this to fall as snow over the hills of Scotland. This is not unusual for this time of year, what is more unusual is the fact we have not seen more snow on the hills so far the autumn. The driest conditions and best of any sunshine will be over the southern half of England and Wales. It will be a cold week more widespread frosts and also patchy fog, most likely in the south where winds will continue to be lightest.'

 

It does suggest benign type weather - but then throws in this line!!

"Winds will mostly come in from a north or northwesterly direction bringing troughs of low pressure containing showers or even some longer spells of rain and stronger winds. The air will be cold enough for this to fall as snow over the hills of Scotland"

Not that it really matters -  it just doesn't look like foggy/high pressure type weather which is more benign is heading to us after next weekend.  To be honest I don't think the models really know what's heading our way after day 7 just yet.

[Polar Maritime]

Just 'Model Output Discussion' please in here. There are other threads for BBC/Meto outlooks, Thanks.

To quote Ali here..

"To be honest I don't think the models really know what's heading our way after day 7 just yet."

Certainly interesting times ahead as even the 'experts' are struggling with very low certainty as we head into wk2. So expect more wild swings in the models over the coming days, with such a turbulent atmosphere atm.

Edited October 31, 2016 by Polar Maritime