DECEMBER 2017 and WINTER 2017/18 CET THREAD
So once again we reach the final month of the year. As usual please can you PM your December CET prediction to me directly rather than posting it in this thread.
Also if you would like to make a prediction for the winter 2017/18 CET please also include that in your PM. I will post a separate table with the winter CET predictions at the end of the first week of December.
All predictions to be made by 23:59 on Saturday 2 December please.
Check out the contingency planners forecast below. Very interesting.
I finish my current job on 8 December and then have 3 weeks holiday until I start my new job on 2 January. So will hopefully be able to post a bit more from next week onwards and get my CET tracker updated throughout the month which I have not had time to do for a while.
Historic summary for December
1971-2000 5.1C
1981-2010 4.6C
1997-2016 5.1C
We have not had a cold December since 2010. three of the last 5 Decembers have been very mild including the record breaking 2015. The other two were average. Prior to that 2008, 2009 and 2010 were all cold.
Here is a chart of the December CET for all years since 1961:
Current model output
850's showing huge scatter. Massive uncertainty beyond this weekend. Anything is possible.
GFS - huge scatter
http://www.wetterzentrale.de/de/show_diagrams.php?model=gfs&var=2&geoid=49069&lid=ENS&bw=
GEM - interestingly much less scatter here. Higher confidence of much warmer weather by Sunday
http://www.wetterzentrale.de/de/show_diagrams.php?model=gem&var=2&geoid=49069&lid=ENS&bw=
ECM - some scatter but generally not looking very cold. Two clear clusters though. One chilly and one quite a bit milder
https://meteoijsselmuiden.nl/knmipluim
Multi op - shows a clear warming signal for next week
http://www.wetterzentrale.de/de/show_diagrams.php?model=multi&var=2&geoid=49069&lid=OP&bw=
Met Office contingency planners outlook
https://www.metoffice.gov.uk/binaries/content/assets/mohippo/pdf/public-sector/forecast-temp-djf-v1.pdf
So this is really interesting. Basically the Met Office is indicating a front loaded winter. December looking like it could be a bit cooler than normal although nothing exceptional. Whereas the winter as a whole is expected to be mild, suggesting potentially very mild conditions during much of January and February if December does end up cool. We shall see.
Just for reference, precipitation is expected to be average in December but well above for the winter as a whole.
https://www.metoffice.gov.uk/binaries/content/assets/mohippo/pdf/public-sector/forecast-precip-djf-v1.pdf
This does tie in with what the Met Office GLOSEA model has been suggesting (a mild unsettled winter overall).
Pattern Matching - JFF
If we look at years where the CET for Sept - Nov is very similar to 2017 the first good match going backwards is 1968. This saw quite a cold December (the whole of the 60's generally saw cold Decembers). January was very mild but then February and March were very cold
1977 is also a reasonable match. This saw a very mild December, a cool January and fairly cold February.
Not many other similar years. You have to go way back to 1811. That saw a cold December and January. A mild February and very cold March.
So not much to go on. Looking a bit closer 1995 is a reasonable match. Cold December, February and March. Average January.
1990 is also a reasonable match. All the winter months were colder than average.
If you looked at Terry Scholey's forecast he is suggesting a volatile winter with some very cold and very warm weather. The years above do have an element of this with some very mild months mixed in. But generally there are a lot of cold months in there.
Personally I do not buy the output from the GLOSEA model. The current synoptics already look different to recent years. Of course we could end up with a Euro high and a mild winter but I think there will be plenty of cold outbreaks this year and at least one month that is very cold.
Latest CET tracker prediction for December
A little above average by the 12th based on current output
Edited by moderator
04 January 2018 15:59:36
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