Model Output Discussion 18th Nov.2013-12z onwards.

[Paul]

You may have noticed some acronyms are have started being underlined this pm - this isn't an advert that'll popout like some sites have on this sort of thing, so don't panic - it's an acronym expander so if you're wondering what things like NAO or UKMO are - mouse over them to get the full meaning.

[MR EXTREMES]

to be fair beyond t180 it looks like the pattern being dominated by low pressure systems sweeping through as the heights in the alantic don't really hold firm.

although there is a possibility that it will stay chilly for a little longer than expected.

[Matty M]

Talk about Polar Low prime environment between North Scotland and Svalbard here.

 

[bluearmy]

 

The Azores low may help to prolong it a little that is if it even pans out like this, but the Low coming off the Seaboard is going to end the flow.

 to finish your sentence - 'and bring a snow event somewhere in the uk' ......................

[No Balls Like Snow Balls]

Some very cold days and nights coming up at the end of the week (end of high res), will feel much colder in the strong winds.

 

 

 

Edited November 29, 2013 by No Balls Like Snow Balls

[Cecil Hogmanay Melchett]

BITTER Polar North westerly on GFSZ .

TREMENDOUS stuff for all cold lovers..

[Matty M]

Quite big differences between UKM and GFS over North America at 144hrs.

 

Lots of chopping and changing ahead.

[Ian Brown]

Ian-

 

rem what I said last year - 2 lows separating over Greenland ( West coast)

http://modeles.meteociel.fr/modeles/gfs/runs/2013112912/gfsnh-0-180.png?12

 

not as good as 2010 but a split flow none the less normally means no toppler-

 

All the atlantic low will do is disrupt out & slide SE...

 

UKMO 144 upper air is EPIC- deep cold waiting in the wings.

 

It won't slide SE, the Azores High will end up over us.

 

Yes cold air on the UKMO, but you can already see the end game.

   to finish your sentence - 'and bring a snow event somewhere in the uk' ......................

 

No, the cold is cut off from the NW. Yes there is a window for snow showers for the usual spots in this set-up but not frontal snow.

[Ian Brown]

http://modeles.meteociel.fr/modeles/gfs/runs/2013112912/gfs-0-192.png?12

 

And there we have it.

[Snowman.]

http://modeles.meteociel.fr/modeles/gfs/runs/2013112912/gfs-0-192.png?12

 

And there we have it.

There we *don't have it.

 

[Joe Levy]

http://modeles.meteociel.fr/modeles/gfs/runs/2013112912/gfs-0-192.png?12

 

And there we have it.

Yes - in the low res section at 204 hours away. On this run maybe, but far too far away to be assertive about anything. Besides, let's not look at the collapse of the cold spell, when it hasn't even started yet!

[radiohead]

Wow. Sustained winds reaching 84-88mph there.

 

Edited November 29, 2013 by radiohead

[Tom Jarvis]

http://modeles.meteociel.fr/modeles/gfs/runs/2013112912/gfs-0-192.png?12

 

And there we have it.

remember the GFS has a very good habit of overdoing lows and underdoing the strength of the HP if we take that into account the low should slide southeast

[Mucka]

http://modeles.meteociel.fr/modeles/gfs/runs/2013112912/gfs-0-192.png?12

 

And there we have it.

 

You can see the low disrupting on the NH view. Yes when it phases with the trough it will modify the flow but if it disrupts enough it could bring a big snow event - assuming we ever see these charts again.

[Barry12]

Still -8 and -6 uppers for Northern UK at day 10, with -10's still for parts of Northern Scotland.

 

Edited November 29, 2013 by Barry95

[The Northern Ramper]

It won't slide SE, the Azores High will end up over us. Yes cold air on the UKMO, but you can already see the end game. No, the cold is cut off from the NW. Yes there is a window for snow showers for the usual spots in this set-up but not frontal snow.

Why would be looking for the end game before it has even started?

[Captain Shortwave]

Wow. Sustained winds reaching 84-88mph there.

 

I suddenly feel like taking a weekend break to the Isle of Skye  

Western Scotland would be absolutely clobbered if this run came off. Though there would be snow for many on the back edge of the cold front. 

Good news is both the GFS and UKMO would deliver a pretty darn potent northerly at that is what we need to look at for the time being.

Edited November 29, 2013 by Captain shortwave

[Snowman.]

Blow torch is a go!

 

[bluearmy]

No, the cold is cut off from the NW. Yes there is a window for snow showers for the usual spots in this set-up but not frontal snow.

the cold can be cut off but where the fronts meet the surface cold will see a snow event ian.anyway, the upstream jet phasing makes the run post day 7 in our part of the hemisphere unreliable in the extreme

[MR EXTREMES]

to be fair ian b it does look like the azores high will sink south with the next low pressure sweeping in from the nw so maybe a little milder but still below average then perhaps a reset pattern and start all over again.

[Snowman.]

Dat cross-polar flow.

 

[Yarmy]

http://modeles.meteociel.fr/modeles/gfs/runs/2013112912/gfs-0-192.png?12

 

And there we have it.

 

Yes, but didn't you say the 12z was over-progressive? Anyway, I'm more concerned with getting that arctic air here to start with because we are still well outside the reliable time frame for that.

[gottolovethisweather]

And now for the decent model.

UKMO looking good for cold air moving down the UK at T144

 

UN144-21.gif

 

UW144-7.gif

 

All jesting aside, the undecent model that is the GFS (poorly slated due for being a 4 runs a day model) picked up the change in flow on the 3rd December back on the 24th November, well at least it did to my eyes. All of this coming courtesy of the GEFS ensembles spread. Yes of course, we have not arrived at said timeframe but t+216 hours, that's not bad for a bad model.

 

Anyway, I digress, so let's have another chart. I also await the latest ensembles suite with added impetus than over the prior five days.

 

Yes, the UKMO is peachy, I agree, FWIW.

 

Now here's the update on my surface feature from the 3rd December, by the 7th December it's going nowhere fast, good news! In four days it has wandered around the Atlantic like a wet weekend, it might not be a wet one but it certainly looks potentially a SNOWY one.

 

[radiohead]

I suddenly feel like taking a weekend break to the Isle of Skye  

Western Scotland would be absolutely clobbered if this run came off. Though there would be snow for many on the back edge of the cold front. 

Good news is both the GFS and UKMO would deliver a pretty darn potent northerly at that is what we need to look at for the time being.

 

Indeed. Heavy rain with sustained hurricane force winds turning to blizzards if that came off. It would certainly be wild up there!

[Ian Brown]

the cold can be cut off but where the fronts meet the surface cold will see a snow event ian.anyway, the upstream jet phasing makes the run post day 7 in our part of the hemisphere unreliable in the extreme

 

No, the less cold air returns from the NW so you see a weak system coming SE and the cold air is mixed out so any snowfall is usually very temporary and confined to higher parts, often there is no PPN left on these systems by the time they reach the SE.