Model output discussion 10/02/21

[minus10]

not what you want to see in spring ....will be gone on the pub run..

[Guest]

7 minutes ago, minus10 said:

not what you want to see in spring ....will be gone on the pub run..

Big old 180 flip from this morning and big old crash through the Easter weekend. Still plenty of time for those colder runs to do one over Easter however the Ops run wasn’t even the worst on the 12z ensemble suite. 

[minus10]

Mmmm.....

[damianslaw]

Bit of a shake up on the cards after a week or more of anticyclonic conditions ruling the roost, low pressure about to gain the upper hand for the week as a whole. Becoming more unsettled more so in the north and west, patchy rain moving across the UK tomorrow, and a cold front sweeping through Thursday will be followed by colder polar air, showery and windy, with wintry precipitation higher ground in the north. The weekend currently forecast rather cool and cloudy but probably drying out.

As we end the month and enter April, models want to build high pressure out to our west, where it will end up - if it does, will determine the easter period. We need a good few days yet to begin to call how things may pan out, at this stage lots of possible options, something warmer and dry, colder and dry, colder and showery or just average.. 

[Frosty.]

According to the GEFS 12z there is plenty of support for high pressure during Easter ...however, the position / orientation of the high would make a big difference to how it would feel at the surface, ideally the high would become centred over the u k or just to the east...but...anyway, on the face of it, the mean looks settled for the all important long holiday weekend as things stand..fingers crossed for a favourable outcome!  

[Sunny76]

3 hours ago, Scorcher said:

April 2018 wasn't special for warmth either. I think people's views of that month are skewed by that remarkable hot spell mid-month. Other than that rather brief spell, it was mostly cool and had a cool final week.

May was a wonderful month but I recall it starting cool before warming up at the end of the first week. We barely looked back from then until the end of July- it was warm to hot almost all the way through.

That’s right, it actually took time for things to warm up properly in spring 2018, bar the odd warm day here and there. 
 

I was working outside in April 2018, and had to cancel a paint job because it was too cold, temps were struggling to reach 8-10c during the second or third weekend. 
 

Like you say, the warmth arrived towards the last week of April, and continued into May, when things started to become much warmer, and then quite hot. We had some severe storms in the London area around the evening of May 26th, a Saturday night. And some more storms broke out during the bank holiday Monday and into the midweek that followed. 
 

Apart from the odd thundery spell, it was consistently warm or hot and sunny all the way until mid august. 
 

By far a better set up compared to 2020, which produced a much better April and very warm and sunny May, early and late June, but the summer was a slight let down. 

[Man With Beard]

Not sure the coming cooler weekend is that worthy of being called a "return to winter", I'd expect the south to hold onto double figures throughout, and then high teens / possibly 20C by early next week:

[LetItSnow!]

7 minutes ago, Sunny76 said:

That’s right, it actually took time for things to warm up properly in spring 2018, bar the odd warm day here and there. 
 

I was working outside in April 2018, and had to cancel a paint job because it was too cold, temps were struggling to reach 8-10c during the second or third weekend. 
 

Like you say, the warmth arrived towards the last week of April, and continued into May, when things started to become much warmer, and then quite hot. We had some severe storms in the London area around the evening of May 26th, a Saturday night. And some more storms broke out during the bank holiday Monday and into the midweek that followed. 
 

Apart from the odd thundery spell, it was consistently warm or hot and sunny all the way until mid august. 
 

By far a better set up compared to 2020, which produced a much better April and very warm and sunny May, early and late June, but the summer was a slight let down. 

Without meaning to derail the conversation, a quick addition was that Apr. 2018 was also horrifically dull in the first half of the month. I remember a period from about Mar. 22 to just slightly before the heatwave where there were barely any sunny days with seemingly endless dull & dreary cold days, but that kept minima up so overall it was a very mild April in the C.E.T., but only really warm from the 17th to the 23rd. After that I remember cool and showery weather returning with an exceptionally cold and dull spell with about 24 hours of rain on the 29th/30th.

 

End of my derailing  

[Sunny76]

52 minutes ago, Man Without Beard said:

Not sure the coming cooler weekend is that worthy of being called a "return to winter", I'd expect the south to hold onto double figures throughout, and then high teens / possibly 20C by early next week:

I don’t want any more cold weather now. Would like some warmer sunnier days with the odd bit of rain mixed in.

[Sunny76]

51 minutes ago, LetItSnow! said:

Without meaning to derail the conversation, a quick addition was that Apr. 2018 was also horrifically dull in the first half of the month. I remember a period from about Mar. 22 to just slightly before the heatwave where there were barely any sunny days with seemingly endless dull & dreary cold days, but that kept minima up so overall it was a very mild April in the C.E.T., but only really warm from the 17th to the 23rd. After that I remember cool and showery weather returning with an exceptionally cold and dull spell with about 24 hours of rain on the 29th/30th.

 

End of my derailing  

It was also dull and cold at times between late March and mid April. There were milder days, but it felt cold, as we just had a cold March and the very cold period in late February before that. 
 

I would love another repeat of 2018, but have a feeling this coming summer will be a little hit and miss. Maybe a better second half of summer in store.

[minus10]

Looks like GFS not that keen to dispense with the colder theme yet for the beginning of April....

 

[minus10]

Gfs 0z still going with this cooler/ colder theme for beginning of April..

seems to be a signal it is reluctant to lose. Even ecm 0z is showing this theme...

[mb018538]

Lots of forecast headaches early next week arising from a trough disruption out to the west of the UK. Pressure ensemble shows a marked split in outcomes:



So...by day 10, you've got:


Probably best to wait another couple of days until this is resolved better.
 

[Northernlights]

28 minutes ago, minus10 said:

Gfs 0z still going with this cooler/ colder theme for beginning of April..

seems to be a signal it is reluctant to lose. Even ecm 0z is showing this theme...

Very normal for this time of the year especially the NE of Scotland.Birthday 4th April has had snow falling on numerous occasions in the last 60 odd years. N and E winds reach their highest frequency at this time of year.

[Scorcher]

30 minutes ago, minus10 said:

Gfs 0z still going with this cooler/ colder theme for beginning of April..

seems to be a signal it is reluctant to lose. Even ecm 0z is showing this theme...

It's miles into FI though. How come you never mention the prospect of warmer conditions within the reliable time frame?

They may be question marks still over the evolution from the weekend onwards but it does seem we will import some tropical maritime air for a time.

Sunshine levels very much up in the air still dependent on the final setup.

The GFS looks the pick of the bunch this morning with the possibility of 20C in the south still there.

[Scorcher]

12 minutes ago, Northernlights said:

Very normal for this time of the year especially the NE of Scotland.Birthday 4th April has had snow falling on numerous occasions in the last 60 odd years. N and E winds reach their highest frequency at this time of year.

Agreed, there is absolutely nothing abnormal or even noteworthy about a chart like that in early April- happens almost every year and is simply a normal spring fluctuation.

[minus10]

35 minutes ago, Scorcher said:

It's miles into FI though. How come you never mention the prospect of warmer conditions within the reliable time frame?

They may be question marks still over the evolution from the weekend onwards but it does seem we will import some tropical maritime air for a time.

Sunshine levels very much up in the air still dependent on the final setup.

The GFS looks the pick of the bunch this morning with the possibility of 20C in the south still there.

It is in FI and yes there is some warmer weather on the way which i am looking forward to. Apolpgies if i havent referred to the warmer spell however working outside it does interest me when a colder signal is shown for a while although i am aware this will probably change and is very much in line with this time of year. Be interesting to see how it develops....

 

[damianslaw]

As others have said northerlies reach their yearly peak April-May, far more chance of verifying now rather than other times of year, not saying we will have one, but probabilities increase likelihood.

[MP-R]

About 5% of me would like a scenario that sees snow on the Mendips - haven’t seen that in April since the 2008 dusting and properly since 2000! Incidentally, there’d been 10cm on the Mendips in mid April 1999, only a year before...

Anyway, interesting model watching and very easy to see how an eastward or westward shift in the same pattern could mean the difference between a spell of late winter weather versus a potentially summery feeling spell of weather. Personally, I’d prefer the latter, although not for too long at this stage.

Between now and then, another brief unsettled spell from tomorrow and I wouldn’t be surprised to see some wintriness in the showers on Friday/Saturday.

[damianslaw]

No posts 8 hours, where is everyone! Models are showing a cold outlook for Easter period, long way off, but interesting to note. ECM going for low pressure swinging in from the NW then transporting cold arctic air. GFS showing a different evolution to cold, instead it builds heights to our west which quickly retrograde to the NW pulling in a cold NE feed.

 

[stodge]

The GFS 12Z OP keeps the signal for something rather colder for Easter.

The key is the small LP which forms close to the Azores - this forces ridging further to the west and eventually north west creating heights over Greenland and allowing the trough to drop to the east of Scandinavia and sending a cold arctic blast south and west over north west Europe.

We know northern blocking is most prevalent in April and May and this evolution is far from unusual at this time of year as spring is the time of conflict between warmer and colder airmasses.

[I remember Atlantic 252]

10 hours ago, damianslaw said:

As others have said northerlies reach their yearly peak April-May, far more chance of verifying now rather than other times of year, not saying we will have one, but probabilities increase likelihood.

Easterlies too, April/May most dominant

[KTtom]

Not sure what to say, depending on your persuasion, interesting or horific charts on view for Easter weekend...more likely to be building a snowman rather than a sand castle!

 

[damianslaw]

3 minutes ago, KTtom said:

Not sure what to say, depending on your persuasion, interesting or horific charts on view for Easter weekend...more likely to be building a snowman rather than a sand castle!

 

Think time for a white Easter thread in historic weather thread..

[minus10]

24 minutes ago, stodge said:

The GFS 12Z OP keeps the signal for something rather colder for Easter.

The key is the small LP which forms close to the Azores - this forces ridging further to the west and eventually north west creating heights over Greenland and allowing the trough to drop to the east of Scandinavia and sending a cold arctic blast south and west over north west Europe.

We know northern blocking is most prevalent in April and May and this evolution is far from unusual at this time of year as spring is the time of conflict between warmer and colder airmasses.

Yes that interplay between warm and cold airmasses can be seen well on the later part of gfs 12z run

Quite a mixture there. 

Also should be some interesting skycapes in any northerlies that do occur at this time of year. Showers can be lively shall we say...