Model output discussion 25th Jan - The final third of winter beckons..

[Ali1977]

There are some fantastic GEFS out to 180, including the control which has a good snow event primed.  The mean doesn't look as good as it may have done as 3/4 ENS go off on a tangent.

We have a fair few with -10/12 uppers by day 8.  

[Cheshire Freeze]

Control run shows how the cold is kept in better shape when travelling across a more N'ly latitude

As cold as you'll see Scandi that, pretty much

[jvenge]

Mean temperature from GEFS. The cold is pushing further west, but at the moment nothing exceptional for Western Europe.

[Troubleatmill]

Ensembles give us no clue as to the evolution. Better than they were when only the Op had us under the Easterly which should give us an indication they are trending in the right direction, but who would want to make a forecast based on these!     

[Cheshire Freeze]

2 minutes ago, Nicholas B said:

Ensembles give us no clue as to the evolution. Better than they were when only the Op had us under the Easterly which should give us an indication they are trending in the right direction, but who would want to make a forecast based on these!     

They'll shift one way or another over the next 48 hours. Toss of a coin as to whether we get the deep cold in looking at those. Very few 'flatliners' as Feb would put it which gives some degree of confidence that it may not be a prolonged affair anyway.

[JamesL]

I would almost bet my last pound coin that if this trend for westward corrections continues, next Thursdays potential battleground will just effect the SW of Ireland. 

 

Historically, blocking is inderplayed and ends up further west with the Synoptics on offer currently. 

 

Just my take on things right now. 

Edited February 2, 2017 by JamesL

[Ravelin]

GFS 06Z Op & Control still on the extreme cold end of the ensemblies for my local in the mid term.

That's at least 5 run in a row now they've done that. Got to be 'sniffing' at something surely as normally you'd expect them to bounce around at least a bit within the spread at that range.

Then again, I've seen this winter consistently decent looking ensemblies change to **** within a day or two so taking nothing for granted.

[The Weather Dragon]

The models are currently showing a large blocking high pressure area to our east and low pressure associated with a strong canadian lobe of the polar vortex to our west. The UK looks likely to be stuck (as we often are) in a battleground situation where there are many possible outcomes - a very dynamic situation to be carefully monitored.

Edited February 2, 2017 by The Weather Dragon

[SLEETY]

40 minutes ago, CreweCold said:

Control run shows how the cold is kept in better shape when travelling across a more N'ly latitude

As cold as you'll see Scandi that, pretty much

I've seen  850s of -40 over Scandinavia before ,with max daytime temps of -30 in Helsinki doesn't seem to happen anymore ,one reason why easterlies here are not as cold anymore.

[Luke Attwood]

One of the the problems is the low pressure in the Atlantic.we have the block In place next week,but one of the problems moving the cold air west is due to the lows pushing east and north,this is the wrong track! We really need them to dive south and then east,or just straight north and then west.until the latter happens we won't see a freeze up.just chilly conditions nothing to extreme.do people agree with me here?

[Troubleatmill]

1 hour ago, CreweCold said:

They'll shift one way or another over the next 48 hours. Toss of a coin as to whether we get the deep cold in looking at those. Very few 'flatliners' as Feb would put it which gives some degree of confidence that it may not be a prolonged affair anyway.

Yeah see what you are saying about the flatliners. Models have always had a tendancy to break down blocking to the east too quickly or easily so not too worried about that yet as it could well change......If we get lucky and the stars all align for the cold to reach our shores in the 1st place. 

One way or another we will have a decent idea by Saturday what's in store like you say!

[Mucka]

The balance has tipped back toward an Easterly before mid month again today with the strongest signal yet for UK cold spell.

The GFS and ECM ensembles are both much improved and the MetO now on board while operational output has trended the block West.

For me this is the first time the output has indicated a greater than 50% chance of an Easterly setting up before mid month but still not nailed on with enough scatter within the ensembles to warrant caution.

As Steve M noted, the Scandi high is now all but assured and that is a big part of the puzzle which has seen the ensembles improve, even though there is very little agreement on the exact nature of the block - how far West and North will it be, how strong will the Easterly flow be, how soon will it get here, how well oriented will the block be to draw in the Euro cold pool, how well will it resist the Atlantic, how much undercut will follow etc etc etc.

We are seeing that small changes early in the output make big differences in potential blocking scenarios by mid term and with the Scandi high  being such a fickle beast these differences are often accentuated with placement of the high a few hundred miles North/West/South /East of the last run making all the difference to the weather type we see. In that respect nothing is nailed down and won't be for a while yet.

This isn't so much the thrill of a rollercoaster ride as an epic trek through the dense jungles of FI - inching forward as we hack away at the strangling vegetation until we discover what secrets lie beyond. 

 

Edited February 2, 2017 by Mucka

[Paul]

Just moved a whole bunch of posts into the model banter thread, because they had zilch to do with the model output - winters of the 70's, meto updates and the like don't fit in here.

 

[Alexis]

2 hours ago, SLEETY said:

I've seen  850s of -40 over Scandinavia before ,with max daytime temps of -30 in Helsinki doesn't seem to happen anymore ,one reason why easterlies here are not as cold anymore.

The all time record low for Helksinki is -34.3C. I don't know if there has ever been a day with a max temperature of -30?

[Scandinavian High.]

In the short term the storm looks like it could pack a punch for northern France Saturday is this nailed on to hit France or could it come across southern England..

[Glenn Redwood]

Is the track of Saturdays storm good going forward for the block and our chances of cold?

[Ali1977]

39 minutes ago, Glenn Redwood said:

Is the track of Saturdays storm good going forward for the block and our chances of cold?

At T48 its way early to tell, however toggling between the last 2 runs we have another Westward correction, which isn't a bad thing.

Edit - by T90 we are v similar to the 06Z, so I think to this juncture we know where we'll be sitting, it's now about how the block holds up against the incoming Atlantic, and where the block sits to our NE.

By 132 again quite similar but a noticaby stronger block, it's just not quite oriented do really produce the good but still another improvement I'd say.  Lets see where the Atlantic front on it's way in goes - slider event then easterly reload hopefully.  The Scandy block is further North so this may help if a reload is on, it shouldn't sink as fast as on the 06z.

Edited February 2, 2017 by Ali1977

[Daniel*]

Comparing 12Z to 06Z I'd say an upgrade. Stronger heights - centred further west.

[Geordiesnow]

The Atlantic vs Scandi block battle continues with a statemate over the UK virtually, it does look like the westerlies will win out initially but the models seem to hint the block battling back and we get under a more continental airflow.

I see very little evidence of a convective easterly though which to be fair most on here want too see but a chilly airflow from the continent does look possible sometime soon.

[Daniel*]

Low risk of snow for Southern England on Saturday with a shortwave tracking  S of the south coast very marginal. Also Sunday some sleet/snow could be in places. As tweeted by Ian F.

Edited February 2, 2017 by Daniel*

[warrenb]

GFS on it's own at 144 with both GEM and UKMO going with azores link up

 

Actually liking the GEM as it then pushes the block further west and the trough to the west can only disrupt one way.

Edited February 2, 2017 by warrenb

[Day 10]

GFS & UKMO at 144

[There's a storm a coming]

5 minutes ago, warrenb said:

GFS on it's own at 144 with both GEM and UKMO going with azores link up

And as been discussed on here plenty...that will lead to the UKMO outlook of mostly dry weather moving in and any fronts decaying in the west...it will also turn colder as winds swing round to the south east. I must admit tho. That is a mighty big block on the 144hr ukmo

Tasac

Edited February 2, 2017 by There's a storm a coming

[blizzard81]

4 minutes ago, warrenb said:

GFS on it's own at 144 with both GEM and UKMO going with azores link up

Yes, fabulous Gem and very similar to the ukmo at 144hrs. Would be nice to see similar on tonight's ecm.

[ITSY]

May I be the first to share this BEAUTY from the GEM: