Model Output Discussion - Spring Has Sprung

[Frigid]

 Scorcher True, forgot to consider the strength of the sun at this time of year and possible inversions. Mild days in the mid to high teens likely. Nights would be chilly though if skies clear. 

[Daniel*]

4 hours ago, Frigid said:

Mild days in the mid to high teens likely.

It seems some are in denial. The mean for Manchester has highs barely in double figures for most part. It’s certainly a cool outlook with winds frequently coming from northerly direction with cool air aloft. A bit milder this weekend with high covering UK briefly, then it looks to re-centre further NW. it’s a very poor outlook if you’re looking for warmth. If only if it was winter comes to mind.

Edited April 16 by Daniel*

[andymusic]

gonna be a bit chilly in Europe & the UK

Edited April 16 by andymusic

[seabreeze86]

Settled spell starting to look like more of a settled snap. What’s it going to take to get a proper settled spell of weather 

[stodge]

Evening all

The HP will take its time to build in across the British Isles at the end of the week so we should have a spell of quieter weather, drier certainly but not excitingly warm, average at best and with the possibility of some chilly nights leading to ground frost in sheltered rural areas.

Into next week and we still lack clarity - with low heights over the Mediterranean and Iberia the obvious option is for the HP to drift north or north west with the trough setting up to the north east pulling in chilly NE'ly winds and for the latter part of the month LP forming to the north coming SSE into the North Sea and bringing cloud and occasional, probably light rain mainly to eastern parts. JMA offers the possibility of a return to more Atlantic dominated conditions for early May but I'm not seeing any significant warmth for the rest of this month.

[Addicks Fan 1981]

 stodge tell you what we need Tamara for some diagnostic input and insight, that at this stage would be helpful for everyone.   

Edited April 16 by Addicks Fan 1981

[WYorksWeather]

 Daniel* It all depends on the averaging used. By more recent averages means will come in a couple of degrees below. If you refer to older 1961-1990 averages as used for the Central England Temperature, then it's close to or just a little below average. As an example, yesterday's CET report was 8.0C, middle of this week from around now until Friday will be a bit below that, then warmer at the end, CET average for April is 7.9C on 1961-1990, so pretty much bang average.

I do agree with your main point though aside from that bit of nit-picking - there's no sign of anything on the warm side really, if we mean 20C+ at the surface, for at least the next 10 days.

 

[Daniel*]

25 minutes ago, WYorksWeather said:

It all depends on the averaging used

Well the data suggest otherwise also signalled below on 1961-1990, below is Birmingham next week looks even cooler than this week, you must also consider the average for further in April is warmer, so using overall mean is not wise. 

[Derecho]

2 hours ago, andymusic said:

gonna be a bit chilly in Europe & the UK

The chilly weather over Central Europe keeps subtly getting upgraded, so to be fair to @Daniel* this is looking like quite the transition now till the end of the month given recent exceptional warmth.

The warmth of earlier in the month is transferred to central Asia instead. Some above average temperatures in the Arctic for the first time in a while as the cold air bottled up there is moving into Central Europe.

Global temps nudging downwards a tad as well from the record highs we have been seeing this April. The El Nino feedback perhaps beginning to wane somewhat.

[Sherry]

 Daniel* those temps graph you bring up always end up lower than the real temp 

[SunnyG]

 seabreeze86 Moving to another country, like Spain or Greece.

[Rain All Night]

5 hours ago, Rain All Night said:

0z deterministic runs, out to Tue 23 Apr (day 7)

0z ensemble means, out to Wed 1 May (day 15)

GEFS diverges early (day 6) by sending low pressure over the top of our high from west to east, and then again subsequently by not sending as much high pressure north-westwards as the other two models do.

Incidentally though, this doesn't make a whole lot of difference to the prognosis for us: a warm(er) settled weekend followed by a change to cooler conditions not of Atlantic origin.

We're not quite yet at the point where we can gain much insight into how the month is going to end, but I suspect we're not too far off.

12z deterministic runs, out to Tue 23 Apr (day 7)

ECM machine learning model - yes please! GFS - no thank you!

12z ensemble means, out to Wed 1 May (day 15)

Wow, it looks like we will be under a reversed, initially northeasterly flow from the middle of next week through to the end of the month. That's not going to bring the warm conditions I've been hoping for, but at least it's something interesting.

I don't remember the last time the UK experienced a northeasterly flow. Does anybody know when it was?

[Sun Chaser]

6 hours ago, Rain All Night said:

I don't remember the last time the UK experienced a northeasterly flow. Does anybody know when it was?

I believe it was present some of the time from mid May to early June last year - with the high to the west our flow was usually easterly or northeasterly. Telltale sign being that we had three weeks of unbroken sunshine while the east was generally quite dull!

[Daniel*]

“Slightly below normal” involves 5C even 6C below average T850s. A long time since I’ve seen such a deviation below.

Edited April 17 by Daniel*

[Alderc 2.0]

 Daniel* horrible timing, no way that delivers ‘warm’, even with stronger sunshine will struggle to get past 9-12C just a continuation of what we saw Nov-Mar.

Edited April 17 by Alderc 2.0

[Frigid]

 Daniel* A remarkable switch to something cooler, this would've been a notable cold spell in winter. I wonder what triggered this response..

At least it looks dry. The CET will tank if frosts occur, what a strange month this is coming out to be. 

[Daniel*]

2 minutes ago, Frigid said:

A remarkable switch to something cooler, this would've been a notable cold spell in winter. I wonder what triggered this response..

Still seeing drips of SSW which occurred earlier in March this could be what’s responsible, it was a significant event so of course has potential for extended influence. I don’t believe it’s result of MJO that’s been in COD. Perhaps weakening El Niño also a factor nothing we could get on side during winter remained strong.

 

[daz_4]

The outlook for Central Europe is absolute disaster. Everything is at least a month ahead and in full bloom. The frost will kill pretty much everything unfortunately.

[ANYWEATHER]

13 minutes ago, daz_4 said:

The outlook for Central Europe is absolute disaster. Everything is at least a month ahead and in full bloom. The frost will kill pretty much everything unfortunately.

History tells us that this can be a big scenario at this time of year. Anyway ,a cold outlook to average ,although  the relentless rain train ,just about coming to a halt, although there still looks like a peppering of showers at times ,these still wintry.  The incedence of frost looks problematic, especially for farmers and growers,  and although there looks a fair amount of dry weather going forward,  colder than average temperatures won't be what farmers are looking for, to help dry out the land   ,and germinate crops ,much quicker if the weather was warmer....

[LetItSnow!]

A brief overview of the GFS 0z.

By the weekend we're under high pressure but with rather chilly uppers, particularly in the far east, so while even by day it may feel a tad nippy it will sure be quite chilly by night and the start of the frost risk is already apparent.

What's of interest is that by Monday the 22nd we see the high pressure far north enough to establish a north-easterly flow over much of England and Wales, more substantially so than the previous run. I imagine this will bring very raw, cloudy and quite showery conditions so in the south the long awaited dry spell may end up being rather soggy. Some notably chilly uppers on this run with about -5 and even some isolated patches down to about -7C on the east coast. I feel like this could be a particularly cloudy and showery affair due to warmer than average SST anomalies in the North Sea at the moment.

The raw, showery theme is maintained up to Wednesday the 24th with north-easterly winds continuing though uppers moderating. The previous run had a trough over and to the east of the country which was far more unsettled whereas this, while still unsettled, wouldn't be quite as so, so there's some question as to how much an effect low pressure will have at this time though winds are likely to be from a northerly quadrant.

I'd go up to day ten itself but for some reason I can't, all the charts seem to be stuck on midnight on the 26th thereafter.

So, what does it show? It looks like a persistent pattern of chilly weather will likely take place in the second half of April. Will it be exceptionally cold and with buckets of snow? Very unlikely. But anyone saying it's a mild outlook is letting their bias overlook the forecast, end of. It looks to me a very normal pattern that you'd expect to see in any given April and what would be very normal 40 years ago, but coming after such an exceptionally mild first half to April it's going to be a shock. Those who were hoping for the first signs of summer will have to wait, and in some areas it may not even be overly dry, though out west (especially you, Ireland!) there may be more shelter.

Personally I'm delighted to see such normal, benign synoptics after months of bloated heights to our south.

April 2024 is looking like a month that will be remembered for two very different halves, not unlike April 1995 which was similarly exceptionally mild before switching to a cool, quite northerly second-half.

Edited April 17 by LetItSnow!

[Daniel*]

Even this weekend has downgraded, it looks rather cold for most as NE’ly is introduced. Warm in west of Ireland closest to ridge. 

[Scorcher]

 Daniel* Why do your posts always have to be so antagonistic?

Not true at all that the temps won't get out of double figures in Manchester even in the setups shown this morning by the models.

850 hPa temps were much lower in April 2021 than what is being shown for next week in this area and we reached double figures in the afternoons for the most part.

April 13th 2021- we reached 12.6C in this setup (after a frost I might add).

GFS surface temp chart for next Wednesday:

Admittedly this NE flow is not good for the east but it's not terrible for all of us by any means. Anywhere west of the Pennines may get close to average in this setup by day.

A lot of hyperbole about this spell from certain posters.

It's certainly going to be more notable in London relative to average than it is in Manchester.

Edited April 17 by Scorcher

[Frigid]

 daz_4 Vienna has seen the first half of April average 16C, with most days in the upper 20s. The cold spell will definitely be a detriment to new foliage but it is finally going back to normal after such a prolonged heat spell. 

[Neil Harris]

 LetItSnow!

Keep the similarities to 1995 up please! Very hopeful of a repeat

[LetItSnow!]

16 minutes ago, Scorcher said:

A lot of hyperbole about this spell from certain posters.

I'm not quite sure I agree with this. No one is claiming an April 1981 redux but more that the signal for the next 7 to 10 days is looking fairly chilly and likely to feature some chilly nights, so it'll be below average, particularly in the east. Most posters know the strength of the sun is enough to get temperatures in double digits even with cool uppers. If you're in the far north and west it'll likely be better, but if we get cloudy NE/E winds with cold uppers then quite a bit of the country from the Midlands east could struggle with maximum temperatures if there's a lot of cloud and nagging sea breezes. No hyperbole going on imo.