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BornFromTheVoid

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Posts posted by BornFromTheVoid

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

    in Spring Weather Discussion

    Posted · Edited by BornFromTheVoid

    First projections for March

    March2Project.thumb.png.4fa1461a5811bccf02d0f093e852bb0f.png March2Prob.thumb.png.43e1dcd669ca8fcc5caf58ff4ede5919.png

    The chances of finishing:
    Close to average (6.2 to 7.2C) is 26%
    Above average (>7.2C) is 5%
    Below average (<6.2C) is 69%

    GFS for the 2nd to 7th looks like average about 4.3C, or 1.1C below the 91-20 average


    EDIT: Alternatively, quite a different picture when using the 1961-90 average (1C colder).

    Close to average (5.2 to 6.2C) is 31%
    Above average (>6.2C) is 30%
    Below average (<5.2C) is 39%

    Climate Questions

    in Climate Change

    Posted

    On 26/02/2021 at 14:48, Snipper said:

    Observations? Probably coincide with the magnetic poles flipping.

    39772864-0-image-a-29_1614280670702.jpg

    6554b6be8c0d829a8bf63ae0c82cf121_link.pn Climate change has weakened the Gulf Stream System 'close to tipping point' | Daily Mail Online

    WWW.DAILYMAIL.CO.UK
    Known formally as the Atlantic Meridional Overturning Circulation (AMOC), it is the driving force which brings warm water from the Gulf of Mexico up to the UK.

     

    It's an interesting study, noting a long term decline that has accelerated since mid-20th century. They still think it's many more decades away from slowing to the point where it become unstable.
    The cause isn't entirely clear either (though previous related studies have suggested fresh meltwater from Greenland is a major driver), so we'll need to wait for further studies for clarification.

    • Like 1

    Annual CET

    in Spring Weather Discussion

    Posted

    I thought some might find this interesting.
    It's a comparison of the daily mean cold and warm records over time. A clear switch from record cold dominant to record warm dominant during the early 1900s, with the difference between the two accelerating from 1988 and continuing to do so.
    Over the last 30 years (1991-2020) there's been 10 warm records for every 1 cold record. The previous 30 years (1961-1990) there was 2 warm for every 1 cold record.

    CET_WarmvColdLong.thumb.png.0493c08fe67aab96a46a2d6cb13ba575.png

    • Like 5

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

    in Spring Weather Discussion

    Posted · Edited by BornFromTheVoid

    The February CET came in at 5.1C:

    0.2C above the 91-20 average
    1.3C above the 61-90 average
    1.1C above the 20th century average
    1.1C above the 19th century average

    Feb21Long.thumb.png.81d1a785fd4bc79bd527efe5d54def45.png

    Compared with 1991-2020 average, 17 days were above, 10 days below and 1 day equal to the average.
    Five days were in the top 10 warmest, but no absolute warm or cold records occurred (although the 24th just 0.1C shy of equaling a warm record).

    FebCET21.thumb.png.fcdf38852e84defe92fcc7d27eef1dd8.png

     

    EDIT: We also nabbed a record high minimum on the 21st, with 8.5C. This beats the previous 8.4C record from 1903.

    • Like 3
    • Thanks 3

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

    in Spring Weather Discussion

    Posted

    Current daily record for the 24th is 11.4C from 1846, which we might threaten tomorrow.

    Looks like remaining quite mild overnight, so a minimum above 8C seems possible. Then how high maxima reach will depend on how much progress the cold front makes during the day. If it stays further west then 14C+ could occur widely, but if it moves further inland then cooler maxima might occur in northern parts of the CET zone.

    • Thanks 1

    Arctic Refreeze Season: 2020/21

    in Climate Change

    Posted

    Over the last 10 days, persistent southerly winds have been driving open water north of Svalbard towards the N. Pole. Further, in the last few days, sea ice has been breaking up and moving away from the north east of coast Greenland. Unusual for Feb, but I'm not quite sure if it's unprecedented...

    NP_Anim_22.thumb.gif.2ddb2107e18624db28ccce38a8db07ff.gif

    • Like 2

    Climate Questions

    in Climate Change

    Posted

    30 minutes ago, Kirkcaldy Weather said:

    Wasn't sure what thread to put this in, long thread with this tweet but something which I wish more would acknowledge rather than try to say its a full story of warming which is incorrect as these record cold events still happen each year around the world 

     

    The relevant experts in the area (Judah Cohen, Jennifer Francis, James Screen, etc (Maue is not one)) have been quite active lately on social media discussing their perspectives. There's a pretty healthy debate at the moment about how much of the recent cold outbreaks can be linked to climate change. It can sound a bit counterintuitive (warming causing regional cold), which means a lot of people get frustrated and assume somebody is lying.
    It basically comes down to the effects of Arctic amplification (accelerated warming in the Arctic relative to the rest of the planet) and the different mechanisms by which this alters the jet stream and the stratospheric vortex. It's an area of active research and debate at the moment.

    One of the main mechanisms is through the strong loss of sea ice and warm SSTs through Autumn in the Kara and Barents Seas. This is linked to increased Ural blocking and increased Siberian snow cover, which also occurred during Autumn, which is then tied to a greater chance of SSW events. These features were highlighted by Judah Cohen and others as likely to increase the chances of a SSW and cold outbreaks before winter (I also included it on a blog post here)

    It's not entirely accurate to place full blame of recent cold outbreaks solely on climate/Arctic change, but it's also inaccurate to dismiss the idea out of hand too. These things can never be said with certainty, but only in terms of probabilities

    • Like 6

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

    in Spring Weather Discussion

    Posted

    Latest projections and probabilities

    Feb16Project.thumb.png.60965be48e38d29c4200628e95619630.png Feb16Prob.thumb.png.f7fc6ff737fc8c0ac4f018b444f678ec.png

    The chances of finishing:
    Close to average (3.9 to 4.9C) is  to 61% (two days ago it was 47%)
    Above average (>4.9C) is to 10% (two days ago it was 7%)
    Below average (<3.9C) is to 27% (two days ago it was 46%)

    GFS for the 16th to the 21st averages about 7.6C, pulling the CET up to 4.1C.

    Lots of very mild days coming up, but they no longer look like threatening any daily records.

    • Like 1
    • Thanks 1

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

    in Spring Weather Discussion

    Posted

    1 minute ago, feb1991blizzard said:

    Hmm - i would suggest a greater than 80% chance of finishing above 4 now tbh with a 50% chance of over 4.5

    Might well be right. For my projections I use the GFS to estimate the next 5 days, and then use the data from the CET record to project the remaining days of the month (I try my best to leave my own feelings out of it). They aren't always the best because they don't take into account the medium term trends, but then it's less likely to get caught out by models flip-flopping. 
    However, using my method, currently there's a 47% chance of finishing 4C or higher, and 22% of 4.5C or higher. These are all before corrections too.

    • Like 1
    • Thanks 1
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