December 2016 C.E.T. forecasts -- start of 2016-17 competition year

[BornFromTheVoid]

Minimum today is -0.8C, while maxima look like reaching the mid 5s, so around 4.0C or 4.1C is likely on tomorrows update.

After that, the 06z GFS has the CET at:

3.7C to the 5th (2.3: -3.8)
3.8C to the 6th (4.6: -0.4)
4.6C to the 7th (9.0: +4.2)
5.4C to the 8th (11.5: +7.1) [Daily record: 12.1C]
5.9C to the 9th (10.0: +5.5)
6.5C to the 10th (11.2: +6.9) [Daily record: 10.9C]
6.6C to the 11th (7.5: +3.3)
6.6C to the 12th (7.3: +3.1)
6.8C to the 13th (8.5: +3.9)

So, a couple of daily records are now under threat and with it the chances of a significantly below average month begin to fade.

However, the forecast can change and as the graph below shows, using the values so far plus the forecast for the following 5 days, the upper and lower likely ranges are still 6.2C to 2.1C. The forecast beyond 5 days, which should be taken with a pinch of salt, is much milder than even the upper 90% value shows though.

[damianslaw]

1 hour ago, BornFromTheVoid said:

Minimum today is -0.8C, while maxima look like reaching the mid 5s, so around 4.0C or 4.1C is likely on tomorrows update.

After that, the 06z GFS has the CET at:

3.7C to the 5th (2.3: -3.8)
3.8C to the 6th (4.6: -0.4)
4.6C to the 7th (9.0: +4.2)
5.4C to the 8th (11.5: +7.1) [Daily record: 12.1C]
5.9C to the 9th (10.0: +5.5)
6.5C to the 10th (11.2: +6.9) [Daily record: 10.9C]
6.6C to the 11th (7.5: +3.3)
6.6C to the 12th (7.3: +3.1)
6.8C to the 13th (8.5: +3.9)

So, a couple of daily records are now under threat and with it the chances of a significantly below average month begin to fade.

However, the forecast can change and as the graph below shows, using the values so far plus the forecast for the following 5 days, the upper and lower likely ranges are still 6.2C to 2.1C. The forecast beyond 5 days, which should be taken with a pinch of salt, is much milder than even the upper 90% value shows though.

How many daily records were broken last December, I'd be highly surprised to see similiar temps as occured this time last month occuring this December. 

[BornFromTheVoid]

51 minutes ago, damianslaw said:

How many daily records were broken last December, I'd be highly surprised to see similiar temps as occured this time last month occuring this December. 

5 daily records last year, 16th, 17th, 18th, 19th, and 27th, and another 8 days in the top 5 warmest. The stats above include last December.

[Carl46Wrexham]

Late prediction : 7.1c

 

Got a bad feeling that we are going to be stuck in a mild cruddy rut for a while.

Edited December 4, 2016 by Carl46Wrexham

[Chris.R]

You've missed the boat :-(

[Nouska]

3 minutes ago, Chris.R said:

You've missed the boat :-(

Wish I had missed the boat!

A Titanic episode for a lot of us and not a bloody iceberg in sight.

[I remember Atlantic 252]

You got it Carl! winner I think, if not too late

[Relativistic]

1 hour ago, Nouska said:

Wish I had missed the boat!

A Titanic episode for a lot of us and not a bloody iceberg in sight.

Happens often, people's predictions are too readily swayed by the first few days. July 2015 was a classic example of this.

[Roger J Smith]

I went in search of promising leads on a colder second half of December that can bring a mild month down. Using 1st-16th for first half and 17th-31st for second half, I found these to be the largest falls in CET. I have listed the November CET values and average of 24-30 Nov to provide a better idea of whether these cases have any chance of being good analogues for this year. Notes also on when the cold arrived. This includes all cases with a drop of 5.0 or greater from the first (extended) half to the second half of December.  The mean drop for all years 1772-2015 was 0.8 C deg.

 

YEAR __DEC 1-16_17-31 __ DROP _/_ DEC CET _ NOV CET, (24-30) __ COLD ARRIVED

 

1961 ______ 5.4 ___ --1.2 ____6.6 __/_ 2.2 ____ 6.0 __ (4.8) _______ 15th

1891 ______ 7.1 ____ 0.9 ____ 6.2 __/_ 4.1 ____ 5.6 __ (2.3) _______ 17th

1860 ______ 4.3 ____--1.6 ___ 5.9 __/_ 1.5 ____ 4.5 __ (4.3) _______ 13th

2000 ______ 8.7 ____ 2.8 ____ 5.9 __/_ 5.8 ____ 7.0 __ (8.6) _______ 16th

1979 ______ 8.6 ____ 2.9 ____ 5.7 __/_ 5.8 ____ 6.8 __ (9.1) _______ 19th

1794 ______ 6.4 ____ 0.8 ____ 5.6 __/_ 3.7 ____ 6.1 __ (6.8) _______ 15th

1799 ______ 4.0 ___ --1.6 ____5.6 __/_ 1.2 ____ 5.6 __ (4.5) _______ 12th

1956 ______ 8.4 ____ 2.8 ____ 5.6 __/_ 5.7 ____ 6.0 __ (5.5) _______ 19th

1948 ______ 8.4 ____ 2.9 ____ 5.5 __/_ 5.7 ____ 7.3 __ (3.6) _______ 19th

1831 ______ 8.4 ____ 3.0 ____ 5.4 __/_ 5.8 ____ 5.6 __ (4.8) _______ 23rd

1938 ______ 7.0 ____ 1.6 ____ 5.4 __/_ 4.4 ____ 9.4 __ (5.7) _______ 18th

1841 ______ 7.0 ____ 1.7 ____ 5.3 __/_ 4.4 ____ 5.2 __ (5.4) _______ 17th

1992 ______ 6.1 ____ 0.8 ____ 5.3 __/_ 3.6 ____ 7.4 __ (7.1) _______ 17th

1776 ______ 6.7 ____ 1.7 ____ 5.0 __/_ 4.4 ____ 6.2 __ (2,4) _______ 17th

______________________________________________________________________

Of these possible analogues for a colder second half, the best one as set up by November would appear to be 1891. There are maps available for that year. The late November chill looks to be more of a trough with cool mP air masses than this year's anticyclonic blocking. The cold broke through a fast westerly flow in stages by north-south ridge building phases. There was severe cold 21st to 25th then a milder end to the month. The 1776 analogue looks close for November but no maps exist. The third best analogue appears to be either 1948 or 1961. Of those two, the late November chill for 1948 was also associated with European high pressure. After two very mild weeks, the European anticyclone pushed back west and dropped means below normal. The eventual cold was never all that strong, two days (26th-27th) had subzero means. In the 1961 case, the coolish end to November was fairly bland troughing, then after two weeks that were not much milder than average, a very cold spell set in lasting into the first two days of 1962 when it reached means of -4 C. Most of these cold days were associated with near continent high pressure but a northerly was involved near the end of the spell. 

I think the chances are fairly good that we see a mid-month reversal this month. The energy peak already showing up on model charts around 12th to 15th is well timed for that to be the outcome. 

[Summer Sun]

4.2 to the 4th

1.2 below the 61 to 90 average

1.7 below the 81 to 10 average

[Timmytour]

Will December finish above November again?   It's been 97 years since two Decembers in a row finished higher than November. Unfortunately, if you are looking for signs, they are not good. Following on from a dry October and November the following winter was mostly mild and wet. The major winter weather event happened in mid November!

December was warmer than November for the three consecutive years 1910 to 1912, making if five years in total for the 1910-1919 decade......quite remarkable considering outside that decade there have only ever been two other occasions on which successive warmer Decembers have registered   (1842-43 and 1857-58).

So if it did turn out to be warmer than November this year, and though I'm sure most of us don't want it to it's certainly not impossible that it does, it would at least register as part of a rare weather sequence!

 

[NorthYorksWeather]

4.9c to the 4th here, 1.1c above the 1981-2010 average.

After an overnight min of -3c and a high of only 1c so far today I'm expecting a big drop by tomorrow.

[Mapantz]

Started off in negative territory for the first few days here, slowly going back up though. 2.5°C to the 4th (meto region average 4.8°C) an increase inevitable after today's max of 10.1°C

Edited December 5, 2016 by Mapantz

[The PIT]

Sunny Sheffield  5C +0.4C above average 1981- 2010 Today will make a dint in it as well bringing it down to average.

[Summer Sun]

3.8 to the 5th

1.5 below the 61 to 90 average

2.2 below the 81 to 10 average

[The PIT]

Sunny Sheffield probably at the low point for the month 4.2C -0.4C below 1981- 2010 average. Depends on how mild tonight becomes.

[snowray]

Such a pity that 3.8c will be rising very quickly in the next few days....

 

[Man With Beard]

Well if the upcoming pattern holds, I wonder if a CET in excess of 6C will be possible, which will mean Lettucing Gutted getting very close to the top for the second December running!

[I remember Atlantic 252]

1 minute ago, Man With Beard said:

Well if the upcoming pattern holds, I wonder if a CET in excess of 6C will be possible, which will mean Lettucing Gutted getting very close to the top for the second December running!

well done Craig! and for 2nd Dec on the bounce, I, 'the ultimate Atlantic air winter believer' has guessed too low! 

[Singularity]

Well the horrendous model inaccuracy of the final day of Nov has made a total mess of this month. Only hope is that mid-lat block can set in by the midpoint of the month with clear enough air to allow nights well below freezing. Then a figure in the 3s is possible to mitigate damages. Without that, the later month cold signals would have to amount to something truly exceptional to place the CET much below than the LTA, which will have a lot of met. organisations feeling very bothered indeed.

[Summer Sun]

4.0 to the 6th

1.2 below the 61 to 90 average

1.8 below the 81 to 10 average

[NorthYorksWeather]

3.5c to the 6th, 0.3c below the 1981-2010 average.

Looking at the models that could well be the low point for the month, we shall see.

[The PIT]

Back up to 4.6C bang on average. If ECM comes off god knows where it will end.

[snowray]

Indeed, highs of 13, 14, 15c have only just started to go down by a degree or so, very mild night coming up and big increase in the CET tomorrow. I'm afraid that this is a trend that is likely to continue for quite some time.

[The PIT]

I wonder if we can beat 8.6C here that we recorded in 2015