Model Output Discussion - 30th November onwards

[Gaz1985]

Pretty darn cold, -12 uppers getting into NE England. Shetland sub -14 air. 

 

 

But thank fully pressure begins to push down on the country from the west 

 

Edited November 30, 2013 by Gaz1985

[heath]

Newbie here, but GFS 18z seems to bring forward the northerly even compared with ECM, and Thursday looks bitter now, as well as Friday.  Am I right?

[Gaz1985]

Coldest of the uppers moving away to the east

 

 

 

 

 

Pressure building over the UK

 

Edited November 30, 2013 by Gaz1985

[MrSunshine]

Newbie here, but GFS 18z seems to bring forward the northerly even compared with ECM, and Thursday looks bitter now, as well as Friday.  Am I right?

 

Yes indeed you are correct. 

[bryan629]

Newbie here, but GFS 18z seems to bring forward the northerly even compared with ECM, and Thursday looks bitter now, as well as Friday.  Am I right?

yes you are the gfs is beginning to come into line with the euros , as its lagging behind as per usual... nevertheless beginning to smell the coffee.

[nick sussex]

NOAA state forecast for Illinois:

 

WEDNESDAY THROUGH FRIDAY...
THE UPPER LEVEL RIDGE SHIFTS TO THE EAST WITH SOUTHWEST FLOW SETTING
UP THROUGH LATE FRIDAY.  THE UPPER LEVEL TROUGH AXIS PASSES OVERHEAD
SATURDAY.  LONG DISTANCE GUIDANCE AGREES ON THE OVERALL
PATTERN...BUT THE GFS AND ECMWF DIFFER GREATLY ON WHEN THESE
FEATURES WILL IMPACT THE REGION.  WENT WITH THE MORE STEADY ECMWF IN
THE LONG TERM AS THE GFS LOOKS MUCH TOO FAST.

 

 

[bluearmy]

NOAA state forecast for Illinois:

 

THE GFS LOOKS MUCH TOO FAST.

 

pah - what do those NOAA people know - its not as if its their model .......................... doh!

[Jason M]

By 180 hours on the pub run pressure is trying to build over scandi. Worth just keeping an eye on over the next couple of days. It's still an outsider but I'd be wary of discounting it yet.

Jason

[nick sussex]

pah - what do those NOAA people know - its not as if its their model .......................... doh!

I don't think the GFS has recovered its reputation in the USA since the Sandy debacle.It must be painful for NOAA to have to keep criticizing their own model. But at least they're generous with their data not like some models! Anyway I'd better not open that pandoras box!

Edited November 30, 2013 by nick sussex

[cold snap]

Didn't mr murr say something about a scandy high ?

Might see one here on the 18z ,

[nick sussex]

Didn't mr murr say something about a scandy high ?Might see one here on the 18z ,

Take out the model bias and  you'd probably have one in this run. The hints keep appearing, you never know!

[garbagebags]

So many people, always going on about wishing for a scandi high. You do realise its not nearly cold enough to get any fun and games from a scandi yet?The only event that would be productive at this stage in the game would be a northerly or derivative thereof. An easterly would simply not be cold right now. The East isn't cold enough. 

[cold snap]

Nearly with a Scandinavia high ,it try's

See you in the morning

[Rocheydub]

I don't think the GFS has recovered its reputation in the USA since the Sandy debacle.It must be painful for NOAA to have to keep criticizing their own model. But at least they're generous with their data not like some models! Anyway I'd better not open that pandoras box!

Place it down, very gently, on the table. Now move back Nick, in slow, steady, and careful steps! This could explode right before your eyes!!!

 

 

Anyway, back to reality. I'm a coldie, and I do believe we're in for a cold couple of days, BUT...There's a vast difference between the main NWP that we seriously cannot take anything for granted beyond 72/96 sort of era. SM is the best man at explaining 'biases' etc, so I won't even go there, but I do offer words of caution for those viewing the model thread who aren't experienced… This is just a computerised prediction of the future. It may/may not happen, but please don't personalise the predictions of members here based on what the NWP say, it's their thoughts, and that's all.My opinion? Yes, the evolving of the ECM up to T144 or so, is what I want to see, but I fear it's not what we will see. We were all spoiled with the winters of 09/10  and early 10, not what we will ever see again IMO, but there is good support for a relatively cooler than normal scenario for the forseeable.

 

But…. The weather will do, what the weather will do, and you, nor I, can effect that!!!

[jam]

So many people, always going on about wishing for a scandi high. You do realise its not nearly cold enough to get any fun and games from a scandi yet?The only event that would be productive at this stage in the game would be a northerly or derivative thereof. An easterly would simply not be cold right now. The East isn't cold enough.

This is bought up every yr... the east will be cold enough if the high is over scandi.. a couple of days is all it needs for the temp to drop significantly

[nick sussex]

So many people, always going on about wishing for a scandi high. You do realise its not nearly cold enough to get any fun and games from a scandi yet?The only event that would be productive at this stage in the game would be a northerly or derivative thereof. An easterly would simply not be cold right now. The East isn't cold enough. 

Get the synoptic in first then worry about the cold. We don't have the luxury of ordering Scandi high appearances, I can guarantee you that a Scandi high given the earlier northerly into Europe will be cold, the 850's are misleading with Scandi highs in winter, of course we'd like to see sub -10 850 cold which is plausible if the high is further north to give a better chance of snow showers. Anyway that's well into the future, its only a chance at the moment but certainly can't be discounted.

[Jason M]

So many people, always going on about wishing for a scandi high. You do realise its not nearly cold enough to get any fun and games from a scandi yet?The only event that would be productive at this stage in the game would be a northerly or derivative thereof. An easterly would simply not be cold right now. The East isn't cold enough.

Sorry, but that's just wrong. We are looking out towards the middle third of December and will be entering the business part of winter. A scandi high is no guarantee of snow and deep cold but it's very possible.

[Yarmy]

So many people, always going on about wishing for a scandi high. You do realise its not nearly cold enough to get any fun and games from a scandi yet?The only event that would be productive at this stage in the game would be a northerly or derivative thereof. An easterly would simply not be cold right now. The East isn't cold enough.

The Northerly delivers the cold to the continent. Any Easterly flow after that is thus taken care of. But we ain't got a Northerly yet so it's all speculation. Lots of posts this evening bemoaning the inevitable return to zonal mid-Dec yet not a single EC ensemble member showed that last night (out of 51).

[legritter]

Certainly a better run tonight from GFS but still v big differences at same time frames .and it does not take much time for a cool down of northern and central Europe with the right pressure pattern .,but i think we can close this Autumn tonight gang with a big celebration for us Model watchers ,uncle frosty will be dishing out the stellas in the morning after the morning runs ,All to play for ONE HOUR TO GO , What will the winter bring , 

[Cloud 10]

Certainly a better run tonight from GFS but still v big differences at same time frames .and it does not take much time for a cool down of northern and central Europe with the right pressure pattern .,but i think we can close this Autumn tonight gang with a big celebration for us Model watchers ,uncle frosty will be dishing out the stellas in the morning after the morning runs ,All to play for ONE HOUR TO GO , What will the winter bring , 

 

Hopefully plenty more wintry fax charts such as this new 120 hrs one.

 

[Frosty.]

The good news tonight is the ecm 12z op and ens mean which show a 48-60 hours Arctic blast and then a fine and frosty spell. This is just the opening salvo for hopefully many more wintry spells through the next 15 weeks, it's only just begun.

Add the latest fax chart to the good news too :-)

Edited November 30, 2013 by Frosty.

[bluearmy]

Fax goes with raw ukmo output.

The London extended chillier than I expected having viewed the Dutch. Perhaps we will be cloudier and cooler by day under any MLB.

[Vorticity0123]

As the possible cold snap is nearing, I'll try to give a summary of today's output (GFS and ECMWF)

 

Unlike the 12Z run (which showed no ridging between Iceland and Greeland), the 18Z GFS shows the England High connecting to the Greenland high, which is a good thing regarding the amount of possible amplification of the ridge and trough (and as a result a more potent and persistent northerly).

 

T+126 GFS 18Z

 

However, at T+144, the GFS shows too much low pressure activity near the fragile high pressure area near Iceland, which in turn leads to a deamplification of the ridge. Also note that the low pressure area to the west of Spain (which just sits there for the next 6 days) also barely connects toward the low pressure areas to its north, resulting in a west-east oriented trough to the west of Iceland.

 

T+144, GFS 18Z

 

As for the ECMWF 12Z run, it also shows the connection between the Greeland and the England high, but it maintains the amplified version of the ridge somewhat longer. It appears like this is because the low over Nova Scotia isn't very deep (giving less energy being sent in between the ridges). However, the connection with the low pressure area west of Spain seems to be more firm. This results in a rather long north-south stretched through, which in turn allows the amplified ridge to remain in place for quite some time.

 

T+144, ECMWF 12Z.

 

And finally, for comparison with the 12Z GFS, the track of the low pressure area forecast near Newfoundland at T120 is shown below:

It shows the low pressure area moving with a pressure near 990 hPa toward Europe, giving the high pressure connection no chance to build. 

 

Overall, there is still quite some uncertanity regarding the outcome, depending on a couple of low pressure areas which may interfere or not interfere. The presence/absence of one of those can create a major change in setup and therefore also have a large impact on the possible northerly in western Europe. It will be interesting to watch how it will unfold.

 

Sources: 

http://moe.met.fsu.edu/cyclonephase/gfs/fcst/index.html

http://www.wetterzentrale.de/topkarten/fsfaxsem.html

Edited November 30, 2013 by Vorticity0123

[fergieweather]

Fax goes with raw ukmo output.The London extended chillier than I expected having viewed the Dutch. Perhaps we will be cloudier and cooler by day under any MLB.

Yup. Aside from snow in N/NE & strong winds in some areas, it's a coastal flooding threat that grabs our attention at that juncture in the output timeline.

[Frosty.]

God I love all those troughs swinging south embedded within the strenghtening arctic airflow..wish it could last a lot longer. Fantastic fax chart.