The hunt for cold - Model discussion (late November)

[feb1991blizzard]

Heavy PPN turning to snow and moving through large parts of  Central parts.

[ICE COLD]

Not really shore what to make of the ECM clusters this morning. Cluster 4 maybe looks the best for a scandy high ? 

EDIT- Actually cluster 3 has high pressure to the north with a through over us . Maybe that would hold some hope . 

Edited November 30, 2018 by ICE COLD

[sebastiaan1973]

A tweet by A. Masiello: +MT in the 6-10 day will lead to a jet extension day 10-15 which supports the NPO flip that brings the relaxation period mid-month. But, during that time, the flow is gearing up for the next Eurasian Anticyclone.

http://twitter.com/antmasiello/status/1068312377026859008

Edited November 30, 2018 by sebastiaan1973

[shaky]

The differences between the 00z gfs and 06gfs at just 96 hours is ridiculous!!gone is the snow potential for midlands and wales and the shortwave doesnt even slide away into the continent!instead joines forces with the low coming out of the states and therefore everything flatter and not as amplified early on!

[Methuselah]

Nothing all that exciting from the GFS this morning...At T+384, things look almost like a text-book winter weather pattern:

[feb1991blizzard]

16 minutes ago, ICE COLD said:

Not really shore what to make of the ECM clusters this morning. Cluster 4 maybe looks the best for a scandy high ? 

EDIT- Actually cluster 3 has high pressure to the north with a through over us . Maybe that would hold some hope . 

I dont rate those at all tbh - the flow is broadly from a Westerly quadrant.

[bluearmy]

10 minutes ago, Ed Stone said:

Nothing all that exciting from the GFS this morning...At T+384, things look almost like a text-book winter weather pattern:

Seriously Ed, you need to stop using day 16 op charts to make a point, whichever direction they are headed in .......

eps clusters are now five again in extended so the mist which was possibly clearing is maintained .... looks like plenty of possibilities at day 10/11 for coldies 

 

[Methuselah]

6 minutes ago, bluearmy said:

Seriously Ed, you need to stop using day 16 op charts to make a point, whichever direction they are headed in .......

eps clusters are now five again in extended so the mist which was possibly clearing is maintained .... looks like plenty of possibilities at day 10/11 for coldies 

 

Which was my point, BA: posting day 16 charts, even when they don't show Snowmageddon, is pointless...? The weather will simply carry on regardless...

The GFS Para for next Monday, on the other hand, is a different matter:

Edited November 30, 2018 by Ed Stone

[nick sussex]

Still that low to the sw and whether it phases with the upstream low remains uncertain.

For those hoping for a chance of some snow , the no phase option is crucial .

You also want a shallow feature , the deeper the low the more likely it is to phase.

After this drama the models try and displace the limpet high to the south but I’d stress don’t believe this until it’s shown within the more reliable timeframe .

We’ve seen this tease shown for a few days which hasn’t survived contact in further runs .

The ECM has the most promising output as we see a small Scandi high develop and if the upstream pattern was a bit more conducive it could get interesting but again will this survive in later outputs .

 

Edited November 30, 2018 by nick sussex

[snowray]

Well at least the control run is going for it.

[snowray]

White Christmas anyone?

[tight isobar]

4 minutes ago, snowray said:

White Christmas anyone?

A feasible-outcome !!.

With date exactions, on stills about the turning point!!!

[Met4Cast]

In any case there's fairly good support for temperatures to drop well into single figures by the second week of December

That to me is suggestive not mild Atlantic weather, but either Easterly winds (not deep cold) or a cold PM zonal type pattern. Uncertainties continue going forward towards week 2 of December, mild? Unlikely. But how cold and will it be blocked?

Edited November 30, 2018 by Daniel Smith

[gottolovethisweather]

3 minutes ago, Daniel Smith said:

In any case there's fairly good support for temperatures to drop well into single figures by the second week of December

That to me is suggestive not mild Atlantic weather, but either Easterly winds (not deep cold) or a cold PM zonal type pattern. Uncertainties continue going forward towards week 2 of December, mild? Unlikely. But how cold and will it be blocked?

I'm still going for a short period of High-Pressure dominance, akin to UKMO at t+168 if only lasting for a few days. Is there a dry signal backing those charts up as well, come the 2nd week of December?

[Iceaxecrampon]

06Z

11-12-18

+264 I know.... I know

[Iceaxecrampon]

Cumbria temp ensembles pretty flat - not having it.

 

 

[Methuselah]

1 minute ago, Iceaxecrampon said:

06Z

11-12-18

+264 I know.... I know

I wouldn't worry, Iceaxe: sixteen days back, we were all being treated to a legion of 'all roads lead to cold' posts...That all turned-out well, didn't it - despite the models mostly 'smelling the coffee'?

[Iceaxecrampon]

1 minute ago, Ed Stone said:

I wouldn't worry, Iceaxe: sixteen days back, we were all being treated to a legion of 'all roads lead to cold' posts...That all turned-out well, didn't it - despite the models mostly 'smelling the coffee'?

Yes - The Hunt for Cold thread -  soon to be the Clutching at Straws for Cold thread.

 

[SMU]

Morning -

The pendulum has swung back a little more towards cold today with again some transitory snow episodes in the mix- at this stage difficult to pinpoint any of these but somewhere around up towards the England / Scotland border could be a good shout ( with the premise that corrections south do occur )

We have a right old mix of solutions out there - The very worst could see the mild air cover the UK, the very best sees the lows track well south leaving the majority of the UK in the polar air-

The ECM in particular tries to hold the atlantic up with some wedging of high pressure over Scandi - This is great, & whilst this initially wont create masses of deep cold the opportunity does arise again of low pressures undercutting into colder air - especially if we get some amplification behind -

A bit of a rollercoaster at the moment & probably another 24-48 hours to resolve how much high pressure we get ahead of the first low which in turn creates a domino effect down the line -

An interesting period coming up!

 

[BLAST FROM THE PAST]

4 hours ago, northwestsnow said:

Thanks John

Phew, i was feeling a bit lonely with my optimism !!

Never lonely .  I think Cumbrians, Northumbrians, Scottish will be increasingly pleased over the coming week to 10 days whilst the south better make sure any leaks are sorted as LPs and main fronts come on southerly track bringing a thorough soaking.  For me though that is good going forward as increasing chances of a ridge developing and then holding into a cold flavour.....I think there will be some ‘not really expected’ transient snow events for places further south than the borders.....no deep cold yet....

 

BFTP

[Nick F]

I'm not so enthusiastic as I was a week ago that we'll see proper blocking anytime soon, i.e. next few weeks, as there just looks like too much El Nino westerly momentum and a trop PV too close to the NW to allow blocking to form near enough to the UK or position ideally for any deep cold to spread across the UK.

Looks like the models are picking up some transient eddies in the generally fast zonal westerly jet stream ploughing across the N Atlantic into western Europe, which may form some transient ridges that could pull down some cold arctic air to bring a brief 1-2 day cold snap, with snow for northern UK a real posibility.

But I do feel that there is not going to be enough amplification in what is an enhanced jet stream over the N Atlantic - fuelled by cold over NE USA/E Canada over the next week or two and strong westerly momentum over the Pacific.

I did think we may get some help from MJO, which is headed into phase 1 to start December, but it does so at low amplitude signal on most model forecasts, so unlikely perhaps to create enough amplification in the upper flow to allow high latitude blocking. Plus the  recent record high AAM / growing El Nino (Modoki) is creating poleward flux of westerly momentum which in turn is creating a strong zonal jet stream across N Pacific, N America and N Atlantic - which will not allow for much amplification. The MJO will quickly orbit through to phases 3 and 4, which are even more hostile to high latitude blocking as we head towards Xmas.

However, the state of the stratospheric polar vortex remains intriguing as we head through December, with forecast pulses of poleward wave activity hitting the PV over the next few weeks according to 10hPa wind/height forecasts, so be interesting to see how this impacts the sPV, i.e. displacement later in Dec or SSW in the New Year perhaps.

Edited November 30, 2018 by Nick F

[Spah1]

Lots of people commenting recently how the NH is predisposed to blocking throughout December. 

The MO isn't having any of it however. 

Blue commenting this morning to look for height rises to Scandi, I hope he's right.

Nothing worse than a warm Christmas. 

[booferking]

34 minutes ago, Nick F said:

I'm not so enthusiastic as I was a week ago that we'll see proper blocking anytime soon, i.e. next few weeks, as there just looks like too much El Nino westerly momentum and a trop PV too close to the NW to allow blocking to form near enough to the UK or position ideally for any deep cold to spread across the UK.

Looks like the models are picking up some transient eddies in the generally fast zonal westerly jet stream ploughing across the N Atlantic into western Europe, which may form some transient ridges that could pull down some cold arctic air to bring a brief 1-2 day cold snap, with snow for northern UK a real posibility.

But I do feel that there is not going to be enough amplification in what is an enhanced jet stream over the N Atlantic - fuelled by cold over NE USA/E Canada over the next week or two and strong westerly momentum over the Pacific.

I did think we may get some help from MJO, which is headed into phase 1 to start December, but it does so at low amplitude signal on most model forecasts, so unlikely perhaps to create enough amplification in the upper flow to allow high latitude blocking. Plus the  recent record high AAM / growing El Nino (Modoki) is creating poleward flux of westerly momentum which in turn is creating a strong zonal jet stream across N Pacific, N America and N Atlantic - which will not allow for much amplification. The MJO will quickly orbit through to phases 3 and 4, which are even more hostile to high latitude blocking as we head towards Xmas.

However, the state of the stratospheric polar vortex remains intriguing as we head through December, with forecast pulses of poleward wave activity hitting the PV over the next few weeks according to 10hPa wind/height forecasts, so be interesting to see how this impacts the sPV, i.e. displacement later in Dec or SSW in the New Year perhaps.

Thats interesting update as @Catacol  was going for a strong MJO wave and blocking highlighted below for mid month onwards.

Key to this will be the MJO. We continue to see forecasts of a strong MJO wave and without doubt the signal for blocking to return under a Nino base state will return:

[johnholmes]

Sorry I posted in the wrong thread but hope a mod will drop it and its links in here, Met O 6-30 day area, but the words below, sorry not got time to do the links at the moment

So what was the reason for the post I made earlier?

As someone kindly pointed out it is rare for me to give support to you coldies. Believe it or not I am one myself, in moderation though having lived and remembered 47 and 62-63.

Anyway below are the usual 500 mb chart links

First the NOAA from last evening; this shows the Atlantic fairly strong flow all of you are so happy with. Look NW of the UK though, Greenland area and you will notice the very first signal of height rises coupled with a ‘bulge’ in the 500 mb flow also over Iceland?

Far too early to get excited BUT it MAY indicate a change in pattern. Looking at the 8-14 day version and it also shows such a signal. To be honest it is not that often that both pick up on any marked upper flow change on the same day.

So to the ECMWF-GFS from this morning.

Both these have a similar slight suggestion of ridging/height rises in a similar area. One other thing to watch on these two charts is the tendency (over the past couple of days), for the flow into the UK on the EC for the flow to veer just north of west.

So there is a glimmer, no more than that for the possibility of a change in pattern. I would want to see 2 or perhaps 3 more outputs emphasising this before I would believe it is a ‘real’ probability. Currently 15% perhaps.

What we will have even if this does not occur is a more general Pm air mass more often than a Tm air mass. This will mean some colder if brief interludes over the coming week or so. As the Atlantic upper flow is so strong further spells of wet and windy, possibly very windy in exposed W/NW’ern areas is going to occur.

I’ll keep you posted but DO NOT get excited yet!

[Paul]

The Netweather winter forecast is online:

https://www.netweather.tv/weather-forecasts/uk/long-range/seasonal

Discussion thread here: