Model Output Discussion - mid Autumn

[TSNWK]

big shunt south with colder air - -4 over south coast / on 00Z it was the 0 line.

[Captain Shortwave]

Looks like the main emphasis will be on showers pushing south west from the North Sea on Thursday night into Friday. Obviously this gives scope for streamers to form in favoured spots, so anywhere downwind from the Wash looks a good bet for example. 

[MJB]

Nice from the 6Z 

2 minutes ago, Captain Shortwave said:

Looks like the main emphasis will be on showers pushing south west from the North Sea on Thursday night into Friday. Obviously this gives scope for streamers to form in favoured spots, so anywhere downwind from the Wash looks a good bet for example. 

Plenty in the N Sea

[TSNWK]

Nice little upgrade both locally with colder uppers end of this week and bit more into greenland heights at broaader scale.. now to see if we can improve on mid range.

Edited November 27, 2023 by TSNWK

[Mcconnor8]

7 minutes ago, TSNWK said:

big shunt south with colder air - -4 over south coast / on 00Z it was the 0 line.

It is really just syncing itself with the ECM/UKMO as it was way off for Weds/Thurs, very poor from the GFS output last couple of days

[Captain Shortwave]

It looks like the cold pool that reaches Iceland may curve back towards the UK on this run.

 

A snow event possibility and it also should extend the cold period as the phasing of low heights pushing into the Atlantic will be slower.

[Notty]

39 minutes ago, Cambrian said:

T850s for today and day 5 on the 0z ECM ensemble mean - now that really is a seasonal transition! By then, it’s a cyclonic northeasterly flow for the UK and Ireland. 

  

Next weekend, the first weekend of meteorological winter, and the following days, continue cold and changeable, as Atlantic low pressure systems chance their arm against a block of deepening cold, here at day 6. 

  

The engagements are being consistently modelled to the south of the UK and Ireland, putting us very much in the boundary zone. A very interesting place to be during the first week of December!

By day 9, there may be a brief build in surface pressure over Western Europe in the gap between Atlantic and European troughs, but no relenting of the cold, just subtle movements in the location of the boundary zone. 

  

The extent and nature of the building of heights in that gap to the west of the UK and Ireland around day 9 will determine how prolonged the cold spell is. 

A strong build from the south could bring us a very seasonal anticyclonic period with a lot of trapped cold air and frosty. 

A strong build from the north could elongate the European trough further west pulling us into a very cold east or northeasterly flow and more entrenched cold. 

Lack of a strong build of heights to block the gap will allow further attempts at incursion of the boundary zone and further “mixed wintry” events for the UK and Ireland.

The models are clearly undecided as yet!

I can see Bill Giles now saying once you get that deep heavy cold air blocking in Europe it’s very hard for anything to shift it.

[Notty]

9 minutes ago, MJB said:

Nice from the 6Z 

Plenty in the N Sea

That little feature in the North Sea is still showing up.

[MJB]

138 H

 

Much Better , LP out West bumping into cold air ....hopefully

 

 

Edited November 27, 2023 by MJB

[Met4Cast]

As expected the low looks increasingly likely to miss the UK entirely; 

[Battleground Snow]

Just the 600 mile difference in the position on that Atlantic low, it will probably get close to the UK on this run, but hard to have faith in the gfs with them features atm

[danm]

11 minutes ago, MJB said:

Nice from the 6Z 

Plenty in the N Sea

Plenty to happen and be resolved before then, but if this happens I'd like more of an easterly element to the onshore wind to drive any snow showers further inland. I sometimes find when we have too much of a NE'rly element, the showers hug the coast and only hit a few favoured spots. 

[TSNWK]

huge differences upstream at day 6 - and for the much better

[BartyHater]

Quite a change on the 06 GFS, with the colder air now winning out and forcing the weekend low to slide towards NW Iberia. That said it’s not difficult to see a route back to milder weather post 168hrs, but hey-go that’s a long way off for now….just under 168hrs to be precise

[Midlands Ice Age]

That's more like it..

As we reach December we see 'white' over large areas of Siberia for the 850's in the above charts. This means we have got below -30C for the first time this season.

It  also probably  means that the strat Canadian warming is having an effect. Look at how relatively warm they are  in NE Canada.

MIA

Edited November 27, 2023 by Midlands Ice Age

[throwoff]

Wouldn't be a NW mod thread without people panicking over the breakdown of an event before it has even started.

It is still looking like a nice little spell. Much better than we have had for a long time. 

[bluearmy]

15 minutes ago, Midlands Ice Age said:

That's more like it..

As we reach December we see 'white' over large areas of Siberia for the 850's in the above charts. This means we have got below -30C for the first time this season.

It  also probably  means that the strat Canadian warming is having an effect. Look at how relatively warm they are  in NE Canada.

MIA

Strat temps in Canada don’t really rise notably until into week 2. The lack of deeply cold uppers in e Canada and Greenland is likely down to the lack of sustained organised tpv we’ve seen in that locale thus far 

 

current momentum is for lower uppers to establish in that area by end week 2 as the pattern attempts to solidify a pos NAO 

Edited November 27, 2023 by bluearmy

[andy989]

I advise the less seasoned visitors in this thread to avoid reading the 6:am panic posts. They tend to be panics from a single frame. You’ll notice the more notable posters wait until later in the morning to comment when they have a fuller view of the models, rather than single frames. 
 

Before I get jumped on, yes discussing single frames is fine as this is the model thread after all. But jumping to wild conclusions after a frame, only to jump wildly the other way on the next run (from the same posters) can be very disorienting to anyone trying to learn 

[Mcconnor8]

43 minutes ago, sheikhy said:

Finally gfs o6z goes south!!!!!taken forever!!more the typical gfs behaviour over the last couple of days!!

GFS really is so hit and miss, sometimes it picks up pattern changes early like with this spell so can be useful in the extended, but it has a real problem with blowing up lows way too much and their positioning sometimes like with this one over the last couple of days and when it is way out of sync compared to UKMO/ECM at shorter time frames it always back tracks at the last minute. It was very clear that this low would be shifted South to match up with them yesterday.

[gaia rules]

UKMO HD brings that second low further north so although in FI still worth watching seeing to see if this gathers traction

[Battleground Snow]

I feel the gfs is still playing catch up regarding the blocking, so it's output is highly questionable at present. 

Edited November 27, 2023 by Battleground Snow

[Methuselah]

1 hour ago, Turnedoutniceagain said:

"Winter's over.....etc etc"

It hasn't even started yet! 

[Purga]

The Atlantic is running up against the block to the NE on the 06z and the trough to the west looks like disrupting under it - good to see.

[Dennis]

im strong

[MATTWOLVES 3]

Ecm goes with a scandy High idea..GFS says ok so called King of models I will play along with that idea..we don't want anybody thinking we are in agreement...so I'll move the timescale forward a bit  

Bill giles Hell yeh boys

Look at the map...dam that M4 corridor somethings never change

Edited November 27, 2023 by MATTWOLVES 3