Mike Poole

Just started to snow here! Light at the moment. Here’s HARMONIE 0z take on the track and pivot, this model has been quite consistent on the last few runs: If anything, the precipitation looks a bit stronger on the radar though.

Thanks, yes my location was looking good to benefit from the pivot on last night’s high res models and so far I’m happy with what’s happening on the radar.

Here you are, shouldn’t be long! My location, about an hour away...

No it isn’t. The top half of that showing red dies out it is the bottom half that goes on to deliver whatever snow we get as per the latest models.

Yep, the // went bad, but the op GFS, that seems to have gone the full seahorse at T348:

Where’s this one going? GFS // T252 Answer, not where I thought it was at T282: But you can’t really get to Scandi high from where we were without a ridge across the UK, let’s see if it happens...

Nope same time, Meteociel is 1 hr ahead mate!

HARMONIE 18z take: Radar check about 10pm: Not bad, and there is more significant precipitation to the south of that band than the north, so the onward evolution looks consistent to me.

The thing with long chases, and this is definitely one, we’ve been on it since weeks before the SSW on 5/1/21, for me, is that they are great fun -provided they deliver in the end. March 2018 was the classic example of one that did. Despite having seen nothing but a few polystyrene balls of graupel this year, I am still fully committed to this chase and think it will deliver. Hope to see snow tomorrow! And then I look for what is next, and I think the SSW has not gone away, has yet to impact fully and we not be done with warmings yet either, here zonal winds plot: The MJO may help to get the blocking we want in the trop. The NAM plot shows the downwelling from the SSW and the hiatus that has so far prevented the blocking patterns developing, but that may be about to change (note GFS 0z forecast); If the combination of the 5/1/21 SSW and the MJO now contrive to get blocking in the right place, then any further strat warming events may reinforce the pattern. Meanwhile the ECM T240 mean has a wedges and sliders look about it, a displaced Azores high, and trough into Europe. So the big picture is all good.

I think the latest NAM plot from Stratobserve is interesting, and reflects the way things seem to be panning out. You can see the downwelling initially quite well but then it hits a hump while the trop was not willing to properly engage, and then hopefully, by this run anyway, that hiatus is now behind us, maybe aided my MJO:

It’s possible they might have been and gone, and are on their way out again between the 24hr time steps.

ECM T168, for most of the country the cold won’t be there until the low has gone through, maybe some back edge snow for the south, more for the north:

ECM T144, maybe a slider here:

ECM T120, looks like more of a wedge at this point than UKMO for comparison:

HARMONIE 6z take on tomorrow’s snow: An area in central southern England might benefit from a longer period of snow due to that pivot towards the end, which fits with the detail of the MO warning.

Develops to this, T192: Good run this, exactly what we should be seeing given background signals...

It would be later than that if we did, so all good here at the moment.

Nah! I’m a meteociel addict, Griff.

What’s up with the pub run? Stuck on T18 on Meteociel...

It certainly will be inconclusive at this stage, and it is not the local pattern that is of interest to me at this stage, this is 10 days plus out, it is the wider pattern, hence highlighting the -NAO on the charts, get that in first and the cold will follow, and get the cold in second and the snow will follow...

Short term update, here HARMONIE cumulative snow covering Sunday: Something for those who haven’t seen any snow so far...EURO4 Bit of a Jackson Pollock that one, as it seems to record it in the sea too, but never mind, snow chances on Sunday...and better chances longer term into February.

ECM clusters, T192-T240, and T264-T360: There’s a lot going on there! But to simplify things look at the green borders = -NAO. The later chart has all 16 going for it. The details of where the block will be and how it will affect the UK are for future runs, but my opinion is we are now in the game for February like nothing so far this winter, so relax for the next day or 5 and then watch the wintry synoptics show on the op runs.

I think a consistently inconsistent signal in FI for some real cold is now starting to show up. Like the end of the GFS 12z, and some earlier // runs. Likely due to continued effects of the SSW and some help from the MJO. Still way out in FI at the moment, but given the reasoning why this is a plausible evolution, I would expect the signal to increase rather than fade away in subsequent runs...we will see...

Hey, well we can wait for the cold a couple more weeks, it is not like we have anything else to do is it?

Yes, clusters do suggest an improvement but we’ve uncertainty to get through before then. ECM clusters T192-T240 6 clusters: T264-T360 4 clusters: With the earlier set there is blocking to the north but too far and doesn’t benefit the UK from a cold perspective, the later set hint at bringing blocking to the regions where it might actually benefit the UK, note only one of the 12 charts has a blue +NAO border, 8 have green -NAO borders. Hardly worth pointing out there is no raging Atlantic zonal weather in any of this. But we are into February by this point. 2 months off winter gone with nowt for many, the chase goes into the final third...and then into extra time (March has delivered twice in the last decade). Not ruling out a penalty shoot out in April!