Model Output Discussion - Spring Has Sprung

[Lukesluckybunch]

Control 180!

[Don]

Latest Metoffice forecast for my location has gone from max's of 6C for Friday, Saturday and Sunday, to 8C, 8C and 7C in the last hour!  Expect a move towards the GFS from the 00Z UKMO!

[Derecho]

 WeatherArc

Yup, out of all the charts today this frame from the EC at T240 really caught my eye though probably wouldn't verify of course.

If that was over the UK in May the uppers would be reasonably impressive in years gone by but to see a plume that strong in mid-February really is quite something.

Edited February 5 by Derecho

[Jason M]

 Derecho That is very impressive. Would be pretty impressive if we were in April let alone early Feb.

This summer has real potential IMHO. Could be a absolute beast for heat over Southern Europe in particular.

 

[damianslaw]

Oh well tomorrow is another day as they say, will we see more swings in the output run to run or a general coalescence.. I sense another rollercoaster ride on the way predicting Thursday onwards.. buckle in..

[Don]

2 minutes ago, Jason M said:

That is very impressive. Would be pretty impressive if we were in April let alone early Feb.

Are we heading for a mid February heatwave as opposed to a cold spell?  Something similar happened in February 2019 when the LRM's pointed to cold, but ended up being record breaking warm with 70f breached for the first time in winter!

[Derecho]

 Jason M It'll be interesting for sure though I think models are bullish on a return to a La Nina this year. El Nino conditions should quickly decline but its footprint will be slower to filter out of the atmosphere. Sods law means we will probably see a cold April like 1998 or 2016....

Summer forecasting as we all know is even more chaotic but it wouldn't be surprising if we saw another 35C again. Aside from that I reckon we'll get an exceptionally active hurricane season (perhaps record breaking with Tropical SSTs being so high) and a better shot at northern blocking early on next winter.

[Don]

 damianslaw

Lets hope for a better day tomorrow, but I'm not expecting one (in terms of this rollercoaster ride)!

Edited February 5 by Don

[Jason M]

 Don Could easily see that this month.

I'm personally very unconvinced that we will see any meaningful cold spell now. Of course, can't rule it out completely but from the output I'm seeing, it looks like we are headed for a mid lat high rather than northern blocking. I think we will get another high near or over the UK and that will pretty much be that for Feb. A first Spanish Plume of the year as suggested by others is a real possibility. 

Lots of water to pass under the bridge before that though, as for many a good old fashioned soaking looks to be headed our way 

 

 

[markw2680]

Quite often you see let’s say a slider coming in only for it to all of a sudden become a big round thing going north and then few days later the models then latch back onto the slider solution. I’m not saying that’s going to happen but I really wouldn’t be surprised.

no model has won or lost and they never will, they are purely computers giving a prediction of which in the end they will pretty much meet in the middle give or take a little.

lets see what the morning brings but I can pretty much say confidently that this low is not handled correctly just yet

 

[E17boy]

It has been a really bizarre day I am sure many of us are going to sleep with that sinking feeling. This is not a moan post but it’s just to emphasise how strange todays output has been. With eyes up hunting cold this morning to the first warm plume this evening. Just feels now that the dark clouds have covered the horizon that showed some hope. Will tomorrow be another drama?? 

I am exhausted after today

take care all 

[Rain All Night]

13 hours ago, RainAllNight said:

0z deterministic runs, Mon 5th to Mon 12th (day 7)

Hats off to the UKMO and the GFS for their persistence with their respective diametrically opposed solutions, and well done to the ECM for producing a believable middle ground instead of blowing up the low. The situation after the "big low" departs looks like a real mess that's going to take a few more days of runs to clarify.

0z ensemble member 850hPa temps (for Dorset), Mon 5th to Tue 13th (day 8 )

Fairly unanimous agreement that modest cold is coming to the south coast from about the 10th onwards. Note those fabulous wind roses on the ECM meteogram, in conjunction with my comments on the ECM ensemble mean below.

ECM

GFS, UKMO, ECM meteogram (black line shows day 8; note the wind roses)

0z ensemble means, Mon 5th to Tue 20th (day 15)

The ECM ensemble mean is great whether it's dry or cold that you want, with a mean anticyclone showing over the UK and/or Scandinavia for a significant part of the run. The GFS mean isn't as good for cold, with heights stronger over and to the south of the UK but weaker elsewhere. The GEM ensemble lets the mean Atlantic depression reach the southern UK twice, once as soon as our "big low" has departed, and then again right at the end of the run, but builds a similar mean anticyclone to the ECM in between. ECM and GEM both have some mean heights up in the south Greenland/Iceland area at the end of their runs.

12z deterministic runs, Tue 6th to Mon 12th (day 7)

As of this afternoon, the last remaining model showing a flatter and more southerly-tracking low for this week has dropped that solution, so the next question is what the low will do after it reaches us, with ECM and GFS both currently sending it northwards, which would be a disappointing solution if correct; other models show it moving east, northeast, or simply filling in situ over the UK.

By day 7, the charts are again messy as has generally been the case for the past several runs, but one thing that seems to be generally agreed upon is the appearance of the next Atlantic low to the east of Newfoundland. Normally I'd be worried about whether that low might soon be coming to steamroll over us, but the ensemble means I've shown further down this post suggest to me that this is not going to be the case. The GFS currently stands alone with its suggestion of mild southwesterly winds being pushed up by high pressure returning over Iberia.

12z ensemble means, Tue 6th to Tue 20th (day 15)

As mentioned above, it doesn't look like that next Atlantic low is going to make it as far as the UK. A couple of days ago, the build of heights showing on the ensembles looked as though it might become an Atlantic ridge. Then it briefly looked like it might instead be a Scandi high, and now it looks more assuredly like a UK high, with a chance of it subsequently retrogressing to a Greenland high, which I'm sure many here will be hoping for (and without any delay!)

As a fan of dry synoptics, I'm pleased to see that high pressure should be returning for mid-month.

Edited February 6 by RainAllNight

[Daniel*]

Robust signal for retrogression to Greenland we want to see it get closer though.. the winter is over posts do not stack up with highly amplified northern blocking guidance like this.

 

NAO/AO the AO is trending significantly -ve

Edited February 6 by Daniel*

[Jordan S]

Was gonna do an update tomorrow/Wednesday but will just post this instead now, Gfs attempts to move high pressure drifting over us next weekend, towards Scandinavia which is what I would expect given the expected outcome around mid month, although on this run it “fails” very quickly but full on mild southwesterlies across the UK are not likely for next week especially late on even when rogue Gfs runs suddenly suggest so.

That doesn’t mean it’s wrong ofcourse, just highly unlikely at the moment in my view, I understand I’m in the minority now suggesting this.

 

There is still a higher chance than not for colder and blocked synoptics to our northwest/east to favour uk cold eventually next week, but it really now comes to exact days being pushed back slightly to 14-15th onwards. With less cold conditions possibly having an influence on Monday and Tuesday in the south and southwest. You have heights generally transferring towards our north/northwest afterwards. 

It has to be said, cold air enough to produce snow on southern hills and lower ground in central areas in any showers during the weekend is now very unlikely with low pressure and milder air in the south more influential than previously thought.
 

For the middle part of next week still looks potentially cold enough for snow for a few but it doesn’t look as unstable especially over northern areas next week as originally thought for now, neither quite as cold, some places may indeed start the week dry with the threat of milder temperatures in the far southwest on Monday. Also in regards to where high pressure sits ie Scandinavia or Greenland.. and what I hinted at just above thi part of the post, pressure now looks more likely towards Greenland than over Scandinavia later next week, this would allow wetter conditions into the south with increased battleground scenario snowfall in central area’s slightly after mid month, but the depth of cold open to some question this far out as expected especially with the initial delay in colder conditions.

In the short term rain potentially causing flooding problems in the south with heavy and persistent rain periodically from late tomorrow to Friday, possibly over 2 inches for some and snow causing temporary problems in northern parts of wales, north England, then high parts of Northern Ireland and parts of Scotland with maximums of 20-30cm likely on the highest grounds in worst effected parts rather repeated from previous outlook for the Thursday snow I know.

Goodnight all and enjoy whatever snow you get further north on Thursday/Friday.

Will do another lengthy update on Thursday evening.

[Geordiesnow]

 Derecho

The chart you posted of course won't verify like that but as with the recent plume which bought the record breaking January temperature over Scotland, it's a warning sign that it's possible and as others alluded too, goodness knows what sort of temperatures we are going too see in the northern hemisphere this summer, going to be interesting for sure, whether the UK will benefit in any of that heat is of course a totally different matter. If the drought across Spain continues then a strong heat dome developing there looks almost certain. 

I think today's runs shows if something is wrong on the early part of the run you can scrap the rest of the run and also shows unless there is agreement across the board then nothing is guaranteed.

Let's hope the lows can be a bit more "squashed" so somewhere in the UK can get a major snow event. Southern and the central belt of Scotland looks the most likely for this to happen.

 

[WeatherArc]

 Derecho Didn't realise apparently one of the 12z GFS ensembles agreed with the euro, uppers aren't as warm but 15 degree 850s in Feb is impressive. Proper plume as well, coming straight up from Africa. 

 

[Battleground Snow]

Still a big difference in where the snow boundary sets up looking at ECM v gfs for Thursday.

Also the low blowing up less at 90, models really struggling to resolve this situation at such a short timescale 

[Daniel*]

1 hour ago, Geordiesnow said:

chart you posted of course won't verify like that but as with the recent plume which bought the record breaking January temperature over Scotland

The affected areas of NW Scotland were under 6-8C 850hPa temps which were far from record levels, they were much warmer further SE winds were coming up from tropical Atlantic, record warm SSTs it’s likely this played a major role and very strong winds were observed allowing for significant foehn warming. 

[feb1991blizzard]

Icon 0z is hideous.

[Daniel*]

GFS back with E’ly and height rises to NE into early next week, UK cold pool developing still possible in mid February. The NWP is having a nightmare. 

[Lukesluckybunch]

Pretty dire output this morning..ukmo average at best..gfs decides to develop a pretty week easterly at day 7/8..but there's a real lack of cold with in it!

[feb1991blizzard]

 Lukesluckybunch

GEFS are an improvement but come with a big red warning for accuracy, have you ever seen a 12c 850mb temp spread at Day 2.5 before?

[frosty ground]

The GFS is now a colder run at the surface than the UKM with temps surprised to 1 or 2 above freezing.

quite a few changes like obvious outlier of a plume on the 18z has now vanished. No wintry wonderland so simple one lines only 

[frosty ground]

Just look at the spread in the ensembles for this week as @Weather-history points out in the NE regional.

Nothing is settled yet

[Ali1977]

Upgrade from Arpege, and snow line back south 

 

UKV also south again and it doesn’t send the system north introducing the warm air, midlands primed 

Edited February 6 by Ali1977