Stratos Ferric

8.7C

Slightly below par... 6.2 C

Could still go either way this month, and GFS is continually imprecise when it comes to picking major changes in trend. However, on the basis that in the best of times three cold months was a rarity - and we no longer inhabit the "best of times" - I'd take a punt on the upwards side. 4.2C

Quite a change since my last update. As the narrative in the attached suggests, it's hard to place this month properly in context. Assuming a month end mark of 1.4C, then by recent standards it's exceptionally cold. Taking the deviation from the running ten year mean for the month (= -3.8C) then it ranks 4064/4106, i.e. just about in the coldest centile (1%) of all months since 1668. Feb 1986 (-4.5); Dec 1981 (-5.1); Jan 79 (-5.1); Jan 1963 (-5.6); and Feb 63 (-4.5), in recent times all came in colder on this measure, but they set in context that, relatively, this month is much colder than it has been in absolute terms. Amongst Januaries alone, it would rank 329/343 on the same anomaly basis. Expand the reference period to 30 years and the rating drops to 322/343 - reflecting the impact of recent warming on the comparative baseline. This month will also end the record breaking spell without a sub 3.0C month (ditto sub 2.0C, though almost certainly not sub 1.0C). It may be a long time before we see its like again - unless, of course, we are entering a period of sustained cooling. Personally I doubt it, but then I would have doubted that we could come in this far below 3.0C again.

Latest projection from Stratosdale herewith. Sub 2C now looks unlikely, but not yet out of the question. Coldest month of the christmas pudding would require a major shift in projection, but coldest January is probably still better than evens, probably around 70-30 I'd say. Certainly sub 3C though.

This from the Daily Telegraph last January... The temperature at Benson was the lowest in England since the current cold spell began last month, and the second lowest ever recorded in the area. The coldest was -2F (-18.7C) on Jan 14, 1982. I'd like to see Benson verified: it's at least 7C colder than anything else in the very near vicinity at present (two stations I can see in Wallingford) and 10C and more colder than the rest of the Chilterns escarpment. That said it is an RAF station, so the readings ought to be robust, and another private station nearby is also showing -15C. Looking at the drop off in visibility they've got an inversion now, cold air draining off the hills to the NE. Will be interesting to see how much lower it gets, if it gets much lower at all. Will need the breeze to stay very gentle and around its current vector.

At last a month to challenge the 3C mark. All the elements are in place for once: cold air from a block with decent snow cover over a large part of the country. This latter is vital because it causes significant "drag" on any breakdown, tempering the effect of any milder air mass potentially for several days. Some exceptionally cold days also put negative degrees in the bank - another absent feature in recent years. Attached plot projects forward from today, and includes the actuals for three recent markers, the Januaries of 1979, 1997 last sub 3C January, and 2009.

I very much doubt that any absolute cold records will be broken, but there are some spectacularly low temperatures around in central England this evening, and several "coldest since" type records are possible tonight. The evening drop off at Benson, and Woodford, for example, is remarkable by any standards, but in recent times almost certainly unprecedented, and indicative of locations sitting in sinks below uplands, with snow lying, fairly still air, and clear skies; perfect conditions for cold pooling. The records set, for example in December 1981, occurred in not dissimilar conditions BUT built up over several days. The record minimum set at Shawbury, for example, and the minima in same period in the Scottish glens (e.g. Braemar) were marked by days where maxima stayed well below, if memory serves me right, -10C, with freezing fog abounding. The current set up is likely to be too mobile, and also there is some ephemeral cloud around, both of which will spoil exceptionally low temperatures. Therefore, I'd suggest, some notable lows tonight, but not setting absolute records for the UK, nor coming close to it.

Definitely caught in a remarkably persistent convergence zone here. Drifts outside up to around 40cm, but level snow slightly less than I estimated last night, probably 3-4cm. Can't remember an accumulation from showers (without any frontal influence) like this for years.

Seem to be located under a long street of showers here in Upper Stratosdale. Near blizzard conditions at times, and like a giant christmas snowstorm through the window. Needed all the traction control the car could muster to get home at 21h, and then only just managed it. Suspect there will be some marked local variation in depths hereabouts in the morning. Wind has scoured the yard clear of snow, but it's piled up to 6" plus on the far side. Suspect level depth at the moment will be around 4-5cm.

Mix of sleet, and more sleet, here in Stratosdale. Surprising because it was around 5C when this started down in the valley, though a couple of degrees cooler up here. Didn't think this front would have anything wintry on it. Sleet seems to be this season's black up here.

4.8 C

Very wet sleet here, as there was around nidnight last night. Now snow visible, but melting grains in the raindrops on the velux.

7.6C

10.2C