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

[Relativistic]

14 minutes ago, Froze were the Days said:

Still struggling to get that first -1c anomaly for a winter month on the 1961-90 CET series for over a decade now!...

Both November (2016) and March (2013) have managed it in the same period. Surprising since December, January and February are more likely to see larger negative anomalies. Fingers crossed for February.

[feb1991blizzard]

could be about to do an unwanted double on CET competition, in December 19 i went for 5.6c and lowered it to 4.6c right at the end of November, In Jan 2021 i went for 3.5 or 3.6c i cant remember, lowered it to 2.4c, so i have never got one bang on the nose but could be about to do the would have got one if only i hadn't changed double.

Mind you i think Roger has form for this as well from Memory - regretting changing his forecast.

Edited January 21, 2021 by feb1991blizzard

[Frigid]

This January has 2009 written all over it, even the CET is showing that. Feel like it will probably land around 3.0 to 3.3 after corrections.

[Timmytour]

1 hour ago, Relativistic said:

Both November (2016) and March (2013) have managed it in the same period. Surprising since December, January and February are more likely to see larger negative anomalies. Fingers crossed for February.

We just can't seem to get a consistently cold January or February!

Has there ever been another time in UK meteorological history when somebody could look back at the previous ten years and declare the coldest month in all that time was a March?

 

[damianslaw]

38 minutes ago, Timmytour said:

We just can't seem to get a consistently cold January or February!

Has there ever been another time in UK meteorological history when somebody could look back at the previous ten years and declare the coldest month in all that time was a March?

 

It all depends on how things fall. We can have switcharound months which end up close to average but the finish figure disguises what happened. Cold and mild halves cancelling each other out. Jan 13 a good case in point. Feb 09 another case in point. Sometimes we have cold halves back to back such as Dec 09 and Jan 10, a rolling severe cold spell second half Dec and first half Jan. 

This month is remarkably similar to Jan 09, might it be followed by a cold snowy first half to February?

[BornFromTheVoid]

Latest projections and probabilities

 

At the moment, we have 91.2% chance of finishing between 2.5C and 4.0C before corrections.

The chances of finishing:
Close to average (3.9 to 4.9C) is  to 5.2% (2 days ago was 29.8%)
Above average (>4.9C) remains at 0.0% (2 days ago was 0.0%)
Below average (<3.9C) is  to 94.8% (2 days ago was 70.2%)

Coldest outcome is  1.5C.

[Roger J Smith]

Here are the answers to the March supremacy questions ...

Rank ___ March CET ____ coldest for interval ______ duration

_ 01 ____ 2.7 2013 ______ Jan 2011 to Jan 2021 ____ 10 yr 1 mo and counting

_ 02 ____ 3.7 1970 ______ Mar 1970 to Nov 1976 __ 6 yr 9 mo

_ 02 ____ 1.9 1883 ______ Feb 1881 to Jan 1886 ____ 5 yr 0 mo

_t03 ____ 1.8 1748 ______ Mar 1746 to Jan 1751 ____ 4 yr 11 mo *

_t03 ____ 2.3 1837 ______ Feb 1833 to Dec 1837 ____ 4 yr 11 mo

_ 05 ____ 1.2 1785 ______ Mar 1785 to Nov 1788 ____ 3 yr 9 mo

_t06 ____ 2.5 1770 ______ Feb 1768 to Dec 1770 ____ 2 yr 11 mo **

_t06 ____ 1.0 1674 ______ Jan 1674 to Nov 1676 ____ 2 yr 11 mo

(Mar 1962 only coldest from Jan 1962 to Nov 1962)

______________________________________________________________________________

Nov 1915 (2.8) was coldest Feb 1908 to Nov 1916 (8 yr 10 mo) which prevented

Mar 1916 (3.3) from being coldest otherwise Dec 1910 to Nov 1916, and also

Nov 1910 (3.2 ) cut into that almost-coldest by taking away Feb 1908 to Nov 1910.

also Nov 1923 was tied coldest (3.3) in the interval Mar 1919 to Feb 1925, Feb 1924

and Nov 1919 tied it, so it was coldest Dec 1919 to Jan 1924.

____________________________________________________________

* tied coldest in that interval since Feb 1748 also 1.8

** tied coldest in that interval since Jan 1769 also 2.5

=======================================================

Summary: As suspected the current spell is considerably longer than second place Mar 1970 to Dec 1976 and is also longer if you want to measure intervals when people knew it was the coldest (note most but not all of the intervals drop the cold March into an ongoing mild spell and replace some other month's feeble claim to coldest, so for us, we've known about March 2013 for 7 years 11 months as of end of January. In the 1970s they knew about March 1970 from the start, but it would have been noted then that March 1970 was not as cold as Feb 1970 (2.9) which was the coldest month from Mar 1969 to Nov 1976.

Also there has been one interval in which November was coldest for longer periods than the 1970-76 March supremacy, so that drops 1970-76 to third place for non-winter month supremacy. A second long November interval drops all the others in the list by two ranks in that regard.

[damianslaw]

May see somewhat of a stall over coming days, might just nudge up to the 61-90 average.

A rise then expected from the 26th, before a cool down of sorts by month's end. 

It's going to be a very close call whether we end up below or above the 61-90 average, much will depend on any downward corrections. 

[Daniel*]

3 hours ago, damianslaw said:

May see somewhat of a stall over coming days, might just nudge up to the 61-90 average.

A rise then expected from the 26th, before a cool down of sorts by month's end. 

It's going to be a very close call whether we end up below or above the 61-90 average, much will depend on any downward corrections. 

Really a stall? ECM is forecasting some very cold nights, maxes generally 2-4C Saturday - Monday, few might see ice days.

[The PIT]

Sunny Sheffield at 2.7C -1.3C below average, Rainfall unchanged at 11.7mm 137.9% of the average.

A slight drop probably over the weekend then a slow rise after that.  Guessing final figure around 3.0C to 3.2C for us.

[Summer Sun]

3.4c to the 21st

0.2c below the 61 to 90 average
1.1c below the 81 to 10 average

___________________________

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

[Don]

4 minutes ago, Summer Sun said:

3.4c to the 21st

0.2c below the 61 to 90 average
1.1c below the 81 to 10 average

___________________________

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

Should see a drop over the next few days before ticking back up again next week.

[Methuselah]

11 minutes ago, Summer Sun said:

3.4c to the 21st

0.2c below the 61 to 90 average
1.1c below the 81 to 10 average

___________________________

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

That really highlights just how much warmer Januarys are becoming, and how much more marginal, snow 'events' are getting . . . it also reassures me that my Retrospection Specs are not as rose-tinted as I once feared.

[summer blizzard]

An impressively narrow CET range this month.

[Roger J Smith]

EWP now estimated to be at 95 mm and heading still for around 130 mm (current 9.5 day projection shows the required 36 mm estimates fairly close to a north-south line through central England). 

My estimate on CET after reviewing 12z GFS guidance is 3.5 before corrections and 3.2 after. Current values will slump down to 2.9 or so then rise as high as 3.8 before sliding back at end to 3.5. 

[ItNeverSnowsInWindsor]

Nice to prove the long range Met Office forecast for a mild winter wrong for a change with below average temperatures as long as February plays ball!

[damianslaw]

20 hours ago, Daniel* said:

Really a stall? ECM is forecasting some very cold nights, maxes generally 2-4C Saturday - Monday, few might see ice days.

Yes looking a bit colder than I was expecting next 3 days or so, likely to drop back into the 2s by Monday, then a rise but possibly shortlived, before a stall or slight drop. Increased chance we might end up with our coldest Jan since 2010 now.. 

Edited January 22, 2021 by damianslaw

[Summer Sun]

3.4c to the 22nd

0.2c below the 61 to 90 average
1.1c 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

[BornFromTheVoid]

Latest projections and probabilities

 

At the moment, we have 91.2% chance of finishing between 2.5C and 4.0C before corrections.

The chances of finishing:
Close to average (3.9 to 4.9C) is  to 4.8% (2 days ago was 5.2%)
Above average (>4.9C) remains at 0.0% (2 days ago was 0.0%)
Below average (<3.9C) is  to 95.2% (2 days ago was 94.8%)

Coldest outcome is  2.3C.

[The PIT]

Sunny Sheffield up to 2.8C -1.4C below average Rainfall unchanged.

[Roger J Smith]

EWP projection had risen slightly based on 8.5d GFS projection on 06z -- despite being slightly lower at present than previously estimated (92 mm to 21st, probably stayed there after small additions on 22nd). The average grid forecast appeared to be above 40 mm and close to 45, which set 137 mm as the target. This marginally improves scores for 150 and 151.3 mm.

The 12z GFS projections are somewhat lower (30-35 mm) and might drop the outcome to around 125 mm. In any case, the next excel file update can wait to end of month as these changes will be minor in either case. 

 

[Timmytour]

On 21/01/2021 at 18:37, Roger J Smith said:

Here are the answers to the March supremacy questions ...

Rank ___ March CET ____ coldest for interval ______ duration

_ 01 ____ 2.7 2013 ______ Jan 2011 to Jan 2021 ____ 10 yr 1 mo and counting

_ 02 ____ 3.7 1970 ______ Mar 1970 to Nov 1976 __ 6 yr 9 mo

_ 02 ____ 1.9 1883 ______ Feb 1881 to Jan 1886 ____ 5 yr 0 mo

_t03 ____ 1.8 1748 ______ Mar 1746 to Jan 1751 ____ 4 yr 11 mo *

_t03 ____ 2.3 1837 ______ Feb 1833 to Dec 1837 ____ 4 yr 11 mo

_ 05 ____ 1.2 1785 ______ Mar 1785 to Nov 1788 ____ 3 yr 9 mo

_t06 ____ 2.5 1770 ______ Feb 1768 to Dec 1770 ____ 2 yr 11 mo **

_t06 ____ 1.0 1674 ______ Jan 1674 to Nov 1676 ____ 2 yr 11 mo

(Mar 1962 only coldest from Jan 1962 to Nov 1962)

______________________________________________________________________________

Nov 1915 (2.8) was coldest Feb 1908 to Nov 1916 (8 yr 10 mo) which prevented

Mar 1916 (3.3) from being coldest otherwise Dec 1910 to Nov 1916, and also

Nov 1910 (3.2 ) cut into that almost-coldest by taking away Feb 1908 to Nov 1910.

also Nov 1923 was tied coldest (3.3) in the interval Mar 1919 to Feb 1925, Feb 1924

and Nov 1919 tied it, so it was coldest Dec 1919 to Jan 1924.

____________________________________________________________

* tied coldest in that interval since Feb 1748 also 1.8

** tied coldest in that interval since Jan 1769 also 2.5

=======================================================

Summary: As suspected the current spell is considerably longer than second place Mar 1970 to Dec 1976 and is also longer if you want to measure intervals when people knew it was the coldest (note most but not all of the intervals drop the cold March into an ongoing mild spell and replace some other month's feeble claim to coldest, so for us, we've known about March 2013 for 7 years 11 months as of end of January. In the 1970s they knew about March 1970 from the start, but it would have been noted then that March 1970 was not as cold as Feb 1970 (2.9) which was the coldest month from Mar 1969 to Nov 1976.

Also there has been one interval in which November was coldest for longer periods than the 1970-76 March supremacy, so that drops 1970-76 to third place for non-winter month supremacy. A second long November interval drops all the others in the list by two ranks in that regard.

Awesome analysis. Many thanks Roger

[Summer Sun]

3.3c to the 23rd

0.3c below the 61 to 90 average
1.2c 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

[damianslaw]

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.

[Weather-history]

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