bluearmy

I dònt think the 12z gfs did a terrible job earlier - it's just post day 8 when they lose resolution at the point where we have another pulse on the jet heading east ........ never going to end well!

whilst we are on the subject of model bashing, let's not bother with ops post day 7/8 - just a waste of time taking them seriously at that range. I think the issue here is gfs is likely wrong in what should be a timescale where it shouldn't be - how wrong remains to be seen. The next few runs should reveal the answer.

Ecm used to over amplify - full stop. Since its upgrade autumn 2016, the bias to our west seems to have moderated but we haven't tested Scandinavia apart from last Jan (illustrated earlier by mwb). Note that the eps clusters have the op with only 10% support in the mid term (although there are six clusters ). In the 8/10 day period the clusters reduce markedly and the ridge to the north more than northeast has good support. this has a fair way to go yet and I doubt we have seen the correct solution.

They are playing the odds on next week being mainly anticyclonic - which is currently what I would do in their position!

Note that 30hpa splits 6 hours before 50hpa ......... (some will say this isn't a true split yet) 10hpa looks stretched by day 10

I know the gem isn’t particularly trusted on here but it’s value imo is that occasionally it picks a winner. It picked this Scandi ridge first and it might just be right on this occasion. About forty five mins till we know where ec op is heading ...... initial ridge may be a bit flat (ironically advecting lower uppers) but the second coming via the stalling trough could be the interesting part.

Gfs remains progressive with the split jet heading ne rather than north which would prop up the block with some WAA too much reference to meto forecasts for next week and their indication of a breakdown - they are nothing like gfs. They reference an uncertain timescale to a breakdown from the west by the end of the week. Ukmo currently shows Monday lunchtime at T144. GEM only reaches Friday lunchtime. Some of you are getting way ahead of yourselves on timings i would expect a less robust block on ecm tonight, simply because the outlook on this block is uncertain and we have seen the op alternating between amplified over Scandi and less so. An amplified run this evening will carry some weight then.

If you read the NOAA cpc analysis each day, you will see them referencing telecons all the time. Thats more in the two week area - more than that is going to be fraught with risk

I like Dennis but I clearly spend too much time on here as I remember most of his posts ..... as you say, perhaps he is a good analyser btw, the blocking signal he showed on that post was very weak - I recall asking him where it was !!

The conundrum at T300 is whether the bigger mobile cluster is more likely or the 75% more blocked clusters - very different surface conditions??? who’d be a forecaster !!

At their low res post day 8 they certainly should be ! i do recall a few years ago that a 12z run of the gefs suddenly picked up Scandi highs from pretty well nowhere and all the nwp followed suit. One swallow .......... I guess they may refer to the current direction of travel on the gfs/gefs and hold back a bit on a very cold forecast for later next week and beyond (if mogreps and eps are in agreement) but I’m pretty sure that Ian told us they will not use ncep as anything like their primary guidance.

Exeter will not be making a forecast for next week based on any op output They will mainly use mogreps and eps the eps bring the Atlantic into the west as next week progresses - how Far East ? How quickly? If the op is right then the eps will catch up and their forecast will evolve i know we live in a ‘want it now’ society but not everything works like that ! Patience .... gfs is right about something in its general evolution but try working out what it is and whether it’s going to scupper the other models current view.

Can we just wait an hour for the updated meto to come out the forecast for next week said becoming milder in the west as the week progresses but uncertain as to timing - would you predict anything different ???

Based on one gefs run from xmas eve - a stuck clock as they say dave ..........

I wonder if this will become a perfect illustration of how low res output struggles to resolve a split jet - hope so!

But it hadn’t run at that point ??? exeters update merely reflects their modelling - Scandi ridges are generally tough for models so things can easily change most models now showing a decent easterly flow now - lets see what ecm makes of it

There really is no easterly yet - no cross model agreement. We surely aren’t going to refer to a transient lee flow from the east as an easterly?? Need to see the next suites and then tomorrow’s 12z’s should be there or there about agreement wise. Looking at the eps clusters for days 5/8, I wouldn’t be making any predictions!

Given the way things have planned out thus far this winter I wouldn’t be predicting anything !!

Don’t upset Judah again ed ........... he seems a bit precious sometimes !

We sort of still are, save for a transient ridge . ................ and it certainly is going this week !!!

Gfs 06z op is a pretty good fit with the eps mean at day 10 .

Strangely, with this evolution, the weaker and shorter the easterly flow , the lower the uppers. a big amplified ridge at the beginning cuts offf the cold uppers getting south. Whilst the ecm op looks less exciting then yesterday's 12z re the scandi high, it's position by day 10 isn't too different re the Atlantic. Re the extended eps, same theme but a slightly stronger Atlantic and azores though nothing much more than run to run variance. Suspect the clusters will be slightly less majority undercutty than last set.

With the set up at day 8, I'm not going to pay too much attention to the gefs into low res. Similarly the eps post day 10. These split jets are notoriously tough to model, even in high res.

You could argue that the mean at day 8 is marginally better on the 18z than the 12z. Not allot in it - slightly less amp over scandi but better alignment of the Atlantic trough for some WAA.

Is anyone ? Nothing definitive we have seen as yet points to such a thing. The trends are there for sure but to extrapolate to that is a fair old step