Model Output Discussion - The final stretch to Christmas

[mulzy]

Not great ECM ensembles. The pattern looks like flattening out with an invigorated PV over Greenland and a strong North Atlantic jet. Looks like the game is up on chasing the Easterly for now...

Edited December 24, 2014 by mulzy

[Mark Neal.]

@danholley_: Still large amounts of uncertainty over Boxing Day's low; 12z EURO4 turns rain increasingly to snow over Wales + parts of W Mids on Fri eve

Dan is a meteorologist for Weatherquest and BBC look East Weather presenter.

[Daniel*]

Hopefully ian fergie can shed a bit more light on this weekends low!! Am not really looking to far ahead when we got some excitement snowise in less 60 hours!! But that low keeps pushing south steadily!! My thinking is it will eventually run directly though the midlands!

Be careful what you wish for... low might end up South of the South Coast by this rate

[Frosty.]

I really think there should be greater emphasis on the short term gain for cold synoptics rather than star gazing beyond next week for something less cold, this happens too often on here. We have a week of cold weather guaranteed and beyond that, things will keep changing and the cold spell could go on and on and morph into something snowier

Edited December 24, 2014 by Frosty.

[The Enforcer]

Difficult to see snow on the 27th of the month.

According to the maps( GFS model) only in central England and from the 300m and above.

The precipitation but there is few

I wouldn't rely on precipitation forecasts shown by models, certainly not at that range. Here's just a couple of examples of even shorter range forecasts for Central Southern England from earlier this year, which have led to me getting soaked by several hours of heavy rain when I was expecting dry conditions:

 

Example 1:

Forecast - Dry: Actual - Heavy Rain:

 

Example 2:

Forecast - Dry: Actual - Heavy Rain:

 

The differences are truly astounding.

 

In the situation on 27th/28th I have my eye on the occluded front on the fax charts that is travelling down from Iceland behind the cut-off low:

Edited December 24, 2014 by The Enforcer

[legritter]

A MERRY CHRISTMAS AGAIN TO ALL MY WEATHER MATES , :smiliz64: STAY HAPPY and remember everyday we will see new data ,the last couple of days as an example ,[how far a developing low pressure can be modeled ] and thats at fairly short range compared to what us model watchers are striving to predict .thats why uk met give a 15/30 day update everyday ,current data points to high pressure somewhere to our east come the next week ,with met office on their models forecasting the atlantic coming back in ,but looking 30 days ahead i feel even for super computers so many things could change at this range .for those seeing snow during friday sat ,enjoy it ,and perhaps our low will pause for several hours to salute us modelers ,that will do me fine here in somerset ,well i,m going to have another STella all enjoy this  christmas ,and a big thank you to the team who keep our forum up and running 

[Skullzrulerz]

Just like to remind pepole that every run is different neither two are the exact same.

So at the moment ECM and GFS want the high pressure to get kicked out of the uk then the pain odd mild old West huts the uk and end of story.

However as I said it's just ONE run it may become a trend or it may not that's what model watching is all about guys and girls.

Take the GFS for example.

Yesterday it was the star of the show in the pub run. With cold to very cold conditions for most of the run

Now look at it. What do we have now?

The pub run tonight i think may be better for coldies but we shall see.

[ANYWEATHER]

@danholley_: Still large amounts of uncertainty over Boxing Day's low; 12z EURO4 turns rain increasingly to snow over Wales + parts of W Mids on Fri eve

Dan is a meteorologist for Weatherquest and BBC look East Weather presenter.

To Be Honest, I cant see any detail that far out at the moment, Lots of changes even into the nearer time frame...

[Mark Neal.]

To Be Honest, I cant see any detail that far out at the moment, Lots of changes even into the nearer time frame...

I don't think anyone can tbh, he has access to the Euro4 model out longer than we can see however

Edited December 24, 2014 by Mark N

[Man With Beard]

www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

A build of heights into Scandinavia for the new year on that ... but I'm starting to lose my mind with model watching, anything beyond about T72 seems utterly useless at the moment.

Edited December 24, 2014 by DiagonalRedLine
Added in chart

[Troubleatmill]

www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

A build of heights into Scandinavia for the new year on that ... but I'm starting to lose my mind with model watching, anything beyond about T72 seems utterly useless at the moment.

Sure is a truly remarkable run of inconsistant runs from all models, reminds me of the true blues against the dirty yellows! Edited December 24, 2014 by Nicholas B

[mushymanrob]

We have a week of cold weather guaranteed and beyond that, things will keep changing and the cold spell could go on and on and morph into something snowier

Karl mate... That is simply not true. We do not have a guaranteed week of cold, this is totally misleading. Both the gfs and ecm have the milder uppers over us by Wednesday and predicted daytime maxs of pretty normal. We might get an inversion but that would lead to dull raw but dryweather. Neither of use to coldies or mildies alike.

[Biggin]

t72 fax shows how things can change in 12 hours when fast forming depressions are involved

A chart and clue would be nice or are we sposed to guess. 

Edited December 24, 2014 by Polar Maritime
To move discussion on.

[Matty M]

GFS 18z really going for snow chance for central areas Saturday AM

[Met4Cast]

Even further South on the 18z, only by about 50 miles but it makes all the difference when it comes to how far South the snow will come

 

 

 

[I remember Atlantic 252]

GFS 18z really going for snow chance for central areas Saturday Am

 

northern areas, my location needs the low to track further south

[Gibby]

I know a lot of people criticise this 10 Day Mean Chart chart saying it doesn't represent a true picture of Synoptics likely at that time and while I can see where people are coming from it is far from a useless tool in seeing where the balance of the situation is biased and though it wobbled towards a cold Euro High for a while recently it never quite shown it being a reality and tonight's chart reflects the biggest slide yet into milder territory after a post Christmas cold period.

http://www.wetterzentrale.de/pics/Reem2401.gif

Edited December 24, 2014 by Gibby

[Met4Cast]

I know a lot of people criticise this chart saying it does 't represent a true picture of Synoptics likely at that time. While I can see where people are coming from it is far from a useless tool in seeing where the balance of the situation is biased and though it wobbled towards a cold Euro High for a while recently it never quite shown it being a reality and tonight's reflect the biggest slide yet into milder territory after a post Christmas cold period.

http://www.wetterzentrale.de/pics/Reem2401.gif

 

Trouble is, if the operational runs can't come to a solution with tracking of the low and then the orientation of high pressure afterwards, how can we expect the ensembles too? In situations like this when the whole pattern is balancing on a knife, the mean charts are utterly useless because any signal there might be gets muted by charts going off in the other direction.

[Gibby]

Trouble is, if the operational runs can't come to a solution with tracking of the low and then the orientation of high pressure afterwards, how can we expect the ensembles too? In situations like this when the whole pattern is balancing on a knife, the mean charts are utterly useless because any signal there might be gets muted by charts going off in the other direction.

But if this becomes reality it will of proven to of been the best guide yet as it is the one chart that has not changed majorly in recent days.

[Met4Cast]

But if this becomes reality it will of proven to of been the best guide yet as it is the one chart that has not changed majorly in recent days.

Only by coincidence - There have been many, many times where the mean has been utterly wrong at that time frame because the signal gets watered down and eventually muted out

[bluearmy]

A chart and clue would be nice or are we sposed to guess.

How about you look at the fax charts yourself!

Between 7pm and 10:30pm you can look at T72/84/96 for the same point in time.and judge how the charts have evolved.

If i have the time i will attach charts. Otherwise I think I gave enough clues about where to look.

The more you do for yourselves the better you'll become at this. Nearly everyone on here is self taught and that's impressive.

[bluearmy]

whilst the ecm mean and extended ens are not showing too much of easterly interest, the uppers spreads still provide for a nor'easter and until they don't, the ridge getting far enough North cannot be discounted.

In the distance, the mean still provides for upper Scandi ridge and se euro trough which could jut about get the cold this for and at the very least allows for the uk to be in any battleground that might evolve between the air masses. Given the week 2 GEFS members and indeed the Gfs ops, that should come as no surprise.

[Cloud 10]

I know a lot of people criticise this 10 Day Mean Chart chart saying it doesn't represent a true picture of Synoptics likely at that time and while I can see where people are coming from it is far from a useless tool in seeing where the balance of the situation is biased and though it wobbled towards a cold Euro High for a while recently it never quite shown it being a reality and tonight's chart reflects the biggest slide yet into milder territory after a post Christmas cold period.

http://www.wetterzentrale.de/pics/Reem2401.gif

 

The ensemble mean  is generally the best tool to use at day 10 as it verifies the best,however in this case there is a high spread of solutions around Scandinavia on that ECM chart,so much lower confidence on this occasion.

 

[Man With Beard]

I know a lot of people criticise this 10 Day Mean Chart chart saying it doesn't represent a true picture of Synoptics likely at that time and while I can see where people are coming from it is far from a useless tool in seeing where the balance of the situation is biased and though it wobbled towards a cold Euro High for a while recently it never quite shown it being a reality and tonight's chart reflects the biggest slide yet into milder territory after a post Christmas cold period.http://www.wetterzentrale.de/pics/Reem2401.gif

Like all the models, the ECM mean made an utter pigs ear of the phantom North-Atlantic block. I agree with other posters, though I always look at the ECM mean and consider it, I think we need to get the events of Saturday out of the way before I can take any model seriously at 10 days right now. Anything from an Atlantic return, to a full-blown easterly with ridging from Scandi towards Greenland, is possible to me at the moment.

[Long haul to mild]

I know a lot of people criticise this 10 Day Mean Chart chart saying it doesn't represent a true picture of Synoptics likely at that time and while I can see where people are coming from it is far from a useless tool in seeing where the balance of the situation is biased and though it wobbled towards a cold Euro High for a while recently it never quite shown it being a reality and tonight's chart reflects the biggest slide yet into milder territory after a post Christmas cold period.http://www.wetterzentrale.de/pics/Reem2401.gif

For me that is a typical chart that the models spew out with monotonous regularity in situations like this for the UK. It is a bit like predicting that either Chelsea or Man City will win the League; i.e. the safe bet. It may well end up being right but I have a feeling we have a few surprises to come. History tells us that blocks to the East are harder to shift than the models give them credit for.

Merry Christmas all!