[Model Output Discussion - Into Winter]

30 minutes ago, Hatewarmth said:

For wintry synoptics, the reliable is generally up to date 4 (96 hours) and the age-old rule, "if the UKMO-GM is not showing it, be very worried".

[Model Output Discussion - Into Winter]

Pretty decent mean from the ECM suite at day 10.

[Model Output Discussion - Into Winter]

GEM and ECM det runs are decent right out at days 9-10.  A big worry is the poor UKMO run (at day 7).  Still, a lot to be resolved.  Hoping for a great eps set this morning.

[Model Output Discussion - Into Winter]

Just now, Battleground Snow said:

I imagine the deep cold will be close when the 144 ukmo chart updates, it's almost an easterly flow 

Indeed.  UKMO day 6 close to a good chart.  Close but no cigar I reckon.

[Model Output Discussion - Into Winter]

So much time is spent with the GFS and GEFS.  I weep…

[Model Output Discussion - Into Winter]

8 minutes ago, northwestsnow said:

EC mean looks good to me ..

Yes, it's decent.  Just need to watch the heights to the south (don't shoot me!)

[Model Output Discussion - Into Winter]

17 minutes ago, Ali1977 said:

ECM is cracking for snow in the midlands and south by the way. 

Interesting but way too far out to take seriously.  The medium-term broadscale pattern from the ensemble suites suggests an atlanctic ridge days 10-12.  Let's see how that evolves.

[Model Output Discussion - Into Winter]

Merry Xmas all.

The UKMO is the most interesting evolution in the medium term.  Less influence of the AH and seemingly more trough disruption.  ECMWF det not interested in this type of evolution.  One to watch...

 

[Model Output Discussion - Into Winter]

Outer reaches of GEFS continue to impress...

 

[Model Output Discussion - Into Winter]

FWIW, outer reaches of GEFS continues to improve.

[Model Output Discussion - Into Winter]

Outer reaches of the GEFS but this is where we want NWP to follow:

[Model Output Discussion - Into Winter]

No point trying to sugar coat the NWP - it’s poor.  We really are dependent on medium range drivers - SSW, MJO etc. to deliver the wintry goods. The big elephant in the room is AGW.

[Model Output Discussion - Into Winter]

Nothing in the more reliable NWP to get excited about.  December 2023 is likely to outturn a milder than average month after starting so cold.

[Model Output Discussion - Into Winter]

30 minutes ago, Lukesluckybunch said:

nice run from the ICON 12z..looking cold and very windy towards the end!

Not a great chart. 8C and gales in not nice.

[Model Output Discussion - Into Winter]

1 minute ago, Tidal Wave said:

That's the 12z run?

ECMWF det 00z at day 10 FWIW, its clear why there's no comments on it:

Yes, the ECM det is poor - let’s see where it sits within its ensemble suite.  This is going to be a slow burner I feel.  

[Model Output Discussion - Into Winter]

Interesting weeks 5 and 6 on today’s ECMWF sub seasonal.  Let’s see if this the start of a trend.

[December 2023 C.E.T. and EWP forecast contests -- start of 2023-24 contest year -- all welcome]

4.2C and 90mm please

[Model Output Discussion - Into Winter]

50 minutes ago, TillyS said:

 

Siberian highs are less helpful to us than Scandinavian highs though I feel? It’s a much longer route to a cold scenario, although it can happen with easterlies setting in.

The more significant high, and the one which no one is keen to mention for understandable reasons is the one showing up down south. It’s the elephant in the room.   Mind you there is the vaguest hint on the progression from T216 to T240 of that migrating into mid-Atlantic but it’s probably straw clutching for now.

Yes as ever, the Azores High is a significant player during our winters.  Let’s hope is stays  well away.  A new worry is rainfall totals - could be some big totals piling up as the lows meet that huge High to the east.  Mild, very wet and windy in the medium term but then who knows?

[Model Output Discussion - Into Winter]

22 minutes ago, Jacob said:

One question, how low do uppers have to be to get ice days? I'm quite new to this as you can see by my rank

It depends.  Uppers of +3 can give freezing temperatures via an inversion and uppers of -12, especially in early Spring may not result in sub-zero temperatures at the surface.  

[Model Output Discussion - mid Autumn]

Slightly disappointing output this morning.  There is no deep freeze imminent (was this even ever on the cards?).   Chilly for sure but any snow is likely to be over high ground.  NWP also suggests weakening heights over Greenland and more mobility in the outer reaches.

[Model Output Discussion - mid Autumn]

2 minutes ago, Lukesluckybunch said:

Is that snow in the southeast?

Unlikely - uppers too high and too much mixing of the air.  Cold rain and 5C

[Model Output Discussion - mid Autumn]

11 minutes ago, Ali1977 said:

Snow maker ️️️️️️️ surely it’s dumping under that 

Nah, cold rain.  Sleety snow for high ground though...

[Model Output Discussion - mid Autumn]

15 minutes ago, BartyHater said:

The 18GFS absolutely screams ‘thank god I didn’t tell friends and family again this time, I must be wising up at last’

It’s gone tits up because someone broke ranks!  Own up whoever it is…

[Model Output Discussion - mid Autumn]

The lows to the southwest are troublesome - whether they make progress inland is up for grabs - high risk, high reward.  Snow chances are there but also a chance that the cold air could be mixed out.

[Model Output Discussion - mid Autumn]

7 minutes ago, The Enforcer said:

A question:

What causes the kink in the isobars often seen here? Why don't they go straight across the North Sea?

The dreaded shortwave!