Model output discussion - 1st December onwards

[johnholmes]

And in the upper air world what is showing in the 1 to 2 week time frame?

NOAA

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

ECMWF-GFS

http://mp1.met.psu.edu/~fxg1/ECMWF_12z/hgtcomp.html

Some indications showing in the last 2 days or so on all 3 of the slight ridging and +ve heights from Europe into northern Scandinavia. Not really a solid enough signal to me but at least some indication of a 'possible' alteration that 'might' help those of a cold disposition!

[Mark Neal.]

Where the low gonna go. Not heading SE very quickly or will it not at all?

1040mb High over Scandi which is encouraging and cold pool to NE.

Edited December 20, 2015 by Mark N

[ITSY]

Back from hibernation with some interest looming. 

My concern about these charts, fascinating though they are,  is the lack of heights over South Europe and the med. so long as the lows in the Atlantic stall on the way into the UK we could find ourselves with a case of opportunity missed; and boy would it be an opportunity missed given the advection towards Lapland and the polar region...indeed the 18z presents this exact concern and the eastward swing ends up way too far north over mid Scandinavia 

lenty of time for things to change though, and of course this could yet still be the flash in the modelling pan that the pros still appear to think it is...

Edited December 20, 2015 by ITSY

[Ali1977]

Close but no cigar in FI on the pub run!!

[feb1991blizzard]

3 minutes ago, Mark N said:

Where the low gonna go. Not heading SE very quickly or will it not at all?

1040mb High over Scandi which is encouraging and cold pool to NE.

 

Don't think this will deliver a stonking Easterly on this run but I would still snap your hand off for it though, you need that low to the West to disrupt and send energy SE, the orientation of the high needs to be better as well (E to West elongation so the frigid uppers to the East start to move West, the best scenario would be the high to become cut off.

[Daniel*]

+240

Yum..a prelude to a cold snowy UK? The tide may have turned. 

Edited December 20, 2015 by Daniel*

[Carlrg]

Unfortunately the Scandi heights disappearing on this run.

 

[feb1991blizzard]

But not with the low heights engaging to the North of us though!!!!   its all gone pete tong now but I'm happy - bank until around T200 - its the trend that's important.

[Mark Neal.]

Yup shortwave doesn't go SE wards. Low heights start appearing to the North. Good trend up to 200hrs like you said Feb Blizzard.

[Methuselah]

5 minutes ago, Daniel* said:

+240

Yum..a prelude to a cold snowy UK? The tide may have turned. 

https://www.youtube.com/watch?v=SbeLFG6Lglo

[feb1991blizzard]

1 minute ago, Mark N said:

Yup shortwave doesn't go SE wards. Low heights start appearing to the North. Good trend up to 200hrs like you said Feb Blizzard.

Yes a cut off high is great but you need the lows to engage each other over France not Iceland, it was never going to happen on that run as the dig South wasn't far enough.

[nick sussex]

After my earlier tantrum I self-medicated and have calmed down now!

Whether tonights GFS 18hrs run is the last supper before the executioner comes calling we'll see in the morning. The issue is the initial phasing which starts things off on a rocky road.

The ridge needs to be further north and west initially to put more forcing on the troughing to the west to disrupt more energy se'wards.

So tomorrow mornings outputs will likely be decisive because there should be better agreement on how those shortwaves phase with the troughing.

 

 

 

[bobbydog]

57 minutes ago, THE CHOSEN ONE said:

 

Well that's about as vertical as it gets ( think 2010 west of Greenland tip )

That should be a slam dunk easterly.......

however, its not....

 

"your powers are weak old man"......

Edited December 20, 2015 by bobbydog

[nick sussex]

A word about the upstream pattern in terms of what USA forecasters prefer you'll be relieved to know that they don't side with the ECM solution in the New York state forecast.

LATE NEXT WEEKEND...ANOTHER DEEP TROUGH IN FOUR CORNERS AREA SHIFTS
EAST INTO CENTRAL CONUS WITH MODELS SHOWING DESCREPANCIES ON
TIMING...STRENGTH AND MOVEMENT OF SYSTEM AS IS USUALLY THE CASE WITH
THESE SYSTEMS. ECMWF STRONGER WITH CLOSED UPPER LOW THUS CUTTING IT
OFF AND STALLING IT ACROSS SOUTHERN PLAINS FOR SEVERAL DAYS BEFORE
SLOWLY LIFTING NORTHEAST...WHILE GFS AND WPC FOLKS SHOW A WEAKER
INITIAL SYSTEM LIFTING NORTHEAST SAT NIGHT-SUN ACROSS FORECAST AREA
WITH BOTH HAVING A CLOSED SYSTEM COMING OUT OF LOWER MISSISSIPPI
VALLEY EARLY THE FOLLOWING WEEK.

CURRENT SUPERBLEND IS HEAVILY LEANING ON GFS/WPC SOLUTION BUT
LOWERED POPS SLIGHTLY DUE TO INCREASING UNCERTAINTY. PRECIPITATION
TYPE WENT WITH STRAIGHT RAIN/SNOW OR RAIN-SNOW MIXED BUT A WINTRY
MIX IS POSSIBLE BUT TEMPERATURE PROFILES AND UNCERTAINTY TELL ME NOT
TO GET TOO CUTE AT THIS TIME.
 

The track of low pressure  correlates with how a ridge builds in from the west USA, the ECM is flatter, the GFS more amplified and of course this is effected by the pattern over Arctic Canada which in turn effects the troughing to the west of the UK.

You'll note that this mornings ECM solution had low pressure tracking ne, tonights takes this east into the southern plains.

Tonights ECM was a double whammy in terms of changes, poor phasing and  a less favourable upstream pattern.

Edited December 20, 2015 by nick sussex

[Methuselah]

Right then...If the shortwaves phase with the trough, along a roughly WNW-ESE alignment, and the Scandi HP aligns itself in a 'sausage' shape from, say, the Baltic States to west of Norway, we'll get a Frost Giant later next week? But what if Thor and Freya don't agree to that - what then?

[Daniel*]

10 minutes ago, bobbydog said:

however, its not....

 

I would not draw any attention really I find the models tend to underestimate the sturdiness of these positive height anomalies in the far north - glad to say there is 'A New Hope'.

[Methuselah]

4 minutes ago, Daniel* said:

I would not draw any attention really I find the models tend to underestimate the sturdiness of these positive height anomalies in the far north - glad to say there is 'A New Hope'.

The way things are going at the moment...May the Fourth be with you!

[bobbydog]

12 minutes ago, Daniel* said:

I would not draw any attention really I find the models tend to underestimate the sturdiness of these positive height anomalies in the far north - glad to say there is 'A New Hope'.

you underestimate the power of the dark side of the vortex....

Edited December 20, 2015 by bobbydog

[Singularity]

I do find the ECM 12z det. solution to be too 'blunt' with the Atlantic trough just muscling its way east but that's not a very scientific approach. That quote from the NOAA discussion has provided something more convincing and I do hope they're making the right call there.

I continue to track the Kelvin Wave and it's tricky to keep a track of to be honest. The plots used for MJO events show propagation into phase 5 now at a level of amplification that only UKMO has come close to predicting in advance. Yet all models insist on a rapid decline toward lower amplitude, after which GEFS and ECMF suggest an attempted comback that takes it to phase 6, only for there to be sudden death into the COD. It's that initial rapid decline that I'm skeptical about. 

 

Basically, there's scope for upstream amplification to be boosted further which may produce interesting results even if the Atlantic trough doesn't behave nicely during the weekend. Perhaps it will allow a second bite of the apple in terms of driving some decent WAA poleward.

 Fair to say though, we'll be in a far better position to make use of the upstream events should we manage to get a decent block to our E/NE by the start of next week. It would be nice if we could get lucky for once...

[lassie23]

Something is afoot in the models, can't think of a star wars punhttp://www.weatherweb.net/wxwebtv2.php

[Daniel*]

2 hours ago, bobbydog said:

you underestimate the power of the dark side of the vortex....

"I find your lack of faith disturbing.” – Darth Vader

"It’s a trap!” - some weird alien guy

Edited December 21, 2015 by Daniel*

[Mucka]

Some people offer the opinion that we can give 10 day charts more credence than a few years ago as the NWP models have improved so much but I'm not so sure.

 

Just 12 hours ago in the vicinity where GFS was modeling a ridge at day 7 it is now modeling a 925mb low due to the fact it is so much more progressive upstream.

 

 

And although I accept you could say that on a larger scale the longwave pattern is not hugely different, for purposes of weather prediction it is rather a conspicuous difference. 

 

UKMO is quite different upstream albeit slow and flat rather than fast an flat as with GFS almost giving us a col rather than raging Atlantic

Clearly the models are struggling a little here so not worth getting to excited or upset by an individual run until they show a bit more consistency.

One thing that does look certain though is the cold plunge into Europe which is quite possibly, in some regions, going to experience daytime temperatures plummeting from double digit positive figures to double digit negative figures - up to  a 25C difference in some places!

 

 

And only likely to get colder with some extremely cold air possible for eastern/Central Europe

 

If only we could catch an even break we could be tapping into some of that and of course it wouldn't get massively modified travelling over the continent.

 

 

Given how much GFS ramps up the Atlantic it stills surprisingly manages a well aligned Scandi high albeit with the Atlantic going into overdrive to ensure any cold stays out of reach.

 

 

I know it has been a dreadful start to Winter and there is no sign of cold for the UK at the moment but there is clearly huge potential for January cold and if we get lucky I think any cold will be memorable.

 

EDIT

 

Just to add. GFS ensembles are all over the place by day 5 so things really up in the air for what we get in early January.

 

Edited December 21, 2015 by Mucka

[northwestsnow]

GFS defo sniffing around a scandy high in the medium term, i'm not sure given the strength of the jetstream its going to bear much fruit initially but maybe just maybe it will throw a curveball at that relentless PV over Greenland and encourage a split in the jet.

ECM didnt seem remotely interested yesterday so as is always the case with GFS we'll have to wait and see what ecm throws out.

edit GEM very similar to GFS so canadian model thinking scandy high too !!

Edited December 21, 2015 by northwestsnow

[bluearmy]

I wonder how many have spotted the mean upper ridge building week 2 over Alaska, driven by the Aleutian low?

its a big IF, but IF the size and shape of that sceuro ridge have driven enough WAA into the arctic prior to this then we could see a significant double pronged attack on the vortex.  That would drive some effective wave activity into the strat aswell. 

My point is not to worry too much about what this sceuro ridge might deliver for nw Europe now, but what it could do in January as a consequence. See it as a building block for the second half of winter rather than a potential delivery van for an easterly now. 

[chris55]

Both GFS and UKMO looking to build the Iceland ridge around 144. GFS goes on to build a very nice true high - lat high, none of this Euro high hybrid. Doesn't deliver for us but certainly a much more interesting pattern if potential colder conditions is what your after.