Daniel*

My idea of heaven

Extreme snowfall in southern Norway. 1m of snow!

The cold signal is really rather strong in extended taking Birmingham for Jan 16th mean has 2C max and -3C min that’s subzero daily mean signalled 2 weeks from now. It is really rare to see that given the lead. Notice also for date not a single run of 50 even reaching average. It’s a very solid cold signal.

Stay calm down Daniel… these are some of most exciting guidance I’ve seen since 2018, and to think it’s lining up for heart of winter. The potential for impactful wintry weather is increasing further into January.

Good upgrades this afternoon with initial easterly we are seeing more a cut off high to north this is likely linked to better capture of MJO forcing and it helps with a weakening zonal wind. So we are seeing much better CAA, which entertains greater snow shower risk in E/SE possibly even streamer potential for some lucky folks. I posted verification stats and it seemed to fall on deaf ears, there has been a major slump in model performance at day 5. I’m not sure what’s more fickle the model or the model watcher.

Speaking of the devil plotted annual rainfall data for Heathrow 1973-2023 it’s clear the climate is becoming wetter. 2023 finished with 770mm it is fourth wettest year and 4 of the top 5 wettest years were set in 21st century. The 770mm is 125% of 615mm annual 1991-2020 average. The last <500mm year was in 2005 now 19 years ago this very dry threshold used to be much more common decades ago. 2010-11 was rather dry but it has been over a decade now, it’s intriguing what future will bring personally I think this wetter trend is likely to be maintained.

Expecting to see some great charts to come out by the end of this week…. the direction is definitely Arctic winds. Personally I’d prefer easterlies, but we can be bullish colder weather is here to stay and likely the best is yet to come.

To illustrate day 11 on EPS 00z and latest 12z notice how similar they are and blocking near Greenland is even stronger.

Things all appear to be holding very steady viewing latest EPS consistency is pleasing to see.

I’m not really following you, this is trouble with over analysing singular det runs it skews the actual indication from model output . The GEFS are also coldest they’ve ever been in initial easterly attempt down to -8.2C on London on Monday, so rather the cold is upgrading while it will be dry for most. In terms of snow showers realistically this has only really favoured eastern and southeastern England and nothing significant there is still flexibility for these areas I feel whether more dry or not. I don’t know what you were expecting in south of Ireland but it was a foolish hope. I’d say we are in as good position as we can be for the start of January, sea surface temperatures will fall reducing CAA modification, ground temperatures will fall, it has been very mild in recent weeks. Today, 13.7C in Heathrow a spring value. Some areas are currently flooding so the opportunity to dry out is fantastic ans urgently needed, and well no snow will settle on flooded fields.

Even as recent as December 2022, I believe we had good ensemble agreement at day 10. Occasionally it ticks down nicely without much drama the forcing needs to be strong in such instances.

Not the most exciting run from ECMWF but look at polar field an indication normal base state +AO is very far away. I also like that fact that trop vortex is further west in Canada away from Greenland removing a possible obstacle.

Typically we would dismiss something like GFS 12z but it’s strongly in envelope if this is a mean...

Think big improvement is over egging it a bit! Let’s see the next few frames though.

Some very strong gusts of wind here in Docklands, worse than most of these hyped named storms.

t+78 newest on right ridge seems a little more vertical and shallower Atlantic low engaging with high, think this could be good.

GFS is an upgrade it develops a very cold easterly flow into Western Europe, follow the isobars we are getting a pure cold feed from very frozen snowfields of Russia. This was not seen on 18z on right it was coming from Caucasus.

Have a feeling the modelling reverting back well we’re seeing more a “partial split” to vortex is helping if we look at 50mb on ECM 12z we can clearly see a dividing line over Greenland and pole, one segment goes to west of Greenland in Canada ideally it would be further away but it’s not immediately troublesome and another near Kara sea which helps with cold air availability in Eurasia. The blocking in North Atlantic is mostly undisturbed it’s a little wonder the projection is for prolonged -NAO conditions. indeed the 12z EPS has the -NAO going strongly negative near mid month… it all makes for a terrific period of model watching.

I am impressed. 2m temp anomaly to 16th Jan, it seems the cold tap has been unleashed on our part of hemisphere. If you’re going for a milder than average January, well I’d be alarmed. Current indicators are most promising since 2013 I’d say.

Wow the extended….. that is Goldilocks zone. I’m seeing connections recall met office and their extended written outlook: “While there is a chance of brief, unsettled spells, which would bring milder air for a time, it would likely also be accompanied by a period of sleet or snow.”

The uppers don’t tell the whole story if you look at 2m temperatures you will see there is no real recovery still below average. Colder than average dominates but of course increasing scatter as it goes on. No real mild runs really or very slim pickings which is unusual.

I’d say now we’re looking at now more a Scotland based high than a UK high of course it is still generally dry but the trend definitely has been to move that further north. Will be interesting if these corrections continue… especially for southeast.

The means are posted

EPS 168hrs… clearly the op is further north with ridge and less supported. it’s an improvement on 00z gained more height so we can work on this…

This is why you need to give more faith to background signals. Things are looking rather promising tonight, possibly a step change afoot. Of course UKMO 12z backed down but we know this model is more inconsistent at its later stages, recent runs prior were much closer this cut off high lat block, GFS continues to play catch up albeit very slowly….