Tuesday, January 23, 2018

Prospects for 2018.

Each year now when results for the previous year are in, I post some graphs (2017 here), and invite discussion about the coming year, which can be maintained on that thread. Reader Uli follows the prospects for GISS; readers JCH and WHUT remind us about ocean periodicities, and there are many other interests. I don't have strong prognoses myself; I just expect it to get warmer, with variations.

I think 2017 predictions worked out fairly well, mainly because the chief unexpected event, the strong warmth in Feb/March, came early. It created some possibility that 2017 might exceed 2016, but by August that was starting to look unlikely. That left the question of whether it would beat 2015, and that was close in most indices, with those that gave proper weighting to the polar temperatures putting 2017 ahead.

On the prospects for ENSO, Australia's BoM expects a weak La Niña in the short term. The NOAA has been silenced by the shutdown, but the IRI forecasts tend to see this going away fairly soon, with a fair chance of El Niño conditions later in the year.







For the moment, January has already been through two peaks and two dips, but overall, not much different to the last nine months.

So I'll leave the thread there open for comments through the year. Thanks, Uli and all.

8 comments:

  1. The PDO remains positive, narrowly evading the zero line. It's back to 50 and should remain positive throughout 2018, maybe even strongly positive. Ocean heat content is back, almost to its El Niño peak. I think the current La Niña is BoM toast by the end of February. As for an El Niño in the NH autumn, I'm buying that. If right on EL Niño, 2nd warmest year and 2019 sets a new record warmest year and the models will be running too cold; if wrong, 4th warmest year.

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  2. I update my prediction (from Prospect for 2017) for GISS temperature anomaly using data up to Dec17.
    DJF18 0.86+-0.14
    MAM18 0.92+-0.18
    JJA18 0.79+-0.14
    SON18 0.92+-0.15
    J-D18 0.86+-0.12
    Additional I try to predict the MEI values the same way
    DecJan18 -0.82+-0.31
    JanFeb18 -0.68+-0.51
    FebMar18 -0.42+-0.74
    MarApr18 +0.12+-0.90

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    1. Correction to my prediction using data up to Dec17
      DJF18 0.86+-0.14
      MAM18 0.89+-0.17
      JJA18 0.78+-0.14
      SON18 0.89+-0.14
      J-D18 0.85+-0.11

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    2. I update my prediction for GISS temperature anomaly using data up to Jan18.
      DJF18 0.87+-0.07
      MAM18 0.89+-0.17
      JJA18 0.78+-0.14
      SON18 0.89+-0.14
      J-D18 0.86+-0.10

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  3. Nothing earth-shaking this year, with a relatively cool start due to nina. Going to re-use last years forecast: 2018 should end up close to 2015.

    Chubbs

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  4. I've noticed that since November 2017, the Tropics and SH temperature anomalies have dropped, apparently in association with the weak La Nina, but the NH temperature anomaly has risen for the NH winter much like it has for the last four NH winters. The last two NH winters, the NH temperature anomaly rise has been driven primarily by the 30-90N half of the hemisphere as tropical zone (30N-30S) temperatures declined. If the seasonal NH pattern of the last four years repeats again this year, we will see a drop in NH temperature anomalies into the summer with a rise again in the fall.

    The SH is a bit more tricky to forecast, but since it appears to be connected to the La Nina pattern, it should rise a bit as the La Nina weakens this NH summer (as most La Ninas have done in the past), but probably not much. The resulting global average should show an overall drop of about 0.2-0.3C from current NH winter levels into NH summer, but then should rise again in the NH fall. How much it rises in the fall will likely depend on what happens with the ENSO pattern in the tropical Pacific. If ENSO is neutral or returns to La Nina in the fall, then the global average may not rise much, if at all, from the summer levels. However, if ENSO tends toward weak El Nino conditions as many of the forecasts indicate, then the global temperature average might rise 0.1-0.2C from the summer levels. The net result for the year should be a global annual average somewhere near 2015. So I agree with Chubbs in that regard.

    I've added a couple of graphs to make it easier to see the recent global and zonal temperature patterns since 2013 based on daily UM CCI NCEP GFS/CFSV2 estimates here at the bottom of the page.

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  5. Bryan - since 1950, I don't think there has been a 3rd-in-a-row La Nina event. That doesn't make a La Niña later in the fall impossible, just unique.

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    1. JCH, if you allow a 2-month MEI threshold of 1.0 or higher to indicate at least a weak El Nino, then there were three in a row with peaks in 1992 Mar-Apr 2.258, 1993 Apr-May 2.019, and 1994 Sep-Oct 1.437 with intervening neutral conditions but no intervening La Ninas. However, this example is the only once since 1950 that I could find with that threshold definition.

      The 2017 Nov-Dec MEI was -0.576, which could indicate a weak La Nina if you set the threshold at -0.5 for a 2-month MEI. That would mean any subsequent weak El Nino later this year or next year would not be 3 in a row, because there was an intervening weak La Nina. Minor details and only depending on certain definitions, but your point is well taken. Also, my understanding is that the ENSO forecast models have little accuracy beyond about 3 to 6 months. So any ENSO forecast for next fall may be about as good or bad as anyone's guess.

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