Model Output Discussion - Spring Has Sprung

[phil nw.]

Looking towards the end of the week and onwards it's encouraging to see the models showing the jet now gradually moving further north with Azores ridging making an appearance from time to time.

Granted not yet a setting down properly as we will see some Atlantic influence occasionally especially further north.

Still signs at last of a seasonal pattern change as Northern blocking dies away.

The storm track that recently headed well south into Europe is now showing further north and we lose that persistent UK trough that seemed to be never ending.

[stodge]

Evening all

Early days on the 12Z model output so just a quick couple of thoughts.

After tonight's and tomorrow rain it looks like 3-5 days of settled and pleasantly warm weather for most with HP just to the south.

Over the coming weekend, that HP breaks down and with the Atlantic HP aligning negatively, we see troughs of LP and cooler air coming back in from the north west though I imagine rainfall totals won't be that high.

Outside the reliable it's interesting to see both GEM and GFS looking north for our weather as the next push of warmer air and heights into Greenland leads to a new resurgance of northern blocking over Greenland and indeed GFS OP ends very cool and unsettled with LP tracking south from the Arctic in a N'ly flow. Nothing unusual for late April in all honesty and by no means certain.

[WYorksWeather]

The GFS 10-day accumulated precipitation shows a bit more of a traditional NW to SE split tonight. Still some very high totals for W Scotland, NW England and N Wales, but away from those areas, it really doesn't look all that bad, certainly compared to recently.

As we move towards the longer range, it's always a dangerous game making any predictions, but the mean signal is still for any cooler NW / N interlude to be on the short and not too severe side of things. 

As a final note, worth commenting on that absolutely insane GFS control run in deep FI. Couldn't let it go without saying something of course!

At around day 12, things look relatively normal - chilly in the north and relatively mild in the south. But what's that over North Africa?

Stepping forward to day 14, the plume launches northwards.

And this is where we end up at day 15. 20C isotherm just clipping the south coast. 25C possible in London, over 30C in France.

 

 

 

[stodge]

 WYorksWeather You could have commented on the equally insane GFS OP run 

T+324 or roughly a fortnight today:

Both probably for the bin....

[WYorksWeather]

 stodge To be fair, that's not really an equivalent comparison. Eyeballing the red line, the 850hPa average in London for the period in question is something like +3C. The GFS OP at its lowest point reaches -6C, which is about 9C below average. The control reaches +19C, which is 16C above average.

The equivalent cold anomaly would have been a GFS OP or control run with a -13C isotherm on it in London. And I would have commented on that as well - it would be remarkable to see. But near record-breaking cold doesn't happen very often these days.

A reminder of the chart:

[Rain All Night]

4 hours ago, Rain All Night said:

0z/6z deterministic runs, out to Mon 15th Apr (day 7)

Once we've got the nasty little low out of the way today and tomorrow, we get our long-awaited pressure rise from the south, peaking on Friday. Conditions look pleasant for me down here on that day, though it seems that wind will remain a feature.

It's not clear yet how chilly the subsequent northwesterly might be, and on the GEM it even looks like it could have a stormy flavour to it.

Possibly a storm for the Azores propping up the Atlantic high.

0z/6z ensemble means, out to Tue 23rd Apr (day 15)

The Atlantic ridge looks as though it could sink down through the UK (though on ECM it stays to our west), which might provide some further settled weather (or chilly if it stays west).

Interestingly, all three models currently see significant, though at this stage non-specific, height rises in our region into the final third of April.

12z deterministic runs, out to Mon 15th Apr (day 7)

Do you notice how the UK never really escapes those tighter isobars throughout the whole of these runs?

12z ensemble means, out to Tue 23rd Apr (day 15)

ECM still doesn't want to let the Atlantic high move over us, but it's nonetheless looking good for 'spring' beyond that.

[ANYWEATHER]

Gfs ,really shows how difficult it is to develop a foothold  of high pressure across southern Britain ,let alone northern parts ! Big downgrades in the last 24 hrs and I'm not liking the look of where things are going.! The jet stream is way too strong coming across the Atlantic and supresses any kind of development of high pressure across the uk ,apart from some brief ridges from time to time across southern Britain.  Not happy at all with the outlook from the gfs , hope ecm can help us out...

[bluearmy]

Eps mean is strongly keen on higher slp in two weeks which is v notable at such a range

gefs  not too different 

 About time !

[ANYWEATHER]

 bluearmy 14 days!!! it's been saying that for the last 9 months

[bluearmy]

 ANYWEATHER it begins before then!  The point being that mean slp > 1020mb 14 days+ isn’t standard climatology 

[ANYWEATHER]

Bright but cold airmass by day ten , from ecm ,much different from  the gfs version ,and ecm evolution I much prefer, although a few Wintry April showers can't be ruled out especially for northeastern areas of Britain. As it's day ten ,a huge pinch of salt as it won't verify like that, but please ,please ,please let's have some sunshine and no rain, surely not a lot to ask for after 9 months of rain even for our 0.01% corner of the Globe!☺

[Addicks Fan 1981]

 bluearmy can you foresee a CET to say like april 2007 judging by the forthcoming model output? The annoying factor with 2007 was the AO.  It was positive really for most if not all of spring 2007 until the AAM drop when we came into the summer thanks primarily down to the niño to niña transition, the east QBO and other components.     

[Jordan S]

Afternoon

 

Just want to quote a couple of parts of my previous update for this upcoming drier trend around mid month, the outlook is fairly close to what looks like transpiring as we head past the 11th.

On 01/04/2024 at 16:19, Jordan S said:

it's clear that unsettled or even at times very unsettled weather is likely to feature upto 10th April at least, for the majority, with confidence rating of 90+% of this occurring, less unsettled possibly at times after 11th-12th April particularly the south with increased temps for southern UK, but by and large higher pressure although closer to the UK to our south/southeast, not having much or any influence in the UK weather in terms of drying us out for any length of time before and over mid April and that hasn't changed from previous thoughts when I did my previous post.

 

On 01/04/2024 at 16:19, Jordan S said:

from the 13th-14th April increasing incidences of drier conditions perhaps presenting themselves especially for southern and eastern areas, with unsettled weather more likely for the west/northwest of the UK by this time, for a short time, and that does link to my previous two updates suggesting the possibility of this outlook for this time.. BUT I mean less unsettled overall, with a few more drier days, not likely to overall be settled and dry nationwide for any more than a day or 2 I'm afraid given the lows continued proximity to the west of the UK, but perhaps somewhat better than we've had and will have in the next few days to 10th April if that plays out for mid month onwards.

Definitely looks somewhat better than we've been use to for a long time..

High pressure back on the scene, but unsettled interludes as expected, particularly in the north, but now with conditions not particularly warm at first and rather cool at times in the north/northeast with wintry precipitation on some high ground occasionally, driest weather tending to be in the south/southwest through the mid month period.

Now as for last week of April onwards.. taking a snippet from my outlook for the end of April and through May.. I stick by this quoted post of mine below for now, It is more likely to be drier than we've been use to with higher pressure a more frequent visitor to the UK, but the potential for occasional but very wet/thundery spells from our south/southeast, causing potential flooding for brief periods. 

On 01/04/2024 at 16:19, Jordan S said:

latter part of April and especially into much of May, (may) generally be more likely to have more frequent occurrences of dry or drier days than we've been use to for some considerable time, partly given the time of year and warmer temps (higher evaporation rates) but I wouldn't be surprised to see frequent quick breakdowns to thundery/wet conditions particularly from our south/southeast, with the potential for these to cause further flooding problems where they do occur and that does seem more likely before it clears up for a few days at a time with warmer temps, indeed this thundery and overall less unsettled synoptic pressure pattern over Northwest Europe and UK is more realistic and in fact could easily remain for the Summer period in its entirety, but if this where to take place as per what I'm suggesting, then we would be more likely to have a thundery/ fairly, though not very or exceptionally unsettled first few weeks to meteorological summer, certainly less unsettled than what we've had upto now

We'll see how this plays out.

[raz.org.rain]

2 hours ago, Jordan S said:

indeed this thundery and overall less unsettled synoptic pressure pattern over Northwest Europe and UK is more realistic and in fact could easily remain for the Summer period in its entirety, but if this where to take place as per what I'm suggesting, then we would be more likely to have a thundery/ fairly, though not very or exceptionally unsettled first few weeks to meteorological summer, certainly less unsettled than what we've had upto now

TWO posted this yesterday, although it's important to note that it's not a forecast at this point;

Hot and thundery summer?

WWW.THEWEATHEROUTLOOK.COM

---

Summer 2024 hot in the UK with an increased chance of thunderstorms?

 

[Scorcher]

 Addicks Fan 1981 I'm not seeing any parallels with April 2007 at all- other than it being warm so far.

We've only had 13.8 hours of sun here up to yesterday. April 2007 was notable for high sunshine amounts from the start. This month is already miles wetter than the whole of April 2007 was.

[WYorksWeather]

Looking like a fairly warm four or five days after today, and for many areas largely dry. GFS 06z is firming up though on at least two or three days of much cooler conditions from mid-month. Depth of cold and duration remain uncertain.

[Cheshire Freeze]

 bluearmy it’d be quite something to go an entire spring without a UK HP at some point during its course…so it was always likely to perk up.

The kicker will be whether it’s a temporary pattern change or something a bit more substantial.

[Addicks Fan 1981]

 Scorcher the parallel we have with 2007 is the weakening of el niño and also 2007 was an east QBO as well.    

[NeilN]

 Addicks Fan 1981 When the sun shines, we'll shine together
Told you I'll be here forever

[Addicks Fan 1981]

 NeilN flipping curse record of summer 2007 and mirrored where the jet stream was positioned that summer.  Oh the irony of it all    

[Scorcher]

 Addicks Fan 1981 I feel like you're trying to prove a link with 2007 to suggest a similar summer is on the way. March 2007 was also a lot sunnier than this March just gone as well. Where is the sunshine if this year is following a similar pattern?

[Addicks Fan 1981]

 Scorcher I think june will be similar to that year, but i think the rest of the summer will be slightly different.    

[Scorcher]

 Addicks Fan 1981 if the difference between this year so far and 2007 so far is anything to go by, the summer will be completely different to 2007.

[danm]

So what’s caused our wet March with a southerly tracking jet stream? The late season SSW! As it was always going to. Please people don’t wish for one again…

 

[damianslaw]

 danm Interesting video, we've had  southerly jet, but not far enough south to import any easterly and northerly influences, shows SSW's, southerly jets and negative NAO doesn't always equate to cold. Indeed very mild, courtesy of more of a west based NAO and super warm SSTs. 

Back to the models. generally staying changeable, a south west flow becomes westerly then north westerly, possibly northerly and north easterly, the clock time in sync with the weather.

Next week probably much drier than this week, but colder, might we see a run of average/ colder average days, first time in 3 months.

Edited April 9 by damianslaw