Interesting that GFS is MUCH colder for Thursday than ICON, ECM, UKMO etc... opening the door to much more of a northerly blast.

Been a crazy winter of uncertainty at relatively short timescales, nevermind extended or FI lol!

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I wonder if the Tonga eruption pressure wave will mean a change in the model output.

Just notice the GFS Ensemble 850 uppers are trending colder at day 5/6 (makes a change!) Notice a dip in the upper air temperatures. For instance focus on midday on 20th January 12pm:

Starting from this mornings 06z run: - ENS mean of -2.1c

 

This evenings 12z run - ENS mean of -4.0c:

 

Tonight's 18z run: - ENS Mean of -6.4c 

On tonight's 18z there isn't one Ensemble run reaching 850hpa long term mean let alone going above it.

Is something colder brewing in the medium range or am I being too optimistic? ENS rarely trend colder in winter so perhaps we could be in for a surprise but not holding my breath after all the let downs so far this winter esp in December over Christmas time when many models were showing an easterly with snow a few days before and then that record breaking warm NYE/NYD.

What is certain is that some of the runs - esp the Operational are taking the HP further west each run allowing colder air masses in from the north and east...! BUT will this trend continue? Fingers crossed!?

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Aftera slight rightwards shift the Alaskan high reasserts itself.This high somehow has a satellite high which is over the UK. 

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Wx summary temps much as yesterday with the 0C isotherm advanced over Scandinavia and the Alps, less cold in between; and in same position in week 2 though the cold areas getting colder. PPtn on Norwefian coast and also advancing N to the Alps in week 2, dry or very dry for UK

Jet looping N of Britain, sometimes the return leg brings a stronger flow down the N Sea (Thu 20th, Tue 25th, Sun 30th)

GFS op co-ordinates well with the jet; the HP is either over the UK or on the dates above moving a little E-wards with a N-ly plunge fringing the E coast

GEFS also shows dips to cold on 20th and 25th/26th but the ensemble is too scrambled after that to be certain (mean still cool but op & control milder than the mean). Remaining very dry.

ECM still showing yesterday's charts at time of posting. GEM similar to GFS at first but going full-on zonal from Mon 24th

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I wonder if the Tonga eruption pressure wave will mean a change in the model output.

Without a significant literature search if there is indeed any data on the subject, I’d think a sonic pressure wave from an eruption would have as much effect on global weather patterns as a fart would on the ice on your windscreen. Would love to be wrong though 😉 (more conventional methods of clearing screen ice are available)

The dust and ash on the other hand is a completely different story.

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I wonder if the Tonga eruption pressure wave will mean a change in the model output.

yes it has changed our massive Siberian high into a warm pulse from Spain meaning an early spring!! Well that would be the luck 

Still similar patterns today . Not much change on the 06z

HP to remain strongly attached to the UK

I think frost will be possible looking at the 2m charts

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I wonder if the Tonga eruption pressure wave will mean a change in the model output.

There may be some dimming if the ash cloud gets high enough, being in the southern hemisphere they may see colder winter approaching.
It depends how long it goes on for.

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What are the Daily Mirror writers on about? 

UK weather: Sub zero freeze to last all week with -1C chill before snow plume hits

 

I don't see any signs of a sub zero freeze?

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What are the Daily Mirror writers on about? 

UK weather: Sub zero freeze to last all week with -1C chill before snow plume hits

 

I don't see any signs of a sub zero freeze?

The Express weather foracsters must be on loan 

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I wonder if the Tonga eruption pressure wave will mean a change in the model output.

 

Waves travel 'though' a substance.  They do not push it permananently to a new place, so not sure how that will change anything.

As for the ash. I will not effect weather at this latitude, if at all, for a long time.  It could take months for it to reach our latitude.

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Without a significant literature search if there is indeed any data on the subject, I’d think a sonic pressure wave from an eruption would have as much effect on global weather patterns as a fart would on the ice on your windscreen. Would love to be wrong though 😉 (more conventional methods of clearing screen ice are available)

The dust and ash on the other hand is a completely different story.

Posted this on the Tonga Pressure wave topic, but think it bears posting here as well. Here is the LAST recorded METAR from the Tonga international airport NFTF 150505Z 31009KT 9999 TS FEW009 SCT016CB 28/26 Q1008 RMK VA CLD OVER TBU,RAIN ROCK I have never seen Rain Rock reported before.. I assume it is rain with volcanic ash raining out. Frightning.

 

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Louise Lear suggesting another 6 days of High Pressure before becoming mobile, wet and windy from west in ‘invigorated jetstream’. Nice.

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Louise Lear suggesting another 6 days of High Pressure before becoming mobile, wet and windy from west in ‘invigorated jetstream’. Nice.

Where is she getting that from then - I don't see a 168h chart that has the Atlantic at us 

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As you quote, anything after T120 is really just for fun. Maybe she is as bored with the weather as I am!!

 

Where is she getting that from then - I don't see a 168h chart that has the Atlantic at us 

Good model support for HP to be over or near the UK past t168

 

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Visited the archives of 1895...to see how readily and quick a peach of an easterly set up.Tbh the high just west of UK was very similar to now.What was different was the lows weren't glancing but pushing cold air into  East France central Europe instead of East Balkans Ukraine.We really need low pressure nearer to the UK in whatever form to also bring the Siberian high into play  and things could very  quickly change.Thats my hope.

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Where is she getting that from then - I don't see a 168h chart that has the Atlantic at us 

Meteireann has a similar forecast saying that the High Pressure will slip to the South East bringing in more unsettled conditions. I agree that this doesn't seem to be supported by the charts to my eyes at least.

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Where is she getting that from then - I don't see a 168h chart that has the Atlantic at us 

I was just thinking that too. While Louise is obviously a well trained and accomplished long-time meteorologist with all the technology and knowledge at her disposal, from where I'm sitting I'm not seeing a crashing return to Atlantic zonality just yet but more of the same high pressure set up for a good week or so - which in itself is pretty remarkable for mid/late January. Obviously she is seeing something that we are not, so I'm sure it'll come out in the wash soon.

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