IDO

The noticeable part of the next week is upcoming potential destructive storms (to D6 gusts):

Yes, if it is a replay of the last cold spell; the UK high being eased west/NW is a better option and a possibility, bearing in mind it is a repeating pattern that can be noticeable in a trop-driven regime. But so far, looking at the modelled jet, we are less favoured by the split jet versus this recent cold spell UK high. That may change with further runs, but the northern arm is being modelled to be stronger than earlier in January before the UK high developed. That may make it more difficult to sustain higher pressure at higher latitudes.

As always, we should be wary of random cold charts in FI on the models, especially if they are outliers and contrary to solid means. The GFS 06z op falls more in line with the mean from D8-16 with the synoptic: The control also follows this. The mean at D11: An Iberian-centred Euro high. I am sceptical that we will see any blocking from the NE with this setup. That high is unlikely to move east due to the Siberian high & E Euro trough, so retrogression back to the Azores and more likely GH than a Scandi high.

2m temps - 850s - mean: The GFS op a BIG outlier for London. The NH mean similar to this morning. Signs of maybe a retrogression of the Euro high back to the Azores with the tPV lobe over Greenland moving east and a possible Atlantic ridge sometime in the first week of Feb; still my call. But the GFS op maybe seeing something that could override that signal, so one to watch...

This is precisely what you would expect based on consistent mean output; 06z op D8-16: The tPV to our NW is pumping up Sw'ly winds to the UK. There is simply no possibility of an Atlantic ridge with the tPV modelled as it is. I would settle for early Spring rather than a raging zonal westerly. We can only hope the background signal rises above the main driver, the tPV and changes the early Feb outlook.

No sign of cold on the GEFS before month's end (after Sat), and the NH profile suggests that even in the best-case scenario, there is little chance of cold, let alone snow, for most. For London (2m temps): Mild in the dry interludes and the south fairing best. The GEFS mean still not showing anything of interest with the tPV in situ to our NW; D8-16: The Pacific Ridge is a two-edged sword. When the tPV is split, it can allow Atlantic heights, but when parked to our NW, we generally get a more SW'ly flow. Usual caveats but consistent output from GEFS. The GEM mean has a similar idea: Siberian and Pacific mean highs/ridge boxing in the tPV around Greenland. My thoughts are still the earliest week 2 of Feb for possible changes as the tPV leaks are due east late in the means.

There is no sign on the GEFS mean yet of a quantifiable change concerning the UK returning to cold by D16. Taking the last cold spell and the subsequent 3-4 weeks of changeable weather, it may be too early to show up. The GEM and GEFS D8-16 mean: Very similar NH profiles. It does appear the upcoming pattern is of relatively high confidence. The tPV returns to our NW by D16 with a nascent Pacific ridge. Neither suggests an Atlantic ridge is viable in that period or the immediate days post-D16. The usual caveats, of course, but maybe in week two of February before we see another shot based on current means. Before then a cold zonal flush followed by a weaker zonal regime with maybe the south less wet.

^^^ T84 fax:

GFS joined the other models with the Bay of Biscay low supporting the HP as it passes east to west, delaying the colder air departure by a little bit: T132: As of now, all models have this part of the puzzle, so we get a fuller picture of the final fall of the GH. Cold lingers until early Sat. T156: Similar to every other model around that time. EC for example:

The breakdown is almost inevitable. There are differences in the microscale features around the D6-7 charts, so the GFS storm is not sure to be as shown. The difference is the modelling of a cut-off low around D6 that allows the GEM and UKMO to stop the heights from falling as quickly; the GFS does not have this as far north: But it is semantics, with all three ops very similar and the westerly flow incoming with the cold trough edging east, creating that monster low as it rubs up against the colder air. The GEM shows one of my three options: a NW to SE split: The GFS cold zonal. Still, indications as we run down January of Pacific ridging; D16: The mean picked up on this recently. So hopefully only 7-10 days of westerlies.

The D7 UKMO is zonal, we are just in the mini-ridge part of the zonal pattern, so colder uppers hang on a bit longer than some model runs. But the pattern has sunk by D6-7: The GEM op looks wrong. The mean is more representative at D7:

The models bang home the collapse by Friday by doubling down, on the trend. The OPs, I would not care for means with the low from the Azores; it looks like it misses the south comfortably. GFS: Snow for the next six days before the melt: As expected, it is likely to be dry for many. The usual caveats. Post D6-7, we see the pattern return before this cold spell—a barrage of wind and rain until the 29th (south faring better). There seems to be a lot of energy firing up, so some storms and a potent jet. That will likely burn out after a week, giving us maybe longer, drier spells between the systems. Looking at the mean for GEM and GEFS at D16, there are nascent signs of maybe a Pacific ridge developing, but the impact on the UK would be days away from that: Those means are consistent, as with the previous three-week wet spell. For those saying why I am seemingly confident of this spell, it is because the models are significantly better at modelling a westerly pattern like this compared to height rises, which are notoriously unreliable. Some cold weather is incoming, but the UK, as always, has been mainly on the wrong side of this two-week colder interlude for snow for many, and for those hanging on an SSW, it is a poignant warning that even with the SSW (warming), we will need luck.

It is beginning to play out now. Next Friday, the pattern has collapsed, and on Sat/Sun, we lose the cold uppers and enter a westerly regime for around 7-8 days on current GEM and GEFS means. That westerly flow has yet to be qualified: zonal, cold zonal, or N/S. That remains the question for the latter third of Jan. As for further cold interest, the models only go to the 28th, so who knows? But looking at the setup, with blocking East to West over the polar field (Pacific and Siberian mean highs), we do need some of these background signals to kick in and not have the three-week changeable spell we had after the Nov cold. The 12z GEFS mean similar to the 0z from D8-16: Maybe UK N/S split as to wind and rain? As for next week, it is cold down in the south and probably the best is a few flakes locally for the minority. Scotland should get a good fix. The low from the Azores looks like a miss, but I will give it one more day to edge north before writing it off.

D11 GFS: Yuk!!!

Yes, look at the moisture in that low: We can see the oranges as they pass through the low countries. A bit further north, please, even if it may mean rain to snow further south.

A glancing blow:

It is strange as many of the enthusiasts here noted that the models tend to correct south due to a bias that is corrected as we count down to T0!

ICON follows EC, which is common. A variation on that theme for the breakdown: I

The ICON has the low track over France, see the snow accumulation as it moves across: So near...That is quite a dumping and we are running out of time to correct north as the ICON is now coming into line with other models.

...and by D16: Let us hope you are right, but this represents the mean and is consistent with the last 2-3 days' FI output. Looking on Twitter, I do not see anything that would make this an outlier scenario. Since repeated designs are a good starting point for Winter patterns, we got 3+ weeks of zonal after the previous cold spell. But as you imply, just for fun, or not!

Looking at the T210 chart it is horrible; a harbinger of changeable weather for the foreseeable with the tPV circling to the N/NW: T210: Fast Forward three days and deja vu: T306: Consistent stuff from GFS in FI rather than chaos, and usually that means a strong signal.

I think we have reached the point that the micro detail changes are not impacting D9+. The 06z is similar to the 0z. It is slightly colder, and the passing UK high, on a N/S axis rather than E/W as per 0z: That would add a day (+) of cold uppers from the ridge, but nothing interesting. Upstream around the Pacific is where I am looking for short-term changes to stop the HL Blocking from collapsing. So far, there have been no changes there:

The low is further south on this run, so I expect very dry south of Birmingham for the next 8 days:

The EC op is an outlier for pressure at D8 (London): So the ridge over the UK is not as strong as the op suggests. That ties in with the mean, closer to GEFS:

The mean indicates that on the 20th, the 850s drop closer to 0c than -5c, ending the cold period. The EC looks like cold zonal at D8-10: The GFS full-on zonal: There is no respite on the GFS out to D16 until the end of Jan, but the westerlies become less energetic. Hoping that we do not repeat the last cold spell, followed by three weeks of wind and rain. The EC looks far more likely for a short mobile pattern looking at D10, but as we know with EC, that is a fool's errand. The GEM and GEFS mean, D8-16, are similar and suggest something like December, with Siberian and Pacific highs corralling the TPV to this side of the NH: As for the next eight days, added to the last five, a solid cold spell, though for many of us, the absence of a snow event will make it a bit disappointing.