chionomaniac

Just a little note on the GFS ensembles. This morning I suggested that the op was leading the way regarding the outcome from the 19th, when the ensembles were suggesting no return to cold 00z ensembles show divergence on the 19th - mainly mild option despite the Op now look at the 18z GFS ensembles for the 19th. Yep they have all followed the op now. and within18 hours the divergence occurs around the 21st. So the ensembles and op now agree for the 48 hours between th 19th and 21st. But the 21st takes us back into a level where it’s day 7-8 rather than day 6. Imo this is important regarding ops and ensembles. We need to be very careful when monitoring ops and ensembles around these timeframes because it is easy to be caught out by not looking at the exact time when divergence occurs

So, I expected that the ensembles would follow the operational output in the last 34 hours. This has happened- but now the ensembles have reached a point where they will give better guidance we now see the operationals see more what the ensembles were seeing previously. Who’s leading who? I suspect that ops and ensembles will be in sync within 24 hours. ( and I know what way I am hedging)

Remember. EPS at post T+300 does this. It will go but may not be shown for a while on earlier output.

Lol. I wouldn’t react so quickly. I could supply a gym with towels thrown in unnecessarily…..

With every set of runs we would expect one or two to be off kilter. It’s no surprise for me to see that as the ensembles are catching up one or two operationals show a different outcome. With the overall hemispheric pattern I’m not concerned especially as EPS at T+300 plus suggest Iberian low and scandi increased heights

I’d rather be commenting on the models rather than removing posts about which area of the UK they are of. Please help and if a post shows model sequelae of an area you don’t inhabit, then move on, there are plenty more posts to view. Thanks.

Yep. I have managed to embed it in my post too.

Massive 12Z GEFS 500hPa anomaly chart at T +300 for the NH. Wow.

This scenario is a bit like shutting the front door and relaxing but not realising the threat remains because the back door has blown open. It will be a pity that those snowfields will likely melt in that short period where both doors are shut. How quickly will the soil and ground temperatures recover I wonder.

So it looks like the ensembles are catching up with the operational lead now. And a couple of pretty cold runs too… Sometimes it’s a case of following the ops when they are all showing the same trend at a timeframe when ensemble members will find it more difficult. Now the ensembles are getting there.

No SSW is to do with trop wave activity

I would say personally that we still have a bit of time on our hands - perhaps until the end of the year before upper zonal winds will start to propagate to the trop. Until this point the coupling will still be broken. At every level except 2hPA the strat u wind is around average and this decreases the lower you get 2hPA 10Hpa 70Hpa !00Hpa

I suspect that we are seeing the deterministic ops are leading the way over the ensembles here. It’s just at that timeframe where the ensembles will have difficulty picking out the later developments from this type of pattern. I suspect that when the ensembles catch up we will start to see some whoppers in there. Original post: https://community.netweather.tv/topic/98087-model-output-discussion-the-cold-has-arrived/?do=findComment&comment=4765905

All down to the MJO, this one. And if you ignore the CFS and look at the 850 u wind alongside the 200u wind forecast anomalies in the western Pacific then we have movement on this front. So simply put, we can welcome back the cold for Christmas, and this then will give the Strat another push towards breakdown of the stressed upper vortex, probably early Jan for that though. Original post: https://community.netweather.tv/topic/98087-model-output-discussion-the-cold-has-arrived/?do=findComment&comment=4765817

I suspect that we are seeing the deterministic ops are leading the way over the ensembles here. It’s just at that timeframe where the ensembles will have difficulty picking out the later developments from this type of pattern. I suspect that when the ensembles catch up we will start to see some whoppers in there.

Loaded, cocked and ready to fire….

Not really. I guess I had expected the western Pacific activity to get a move on a bit earlier to keep the pressure on the upper Strat. Pressure has been felt most at 1hPa with strong wave 1 activity, but this hasn’t translated down to 10hPa. it’s a bit like the balloon analogy, pressure has been placed on the balloon - but critically it has not popped, nor has any air escaped. So remove that pressure, and the balloon regains it’s shape quickly. That’s effectively what’s happened at 10hPA ( air escaped at 1hPa) so now we have to wait until the NH profile is conducive to further wave activity reflecting into the Strat. And by God, some of the modelling of the NH profile will surely be conducive to that!

All down to the MJO, this one. And if you ignore the CFS and look at the 850 u wind alongside the 200u wind forecast anomalies in the western Pacific then we have movement on this front. So simply put, we can welcome back the cold for Christmas, and this then will give the Strat another push towards breakdown of the stressed upper vortex, probably early Jan for that though.

I think we can leave discussion on whether or not the 00Z is an outlier now. Agree to disagree and move on please

Just a little video from Haywards Heath IMG_4297.MOV

A new car for £140. You did very well indeed.

I’m keeping an eye on this, UKV and ECM say yes, but I am waiting for the Arome later today , when it comes into range

Sure is. And that’s why it’s important to look at the bigger picture at all times. I’m liking this positive CC lol there are those that have the faith looking at the background factors and those that react run by run. Always stick to the background signals when looking at inter run variability. This will act as a good guide. Still could change but now we see ensembles in line with background signals. Hence westerly momentum is stagnated

You couldn’t make this up. Everylow pressure in winter in the history of mankind moves towards the east. Except when we want it to undercut, then it stagnates and moves northwestwards! At least the end result will be just as good

That’s good and close to what I had worked out just looking at the models. Tilt excellent too. Just a few more pumps of hot air and the balloon will fly and the Strat will be brought down. What’s good is that we are seeing a consistent but strengthening signal here, and I believe similar with Eps. Perhaps we will just get a SSW before Jan - either way it will be a close run thing.