Model output discussion - The Hunt For Cold

[carinthian]

On ‎21‎/‎10‎/‎2018 at 09:02, carinthian said:

Morning all, a very different looking chart this morning from ECM with cold advection towards the end of next week now further west into NW Europe. However, we in the Alps have warm air advected from Africa, so that will throw a spanner into our snow forecast calculations ( re above post )  nothing nailed yet for the exact location of the North European trough but this weekends latest runs from the big global models have shown a daily adjustment. Hope to get an update  tomorrow morning from our experts and see what their own model is now showing, but looks like a cold weekend coming towards Blighty, especially.

C

Wow, amazing synoptics for the end of October. This crazy year continues to produce extreme conditons . Temps of 10c or more below average next weekend over much of Western Europe, with extreme values over Iberia. On the other scale, plus 10c above temps over parts of Eastern Europe and Central Europe for a time. Forecasting snow to rain and the other way round is going to be very difficult as the very strong baroclinic zone formulates across Europe. The map below shows unusual October snow cover forecast for parts of the UK . We in the Alps will have a nightmare scenario with heavy rainfall values forecast of over 60mm  that may or may not change to snowfall . At this stage , the Western Alpine regions look prone to be covered in the Arctic mass and risk of some heavy snowfall. However, here in the Eastern Alps , borderline. Its going to be fun next weekend from a weather forecasting prospective and we over here will have to rely on our short range fine mesh model to forecast snow with height nearer the time. However, I think we can all expect some unusual weather, just has 2018 has already delivered to many. Will get back later with thoughts from our experts over here.

C

[Iceaxecrampon]

00z

Well its going to be an early  shock to the system this weekend so far.

Pennine snow down to 200m approx 650ft 

Interesting feature pushing from the continent not cold related but one to watch.

Iain

[Iceaxecrampon]

12 hours ago, sundog said:

End of Oct and start of Nov 1988 was on the cold side too. Winter 88/89 was a terrible one of course.  You just never know how things will pan out. 

Yes

This from 20th November 1988

A great day out in the mountains that weekend but the rest of the winter was largely forgettable

[Rayth]

Some strong and biting windchill to be had on my Sunday stroll ! 

 

[Ice Day]

Well I think it's about time I shifted from summer to winter mode.  Good to be back on the thread and it's great to see lots of familiar faces ready for another roller-coaster ride for winter 18-19.  Having not looked at the charts for a week or so my jaw dropped a little looking at how next weekend is panning out.  Stunning charts for next Saturday with a long-fetch northerly.  Unfortunately about 4-5 weeks too early for anything meaningful away from the tops of the mountains, but certainly something to whet the appetite!

Good to see a lot of cold and snow for Scandi and the Baltic states as well.  Here's to a repeat of Feb-Mar 18 please.

[BLAST FROM THE PAST]

Well 06z shows the cold shot, trough disruption and then a reload down the line.  Lovely run and as I said I’m looking for a month of several attempts with a theme that the cold pattern then dominates and takes hold as we get deeper into Nov towards the end for a cold themed December. It’s miles down the line....but we look like we on our way with interest.

My current country file calendar on October has a bull looking over Loch Lomond with snow capped mountains.  That scene will be repeated very soon. Lovely

 

BFTP

Edited October 22, 2018 by BLAST FROM THE PAST

[Leo97t]

Lovely amount of blocking over the arctic. Virtually a split vortex

[karlos1983]

Hi All, I'm looking forward to our first cold snap after a stunning summer, let's hope it's the first of many! 

Would imagine the high ground of Northern England and Scotland especially will fair best for the white stuff  this time round, but noticeably colder for everyone!

Certainly going to notice that wind chill on Sunday when I'm stood on the side of a football pitch. Bring it on!

[Kirkcaldy Weather]

P1 scandi high with hints of retrogression 

P5 

P15 

P19 

ECM 

[bluearmy]

if we are going to be analysing individual ensemble members on each run in the search for wintry sypnotics then this thread could become the largest NW one ever !!

[feb1991blizzard]

1 hour ago, bluearmy said:

if we are going to be analysing individual ensemble members on each run in the search for wintry sypnotics then this thread could become the largest NW one ever !!

I think that will die out once we get to the point where more OP runs are showing something spectacular, on the other hand if we were to have an 89 or 14 type winter, people will pluck those straws out all winter!

[Skullzrulerz]

Is the GFS run out yet I thought it was 4.30? Not too sure on the times if someone can forward me to them that be greatful

 

ICON has a winds from east but coldest is in Scandinavia area like GFS yesterday

[feb1991blizzard]

1 minute ago, Skullzrulerz said:

Is the GFS run out yet I thought it was 4.30? Not too sure on the times if someone can forward me to them that be greatful

 

ICON has a winds from east but coldest is in Scandinavia area like GFS yesterday

Its coming out now - 16.30 to 1800 - changes next weekend though - an hour earlier.

This is where its up to now.

 

[Skullzrulerz]

3 minutes ago, feb1991blizzard said:

Its coming out now - 16.30 to 1800 - changes next weekend though - an hour earlier.

This is where its up to now.

 

Thank you

[SMU]

24 hours of the GFS 

Image 1 - 12z T150 today

Image 2 - 12z T174 yesterday

Note the clear move to the -6c & -8c isotherms covering a wider area & them both being closer to the UK...

Possible snow event in the offering as the atlantic approaches....

[feb1991blizzard]

1 minute ago, Steve Murr said:

 

Note the clear move to the -6c & -8c isotherms covering a wider area & them both being closer to the UK...

Possible snow event in the offering as the atlantic approaches....

 

Yes - look at the small low over Iceland, now a nice negative tilt on it even compared to 6z with better trough disruption and a better dig south with a better orientated scandi high.

[Ali1977]

Look at that NH view, no PV gaining strength just yet - In fact how often in late Oct can you make out the outline of Canada like this. Interesting times, may come to nothing but nice to see.

[tight isobar]

Yes as alluded...reload...and frontal probabilities!..

The upper airs are fraught with decrease-as evolutions come into play at -48hr prox.

No warming at the strat of note...but hemisphericaly...its dooming at the pole on its own fruition....

Some alarming synops on offer!!!..

We get going early here !!...

Paying attention to mjo forces will be paramount going late oct-early nov!...

And momentumn in genral...

 

Edited October 22, 2018 by tight isobar

[Summer Sun]

Looking at UKMO 12z Saturday has the lowest 850's across the UK

By Sunday the -4's move a bit further east but still on the cold side

[SMU]

9 minutes ago, feb1991blizzard said:

Yes - look at the small low over Iceland, now a nice negative tilt on it even compared to 6z with better trough disruption and a better dig south with a better orientated scandi high.

Yes a couple more runs & it will get the slide more defined- still in the GFs unknown zone atm- its like where shall I place that energy- I know EVERYWHERE...

[tight isobar]

And increasingly IMPRESSIVE nor-hem profile...

A truly exiting set up.....

Edited October 22, 2018 by tight isobar

[Leo97t]

Strat vortex still looks incredibly strong. Fear may disappoint despite some positive signs so far

[nick sussex]

It’s amazing the lack of drama with this northerly ! The models have counted down without a last minute curveball thrown in !

I know most attention is on the northerly but after that what happens to the east and is it possible to get some snow as the Atlantic tries to move in.

It would be exceptionally rare to get frontal snow this early in the season. I still think that’s a long shot .

Preferably that low near Iberia needs to be further east to stop any milder Med air getting thrown too far nw.

So as much as people are looking to the north , later on dew points temps over northern mainland Europe are the area to watch in case we see better trough disruption to the west . 

[tight isobar]

32 minutes ago, Leo97t said:

Strat vortex still looks incredibly strong. Fear may disappoint despite some positive signs so far

The other levels are inept of form...

Refer to 2nd former post.

@Qbo @nina transfer...

probabilities...4-balance...

Edited October 22, 2018 by tight isobar

[BlueHedgehog074]

Skullzrulerz covered it on the previous page, but certainly a high quality High Pressure system showing on the 12Z ICON over Scandinavia. Towards the beginning of next week.

Some remarkable upper 850 hPa cold over the Scandinavian region. A more favourable orientation to the Scandavian High with a longer drawn flow from the North-East and that cold could pounce like a panther towards the U.K. (Though would have to bear in mind some of that upper cold would probably get mixed out fairly quickly as it approached the U.K).