Met4Cast

alan.duckers The Shannon Radar should be re-added to the composite data by late April, whilst it's now operational additional data for calibration is still required, there are also an additional 5 radars being put up. So, hopefully by the end of April the dark spot across southern Ireland will be gone & we'll have a fully functional radar system again.

Unsurprisingly the blocked model outputs from a week or so ago didn’t really materialise, here was a run for today vs how things actually looked today; The teleconnections are sometimes rubbished on this forum if it doesn’t snow in X location but once again they’ve proved a very useful tool in viewing NWP outputs with added context, as they have done for the majority of this winter. It seems instead we’re in for a fairly prolonged period of above average temperatures with the March CET likely coming out above average if the current direction of travel continues. Perhaps signs of something a little colder thanks to Atlantic ridging late March/early April as the MJO continues to progress eastwards through the Maritimes & into the Pacific with AAM tendency fairly positive at the moment as a result.

Background forcing has been against the idea of colder weather since the mid January cold spell, a marker divergence appeared around the 22nd January when I (and others) noted the likelihood of a cold February was diminishing. Indeed, background forcing remains unfavourable for strongly blocked/colder patterns with the Iberian high continuing to play a larger role in the broadscale patterns (despite major SSW) April however does show some tendency towards higher latitude blocking as the MJO continues to progress into phase 7-8 but by this point does anybody really want colder blasts of air? Probably not.

Frigid Unfortunate really because it’s the first good deterministic run for a while I said a week ago now that there’s no sign of anything notably cold or warm and that remains the case going forward through this month. Quite a bog standard affair, boring from a weather perspective but also from a wanting to get out and do things perspective.

RJBingham Yup. I've struggled to see the enthusiasm for anything properly cold to be honest, besides some deterministic runs/outlier ENS members modelling has been pretty consistent with predicting temperatures remaining around average for the foreseeable with very little sign/support of anything significantly colder. Later in the month will likely see some renewed high latitude blocking as the MJO cycles into more favourable phases in the context of rising AAM but by and large, it's game over for cold chasers.

Going back to this post from the 26th February we are now seeing this broader evolution play out within modelling. High pressure forming across Scandinavia but increasing support that it’ll be too far NE to really drive energy SEwards & advect cold west across Europe. The pattern flattening out is now well advertised. I think it’s probably fairly safe to rule out any cold weather through the first half of March & probably beyond now.

The det seems to fall off a cliff in terms of the cold pooling into the UK. Synoptically the det is quite well supported but in terms of cold pool positioning etc, very little support.

Metwatch I don’t think using the BFTE, which was one of the most extreme SSW responses on record is really a fair comparison. The continent warms very quickly through March (typically), direct northerlies are often a much stronger source of cold by late March/April.

Mike Poole The EC46 has been spectacularly poor this year. I wonder if the now daily updates just highlight this more, was a little harder to keep track when the model only updated twice a week. I don't think i'll be putting much weight into it in the future, it's inability to drop a signal that it's latched onto when it's clear the trend has changed isn't great. I think 1-2 weeks it can be helpful to provide support for current trends within other models but as an isolated long-range forecasting tool it's poor.

KTtom Good summary! Rather amusing that we ended up seeing the mildest February on record after a lot of promise during early winter of a backloaded cold one

Total AAM tendency has been strongly negative of late thanks to the MJO decaying into COD, this re-emergence into the Indian Ocean and quick progression eastwards through the Maritimes though has begun to reverse this with AAM tendency now slightly positive. I do wonder just how much overall +ve AAM will rebound to though, a fast MJO progression as is currently predicted would suggest less westerly momentum being injected into the atmosphere, I'd be surprised if we reached values seen through late January/most of February again, especially with El Nino beginning to fade. The recent abrupt decline in AAM tendency combined with the SSW is likely generating the blocking to the NE of the UK across Scandinavia and we are seeing a regressive signal towards Greenland within NWP modelling, the only real issue is the lack of cold across Europe to advect into the UK, I do also think, as stated previously, the high might end up being too far NE to really drive Atlantic energy to the south of the UK and the means are now showing this with winds broadly S/SErly across the UK rather than true easterly, this essentially stalls the low across the UK bringing yet more rain.. wont that be nice. The direction of +AAM anomalies is equally important and we're seeing +AAM anomalies moving poleward as the previous cycle completes, this is suggestive of a stronger jet and is further evidence of a quicker flattening of the pattern. I do think we've probably missed the boat here in terms of anything colder, at least through the first half of the month. Continued MJO progression into phase 7/8 later this month could potentially allow for another attempt late March/early April but honestly but that point we'd need a very direct northerly to produce, an easterly at that time of year is very unlikely to cut it. For those wanting one last bite of cold/snow, the outlook is poor. For those wanting some early spring warmth the outlook is equally poor.

Despite the blocked charts there's very little cold on offer to tap into, ensembles across all models are generally sticking to climatology (average) with temperatures gradually rising a little throughout the forecast period. Blocking to the NE may well retrogress towards Greenland but MJO moving through typically zonal phases and rising AAM suggests a flatter pattern, rather than a blocked one. My expectations are still for the pattern to flatten out rather quickly, at least across the Atlantic sector with a west based -NAO seemingly the direction of travel following retrogression with nothing notable in terms of cold or snow potential, despite the SSW tropospheric drivers are not favourable to produce proper cold weather across the UK. Impressive looking synoptic patterns but sadly, no cold.

GFS det was a rather obvious outlier unfortunately. There continues to be a complete lack of support for colder/notably colder weather into the UK with the majority of ensembles favouring milder weather (at least at the 850hPa level) This comes as no surprise really given the MJOreturning to the Indian Ocean and progressing eastwards through phases not typically supportive of blocking.

Absolutely no support for the GEM det unfortunately, seems to have gone off on one and then some.

Despite a few interesting looking det runs the means are generally against the idea of anything cold/snowy. In fact, could end up being quite mild with southerly winds taking hold!

Addicks Fan 1981 They show the recent decayed MJO signal & expected start of the next cycle over the Indian Ocean, albeit they have been a little inconsistent of late, largely down to modelling struggling with the MJO (SSW related I presume). Can certainly see the uptick in Pacific trade winds.

Yesterday’s CPC MJO update suggests a return to the Indian Ocean before progression through the Maritimes as the cycle resets so further away from the typical “blocking” phases than originally anticipated, having said that the SSW early March could have some impacts on the MJO & thus forecasts are more uncertain than usual. Assuming this is the direction of travel though, the next surge in momentum is fairly predictable with an uptick in frictional torque followed by a return to positive mountain torque values adding westerly momentum to the atmosphere thanks to the MJO progressing eastwards. With that in mind, it continues to seem less likely that’ll we’ll see colder patterns establishing for the UK with high pressure early March likely to be too far NE of the UK with a rather active Atlantic jet hitting that road block, it could potentially be quite wet, especially in the north & west depending on exactly where any blocking highs set up before the patter, I suspect, quickly flattens out coinciding with this next momentum push. I see the Met Office extended is more inline with this & indeed with my thoughts posted yesterday morning a page back. Any blocking is a result of the recent abrupt drop in AAM tendency as westerly winds are scrubbed, i.e increasing easterly trade wind strength. El Niño is on very thin ice now.

I think the separate threads serve well for more prolonged conversations but I don’t see an issue with highlighting various teleconnections or the strat in this thread given the role & importance they play in the weather & the modelling that this thread is for.

Because they go hand in hand with the models, they provide context to modelling which can help to understand why modelling is doing what it’s doing, I don’t see how a bit of knowledge on that is a bad thing? The rest of your post is a little bizarre if i’m honest, nobody has suggested synoptic modelling can’t be discussed?

TillyS The only real "teleconnection" fail this winter was in January when we saw a reflective SSW event, something that's rather rare and cannot be forecasted beyond the short term, the stratosphere is a very important factor & can overrule tropospheric forcing, which is what happened (See my post in the Winter post mortem thread where I explained all of this) Otherwise, they've been a good indicator throughout this winter in terms of broadscale patterns. What you can't do though is take the MJO in isolation like many in this thread do. Many see the MJO phase, look at the composite and expect that to be the pattern that verifies but unfortunately it's not that simple. The MJO is just one variable in the broader windflow budget and you need to look at both tropical & subtropical forcing, looking at just 1 variable will not give accurate results. I hope the thread becomes more filled with teleconnection talk rather than less, these teleconnections drive the models, not the other way around and the more we understand them, the more accurate future forecasts will become. In terms of the shorter term though, yes NWP rules the roost. Teleconnections can only give broadscale indications of potential pattern changes, they cannot tell you it will snow in X location on X day.

AM tendency is rising once again thanks to another strong (albeit likely brief) +EAMT event. In terms of the broader patterns going forward though I'm struggling to see much in the way of a trop response to the SSW next week, MJO forecasts have been all over the place and I suspect we're seeing influence from the SSW there skewing modelling somewhat but general consensus appears to be out of the COD into phase 4/5. In early March this correlates to stronger S European heights and a flatter zonal Atlantic jet (there's a surprise). With the recent sharp fall and rise in AAM tendency it does seem plausible that we'll see the jet stream encountering some road blocks in the form of high pressure, probably to the NE of the UK (though as mentioned previously, the high probably too far NE to influence the UK much) before the pattern flattens out again by the end of week 1 into week 2 of March. Broadly +ve and -ve anomalies are propagating poleward now so a brief relaxation of Iberian heights and a more amplified jet does seem plausible next week but again, not sure it'll be in the right place to influence the UK in terms of colder weather. For the UK at least, a continuation of mild & at times unsettled weather seems the favourite going forward, just to make a change. Quite a tricky period to try and "diagnose" but I've given it a go anyway! This is fairly low confidence. Interestingly the Met Office extended forecast suggests the opposite of this & currently favours blocking/colder temperatures to take hold post March 11th so will be fun to watch that evolve!

My focus is primarily on the stratosphere at the moment & potential impacts from a major SSW during early March. Still not much urgency to downwell the -ve anomalies quickly, modelling now goes out to the 10th March. Strongly -NAM state despite this though but with little blocking to speak of in the troposphere. We've seen quite an abrupt change in MJO forecasts in recent days too, initially looking like a return to phase 5 has now switched to returning to phase 3/4 in the Indian Ocean following the previous decayed signal. Phase 3/4 composites for March are very unsettled for the UK, phase 3 perhaps a little chillier. In essence though - For those still chasing cold/snowier outcomes, I think it might almost be time to give up the ghost.

The lack of posts in here in recent days tells the story I think. No sign of anything remotely cold or snowy in the forecast with modelling overwhelmingly favouring a return to milder conditions right out into the extended. No real urgency in the downwelling of -ve anomalies from the strat.

Thanks for the correction, appreciate that!

I don't think you'll find a single climate scientist that's made this claim. Cold records however are much less frequent and pale in comparison to heat records by a ratio of about 10:1.