Model Output Discussion - Spring Has Sprung

[Snowfence]

Hi everyone, this is my first ever post on netweather. I love reading your posts by the. Way. Loving the GFS 0Z Op showing first signs of the SSW effect - actually having one in FI :

[MJB]

White Easter anyone lol  

[ANYWEATHER]

2 hours ago, Snowfence said:

 

Hi everyone, this is my first ever post on netweather. I love reading your posts by the. Way. Loving the GFS 0Z Op showing first signs of the SSW effect - actually having one in FI :

 

Welcome to the MAD thread

[daz_4]

Interesting differences between GFS and ECM just 4 days away for my location. ECM ENS are really cold with average around -7C while GFS ENS are having none of it.

[Alderc 2.0]

Really uninspiring heading into the later half of March, lots of spread in the ensembles nearly always from my experience means a continuation of unsettled conditions with blocked, either warm or cold outcomes not favoured. 

 

 

[Lukesluckybunch]

Uk mild sector!

[Anthony Burden]

Morning all,GFS keen as usual in fantasy island to bring high level blocking nearly 3 weeks after SSW occurred,still a possibility of a colder end to March on the cards.

[MJB]

 Anthony Burden

Wouldn't that be funny after all the weeks of chasing 

Control says keep your thermals out for a while

 

Edited March 14 by MJB

[Lukesluckybunch]

26 minutes ago, MJB said:

Control says keep your thermals out for a while

The 384 chart on the op..just about somes things up!

Edited March 14 by Lukesluckybunch
Spelling

[Rain All Night]

22 hours ago, Rain All Night said:

0z deterministic runs, out to Wed 20th (day 7)

A brief surface ridge over the weekend, and then some opportunities for some settled weather further south and east into next week.

0z ensemble means, out to Thu 28th (day 15)

Still seeing a convincing signal for an Azores high extension towards the UK around the equinox, followed by a less convincing but nonetheless recurring signal for a pressure rise further west that could force a chillier air flow over us late in the month.

0z deterministic runs, out to Thu 21st (day 7)

The Azores high extension is heading towards the reliable timeframe, but how much of an impression will it make on the UK?

Before that, a little ridge passes over us on Saturday, perhaps followed by an unpleasant-looking low pressure system on Tuesday.

0z ensemble means, out to Fri 29th (day 15)

The signal for what happens after the Azores high extension remains vaguely suggestive of something cooler coming from the northwest, but there isn't a strong Atlantic ridge signal to go with this any more.

[MJB]

 Lukesluckybunch

Worth a laugh 

[JakeWorces]

I see the GFS is up to its usual deceitfulness teasing us with the mirage of a 5+ day dry spell in about a week's time yet again in the 6Z...
I will assume that it will switch to conveyor-belt-of-Atlantic-lows as we get closer to the time 

But I will erect a small shrine to the Azores High in my living room to try and manifest its arrival as suggested by it, so that the ground can finally dry out for the first time in 6 months and I can regain the will to live/step outside 

Edited March 14 by JakeWorces

[Summer8906]

 MP-R Mind you the second chart looks worryingly zonal. For cold weather I'm really looking for something more definitely NW-ly or N-ly which could bring the prospect of late snow but keep the Atlantic deluges at bay.

Edited March 14 by Summer8906

[Summer8906]

 Rain All Night Seems to be a common theme of a drier/settled interlude around the weekend of the 23rd but then yet more cyclonic deluges the following week, albeit colder. Worryingly reminiscent of the end of March 2018, though obviously still FI.

If these are anything like the truth we will have achieved the remarkable (and not in a good way) feat of two exceedingly wet Marches in a row - and two exceedingly wet months in a row.

Two of the four wettest Marches since the war being 2023 and 2024, perhaps. Certainly a remarkable statistic if it happens, but not a good one either!

Edited March 14 by Summer8906

[WYorksWeather]

Attempting to reel in the dry spell - here's how day 8 is looking today on the 12z runs.

OP runs

GFS is dry and very mild, possibly even warm.

ECM much more of a north-south split. Fairly mild and dry in the south, cooler and wetter further north (though not especially cold).

Ensembles

In terms of the ensemble means, they're pretty much as you'd expect. GFS mean has a weaker Azores high than the GFS OP, whereas the ECM mean has a stronger high than its OP.

However, the ensemble means both look like a significant improvement on yesterday if it's dry weather you're after.

GFS 12z OP in detail

Brief aside on the GFS OP - some of the temperature projections if we take this run literally are quite impressive. What an exceptionally mild week this would be for mid to late March!

Of course, this is not a forecast, and is at the top end of possibilities, as the 12z GFS was near the top of the ensemble. Still interesting to see this in the modelling though.

[Mike Poole]

I think a UK high as per GFS 12z around the 8-9 day mark is one plausible evolution, but it is as part of a transition towards blocking further north later as the effects of the SSW start to have some impact, so if it happens I don’t think it will herald the start of a proper settled spell unfortunately.  And there are other plausible evolutions that don’t have the high pressure go through the UK anyway.

[damianslaw]

Mmm jury out on whether we can tap into a lengthy dry spell courtesy of high pressure, as suggested by GFS.

In the reliable, more of the same, after a cooler blip tomorrow, we continue to see a SW flow predominantly, frontal features bringing heaviest rain to the NW, the SE may see fairly dry but everywhere disappointingly dull.. and its the lack of sun forecast that makes the outlook very uninspiring.

Longer term, some signs of a drying up, but also sign of heights either building out west heading north, or north, the eventual outcome could be a chilly showery or wet cyclonic spell in the run up to easter.

March 2024 may end up notably wet, mild but also exceptionally dull, a poor combination. 

[Uncertainty]

Not seeing this phantom U.K. high coming to anything. The last 9 months have seen the U.K. become a beacon of low pressure, rain and gloom. The eps and geps have sacked off any hopes of a meaningful pressure rise. Even a split ssw and high amp mjo into the pacific doesn’t matter anymore. 
 

Im sure it’ll flip eventually, but this is one of my least favourite periods of weather. Always the promise of interesting, settled or cold weather but the reality has been utterly grim. 

[Snowfence]

 ANYWEATHER Thank you - love the madness

[Snowfence]

There are still a few GFS perts keeping the faith with the FI Scandi high...e.g. P6 here just for fun...

 

[Addicks Fan 1981]

 damianslaw quite agree with you there and can foresee this march being a replica of 1998.   Think also the MJO needs to be monitored constantly as well as the hovmoller plots which @CoventryWeatherhas used in the past.

[RJBingham]

5 hours since the last post, not much going on then 

[Jordan S]

On 08/03/2024 at 13:02, Jordan S said:

The couple of updates I made recently on those northeast winds after mid month over the UK looks “nailed” on.. lol ofcourse not, and no doubt will show a different theme by this afternoon (that won’t alter outlook thoughts in this post though) but the Gfs update this morning highlights the anticipated Greenland heights, very mild/warm air trying to establish from our south and colder conditions trying to establish from our northeast very well past mid month.

The synoptics over the UK unlikely to look as extreme or as south shifted in terms of cold air and wintry precipitation as the Gfs is currently showing in reality and my updates recently have eliminated southern UK being in with a chance of wintry precipitation after thinking this could happen just after mid month when I did an update in the first couple days of March, but for northern UK, there is still a reasonable chance of colder (though not exceptionally cold) northeast winds trying to establish past mid month especially post 18th March to put a bit more detail on it,  which is my 25th birthday.

Due to the very cyclonic/unsettled nature of the weather over southern UK and across the “southern portion” of the Atlantic Ocean that looks to still feature throughout the second half of March and likelihood of high pressure nosing into western and Central Europe on occasion this is what will probably prevent colder than average conditions for the most part in central and especially southern UK, very wet at times still and that’s been highlighted well but with much more of the showery unsettled variety than the winter obviously due to increased convection so rainfall totals may actually vary somewhat from place to place here but could see some big showers developing, these wintry at times in the north, shower risk is though highest in the south with that ever strengthening sunlight especially in cooler upper air temperatures that look to be a feature behind southerly tracking lows that bring very mild air ahead of them either close by or over southern regions of the UK.

Thought I’d add a confidence rating to my posts now so you can have an idea how confident a weather event or forecast per day may be to me atleast..

Confidence rating for the post mid month period attempting colder spell development in north UK: 50% so moderate confidence, most of the excess uncertainty coming from how much influence low pressure has in the north,high pressure more often than not largely close by here and that has been the consistent signal but there will be unsettled interludes in the north of the UK too with a continued risk of wintry showers along with dry drier days.

Highs over/close to Greenland a 90% chance of that occurring at frequent intervals for the rest of the March.

Confidence rating of 75-80% for southern regions seeing the wettest conditions overall and a bit milder with a consistent cyclonic pattern with low pressures moving mainly west to east being anticipated but also on occasion northwest to southeast and south to north through the rest of March bar fleeting high pressure systems that swiftly move across the country settling things down on occasion trying to form blocks elsewhere across our part of the northern hemisphere. 

Confidence rating of 60% that the synoptic pattern over west Europe will allow a temporary much warmer than average spell of temperatures into France and southern and southeastern England atleast once before the end of March, overall they look to be fleeting.

The very end of March the Greenland heights may move and weaken slightly south and in the process bringing much colder upper air temperatures south across the whole of the country and into France, bringing the risk of a brief spell of below average temperatures with a bit of sleet/snow in places potentially including the south. Confidence rating for the very end of March potential colder than average blip nationwide, 30-40% with the main uncertainty being time frame given this is 3 weeks away, but to a lesser extent on exact trajectory of potential brief north/northeast air streams widely and whether they stay east of not around end of March.
 

Have a lovely day

Well there’s the briefest of north/northeasterlies if you ever see one..

The key change from the quoted post of mine above being the northeasterly that looked a possibility in the third week of March, wont take hold with blocking to our north proving weaker than expected at first, this also means northwestern areas wetter overall than southern areas. 

In the next few days after a continuation of wetter conditions widely, there is a stronger attempt from high pressure from our southwest to settle things down somewhat over southern UK especially, early next week, but staying more unsettled in the north at times though throughout, nothing exceptional and even here may see some drier days , these drier though not necessarily completely dry conditions may even persist in the south until the 21st or 22nd but like my previous post mentioned, any settled periods rather brief, no more than 3-5 days.

Slightly colder and more widespread unsettled conditions return over most or all of the UK in the last week of March, with renewed risk of snow on northern hills atleast at first but may fall to some lower levels in the north by Easter, with an increased northerly and more especially northwesterly a decent likelihood, the risk of snow further south very low now but not to be discounted. 

Confidence rating of a more drier few days in the south with only occasional small amounts of rain for a few here? 95%

Confidence rating that widespread unsettled and colder conditions return to all areas in the last week or so of March and most likely from our northwest rather than north with snow on hills in the north? 80%

Confidence rating of a notably warmer than average spell moving north atleast once before end of March, has recently lowered to around 20-30%, there is a small chance of a brief southerly from a cut off low either over Spain/Portugal or just to the west of the UK/Europe around 23-25th and higher pressure over central and Northern Europe for a few days helping to draw very warm air north. In any case unsettled conditions would follow behind it and like I said before, it’s fleeting.

 

Higher pressure is still liable to be close to over Greenland especially late in the month.

Edited March 15 by Jordan S

[ANYWEATHER]

Let's start a the very beginning  a very good place to start....both gfs and ecm trend for higher pressure to start moving in by about Tuesday/Wednesday next week. I'm not bothered about cold or even hot ,just want some sunshine and dry weather ,and the sunshine this time of year has some umph to it. Let's hope it's the beginning of the end of the monsoon which has haunted us for the past 9 months ......

[Djdazzle]

 ANYWEATHER Agreed. Anything is preferable to the current crud. Hoping the models start to pick up on a dry spell and run with it. Over the past few weeks, every time that a dry spell has appeared at day 7 / 8, it hasn't made it to reality.