January CET

[SNOWPLOUGH]

Does anyone know when was the last time there was a calender month with an average temp of -0.3C ? Maybe mr.data would know ?

Dan

[Scorcher]

Its been cloudy here generally from the Sunday the 10th of January to Saturday the 16th of January with hardly any sunshine. Its been a case of glut or famine, sunshine wise. At least around here,

There was quite a bit of sunshine in Manchester yesterday afternoon. I was in the city centre yesterday and conditions actually felt rather spring-like, with temperatures around 8C and not much wind around. Although to be fair 8C probably feels warmer than it has done for a long time after what we've had recently. But I do take your point in general about the 'glut or famine'. The sunshine figures have been inflated by those several days of virtually unbroken sunshine we had around the start of the month.

[AderynCoch]

Does anyone know when was the last time there was a calender month with an average temp of -0.3C ? Maybe mr.data would know ?

Dan

February 1986 (-1.1C)

(January 1820 and the Decembers of 1788, 1796 & 1878 all averaged exactly -0.3C)

[kold weather]

0.2 (0.15 rounded up) to the 17th

Last night a fairly cool 1.7

2.0 is about the mark I think (after adjustments)

Yeah I think thats probably about right, the next 2 weeks seem to average between 4-5C I'd imagine looking at the models. The milder days seem fairly well balanced by the cooler days from the looks of things so within a degree of average for the time of year seems probable overall.

3C is still possible of course, but we need an average now around 6.5C, something which both yesterday and today will likely fall short of before the slightly cooler stuff comes back. 2-2.5C is IMO the range we are looking at right now.

[NorthantsSnow]

Well it looks like we might just scrape a colder January than 1997 but it's going to be mighty close.

Still, cannot grumble. The start of this month was superb in terms of cold.

[AderynCoch]

I have to admit that if we can't get a sub-3c month with one of the most severe cold spells for 20-30 years then I will begin to wonder if it really is achievable anymore!

Oh it's achievable, we just need that bit of "luck" so that the cold falls inside one calendar month. As has been pointed out, the month from mid-December to mid-January has averaged very close to freezing - since the Victorian era, only the legendary 1962/63 and legendary (first half at least) 1981/82 have had colder month-long periods so early in the season. However, since the cold has spread itself fairly evenly across two calendar months, the actual monthly CETs haven't been that impressive. Conversely, the likes of January 1985 and January 1987 have seen cold periods fit neatly into the calendar month. February 1986 saw the vast majority of that winter's very cold spell, hence the extremely low CET (-1.1C). The coldest month ever recorded (January 1795) saw the cold fit almost perfectly into it (only 31st December - 30th January was slightly colder than the calendar month).

The same applies to heatwaves and summer months - like its cold counterpart January 1795, the hottest month ever recorded (July 2006) was only a day off being "perfect" (with the period 30th June - 30th July being only slightly hotter).

The timing of the prolonged cold this winter hasn't been kind to monthly CET-lovers (myself included ), but it has still been rather exceptional.

Edited January 18, 2010 by AderynCoch

[ukmoose]

I think there is far too much hanging onto this sub 3C month business.

According to Philip Eden based on his figures we've had a 31 day period and a mid month to mid month period at that which is a fixed period of time in itself, that was sub zero

16th Dec -15th Jan CET: -0.3C (-4.8C)

There were people saying this can't be achieved now.

Furthermore last winter, we had a 11 week period that was sub 3C

:lol:

It's a benchmark. Some people don't like them - that's fair enough but they're still there.

[damianslaw]

Well it looks like we might just scrape a colder January than 1997 but it's going to be mighty close.

Still, cannot grumble. The start of this month was superb in terms of cold.

I believe we will easily beat Jan 1997, it is looking like the coldest Jan since 1987 and the coldest month since Feb 91, as others have stated 2 degrees would be a good bet, slim chance we may even beat Feb 91, if the colder theme being shown for the last week verifies..

[Thundery wintry showers]

Yes, I certainly think we'd be in with a chance of beating February 1991 if the latest UKMO/ECM charts verify- from about T+144 I would expect a fairly hefty spell with CETs in the 0 to 2C region. If GFS's milder scenarios verify, though, and it still cannot be ruled out, then 2 to 2.5 would be more likely than sub 2C.

[Weather-history]

It's a benchmark. Some people don't like them - that's fair enough but they're still there.

The argument is not the benchmark, the argument is whether the benchmark can be achieved and I find it amazing people still question the achievability of this benchmark when we just had a 31 day period that was around the zero mark.

Edited January 18, 2010 by Mr_Data

[Roger J Smith]

The tyrrany of the calendar once again rears its ugly head. These past two winters are remarkable seasons for having most of the good stuff straddling monthly boundaries, failing to be preserved for posterity in monthly CET alone. Same thing happened to some extent in 1991, no? One hopes that the ECM has the pattern better foreseen and that a few more very cold days will at least give this month a nice sub-2 benchmark as it seems possible could be the outcome.

The warmest day of Jan 1814 was 0.8 C, now there's a benchmark not likely to be eclipsed any time soon, even if we take any thirty-one days.

[Thundery wintry showers]

That's another thing that was remarkable about the cold spells of December 1976 through to January 1987- very few of them straddled calendar months, tending instead to be concentrated within calendar months. Interestingly this was also true of many of the cold spells of the 1950s- December 1950, February 1955, February 1956 (markedly so), and January 1959. This was often not the case during the 1960s, however, which often had cold spells straddling December/January and mild spells around mid January. Over a long period of time it should even out.

That doesn't mean the use of calendar months is useless, but rather that it's worth using other measures as well to assess the extent and longevity of cold (or hot) weather, such as those that Osmposm gave earlier.

[kold weather]

I think one of the ultimate straddlers was Jan-Feb 17, the figures from that cold spell over 31 days probsbly rivals something close to Jan 63 but it was all spread out over the 2 onths and so instead we got 2 very cold months rather then 1 sub zero month.

Anyway models now suggestive of at least a HP evolution with something of an easterly, maybe stronger easterly if the GFS is correct...either way this evolution now totally rules out 3C and indeed makes sub 2C much more possible...

[Thundery wintry showers]

Philip Eden's version of the CET goes for -1.3 for 1st-15th Jan and -0.3 for the 31-day period 16 December-15 January:

http://www.climate-uk.com/page2.html

288% of normal sunshine for 1-5 January!!!

[AderynCoch]

I think one of the ultimate straddlers was Jan-Feb 17, the figures from that cold spell over 31 days probsbly rivals something close to Jan 63 but it was all spread out over the 2 onths and so instead we got 2 very cold months rather then 1 sub zero month.

I've just checked and the 31 days from 15th January 1917 to 14th February 1917 averaged -1.2C - more February 1986 than January 1963 but impressive nonetheless.

As for this month, the models are up and down like an elastic yo-yo at the moment but yes it doesn't like true mildness will manifest itself, so 2C or thereabouts looks realistic (and would fit in nicely with my pre-month prediction of 2.0C :lol:).

[Roger J Smith]

One thing that's easy to exceed is average daily sunshine in January in the UK. There are six extra hours available, you can only go low by two hours a day.

[LomondSnowstorm]

Glad my guess of 1.7C is still in the ballpark, though perhaps not the most likely result

[Kentish Man]

Philip Eden's Climate UK (Manley) is on 0.1C while Hadley is on 0.6C (Both Jan 1 -19).

[kold weather]

Well temps today aren't as cold as progged, maxes seem to be betwen 4-5C and the mins came out at 2.5C and so today will only come in a little below average. Next few days look like trending back above average again.

Still every chance of a colder flow for the start of next week which will help to probably halt any rise in the CET but much depends on how cloudy the flow is of course.

Range IMO is between 1.5-2.5C now as an outcome, anything above 2.5C is looking very improbable, 3C now needs 6.73 over the next 12 days and the next 2 days will only further increase that figure.

IF the 0z ECM comes off then something bwtween 2-2.5C is the most likely oucome (given it breaksdown the set-up by the 29th allowing 3 days of slightly milder air again) but if the 06z comes off then the raw figure could well end up sub 1.5C.

Personally, I expect the adjusted figure will end up below 2C, as I'm expecting a good 0.2/0.3C adjustment.

[Optimus Prime]

Still 11 days to go but I think below 3.0c is above 80% now. Below 2.0c somewhere around 40.

The GFS run (which is far colder then then what the GOD is saying...ECM) has the period 21st - 31st at 1.9c. Assuming the CET is 0.7c to the 20th it would finish on 1.1c

[kold weather]

The 0z ECM is much colder then last nights run BUT now the 06z is much milder indeed, somewhere in the middle still seems the most probable outcome IMO.

Looking at the flow progged I still think outcome between 2-2.5C unadjusted, so still got a decent chance of coming sub 2C after adjustments, though the last couple of days could well end up fairly mild and cloudy looking at the synoptics progged, we shall see, will be quite tight I think!

[Snowly does it]

rounded up to 0.8 to the 20th then on Hadley, 7 per day now required to get to 3

Today will be below average and then Friday looks like being the last day anywhere close to the requirement for 3 or even 2.5 before the tail end of the month.

2.5 looks very much the upper marker for me now with 2.0 or thereabouts still favourite (especially after adjustments)

Manley now requires over 5 per day just to reach 2.0

2.0 is the new 3.0 it seems and how ironic if we get stuk on 2.0 at the end of the month like last years 3.0 for January.

[damianslaw]

Agree that 2 degrees is a good bet, however, if a northerly verifies towards the end of the month this will result in much clearer skies and thus colder nights, high pressure would likely follow to produce further cold nights, so still a chance we may eclipse Feb 1991 albeit rather slim, but not out of the realms of possibility. Maxes over the coming days will be suppressed apart from tomorrow, byt Sunday much of the CET will do lucky see maxes of more than 4 degrees.

[West is Best]

Even at this late stage of the month there is a wide range for the final outcome. The difference between the 0z ECM and the 0z GFS could be as much as 2 degrees on the final outcome. I certainly would still not rule out something above 2.5C and I don't even think sub-3C is actually quite as nailed as most seem to assume. A mild night last night followed by a mild day today, for instance, will pull in something above 7C for the day. Much more of that and the monthly mean will rise very sharply.

On the other hand, if the easterly does actually materialise then the opposite could still be true and we could end up at around 1C. Remarkable divergence at short range.

[reef]

Hadley is now on 0.9C to the 21st. Yesterday came in at 4.4C.