January 2021 C.E.T. and EWP forecast contests

[Don]

3 hours ago, damianslaw said:

The current shortlived cold spell might just be enough to enable a below 61-90 finish, even if we see a fairly mild end to the month. I say this given the next couple of days will return below average means, and the last 2 days of the month look average trending below which means there are only likely to be 3 or 4 days in the mild category.

I reckon low 3's is the best bet now after downward adjustments.

[summer blizzard]

1 hour ago, Weather-history said:

24th December 2020-23rd January 2021 CET:  ~2.9C 

What was the coldest 2013 and 2018 30 day period.

[Weather-history]

Just now, summer blizzard said:

What was the coldest 2013 and 2018 30 day period.

If you add  the first 3 days of March 2018 to February's, I think it was around 2.4C for that 31 day period. 

[damianslaw]

44 minutes ago, Don said:

I reckon low 3's is the best bet now after downward adjustments.

Yes most likely landing point, below average possibly more than 0.5 degrees at least wouldn't be bad going at all, and our coldest January since 2010, beating 2013 just and also 2011. Would be good to finish in the 2s but now a tall order.

Edited January 24, 2021 by damianslaw

[Frigid]

30 minutes ago, damianslaw said:

Yes most likely landing point, below average possibly more than 0.5 degrees at least wouldn't be bad going at all, and our coldest January since 2010, beating 2013 just and also 2011. Would be good to finish in the 2s but now a tall order.

I'd say it depends on the downwards correction. e.g by Wednesday we go to around 3c, then a small increase to 3.3 and if the downwards correction is 0.4c which it probably won't be, then my prediction of 2.9 would be bang on. That would also make it the first January in the 2s since 1997.  So so close 

Edited January 24, 2021 by Frigid

[damianslaw]

7 minutes ago, Frigid said:

I'd say it depends on the downwards correction. e.g by Wednesday we go to around 3c, then a small increase to 3.3 and if the downwards correction is 0.4c which it probably won't be, then my prediction of 2.9 would be bang on. That would also make it the first January in the 2s since 1997.  So so close 

Yes will be a close call, I've said how similar Jan 2021 has been to 2009, that ended on 3.0 degrees, high chance could match it.

Would be good to see it followed by a first half to Feb same as 2009, but don't want the second half to be the same, swap it for second half of 2018 that would be an excellent February!

[Roger J Smith]

 

1 hour ago, summer blizzard said:

What was the coldest 2013 and 2018 30 day period.

The 2.9 C quoted by wx-history was a 31 day period (as he says) so assuming you want to know 31-day stats from 2013 and 2018, the coldest ones are these, added 2012 as you may find that interesting by comparison ... any tied values at one decimal precision are sorted by two decimals. 

YEAR ____ 31-d interval _____ CET (1 dec) ___ CET (2 dec)

2012 ____ Jan 13 - Feb 12 ___ 2.1 ___________ 2.11

2012 ____ Jan 14 - Feb 13 ___ 2.1 ___________ 2.13

2013 ____ Jan 10 - Feb 9 ____ 2.3 ___________ 2.33

2013 ____ Jan 12 - Feb 11 ___ 2.3 ___________ 2.34

2013 ____ Jan 13 - Feb 12 ___ 2.3 ___________ 2.29

2013 ____ Mar 9 - Apr 8 ____ 2.3 ____________ 2.31

2013 ____ Mar 10 - Apr 9 ___ 2.3 ____________ 2.34

2018 ____ Feb 2 - Mar 4 ____ 2.4 ____________ 2.43

_________________________________________________________

So 2013 actually had two separate 2.3 C "months" of 31 day cold. Neither 2013 nor 2018 beat 2012 in this regard.

[Don]

1 hour ago, damianslaw said:

Yes will be a close call, I've said how similar Jan 2021 has been to 2009, that ended on 3.0 degrees, high chance could match it.

Would be good to see it followed by a first half to Feb same as 2009, but don't want the second half to be the same, swap it for second half of 2018 that would be an excellent February!

Now that would be awesome!

[summer blizzard]

52 minutes ago, Roger J Smith said:

 

The 2.9 C quoted by wx-history was a 31 day period (as he says) so assuming you want to know 31-day stats from 2013 and 2018, the coldest ones are these, added 2012 as you may find that interesting by comparison ... any tied values at one decimal precision are sorted by two decimals. 

YEAR ____ 31-d interval _____ CET (1 dec) ___ CET (2 dec)

2012 ____ Jan 13 - Feb 12 ___ 2.1 ___________ 2.11

2012 ____ Jan 14 - Feb 13 ___ 2.1 ___________ 2.13

2013 ____ Jan 10 - Feb 9 ____ 2.3 ___________ 2.33

2013 ____ Jan 12 - Feb 11 ___ 2.3 ___________ 2.34

2013 ____ Jan 13 - Feb 12 ___ 2.3 ___________ 2.29

2013 ____ Mar 9 - Apr 8 ____ 2.3 ____________ 2.31

2013 ____ Mar 10 - Apr 9 ___ 2.3 ____________ 2.34

2018 ____ Feb 2 - Mar 4 ____ 2.4 ____________ 2.43

_________________________________________________________

So 2013 actually had two separate 2.3 C "months" of 31 day cold. Neither 2013 nor 2018 beat 2012 in this regard.

I must admit I never remembered the second half of Jan 12 being notable, only Feb.

[Relativistic]

2 hours ago, summer blizzard said:

I must admit I never remembered the second half of Jan 12 being notable, only Feb.

There was an excellent anticyclonic spell mid-January which helped. There was some very mild weather between then and the first 12 days of February (which averaged sub-zero); the 31-day average masks this see-sawing.

Edited January 25, 2021 by Relativistic

[The PIT]

Sunny Sheffield down to 2.6C -1.8C below average. Rainfall unchanged.

[Snowyowl9]

Very cold CET zone last night.

Coldest night in jan since 2010 at -6.1c

[Summer Sun]

3.2c to the 24th

0.5c below the 61 to 90 average
1.3c below the 81 to 10 average

___________________________

Current high this month 3.4c on the 21st & 22nd
Current low this month 0.5c on the 1st & 2nd

[ItNeverSnowsInWindsor]

Same temperature as 1991 now!

What could February 2021 bring 30 years later ?

[Roger J Smith]

We're not greedy, will take 1947 and take our chances on the 2 C warming of the seas. 

As for EWP, another slight rise in the latest estimates, although not much new in the account, 98 mm is my estimate after Sunday added perhaps 2-3 to the 96 reported for 23 days. The 6.5d GFS estimate to end of month is a solid 40-45 mm with those contours separating wetter north from slightly drier south, would bring us in near 140 mm -- adding slightly to the annual points for two slightly higher forecasts. 

Yesterday was provisionally the third subzero CET day of the month but could see that change to four or five after final values. 

[damianslaw]

22 hours ago, summer blizzard said:

I must admit I never remembered the second half of Jan 12 being notable, only Feb.

Remember a 3-4 cold anticyclonic spell mid month Jan 12, which was very welcome after weeks of mostly unsettled atlantic driven weather. It turned milder quickly, before a cold end to January.

The first 12 days to Feb 12 were very cold with a bit of snow on the 4th that hung around. We had freezing rain at some point I remember well.

Its a period not often recalled because it was mostly dry, a drier version of Feb 09 in this respect. Both months did a u-turn mid-month and were very mild.

There have been a number of switcharound Februaries in recent years from cold to mild or mild to cold:

Feb 05: Mild to cold, the cold came just after mid-month though..

Feb 09: Cold to mild

Feb 12: Cold to mild

Feb 18: Mild to cold - relatively speaking

 

[The PIT]

Sunny Sheffield down to 2.5C -1.9C below normal. Rainfall unchanged

[Summer Sun]

3.0c to the 25th

0.7c below the 61 to 90 average
1.5c below the 81 to 10 average

___________________________

Current high this month 3.4c on the 21st & 22nd
Current low this month 0.5c on the 1st & 2nd

[snowray]

Expected a 3c but I thought that there was a really good chance of going back into the 2’s after this cold spell of weather. Not sure what it would take to get a winter month under 3c, something exceptional these days. Temps are always a degree or so higher than what I would have thought, particularly during the day. And there are always these super mild days that turn up where minimum is close to 9/10c and max in the low teens that make a month look rather average in spite of the other 25 days or so being cold or very cold.

Edited January 26, 2021 by snowray

[BornFromTheVoid]

With the provisional data so far and using the GFS 12z for the final 5 days produces a finish of 3.4C exactly. So I'd guess 3.2 to 3.6C before corrections as almost certain.

No point in posting the projections as the 5 day GFS takes us to the 31st

[damianslaw]

8 hours ago, snowray said:

Expected a 3c but I thought that there was a really good chance of going back into the 2’s after this cold spell of weather. Not sure what it would take to get a winter month under 3c, something exceptional these days. Temps are always a degree or so higher than what I would have thought, particularly during the day. And there are always these super mild days that turn up where minimum is close to 9/10c and max in the low teens that make a month look rather average in spite of the other 25 days or so being cold or very cold.

Not had many very mild days this month so far, if any I say, would be interested to know highest CET value day so far. Tomorrow does look mild after a mild night, so it will be one of the milder days CET wise. Thursday and Friday look more near average, and Saturday and Sunday a bit below, so an outside chance may still finish in the 2s dependent on the extent of any marked downward correction.

I expect final figure to be 3.2 or 3.3 degrees at the most, and a good bet with corrections would be 3 degrees, same as 2009, but would be great to drop to 2.9 degrees. 

Probably two out of three days this month I suspect have been below average CET wise. 

Had the dice fallen more favourably then I suspect we could have recorded a notably below average CET this month, easily in the 1s, alas things didn't quite do so after a promising start. Will go down as a close but yet so far sort of month.

Edited January 26, 2021 by damianslaw

[Roger J Smith]

The mildest day in the provisional numbers so far is 9.1 on the 20th. Only one other day (19th) was over 7 C.

In recent decades this passes for a cold January, longer-term it will be very close to the mean of all 363 years (3.3). 

Since the very cold January of 1963, in 58 tries January has been 3.1 or below in only ten years. There have been in addition one at 3.2, two at 3.3, two at 3.4, two at 3.5, none at 3.6, three at 3.7, one each at 3.8 and 3.9 (by 3.9 a total of 23 of the 58 colder than 4.0 assuming 2021 joins this list somewhere).

Once a final number is posted, we can work out how many of these also beat 2021, none are guaranteed to do so at this point.

There has only ever been one January at 3.1, namely 1832. 

Edited January 26, 2021 by Roger J Smith

[The PIT]

Sunny Sheffield at 2.6C -1.8C below normal. Rainfall 115.7mm 142.8% of the monthly average.

Not much of rise expected in the next few days so probably ending here about 2.7C to 2.8C

[Scorcher]

13 hours ago, damianslaw said:

Not had many very mild days this month so far, if any I say, would be interested to know highest CET value day so far. Tomorrow does look mild after a mild night, so it will be one of the milder days CET wise. Thursday and Friday look more near average, and Saturday and Sunday a bit below, so an outside chance may still finish in the 2s dependent on the extent of any marked downward correction.

What is the strict definition of 'very mild' if there is one? The 20th had a mean of over 10C here which must be in the very mild category. The 19th and 20th both reached 11C here which must be close to 'very mild'. 

[Summer Sun]

3.0c to the 26th

0.7c below the 61 to 90 average
1.5c below the 81 to 10 average

___________________________

Current high this month 3.4c on the 21st & 22nd
Current low this month 0.5c on the 1st & 2nd