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Model output discussion - Winter approaches


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A slower run to a blocked solution on the 00z GFS. But a Scandi block still evident. I like the West Country slider late on as well. Not all bells and whistle lime the 12z buy happy to settlef for that going into Dec.

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Hi all . I’m back from my summer hibernation . A warm welcome to all the new members . It’s hard to believe we’re back again chasing those hard to come by good winter charts . It’s true the older

This is the ECM at 96 hrs v's the reanalysis for the 3rd of Nov 2010 and bears similarities in our part of the world now you wouldn't think that the epic winter of 2010 would come from that

Time to start wheeling out the ECM snow depth charts then 😍. Please remember it is mandatory to reply with how unreliable they are and how it accumulates all falling snow even if it doesn’t settle bla

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42 minutes ago, Broadmayne blizzard said:

A slower run to a blocked solution on the 00z GFS. But a Scandi block still evident. I like the West Country slider late on as well. Not all bells and whistle lime the 12z buy happy to settlef for that going into Dec.

I agree with you on that. I have not seen a upper wind flow chart like the one below for a very long time. A  text book prelude to an old fashioned west v east scenario ( remember them ) as we approach the end of the month into December. The zonal jet buckles and weakens near to the British Isles as it comes up against a powerful and developed upper ridge from Central Europe up into Scandinavia. You can almost see the Omega shape that transfers a constant supply of cold air into Western Russia. The million dollar question is whether you in the British Isles can tap into some of that ?  Its an evolving situation but looks encouraging for some early winter, real cold, to develop on a wider scale.

C

wind300kt_20201117_00_240.jpg

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Not much blocking up over the Greenland at T192, those cold charts of the last few days are typically getting watered down!! image.thumb.png.961193f287efaa575868f58d3591803a.png

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3 minutes ago, That ECM said:

At least we didn’t all get sucked in right?🤣

EF93C6DA-E302-4D5B-83F4-2E8C51D075EA.png 😩

AA61D2D0-F95A-465A-AB78-78038E79DC47.pngDay 10 has potential 😩😩🤣

The high quality NWP has been trending the wrong way for a few runs now!  Yesterday’s EPS were rather poor and the ECM sub seasonal wasn’t much to write home about. I fear this is going to be a long winter of chasing!  Hopefully we will strike it lucky at some point over the next 3 months!

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I'm so surprised to wake up and see the more amplified charts in the mid term from yesterday's runs gone up in smoke today.....not. Back to waiting it is.

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Yes it's the same old story once a large chunk of the PV builds to our north west. 

Models showing more mobility this morning with any ridging being quickly flattened. 

The jetstream though likely to track further south at times so transient cold shots, like Thursday, will become more likely. 

It seems the best we can expect for now. 

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image.thumb.png.660e5f954ea7f87520cf80378d5e292e.png

There's still a smaller cluster (19/51) showing a more blocked pattern in the longer term, but the bigger +NAO cluster is growing and is now 32/51.

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9 minutes ago, mb018538 said:

image.thumb.png.660e5f954ea7f87520cf80378d5e292e.png

There's still a smaller cluster (19/51) showing a more blocked pattern in the longer term, but the bigger +NAO cluster is growing and is now 32/51.

Think we need to write this episode off now, trend is everything in my view.

Brush ourselves down, rest and hopefully onwards to next installment

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6 minutes ago, TSNWK said:

Think we need to write this episode off now, trend is everything in my view.

Brush ourselves down, rest and hopefully onwards to next installment

I hereby declare Lockdown Meltdown 1.1 to be over!:santa-emoji:

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Some deflated westerlies win again let's write this off posts this morning. Of course it could be that there is a blocking signal amongst the chaos but that yesterdays nwp was a just a bit too progressive with it.  The Meto extended has always been bout things happening in December rather than November. So it could be that the modelling is correcting on timing rather than regime. Just a thought.

Edited by Broadmayne blizzard
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As Mr Hugo has posted this morning, still a fair amount of westerly momentum in the mid latitudes. With that still in play it's hard to get a block to develop. 

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8 hours ago, DiagonalRedLine said:

Hi Zak, I genuinely felt this was a well thought out post that went into great detail. A good job with it! 🙂 

Sums things up well I feel. It does seem it’s a little all over the place at the moment regarding cold weather possibilities. One real possible trend from some of the charts could be to see a ridge of High Pressure get pushed over the UK into early next week, then hang about close by to our East. However, I think it is a bit early to be sure and there is a chance a more encouraging High Latitude Blocking situation could arise. Would help as well to see a stronger signal for some kind of European trough to the South or South-East of us. But could deliver directly over the UK too if the Lows associated with the UK trough had enough cold air wrapped around them. A number of us would love the snow to come and give us a wave. Fortunate that there’s a few months ahead where that could become a prospect. ❄️

we might need it the other way around by January, a Wave to come and give us the snow, a propagating wave in the stratosphere!

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We have Eastern QBO in the lower strat , hoping this, with a developing -AO can produce the goods for Europe and assist sending the jet south....

We absolutely do NOT want trop and strat coupling !!

As it did last Winter ...

Edited by northwestsnow
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39 minutes ago, LRD said:

Not sure what everyone is complaining about. I mentioned yesterday that GFS is probably being a bit progressive in bringing in the cold but that it still might be picking up on the correct signal

GFS ensembles still look good and the op this morning still reflects what the Met Office are saying - settling down, especially in central and SE areas, possible fog, average temps, less settled the further NW you go, etc, etc

image.thumb.png.7f10b933dc56dac580382110afd94586.png

The ECM output isn't as good as it could be, admittedly, and I s'pose that's why everyone has got the right miseries. It seems to me the ECM clusters and EC46 updates change as much as CFS, GFS and every other operational model we see.

Having said all that, there are big Met Office updates today and tomorrow. If they keep on talking about cold, then I ain't ruling it out yet despite what models may or may not show in the coming days. If it starts to back off then fair enough, we might get another December 'heatwave'

image.thumb.png.bf180ef5702b0cfdeee697289563424d.png

 

image.thumb.png.fd42e1050c24f0d4ee03bc2c4697aa15.png

GFS 00z ensembles certainly don't match the Met Office extended outlook. It's trending unsettled rather than trending settled like this morning's update says below:

Saturday 21 Nov - Monday 30 Nov

Spells of rain will spread southwards across England and Wales on Saturday with brighter, showery conditions in Scotland and Northern Ireland. Sunny spells are expected in the south of the UK on Sunday with blustery showers across the north. For the remainder of November conditions will begin to become more widely settled, especially across the south and east where there will be an increased risk of slow clearing fog. Unsettled interludes bringing spells of rain and strong winds are still likely at times, especially in the north and west. Temperatures look to be around average with increasing incidence of overnight frost, as is typical for this time of year, as well as bringing an increasing chance of wintry precipitation

Monday 30 Nov - Monday 14 Dec

Heading into the middle of December, high pressure is likely to become the dominant weather pattern across the UK, bringing settled conditions to many parts. Occasional unsettled periods with outbreaks of rain and strong winds are still likely at times, these most likely to affect northwestern areas of the UK. Temperatures will probably be close to or below average with an increasing chance of wintry precipitation, notably for higher ground in the north

A bit of a stand off developing perhaps!

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35 minutes ago, mb018538 said:

image.thumb.png.fd42e1050c24f0d4ee03bc2c4697aa15.png

GFS 00z ensembles certainly don't match the Met Office extended outlook. It's trending unsettled rather than trending settled like this morning's update says below:

Saturday 21 Nov - Monday 30 Nov

Spells of rain will spread southwards across England and Wales on Saturday with brighter, showery conditions in Scotland and Northern Ireland. Sunny spells are expected in the south of the UK on Sunday with blustery showers across the north. For the remainder of November conditions will begin to become more widely settled, especially across the south and east where there will be an increased risk of slow clearing fog. Unsettled interludes bringing spells of rain and strong winds are still likely at times, especially in the north and west. Temperatures look to be around average with increasing incidence of overnight frost, as is typical for this time of year, as well as bringing an increasing chance of wintry precipitation

Monday 30 Nov - Monday 14 Dec

Heading into the middle of December, high pressure is likely to become the dominant weather pattern across the UK, bringing settled conditions to many parts. Occasional unsettled periods with outbreaks of rain and strong winds are still likely at times, these most likely to affect northwestern areas of the UK. Temperatures will probably be close to or below average with an increasing chance of wintry precipitation, notably for higher ground in the north

A bit of a stand off developing perhaps!

If you only look at London, maybe. But bigger picture, not so much. Most of the members which go for higher pressure on the 00z have it centred either further west or further north, so London isn't really indicative of that. Plus of course, the settled bit in the forecast is prefaced with 'into the middle of December', and the ensembles only go up to the third at this point so would perhaps only be picking up on the very start of that process. 

dec.png

aberdeen.png london.png dublin.png

Regardless, a ton of time between now and the end of the month, and even longer between now and the middle of December, so things are bound to change - both in the forecasts leading up to it and in the outcome. 

 

 

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06z out to around 280. Pretty mobile, hints of NW to SE jet to our west but appears to scoop up milder air over us each time. 

My first attempt hope I got the jist right

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8 minutes ago, TSNWK said:

06z out to around 280. Pretty mobile, hints of NW to SE jet to our west but appears to scoop up milder air over us each time. 

My first attempt hope I got the jist right

Yes, spot on, compare FI charts from 0z to 06z:

gfs-0-330.thumb.png.141a2e6327d1df1d2e0d6cd9e49baa2b.pnggfs-0-324.thumb.png.18a19e0ace7fcc0777ce570cabea64fb.png

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15 minutes ago, TSNWK said:

06z out to around 280. Pretty mobile, hints of NW to SE jet to our west but appears to scoop up milder air over us each time. 

My first attempt hope I got the jist right

It's a very common scenario of a zonal flow - mild and cold alternating as the lows roll through. 6z shows a pretty typical spell of UK autumn/winter weather.

We just end up with our usual problem on the 6z Op run - very cold and very mild air meeting off the eastern seaboard which fires up the jet. PV anchored it it's favoured spot. Big block out to the east though:

image.thumb.png.39d3e575e3dc18f829522d0db69adcac.pngimage.thumb.png.e3d8db5c102da0186ed34a494b8163a0.pngimage.thumb.png.f1715031d94c72d98ff330e0bf386512.png
 

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