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

[WYorksWeather]

26 minutes ago, Don said:

Would be extraordinary, but wouldn't surprise me in this day and age if it did come off.  However, I hope this does not verify!   What were the 850hPa temperatures during the record breaking warm spell in February 2019?  

Something similar happened 20 years ago at the end of January 2004 when we had that Arctic blast, followed by record breaking warm temps the following week in early February.

Only around 11C (this is the highest 850s I could find from that spell).

I remember speaking to someone on here before Christmas when similar charts came up in the ensembles, but didn't verify, and the highest ever recorded 850s in winter are below 14C. I think the record was somewhere around 12-13C.

A 14C 850hPa in late February under the same conditions I'm guessing would support 23C, or 24C. In this situation though, in late January, it'd be quite a lot lower, but I do think that if all the other building blocks fell into place, it might get us to 19C or 20C, but that's probably unlikely and would require the surface pattern to be perfect as well. I'd be astonished if it didn't deliver at least 15-17C though even without the perfect setup.

[alexisj9]

2 hours ago, The Enforcer said:

You must be joking. Even when conditions favour snow and there is precipitation about, check the yellow circle (December 2022):

Missed me again I see lol

[alexisj9]

2 hours ago, WYorksWeather said:

Has to be said that once again we're now seeing some absurd, probably near record-breaking, mild ensemble members. Not what we want to see, but still interesting to me as someone who keeps an eye on all things records!

This ensemble member gets the 850hPa temperatures to 14C in the far SE corner. Absolutely extraordinary. Perhaps more remarkable is that it isn't the only one, there is a mini cluster of about 10% of the ensemble that supports this idea.

Still unlikely to verify, but worth keeping an eye on.

What's the 2m temps, as that looks like a high, might be freezing at ground level, or might not, all depends on cloud amounts. Freezing fog lasting all day is possible if it's slack under that, if it's windy could be warmer however.

[MattStoke]

Big jump northward of Wednesday’s front on the GFS.

 

Edited January 14 by MattStoke

[Richard Fisher]

25 minutes ago, MattStoke said:

Big jump northward of Wednesday’s front on the GFS.

 

GET IN!. This is more like it.  Let's see whether ECM starts backtracking and pushes it further North. Fun and games back on. I'm still going for 15cm plus for the South with no substantial breakdown next weekend.

 

 

 

[nick sussex]

Utterly nerve-shredding for those in the south and far se with the GFS op and ensemble mean taking the precip further north . 

The UKMO looks totally disinterested judging by the T72 to T96 hr frames .

The ICON still interested . The GEM less interested than yesterday .

A bit frustrating as last nights ECM 18 hrs run still missed but had taken the precip further north so that looked like a more positive trend .

If you’re in the risk area you need the ECM to jump on board this morning and hope the UKMO has got this wrong .

Later the Atlantic looks like moving in around late Friday so make the best of the colder conditions before the mild rainy muck arrIves.

Lets hope this is just a short spell of milder weather .

[Kasim Awan]

WRF and ICON really going for it.

[Ben Sainsbury]

ARPEGE completely avoids the south coast at all with regards to the same system. Still a mixed bag! 

[Kasim Awan]

1 minute ago, Ben Sainsbury said:

ARPEGE completely avoids the south coast at all with regards to the same system. Still a mixed bag! 

For me icon / wrf are better for positioning of troughs. However it is still 5050.

[lassie23]

1 minute ago, Ben Sainsbury said:

ARPEGE completely avoids the south coast at all with regards to the same system. Still a mixed bag! 

Probably still won't be clear where Wednesday's feature is going come Thursday at this rate

[Richard Fisher]

GFS always trumps ECM.

 

[Ben Sainsbury]

Huge shift in the GEFS 00z this morning for my particular location (also representative for those south of M4). 50% of ensemble members now have snow reaching the Bristol area vs a quarter of the members at 18z. 

If we take London, we've also doubled the percentage chance from 28% to 56%. A big EC run coming up.

[Kasim Awan]

3 minutes ago, Ben Sainsbury said:

Huge shift in the GEFS 00z this morning for my particular location (also representative for those south of M4). 50% of ensemble members now have snow reaching the Bristol area vs a quarter of the members at 18z. 

If we take London, we've also doubled the percentage chance from 28% to 56%. A big EC run coming up.

Balance for me is roughly 65/35 in favour of a snow event upto the M4 corridor based on past events and latitude placement often following GFS/WRF/ICON more closely than others. ECM for me less important as it isn't great for placement. Consistency from the 06Z GFS/WRF/ICON more important for me, we can get the others onboard tomorrow.

Edited January 14 by Kasim Awan

[JimBob]

54 minutes ago, Richard Fisher said:

GET IN!. This is more like it.  Let's see whether ECM starts backtracking and pushes it further North. Fun and games back on. I'm still going for 15cm plus for the South with no substantial breakdown next weekend.

 

 

 

This is the model watching thread not make up your own forecast! 

[nick sussex]

Even if the other models jump on board today with the precip going further north that’s not the end of the story .

Theres still 72 hrs where things could still change . 

These set ups are a complete nightmare to forecast !

[JimBob]

Still looking like a cold and snowless spell for most people in the week ahead, but look at the temperatures starting to show for next week! Would feel “spring like” in any sunshine and no sign of the wintery weather returning soon. 

Edited January 14 by JimBob

[northwestsnow]

Fingers crossed for the southern crew if anyone deserves a 12 hour blizzard its you guys and girls..

GFS says yes !!

[nick sussex]

The ECM at T72 hrs has a more oval shaped low and slightly further north  than the UKMO which is flatter .

 

Edited January 14 by nick sussex

[Kasim Awan]

ECM is somewhere between the GFS and Arpege - however it has moved around 150 miles North from yesterday's runs.

[Justin1705]

Much further north for the snow in the south! Got to be honest I’d rather this setup than it being marginal AF ! At least this way we know if it does push into  south England it will fall as snow. Rather than the low being placed on the south coast giving a slush fest for all! Can someone tell me if the models pushed the low further south due to the potential low on Tuesday in northern areas? So if this low on Tuesday doesn’t push as far south as they predict, would this in turn allow the front to push further north in the south? 

[Ali1977]

The GFS MEAN has snow to the midlands on Wed, this is mental. I think more moves north are on the cards now 

 

A few examples, and there are plenty more 

Edited January 14 by Ali1977

[That ECM]

23 minutes ago, Ali1977 said:

The GFS MEAN has snow to the midlands on Wed, this is mental. I think more moves north are on the cards now 

 

A few examples, and there are plenty more 

I hope you are right. For balance, ecm and met current thinking. All subject to change of course.  The north south swings should start to reduce through the day but this could go to the wire if ecm trends further north this evening. Current fax charts have it south of us imo. 
 

As per Kasim my percentage would be 10/90 on hitting. I wouldn’t trust gfs to hand tickets out on a bus.

 

Edited January 14 by That ECM

[Nick2373]

00z pretty much sums up the next few days, colder with a slight feature pushing in Wednesday nothing special perhaps a snow shower if lucky this ties in with the Met and BBC for the South then something more wet and windy from the 21st to 24th then looks to be settling back down  26th onward. the feature for Wednesday looks to be more in favour of a French visit. 

[That ECM]

For those further north I’d be looking at these with some interest.

[TillyS]

Not a lot in the way of snow down south this week unless you believe the GFS which is presumably everyone’s friend now  But some very cold nights showing on the models. I don’t know if the GFS is influenced by its idea of snow cover? As you will doubtless know, this morning’s GFS 0z has the advancing front pushing into southern England. Anyway, deeply cold nights Thursday and Friday ahead of the returning Atlantic: 

I imagine that without any lying snow the temps won’t fall this low in southern Britain?