[January 2024 CET and E.W.P. forecast contests]

21 hours ago, Daniel* said:

Comfortably subzero yes, we should be -2 to -2.5C for the daily mean. Using GFS, you are bound to underestimate the very cold nights in particular.

Rothamstad 1.8C high -5.1C low = -1.65

Pershore 4C high -9.7c Low = -2.85

Stonyhurst estimating using local station 1c high -7C low = -3C

I think we could drop 0.4C... taking us to 3.2C if not likely 3.3C for todays values.

 

[Model Output Discussion - Cold spell ending - what next?]

6 hours ago, AO- said:

Agree, but I think you misunderstood me. There are no-15/-20s  in the northeast. I'm affraid the cold will 'dissolve' with the sun getting more power. 

March is coldest month of year in Arctic areas 1991-2020, above UK/northern Europe there’s still plenty of time for a notable cold blast. 

[Model Output Discussion - Cold spell ending - what next?]

Now this is much more like it from GFS 00z… old school Scandi high, feels predictable what would follow. Growing idea of pattern change from 28th onwards with the risk of much colder weather coming from the east in the days after. 

[Minimum Temperature Watch 2023-2024 season]

36 minutes ago, cheese said:

Might also be because these low temps are usually very isolated to the usual frost hollows, the rest of us will have comparatively unremarkable temperatures.

I think these temperatures need context. Kew Gardens had -7.5C Thursday morning, Bushy Park -7.9C noteworthy for without snow cover. -8C Birmingham Airport ect. Quite a few had coldest January night since 2010.

[Model Output Discussion - Cold spell ending - what next?]

Heathrow 12z EPS

 

12z EPS yesterday 

[Model Output Discussion - Cold spell ending - what next?]

37 minutes ago, Drifter said:

Many scandi highs of the past occurred during +ve NAO phase. 

Aye, I’ve always thought Feb 91 beasterly was one of greatest examples.

[Model Output Discussion - Cold spell ending - what next?]

38 minutes ago, mountain shadow said:

Not all all. 

The reason most of us are weather geeks is the chasing down of rare and unusual weather synoptics.

Scandi Highs in Winter are uncommon and therefore much more interesting than the usual Iceland low and Iberian High.

They’re typically more common later in winter that’s my experience, so it sort of follows climatology, getting one in December which can produce is very uncommon, things tend to settle down more later in winter with high pressure more influential. February is third driest month in London, interestingly on 1981-2010 climatology February was driest month of year. A reflection of how our winters have changed, February particularly has changed similarly December, in contrast to January which has been more static in last 20 years. 2024 likely adding to that. 

[January 2024 CET and E.W.P. forecast contests]

2 hours ago, kold weather said:

Should be comfortably subzero today.

Could well have a CET near 2.5c by 20th (probably between 2.5-3c)  , which would require probably the most exceptional mild spell ever seen in January to get upto 6c+.

With that being said, we are going to have some very mild days coming up so we should still end up comfortably above the 61-90 mean. The 91-20 mean will be tighter if the GFS is correct with a more average final few days,

Comfortably subzero yes, we should be -2 to -2.5C for the daily mean. Using GFS, you are bound to underestimate the very cold nights in particular.

Rothamstad 1.8C high -5.1C low = -1.65

Pershore 4C high -9.7c Low = -2.85

Stonyhurst estimating using local station 1c high -7C low = -3C

I think we could drop 0.4C... taking us to 3.2C if not likely 3.3C for todays values.

[Model Output Discussion - Cold spell ending - what next?]

2 hours ago, TEITS said:

Brilliant post as you have summed this up perfectly.

On a different topic I note some are being a little OTT with regards to next weeks mild weather. Just using the GFS only one day does my location reach a max temp of 13C. The other days for next week is around 8/9C. So just above average and nothing exceptional. What is noticeable next week is just how wet and windy it shall be although thankfully the low pressure on Wednesday should be the last one for a considerable time.

In summary after the wild weather this sunday and early next week the next destination is fairly clear to me. However the route it takes and how long the journey will be is up for debate. If members thought the recent chase was stressful they ain't seen anything yet.

Hi TEITS, nice to see you’re still around   I agree with you, using Birmingham based on ECM 00z fairly representative of CET zone yes notably mild this Sunday into early next week, but afterwards not especially so, perhaps frost and fog could become a feature in the second half of the week. I think there are too many who see oranges and the southerly flows from continent and assume it’s mild/v mild the thing is it’s midwinter, definitely later in February you can see that as seen in 2019, but we’re still in that core part of winter. 

[January 2024 CET and E.W.P. forecast contests]

Expect a notably low daily mean for today. Pershore -9.7C for example, I can’t see high climbing much above freezing.  

[Model Output Discussion - Colder but how cold and for how long?]

GFS 12z reverts back to significant amplification to NE advancing to pole. It would be very curious what would manifest in weeks after.

[Model Output Discussion - Colder but how cold and for how long?]

Newest to oldest for 12z 25th still a very mild position but the base seems to be gaining more height. If these trends continue SE parts especially will start seeing cooler flows from near continent.

[SE, London and East Anglia Weather Discussion - Dec 2023 on]

Hmm… spells of heavier snow for far south? Maybe a surprise is coming…..

…

[Model Output Discussion - Colder but how cold and for how long?]

Rising momentum might not be as outlandish as you think noticeable also met office talking about higher risk of cold easterly winds in Feb clearly that infers Scandinavian blocking. GFS 12z might be onto something…

[UK winters: are they getting colder?]

January is one of the exceptions of winter months, temperature trends in London in last 30 years has been quite static.

[Model discussion highlights]

It’s not pretty viewing but I wonder with rising AAM tendency a currently modelled very mild Euro high turns more into a mid latitude block which allows for more chance of frost and fog especially further south. With AAM looking to rise more empathically in Feb this could then become high lat based. Some stormier weather to come but generally I’d say high pressure looks more likely to rule for quite sometime.

Original post: https://community.netweather.tv/topic/99760-model-output-discussion-colder-but-how-cold-and-for-how-long/?do=findComment&comment=5015043

[Model Output Discussion - Colder but how cold and for how long?]

It’s not pretty viewing but I wonder with rising AAM tendency a currently modelled very mild Euro high turns more into a mid latitude block which allows for more chance of frost and fog especially further south. With AAM looking to rise more empathically in Feb this could then become high lat based. Some stormier weather to come but generally I’d say high pressure looks more likely to rule for quite sometime.

[UK winters: are they getting colder?]

Colder on awful mid 2010s perhaps that was characterised when cool by cold zonal and we do awful for that down here, here in London I’ve noticed more cold spells in recent years with colder night temperatures, definitely more northerly winds, while snow has been generally lacking it is a slight improvement on very low baseline. 

[Model Output Discussion - Colder but how cold and for how long?]

2 minutes ago, Man With Beard said:

Oh, remember that snow area for the south on Wednesday? Well, the ECM ensembles finally dropped it tonight - only about 10% of members good for a covering in the far south, down from 35% last night.

Well the good news keeps coming I did though notice ECM 12z brought some showery activity ashore into SE/EA later on Wednesday the GFS also did this too. New development, perhaps a little snow.

it feels bad to do this with 2 weeks of January remaining but it would probably be sensible to write off the rest of month. Bartlett goes around a lot often wrongly but EPS is very much giving that in late Jan.

[Model Output Discussion - Colder but how cold and for how long?]

It feels a bit premature talking about daily warm records. It might not even be outrageously mild further north taking Glasgow on EPS for example yes comfortably above average nothing exceptional though signalled. 

Further south here for London there is a fairly strong signal for very mild weather in teens early next week there are some suggestions of something closer to normal by end of January, not convinced we are looking at a 2+ week v mild spell.

[Model Output Discussion - Colder but how cold and for how long?]

Doing a better job of thrawting Atlantic but I don’t think it’s going to be enough. Friday looks very cold for most under cold high. Could be some very low minima.

 

[Model Output Discussion - Colder but how cold and for how long?]

Latest GFS making more of a shallow high to our west moving east, which sharpens the cold flow on Thursday interesting changes in short term.

[Model Output Discussion - Colder but how cold and for how long?]

Ironically the rapidly collapsing blocking might be a good thing in terms of snow risk in southern England on Wednesday, see how deeply low heights is to our N/NE, if this was high pressure it would be a guarantee the system would be deflected south and snow would go into France altogether.

[Model Output Discussion - Colder but how cold and for how long?]

It’s not a new revelation I posted EPS a week ago and I did not like the direction it was going, backing away from an extended period of cold weather, a few didn’t like it, weakening the Greenland blocking relatively quickly with strong signal for return of +NAO after 18th, ultimately it is turning out like this. This is not I told you so, just that it is really quite unusual to have EPS make a big flip even in longer range. I do not see it often.

12z EPS NAO on 6th Jan 

 

And now.. the +NAO signal has only strengthened so clearly some more mobile weather is unfortunately coming, it still could be quite cool for northern areas with hill snow. Some suggestion though of late January for NAO returning to neutral with perhaps next opportunity surfacing into early February. 

 

We also see the AO doing a similar thing…

 

In conclusion the less cold/milder weather should be temporary as we see according to Tamara’s musings and reinforced by GLOSEA, likely the best is yet to come, and that could well be in month of February (again!). Seasonal models always painted the late winter period as having the greatest shot of deep cold, and extensive high lat blocking. 

[Model Output Discussion - Colder but how cold and for how long?]

18 minutes ago, Mcconnor8 said:

ECM 18z to +90 looks slightly improved on the 12z similar to GFS/ICON improvements. Slightly colder Northerly with slightly better Greenland heights. 

 

Agreement now for -12C isotherm into northern Scotland on Monday, which is notably cold. There’s going to be some serious building up areas of northern Scotland next week, very low 500hPa temps too signs of real Arctic blast… accumulations exceeding 15-30cm wouldn’t stun me. And not purely a hill thing, I suppose coastal areas too. Early warnings for snow and ice would be justified IMO.