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

[phil nw.]

hello all

Can we stop posting stuff about the Met Office PLEASE. Discussion of what you feel the models are showing not forecasts from others is what this thread is for. By all means post comments about them in the correct thread-many thanks

Following on from that John a number of earlier posts have been removed.

 

Come on guys too many off topic views are creeping in so let's get back on track-models only please.

There are plenty of threads for other stuff.

 

Thank you.

[summer blizzard]

The stronger the secondary low undercutting is from the trough off Newfoundland, the more the high will resist and distort the polar vortex.

[Barry12]

96 hours

 

[Snowman.]

Anomalies  for last frame of the GFS.

 

 

Not really screaming potential but its there, Atlantic blocked by a wandering Azores high and a decent pacific ridge.

 

Just because its not showing anything not doesn't mean it will show it any later, I mean just look at the date its only the 5th.

 

"Lower your expectations and you won't be so disappointed"

 

Cold will come just give it a chance.

 

 

 

 

Even as the strat goes it wants to split the vortex with the main in piece in Siberia that's go to be something to keep your hopes up.

 

I mean look at this latest CFS run.

 

 

 

 

 

Do I dare show you March?

 

 

 

Keep your chin and look forward to the next 4 months.

 

As you never know future generation may never be able to experience the mayhem of knowing what the models are going to do. 

[Yarmy]

The stronger the secondary low undercutting is from the trough off Newfoundland, the more the high will resist and distort the polar vortex.

 

Can I make a small point that when people actually locate the feature they are talking about (as this post does) it certainly helps people (me) to understand what's being said.

[fergieweather]

GFS aside, in nearer-term the 12z NAE signals a small-scale low associated with the occlusion wraparound as it moves SE'ward tomorrow afternoon-eve. WBFL's circa 500-600m in zone between this feature and the cold front (which itself has strong line convection signal)..... we anticipate some wet snow approx Cotswolds down across M4 corridor to the SE as it runs south, aided by slack wind environment. Critical PPN rates only around 2-4mm p/hr needed to help turn this to snow.

Edited November 19, 2013 by fergieweather

[karlos1983]

It seems the low in the Med is a bit deeper, is that helping prop the high up a bit and allowing the possibility of the low going under, rather than getting sucked up by the bigger low off the east coast? 

 

6z

12z

 

I know it has ended up going over, but just an observation in comparison to the 6z

Edited November 19, 2013 by karlos1983

[johnholmes]

Dare I mention the dreaded "faux cold" aka Murr block?.Seems this could be the way the models are trending with colder air in the south East and milder cloudier weather type into Northern Ireland and Scotland?No doubt the 12z will give us something different

 

not faux cold=a daft description, cold is cold, one can have deep cold, ie in depth or shallow cold as in surface high type surface cold?

[Joe Levy]

Still some conflict over the track of Melissa. It will be interesting how the models continue to react as it moves further North

[Ǝssex Ǝasterly]

Why are we tracking 'Melissa'? Is there a chance the UK will still be covered with low uppers and give us a chance of a little snowmageddon 'if' this LP system arrives?

[Man With Beard]

I think there ought to be a bit more reading between the lines that there are some who post on this thread who like to try and suggest how the pattern may evolve some time ahead based on attempts at reading background factors and potential atmospheric signals - but that these are used as a measure of progress to test against and are not intended necessarily to be taken at face value as any definitive long term forecast. This isn't crystal ball gazing - and should not be confused as such, and not discouraged in any way as such posts from members like these can prove useful for discussion and as a learning tool.

Completely agree. For instance, I'm watching for a proper cold period in the 2 next weeks because I've seen the current movement of blocking to our latitudes often being just an early stage in a more general push north of pressure. But that's just me experimenting. I'm sure we all do a bit of this, the models are just a starting point.

[karlos1983]

Why are we tracking 'Melissa'? Is there a chance the UK will still be covered with low uppers and give us a chance of a little snowmageddon 'if' this LP system arrives?

 

Because it will have impacts on what happens to the general pattern I believe. It certainly won';t be bringing us snowmageddon.

[johnholmes]

Why are we tracking 'Melissa'? Is there a chance the UK will still be covered with low uppers and give us a chance of a little snowmageddon 'if' this LP system arrives?

 

none, but ex tropical storms are in plain English-bloody sods to try and predict, they tend to scupper or at least mess up most model predictions. This is partly due to the huge amounts of moisture and heat they inject into the north Atlantic area once they move into that area.

[karlos1983]

Scandi high anyone?

 

[IDO]

Scandi high anyone?

 

Todays CFS 0z run has Scandi High from T252:

To T600:

[Mucka]

Todays CFS 0z run has Scandi High from T252:cfs-0-252.png

To T600: cfs-0-600.png

 

I'd be suicidal if that came off. Very rare for a Scandi high to produce anything worthwhile for the  NW. 

 

Can we all hope for a Greenland high instead, that more often produces country wide. 

 

 

 

Unless something unexpected turns up in the output soon I think I will just have to accept the weather is not always as exciting as I would like it to be.

[karlos1983]

Yuk, this isn't going to end nice at all if I was a betting man.

 

[radiohead]

Arctic High? Split vortex incoming? It's all deep FI of course...

[Mucka]

"Yuk, this isn't going to end nice at all if I was a betting man."

 

 

And a few frames later a split vortex. 

 

 

Not making fun of you, there was no way to predict that. It is just shows we never really know what is around the corner even when the pattern looks flat.

 

Edited November 19, 2013 by Mucka

[Ian Brown]

A progressive 12z with a strengthening PV, we are hanging onto the settled conditions by day 10 but the Atlantic is banging the door down.

[Summer Sun]

Not too far off a bartlett high type set up looks a temporary set up though, with it comes the milder air

 

Edited November 19, 2013 by Summer Sun

[Joe Levy]

A progressive 12z with a strengthening PV, we are hanging onto the settled conditions by day 10 but the Atlantic is banging the door down.

The PV then gets split in two and high pressure is back in control to a degree. As other posters have said, you never know what's around the corner haha!

[ukpaul]

Just follow through the GFS on the hemisphere view, the PV is like a boxer on the ropes getting battered left, right and centre, it regroups only for it to be split apart again. Given the long term signal for this, we can be assured that zonal is way down on the list of possibilities.

[Mucka]

The PV then gets split in two and high pressure is back in control to a degree. As other posters have said, you never know what's around the corner haha!

 

Yup FI is FI. GFS 12z FI could of turned out to be anything with a tweak here or a tweak there, from blowtorch to deep freeze. 

The only time FI is really worth looking at is for a general signal in the ensembles.

I am sure this has been said before (just once or twice  ) but trying to call anything from one run on one model in FI is crazy talk.

[Summer Sun]

Very end of GFS shows the next area of high pressure waiting in the wings, with low pressure anchored over Greenland

 

 

The one crumb of comfort for those seeking colder weather is it would be turning cooler once more

 

Edited November 19, 2013 by Summer Sun