January 2013 CET (2012/13 Competition)

[damianslaw]

Quite a lengthy spell of sub-zero CET values now likely, in any winter obtaining a 10 day spell of mean CET below 0 degrees is good going. How long will we sustain such a spell is the question.

[DR Hosking]

4.4c to 17th

[Robbie Garrett]

If we reach 3.3C by the 20th (a big if) then we'd need to average -2.1C for the remainder of the month to beat January 2010. To get below 2.0C, we'd need to average -0.4C.

No chance at all of beating December 2010.

What's required to beat December 2010? As I'm seeing London hitting -6*C next week on a few occasions according to the BBC (MetOffice data)

[damianslaw]

We could have been looking at very low nightime minima over the coming nights had we built a ridge over the country, alas despite very cold uppers and dry air and deep snow in some places, too much cloud and wind is now going to prevent low temps.

[Weather-history]

Hmmm,it has got me thinking, we not had a cold middle third of January ie 11th-20th January period for sometime. Could turn out the coldest such period for some years.

11th-18th January 2013: 0.6C

11th-20th January 2001: 1.0C

11th-20th January 1987: -2.9C

Edited January 19, 2013 by Weather-history

[hillbilly]

just looked on met office for bradford(my nearest) gave 0.7 average high and -4.9 mins the coldest january since 1908 here only feb 47 colder putting jan 63 in third place

[BornFromTheVoid]

4.1C to the 18th

http://www.metoffice..._info_mean.html

Yesterday was -0.9C. Today's minimum is -2.1C while maxima were around 0C, so a drop to 3.8 or 3.9C tomorrow.

After that, the 12z GFS has the CET at

3.6C to the 20th (-2.0)

3.3C to the 21st (-1.4)

3.1C to the 22nd (-1.1)

3.0C to the 23rd (-0.7)

2.8C to the 24th (-0.5)

2.7C to the 25th (0.0)

2.8C to the 26th (5.2)

[The PIT]

Hurray we've got below average. So far one of the rare occasions where a silly mild spell is countered by an equally strong cold spell. Something we haven't seen for a while. ECM has the cold hanging on longer so it'll be interesting where the CET ends up.

[damianslaw]

Hurray we've got below average. So far one of the rare occasions where a silly mild spell is countered by an equally strong cold spell. Something we haven't seen for a while. ECM has the cold hanging on longer so it'll be interesting where the CET ends up.

One thing which has been very notable during the past 12 months or so, is how we have seen periods of very similiar temps with marked cut off points, what I mean is we have tended to see 2 or 3 weeks of uniform temps with sudden changes. We saw a 2 week cold spell very end Nov- first half of Dec followed by a 3-4 week very mild spell and now we are seeing a 2 week cold spell. I'm not saying this trend will continue but it is just an observation.

Back to the CET still looks like we will finish below average, with a finish somewhere between 2.7 and 3.6 degrees, all dependent on what might happen in the last 5 days. A very mild end to the month would mean a finish close to 3.5 degrees, whereas a more average spell will probably mean a finish near the 3 degree mark and a cool end high 2's. Doubt we will come in below 2.5 degrees - had we clearer skies at the moment though, then low 2's would possibly be achieved as minima would be very low indeed.

Whatever the finishing value, it will mask a month of very contrasting fortunes, a bit like Feb 2012 which saw a very cold first 10 days offset by a very mild second half.

[IanR]

There have been no above average CET months since August 2012 , and even that only just, the south of England was actually below in August. So now we are in 2013 will the trend of below average continue, Whats betting Feb will be below as well, I am finding this very interesting as how long this trend can be sustained, Surely things will have to even out ?

[Weather-history]

Surely things will have to even out ?

You would think so but a point I have made in the past is what balances what out? You could argue that we should get a few milder months soon but I could say the recent cooler months are balancing out 2011. But didn't 2011 balance out 2010? And are recent cooler months since April trying to balance out the very large number of warm months we've had since 1989?

Edited January 19, 2013 by Weather-history

[summer blizzard]

Whilst i cannot guarantee that we won't get a short mild interlude as per ECWMF i do not believe that this cold spell will come to an end for a good while yet (when it does i actually expect high pressure to sit over us).

The aim as far as i am concerned is for 2.4C so that we get a month 2C below the 1981-2010 average (joining Jan 10 and Dec 10) and this looks likely if as expected the models drop the breakdown.

[The PIT]

You would think so but a point I have made in the past is what balances what out? You could argue that we should get a few milder months soon but I could say the recent cooler months are balancing out 2011. But didn't 2011 balance out 2010? And are recent cooler months since April trying to balance out the very large number of warm months we've had since 1989?

Well very long term there will be no balancing as the sun will expand and consume the earth so one could argue there will be no balancing.

[Roger J Smith]

Always look on the bright side of life, then?

I will dig up some Feb normals and trivia and post a thread, so gentlemen (and ladies) start your engines.

[Optimus Prime]

GFS 06Z has the mean temperature 20th - 25th at -1.50c. CET to the 19th stands at 3.8c

Estimated CET tracker;

20th 3.5c

21st 3.3c

22nd 3.1c

23rd 2.9c

24th 2.7c

25th 2.5c

If each day thereafter was to average the 81-2010 mean (4.4c);

26th 2.6c

27th 2.7c

28th 2.7c

29th 2.8c

30th 2.8c

31st 2.9c

Or if -1.5c were to be achieved each day until the end of the month the final value would stand at 1.7c. Considerably colder than January 1947 (2.2c)

[Optimus Prime]

Since December 2008 out of 14 winter months (upto January 2013) 11 have been below normal.

[reef]

There have been no above average CET months since August 2012 , and even that only just, the south of England was actually below in August. So now we are in 2013 will the trend of below average continue, Whats betting Feb will be below as well, I am finding this very interesting as how long this trend can be sustained, Surely things will have to even out ?

December 2012 was 0.2C above average., but yes, since April there has been a predominance of below average months.

Im not a believer that things 'balance out', we generally get what we get. This period is just similar to the prolonged period of above average weather between May 2006 and June 2007.

[North-Easterly Blast]

Since December 2008 out of 14 winter months (upto January 2013) 11 have been below normal.

Feb 2009 was above the 1961-90 average.

Feb 2012 was exactly equal to the 1961-90 average.

Dec 2012 was above the 1981-2010 and the 1961-90 average.

Although we still have 11 days left in Jan 2013 and the last few days are still uncertain, but there is a significant chance now of Jan 2013 being the third coldest in 26 years. We are not going to beat 2010 now, but if we can beat the 3.0 of Jan 2009 then we can achieve the third coldest January in 26 years. Beating the 2.5 in Jan 1997 is still not out of the question.

For anything significant, winter 2009-10 saw all three winter months at least 1*C below the 1961-90 mean. Dec 2010 was the second coldest on record. Dec 2008 and Jan 2009 were both around 0.8 - 1.1*C below the 1961-90 means.

The reason for the cooling in December in the 1981-2010 averages compared to the 1971-2000 averages is that the period 1971 to 1988 was exceptionally warm in relation to Decembers. The December mean for this period is 5.3*C despite Dec 1981 being very cold. Take 1981 out of the equation and the mean for the same period is 5.6*C. As the mild 1970s Decembers dropped out of the equation for the 1981-2010 average and also with the exceptional Dec 2010 we have seen such a marked cooling in the December average. The 1961-90 December mean managed to be 0.4 lower than 1971-2000 due to it containing the cold 1960s Decembers.

When we get to the 1991-2020 averages, the December mean may well reduce further as the mild 1980s Decembers will then drop out of the equation, unless we see a few mild Decembers before 2020. Although at this point it is difficult to say what the averages for January and Februry will be when we get to 1991-2020, as the early to mid 1980s were often cold in January and February.

The clear trend is that December was generally very cold in the 1960s, then was very warm in the 1970s and 1980s, followed by a return to around average in the 1990s and 2000s.

January and February are a bit like December in a delayed fashion. Both these months were generally very cold from 1977 to 1987, both of these months respectively averaged 2.8*C in this period, then both these months were very warm in the 1990s and 2000s. A bit like the mild 1970s / 80s December trend, the period 1988 to 2008 was exceptionally warm in relation to both January and February, averaging 5.0 and 5.1 respectively over this period.

It is true that whilst the 1990s and 2000s are notable for very mild winters overall, the image on these winters being mild was not down to the Decembers.

Edited January 20, 2013 by North-Easterly Blast

[Optimus Prime]

Well I wan't comparing it to the 61-90 temperature series as these are out of date and are no longer used outside of HADCET.

[Stu_London]

Low minima likely to be a feature this week.

Could see the CET get down towards 2C by the end of the week.

Would take quite a chunk off the rolling annual CET (low 2s for January will mean somewhere close to 9.4C in running)

[Relativistic]

Low minima likely to be a feature this week.

Could see the CET get down towards 2C by the end of the week.

Would take quite a chunk off the rolling annual CET (low 2s for January will mean somewhere close to 9.4C in running)

Could be even lower once March is over.

[DR Hosking]

3.8c to 19th

[hillbilly]

my birthday is jan 23 and when i was younger it always seemed to snow on my birthday.am in my mid 40s.anyone got any stats

[reef]

Hadley is on 3.5C, yesterday was -0.2C.

[Isolated Frost]

Feeling happy with my 3.2c, should go sub-3c by Friday, maybe down to 2.8c/2.7c, before slowly rising after the 26th- a below average winter month.