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December 2020 C.E.T. and EWP forecast contests -- start of the new contest year for 2020-2021


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  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

    Sunny Sheffield at 3.8C -2.7C below normal. Rainfall at 23.7mm 27.3% of the monthly average

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    On behalf of J10 and myself, welcome to another new competition year with the winter season of 2020-21 fast (?) approaching (??). The contests will include the CET forecast and the (still optional) EW

    2.4c    52mm of snow

    Excel Spreadsheet ->  December 20 CET.xlsx SummaryPDF Format December 20 Summary.pdf Monthly Scores 3 players got 5.0c spot on. SummerShower,  Downburst and 2010cold 37 pla

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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    4.5c to the 5th

    0.8c below the 61 to 90 average
    1.5c below the 81 to 10 average

    ___________________________

    Current high this month 5.1c on the 2nd
    Current low this month 4.5c on the 4th & 5th

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    Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

    EWP was 30 mm to the 4th and added about 2 mm yesterday. GFS 10-day gives an estimated 28 mm over the grid for 60 mm and then it looks almost dry for the days to end of the run (22nd). Total would be around 60 mm with nine days to go. 

    The CET looks generally cooler than normal most of the time, a few days get up above 6 C but overall would expect the CET to remain in the range of 3.7 to 4.5 most of the way to the 22nd on that guidance. Nothing bitterly cold showing up but the odd day could develop some home-grown chill when fog lingers, so unless these maps are way off or there's a huge reversal at end of month, guesses in the 3s or 4s seem to be favoured. 

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    Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL
    5 minutes ago, Roger J Smith said:

    EWP was 30 mm to the 4th and added about 2 mm yesterday. GFS 10-day gives an estimated 28 mm over the grid for 60 mm and then it looks almost dry for the days to end of the run (22nd). Total would be around 60 mm with nine days to go. 

    The CET looks generally cooler than normal most of the time, a few days get up above 6 C but overall would expect the CET to remain in the range of 3.7 to 4.5 most of the way to the 22nd on that guidance. Nothing bitterly cold showing up but the odd day could develop some home-grown chill when fog lingers, so unless these maps are way off or there's a huge reversal at end of month, guesses in the 3s or 4s seem to be favoured. 

    Cold today quite a few places having an ice day or close to that colder tomorrow generally with dense freezing fog in Midlands/SE.

    510ED231-3F95-4AFB-872A-31E7C9E9E64B.thumb.png.a003f8dbff08d798a0790db532b0e43d.png

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    Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

    Milder conditions into mid-month so we may see a slight rise from about the 10th, but nothing significant, so at mid-month point I suspect we will be very close to the 61-90 average. In a typical year second half of December tends to be colder than the first half, but not always, 2012 and 2017 good examples where early cold flipped to very mild.

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    Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

    Sunny Sheffield down to 3.7C -2.8C below average. Rainfall 25.4mm 29.2% of the monthly average.

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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    4.3c to the 6th

    1.0c below the 61 to 90 average
    1.5c below the 81 to 10 average

    ___________________________

    Current high this month 5.1c on the 2nd
    Current low this month 4.3c on the 6th

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    Posted
  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)

    Here's the CET for December projected forward using the data from previous years.
    Projected finishing values:
    Warmest:  8.5C
    Coldest:  -0.6C
    Top 10:  6.6C
    Bottom 10:  1.1C
    81-10:  4.3C

    Project_12_7.thumb.png.6285eba8b2bbf4e1fc307c9481c8fda4.png

    Same as above, but with the GFS 7 day forecast included (rough estimate from eyeballing the min and max in the CET area).

    Warmest:  7.9C
    Coldest:  1.0C
    Top 10:  6.3C
    Bottom 10:  2.1C
    81-10:  4.5C

    Project_12_7F.thumb.png.2cb70cc572d50c40ce86d1e39af86ab8.png

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    Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

    Sunny Sheffield at 3.6C -2.8C below average. Rainfall unchanged.

    Could well be the low point as it looks like a steady rise should start soon and accelerate over the weekend.

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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    4.0c to the 7th

    1.1c below the 61 to 90 average
    1.7c below the 81 to 10 average

    ___________________________

    Current high this month 5.1c on the 2nd
    Current low this month 4.0c on the 7th

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    Posted
  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)

    Here are the same projections, updated from yesterday.

    Warmest:  8.2C
    Coldest:  -0.5C
    Top 10:  6.5C
    Bottom 10:  1.1C
    81-10:  4.3C

    Project_12_8.thumb.png.4bb65eafc625630a27b2c96c91896a60.png

    Same as above, but with the GFS 7 day forecast included (rough estimate from eyeballing the min and max in the CET area).

    Warmest:  7.7C
    Coldest:  1.2C
    Top 10:  6.1C
    Bottom 10:  2.1C
    81-10:  4.5C

    Project_12_8F.thumb.png.621a2b7090986ccabd1a783e30dd14f5.png

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    Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

    The current GFS run seems to stay in the range of 4 to 5 C generally speaking, no huge changes either way. Towards the end of the run it seems to be trying to open the gates to colder weather but then isn't that often the case with the end of any given GFS run? 

    No big changes in outlook for EWP based on latest info either, would say 80 to 90 mm is about the most likely finish if the last seven days beyond the model run are anywhere near 15-25 mm which would be about normal. That finish is similar to our consensus and just slightly below long-term averages for December (at least in recent times, there were 30-year averages in the past that were lower than 90 mm, the lowest on record being 67.5 mm for 1834-63. The highest 30-year average was 106.6 mm (1896-1925), a value which was almost equalled by 104.1 mm (1977-2006) -- the latest average for 1990-2019 was 101.5 mm. 

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    Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

    Sunny Sheffield still at 3.6C -2.7C below normal. Rainfall 26.6mm 30.6% of the monthly average.

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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    3.9c to the 8th

    1.2c below the 61 to 90 average
    1.6c below the 81 to 10 average

    ___________________________

    Current high this month 5.1c on the 2nd
    Current low this month 3.9c on the 8th

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    Posted
  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)

    Here is the projected CET again, but only the one with the GFS forecast data included. I've added the distribution of projected finishing ranges too.

    Project_12_9F.thumb.png.0bc2ee040eacf75b74f20916340172ef.png ProbDistDec9.thumb.png.bfbc57baa48eba8ec9c9f76fcad885f0.png

    Warmest:  7.5C
    Coldest:  1.4C
    Top 10:  6.1C
    Bottom 10:  2.3C
    81-10:  4.6C

    The most likely finish is between 3.5C and 4.0C (16.5%), but the grouping from 3.5C to 6.0C covers 71%

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    Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
    3 hours ago, BornFromTheVoid said:

    Here is the projected CET again, but only the one with the GFS forecast data included. I've added the distribution of projected finishing ranges too.

     

    Warmest:  7.5C
    Coldest:  1.4C
    Top 10:  6.1C
    Bottom 10:  2.3C
    81-10:  4.6C

    The most likely finish is between 3.5C and 4.0C (16.5%), but the grouping from 3.5C to 6.0C covers 71%

    I must admit its unusual for me to be confident of doing well at anything but i am highly confident my 5.3 wont be more than 0.5 out and have been since day 1, i would have the chances of anything below 2 as 0% and about 1% for below 3.

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    Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

    Rising projections for EWP as the GFS edges towards milder solutions. Currently near 40 mm (36 to 7th, about 3-4 yesterday). Adding at least 30 mm in next ten days, could be 35-40 as 12z GFS rolling out was adding a few mm to the 06z solution that I consulted for ten days. Maps for days 11-16 not looking as dry as previously either, 20 mm potential with rain incoming for Christmas Day according to the last map available. Assuming 15-25 mm for that and rest of month (and it could be more), all told that adds up to around 105-125 mm, so let's say 115 mm.

    Not terribly mild on GFS but I agree the most likely value around 25th is 5 to 5.5 range, if the model is underplaying Atlantic rejuvenation, 6.0 tops. 

    Many might need a colder turn after Christmas at this rate (our consensus was 4.7). 

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    Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

    Sunny Sheffield up to 3.7C -2.5C below normal, Rainfall 26.8mm 30.8% of the monthly average.

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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    3.9c to the 9th

    1.1c below the 61 to 90 average
    1.5c below the 81 to 10 average

    ___________________________

    Current high this month 5.1c on the 2nd
    Current low this month 3.9c on the 8th & 9th

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    Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

    A cold start to December, just like 2012 and 2017, and just like these months a milder middle third looks likely, nothing substantively so, expect to be running close to the 61-90 average by around 20th, possibly a little above mainly due to lack of clear skies allowing for cold nights. Last third of the month very much up in the air. 

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    Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

    Sunny Sheffield up to 3.8C -2.4C below average, Rainfall 30.3mm 34.9% of the monthly average

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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    4.1c to the 10th

    0.9c below the 61 to 90 average
    1.2c below the 81 to 10 average

    ___________________________

    Current high this month 5.1c on the 2nd
    Current low this month 3.9c on the 8th & 9th

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    Posted
  • Location: Erith. SE London/kent 40m asl
  • Weather Preferences: Winter Snow, extreme weather, mainly sunny mild summers though.
  • Location: Erith. SE London/kent 40m asl

    Up we go...🙄

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    Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield

    Sunny Sheffield at 4C -2.1C below average. Rainfall 31.4mm 36.1% of the monthly rainfall.

    Local forecast has us at 5.1C by the 18th we could well be looking at 6C finish for the month as the models are continuing to head for a milder more zonalish outlook.

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    Posted
  • Location: Newcastle Upon Tyne (Spital Tongues)
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Newcastle Upon Tyne (Spital Tongues)

    Here's the projected values, with the GFS 7 day forecast included. The values below in brackets are from 3 days ago, to show the change in projections.

    Dec12ProjectF.thumb.png.a185c313890c709b7c2daf2847099c13.png

    Warmest: 7.4C (7.5C)
    Coldest:  2.0C (1.4C)
    Top 10:  6.5C (6.1C)
    Bottom 10:  3.0C (2.3C)
    81-10:  5.0C (4.6C)

    The ranges of 4.0C to 4.5C and 5.0C to 5.5C are both at 17.7%, the highest of the bunch. The range from 4.0C to 6.0C covers 64.9% of the probability.

    Dec12probDist.thumb.png.8213705b3cc03c013bb65fef5fda1610.png

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