Model Output Discussion - the cold has arrived

[Guest]

For me the trend of the last day or so is clear - the outlook is increasingly cold for the foreseeable - the question is whether the cold weather will go through to Christmas.  If more of a wind picks up then the risk of snow showers feeding inland will increase.  The low to the southwest next week looks increasingly likely to stay south so the cold is here to stay well into the second half of the month.

[BLAST FROM THE PAST]

Well I for one aren’t looking for the breakdown….I’m looking for the bitterly cold easterly gales and drifting snow…..I think Icon says they are coming to a place called Surrey soon 

 

BFTP

[Frostbite1980]

34 minutes ago, Eagle Eye said:

The dynamical recovery of the AO probably has a lot to do with the unstable inertia that has propped up the -VE AO state losing it's support with a loss of AAM and therefore the Eddy's 'retreating' across the Northern Hemisphere battlefield as the Rossby energy transfer retreats to being mostly across the tropics with a flatter Atlantic to probably come into place by early next year. Signs that we could get an increase again in January but for now I'd treat it as signs.

The GWO supporting my view of the jet coming into line with the thermal wave northward transfer (of the jet momentum so the jet reverts back to normal) and eventual pattern flip into circumglobal ridges and it's been a general trend recently. Circumglobal ridges linked with Atlantic influence and mild and wet.

So beyond Christmas things may return back to normal with the occasional colder chance but I keep saying it...

Take this chance on the face of it and it is the best early Winter chance since 2010, as simple as that, we've still got till Christmas before any chance of severe cold setting in goes and even beyond then we don't know for sure that we won't get helpful background influences.

Do you not see a possible recurring pattern in January at the moment then EE?

[Snowman.]

You would thing that there would be a little more convection on that ICON but he ho. It’s so far and models struggle with these things. 

Edited December 8, 2022 by Snowman.

[snowstorm445]

Yeah the Icon outcome is pretty favourable to us here in the Low Countries. Nearly 24 hours of snow by the looks of it! Seems odd that it wouldn't lead to more streamers heading into Southern England as well with those tight isobars.

[Eagle Eye]

4 minutes ago, Frostbite1980 said:

Do you not see a possible recurring pattern in January at the moment then EE?

It's way too early to tell but I suppose it's possible, patterns do tend to repeat and there is the early signal for it but right now it's still a small signal. I'm being wary of calling either way as we would the MJO repeating pattern as an early signal for that and I simply wouldn't know yet. Its a possibility that we could be stuck in a consistent -VE AAM but it's also a possibility that we see a re-transferring of thermal states back to a +VE AAM as the AAM is still fairly nuetral either way so little MJO variations can have a big difference. I'll research more when I get home from school though .

[BlueHedgehog074]

In summary, the models show further cold weather to come for the rest of this week into next week (and perhaps beyond, but far out to be sure). The pressure charts from the ECMWF below, while liable to some changes in some the later frames, shows an idea of the outlook for our part of the Northern Hemisphere for the next 6 days. 

Essentially High Pressure combined with high upper heights over the Greenland area, and a string of Low Pressure systems running along to our South and South-West. There is also a Scandinavian trough of Low Pressure extending some of its low heights and slack surface Low Pressure South-West over the UK further into this week and during the weekend.

Although the source of the cold is originating from the North and North-East for the UK, you can see the flow is slack (isobars well spaced out) and the flow will become variable over the weekend. Lack of winds should mean frosts continuing to form at night, especially inland with clearer skies at times. Could be some cold mist and fog too. Air cold and still enough for frosts to linger throughout the day, particularly in the shade. So will continue to feel like a Winter wonderland in many parts, especially for places that have seen fallen snow so far (latter mostly for some Northern areas and towards Eastern and Western coasts).

In fact, looks to be quite dry away from the coasts and Northern areas, bar one or 2 possible wintry surprises - these always have the possibility to catch people out unexpectedly. That is until sometime next week where you’ll see on the later frames of the ECMWF above that an angry, deep, Western Atlantic Low tries to slowly shift further East towards South-Western parts of the UK. This giving a strengthening chilly South-Easterly flow over South-Western parts heading into Tuesday and Wednesday next week as shown in the last 2 charts above.

With pressure from the Greenland blocking, it’s not yet clear whether this Low will party over the UK at all. Very very possible for the Low to just fully avoid the UK to the South and become squished and disrupted. May just find the blocking over Northern/North-Western UK could be too powerful and win the fight that Azores/Atlantic Low wants to start.

The Low does however have the chance of bringing a more organised area of rain, sleet and snow, with Southern areas of the UK probably seeing the best shot at this. Without that Low having any influence, cold and mostly dry conditions will probably continue to be the theme, nonetheless.  In spite of that, a more cyclonic flow between the North and East could easily be picked up next week sometime. It’s still at a range for that to be possible, particularly later next week. Plus some disturbances could easily pop about in the flow. This of which could drag more organised areas of sleet or snow further inland.

With how things could continue to go, an increased number of wellies and sledges could very well end up getting some attention at some point during the next week or so. 

Edited December 8, 2022 by DiagonalRedLine
Typos

[Dangerous55019]

Hello everyone. 

being as its been a week (or there abouts) since I last posted in here, I thought I'd take a look at the CFS v2 four weekly anomalies, to either help clear the waters for other members or help muddy them? Lol 

Week 1 - 8th to the 14th December: We have a large trough of low pressure centered right over the Midlands and southern UK and stretching out over north eastern Europe, and towards Scandinavia. We also have what looks to be a large blocking area of high pressure over Greenland and north eastern Canada. To my eyes that is going to leave us in an easterly airflow! Cold? Yes! Snow? I'll leave that to our more experienced members! Lol 

Week 2 - 15th December to the 21st December (The Winter Solstice): Pretty much a very similar setup to week 1! But with the trough of low pressure over us here in the UK weakening.

Week 3 - 22nd of December to the 28th December (So covering Christmas): The large area of high pressure over Greenland and north eastern Canada is now starting to extend outwards towards Scandinavia! The trough of low pressure over us here in the UK appears to have vanished... But has it? There's definitely something over us here in the UK, and the rest of main land Europe. But what it will do (as this is three weeks out) I have no idea. 

Week 4 - 29th December to the 4th January (Into the New Year): The large blocking area of high pressure that has been sat over Greenland, appears to be weakening. But there is a trough of low pressure now showing to the north west of Scotland... To my eyes this would leave us in a cold(ish) and unsettled northwesterly airflow. First winter storms? Time will tell.

So there you have it folks! Hopefully this will help some of our more experienced members of this forum. 

[MATTWOLVES 3]

20 minutes ago, Frostbite1980 said:

Do you not see a possible recurring pattern in January at the moment then EE?

Here's my non scientific prognosis without all the big Oxford Dictionary words.

If that PV remains shunted towards the Siberian side we will continue to throw up Wedges of Heights around the NW..and you guessed it...Wedges make sledges...and I'm pretty sure that's becoming a dying trade in the UK just lately.

A PV away from its natural home will help keep the Atlantic quite also,ie....no significant cold pooling dropping into the North Atlantic and acting as pep up for the jet! Obviously other things could ruin it like an extension of the Azores High,but if we keep that subdued and more pegged back towards the South things will continue to prosper moving forward.

And I can guarantee you now folks...you ain't gonna need Wikipedia to translate this post for you,or to ask me to sum it up in layman's terms!

Actually your gonna be more likely to ask me to sort my spelling mistakes out.

Edited December 8, 2022 by MATTWOLVES

[Neilsouth]

13MINS in, big discussion about the charts/models and the low pressure system in the atlantic

[bluearmy]

Gfs 12z has several differences by day 5 to the 06z. the next few frames will reveal if it’s closer to the ec and U.K. 00z 

 

[Ali1977]

Just now, bluearmy said:

Gfs 12z has several differences by day 5 to the 06z. the next few frames will reveal if it’s closer to the ec and U.K. 00z 

 

Just about to say the same , possibly better looking for a snow event 

[tesaro]

What with the P.V on Holiday for the foreseeable and Low Pressure systems bowling along on top of the Jet, it’s only a matter of time before a convective Easterly/North Easterly sets up. Difficult to call a specific Day of course. Possibly some time towards the back end of next Week. Enjoy it, whatever it does
 

[Mark wheeler]

Ukmo 120 

 

Edited December 8, 2022 by Mark wheeler
Wrong 850 chart, now correct

[Ali1977]

Just now, Mark wheeler said:

Ukmo 120 

That looks game on for the south too 

[Guest]

Incredible synoptics again from the GFS at 150 hrs as we look to the north.

[Battleground Snow]

4 minutes ago, Mark wheeler said:

Ukmo 120 

That's the 00z, 

144 12z attached, 156 could be juicy 

[Mark wheeler]

UKMO 144 

Looks like grazing the south coast again . Going to be interesting next 2 frames later .

[ICE COLD]

-11850s into Scotland at T168 on the gfs 

[IDO]

GEM shows how post d6 is fraught with forks in the synoptic pathways:

 

[bluearmy]

Gfs goes Norwegian shortwave at T180 

was wondering how the neg AO was going to drive things into week 2 but that feature will skew the evolution now 

[weirpig]

8 minutes ago, Mark wheeler said:

UKMO 144 

Looks like grazing the south coast again . Going to be interesting next 2 frames later .

Yep that looks like one heck of walloping for some areas.   

[bluearmy]

1 minute ago, IDO said:

GEM shows how post d6 is fraught with forks in the synoptic pathways:

 

That’s gfs op from yesterday!  (I mean it’s the same ) 

Edited December 8, 2022 by bluearmy

[Tim Bland]

47 minutes ago, BLAST FROM THE PAST said:

Well I for one aren’t looking for the breakdown….I’m looking for the bitterly cold easterly gales and drifting snow…..I think Icon says they are coming to a place called Surrey soon 

 

BFTP

Icon is cold and dry? This is total precipitation for the run? ….

[frosty ground]

GFS gets very messy and is on the verge of breaking the cold down for the UK