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Posts posted by BornFromTheVoid

  1. Here's the blog post mentioned earlier where I take a look at the upcoming melt season.


    Samual Hayes explores the trends and the main influencing factors as the Arctic Sea Ice Melt season for 2021 gets underway.

    Obviously it's a little shortened and leaves out some features (such as the uncertainty in volume derived from models vs observations which may be very important this year) but as an basic overview it's hopefully ok.

    • Like 2
  2. 14 minutes ago, Geordiesnow said:

    It is unusual but holes do tend to develop there when the winds come from the Atlantic. In fact if the winds persistently come from the North, a polyna tends to develop to the south of those islands even in colder temperatures but I think what happened here is a combination of thin ice(as the Barants sea did not get too much northerly winds this winter) and a strong storm. Winds may drift the ice back southwards again but l think this could be more worse long term but a short term gain in extent perhaps. 

    They do occur (2006 was the closest to this year) but they've never been quite this big in early April before. Agreed though, winds are shifting at the moment so it's likely to close up again.
    Something else interesting, is that the Central Arctic hasn't yet fully frozen over this year. This has happened only twice before up to this point, in 2018 and 2016.

    Anywho, on a separate note, different things going on around the Arctic.

    On the Pacific side, ice melt in the Sea of Okhotsk is slower than normal, with the current the rank rising from 16th to 21st lowest in the last 7 days. The Bering Sea has even increased ice cover, going from 8th to 12th lowest.

    SoO_4_12.thumb.png.e9e1db98902aa42a8d40f0f6dce25d26.png BerS_4_12.thumb.png.582fca5099125b8372077dbdece06ef2.png

    Meanwhile, on the Atlantic side, sea ice cover in the Barents sea is plummeting, going from 10th to 4th lowest in 7 days. Melt in the Kara Sea has started early too, going from fully frozen to 4th lowest extent.

    BarS_4_12.thumb.png.31c40cc03c053f375a60b99663bbf0c5.png KarS_4_12.thumb.png.fd4543a19472d18745a7ee55de7eea36.png

    Finally, extent in the Central Arctic continues to drop, remaining lowest on record for the time of year & the lowest ever recorded in the first half of April.  Overall were 5th lowest on the 5 day average too, and essentially joint 2nd lowest (with 2020 and 2018) in the single day extent values.

    • Like 1
  3. Latest projections

    AprilProj12.thumb.png.db7952483ed9e77405053aa3c7d5791b.png AprilProb12.thumb.png.70c6107972d4fbe9428ed1bb92871397.png

    The chances of finishing:
    Close to average (8.5C to 9.5C) is 🔻to 1.6% (2 days ago 3.6%)
    Above average (>9.5C) remains at 0.0% (2 days ago 0.0%)
    Below average (<8.5C) is 🔺to 98.4% (2 days ago 96.4%)

    The period of the 12th to the 17th is forecast to average 4.5C, which is 3.2C below the 91-20 average.
    The absolute highest outcome now is 8.7C, so it's safe to rule out anything above 9C.

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  4. 3 minutes ago, Weather-history said:

    One peculiarity about April is that the highest maxima ever recorded during April are not to be found in the last few days  of the month. For instance 25.6C for March was recorded on the 29th in 1968, also 25.0C was recorded on that date in 1929 and 1965.

    The highest maximum ever recorded during  the last 5 days of April is only 26.1C on the 30th in 1952.   26.0C was recorded on 10th of April last year. 

    Similar with the CET maxima. The record high maxima on the 3rd, 23.5C (in 1946), is the 4th highest for the whole month. It's also warmer than any of the record maxima in the last 9 days of April.

    I guess it highlights the potential for maxima in the mid 20s throughout April

    • Like 2
  5. Latest projections

    AprilProj10.thumb.png.ec8825d9cbc159bcb63da4f23d5d46db.png AprilProb10.thumb.png.6f224f37396c73f83e8bf5a8a03a0477.png
    The chances of finishing:
    Close to average (8.5C to 9.5C) is 🔻to 3.6% (2 days ago 7.7%)
    Above average (>9.5C) remains at 0.0% (2 days ago 0.0%)
    Below average (<8.5C) is 🔺to 96.4% (2 days ago 92.3%)

    The period of the 8th to the 13th is forecast to average 4.5C, which is 3.8C below the 91-20 average.

    Some potential low hanging fruit coming up. The record low minima for the 12th and 13th are just -1.7C and -1.4C respectively, and the GFS forecasts something quite close to those values

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  6. Latest projections

    AprilProj8.thumb.png.73048660a9e6e42a5e45faab33c0a4da.png AprilProb8.thumb.png.aa71ec31bd736e4a5f264f1332b72b38.png

    The chances of finishing:
    Close to average (8.5C to 9.5C) is 🔻to 7.7% (3 days ago 11.7%)
    Above average (>9.5C) is 🔻to 0.0% (3 days ago 0.4%)
    Below average (<8.5C) is 🔺to 92.3% (3 days ago 87.9%)

    The period of the 8th to the 13th is forecast to average 5.0C, which is 3.3C below the 91-20 average.

    I've noticed that the GFS has had quite a consistent cold bias throughout the month so far, typically about 2C too cold at night, and 1C too cold during the day.

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  7. Assuming 5.5C mid month, for the second half of the month we'd need to average:

    6.4C to reach 6.0C (achieved in 96% of previous years)
    8.4C to reach 7.0C (achieved in 59% of previous years)
    10.4C to reach 8.0C (achieved in 25% of previous years)
    12.4C to reach 9.0C (achieved in 2% of previous years)

    That's all excluding the end of month corrections.

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  8. Latest PIOMAS  volume is out to the end of March.
    2021 is 6th lowest on record, above 2011, 2016 2017, 2018 and 2019. It's also:
    8,000 km³ below 1980s
    6,700 km³ below 1990s
    3,300 km³ below 2000s
    100 km³ below the 2010s average


    Regionally, volume continues to do well along the Russian Arctic coastline, 5th most volume since 2000.
    For the central Arctic, 2021 has dropped back to 2nd lowest on record.

    EndMarchSiberianSeas.thumb.png.4ba32e5fbbc79b743f598a3ad9e1125d.png EndMarch_CAB.thumb.png.d13523af7788690b511899b0a0b9498e.png

    Here are all the regional comparisons, for 2021, 2020 and the 3 lowest years.


    • Like 1
  9. The single day drop in the CET maxima from yesterday to today could exceed 8C. In the record for April this has only been achieved 15 times.
    Just 2 days have dropped by more than 10C, they are the 12th to 13th last year, -10.6C,  and the 4th to the 5th in 1946, -10.7C.
    The graph below compares those 2 big drops with the potential drop for today. Highlights how impressive this drop is given we started at such a lower point.


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  10. Latest projections

    AprilProj5.thumb.png.54ed612bb00c591d83e6c8c91b9b7aeb.png AprilProb5.thumb.png.f98f5a2f4a48f806503472d5bfcdfc4c.png

    The chances of finishing:
    Close to average (8.5C to 9.5C) is 🔻to 11.7% (2 days ago 19.4%)
    Above average (>9.5C) is 🔻to 0.4% (2 days ago 1.6%)
    Below average (<8.5C) is 🔺to 87.9% (2 days ago 79%)

    The period of the 5th to the 10th is forecast to average 3.2C, which is 5.2C below the 91-20 average.

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  11. Alright a few stats and graphs for March.

    AT 7.2C, March 2021 was the 42nd warmest in a record dating back to 1659. It was also:
    0.5C above the 91-20 average
    1.5C above the 61-90 average
    1.4C above the 20th century average
    2.2C above the 18th century average


    Compared with 1991-2020 average, 16 days were above average and 15 days were below. Three days were in the top 10 warmest, one of which set a new record, 14.3°C on the 31st. This beat the old record by 0.5°C. This was also just the 4th March day to average 14°C or higher.


    No daily minimum records were set.
    Two daily high maximum records were set, with 21.2°C and 20.2°C on the 30th and 31st, beating the previous records by 2.0°C and 1.5°C respectively. The 21.2°C maximum was the 2nd highest on record for March

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