Tuesday, January 3, 2017

NCEP/NCAR December Down 0.09°C - coolest since June.

The Moyhu NCEP/NCAR index fell from 0.48°C in November to 0.391°C (June was 0.369°C). It was an up and down month, cool in the mid, but warm at the end.

I don't normally talk about long term records with reanalysis, because I don't think it is homogeneous enough. But I will note that successive annual averages for the last three years were 0.19, 0.33, and 0.531°C (anomaly base 1994-2013). So up by 0.2°C in 2016. This is an indicator of large margins in other indices. It also means that all months in 2016 were warmer than the 2015 average, including December. El Nino has gone, but it stayed warm.

A feature was again a band of cold from Cairo to Vladivistok through Russia, though most of Asia was warm. Also cold in Canada and north US, though not in the South. Warm in the Arctic - a pattern for the December quarter.

Sea ice in the Arctic became more normal, and the very fast melting in the Antarctic slowed, although still a lot less ice than in other years.


  1. BOM's latest ENSO update is out today... solidly neutral, with ONI rising to the zero line in March. The great global refreeze after the au naturale 2015-2016 has competely unrefizzled, but then, the El Nino never was au naturale.

    Professor Curry has retired. Best to be gone when the stadium wave never shows up.

    1. I see too that UAH is out, and is down 0.21°C. Like NCEP/NCAR, but a bigger drop. But 2016 still squeaked in as a record year.

  2. UM CCI just posted their final CFSR daily GMST estimates for December and I averaged them to get a monthly average. With reference to 1981-2010 for November and December, the UM CCI CFSR went from 0.438C to 0.394C (-0.044C), WxBELL CFSR from 0.429C to 0.376C (-0.053C), and my attempt to adjust the UM CCI CFSR based on the NCEP/NCAR R1 went from 0.621C to 0.577C (-0.044C), while the recently ECMWF adjusted ERAI for November was 0.616C and December was not posted yet.

    Interestingly, the GFS is forecasting a rapid drop in GMST over the next 5 days of about -0.6C. The latest 18Z Jan 3 run starts at 0.608C and drops to -0.010C for the 114 hour forecast valid 12Z Jan 8 according to Karsten Haustein's GISS-adjusted estimates. The GFS 7-day forecast has been running about 0.1C too low recently, so the drop might not make it quite that low. More than likely it will bounce back up again fairly quickly within a week or two after bottoming out. I've been watching it here:

    1. ERAI Adjusted GMST for December is in now at 0.498C, down -0.118 from November.

      Data and maps here:
      ECMWF Copernicus ERA December

    2. Forgot to mention that it was nice NOT seeing any changes to the previous month's data with the ERAI, unlike most non-reanalysis GMST estimates. I checked every month back to 1979 and all were the same.

    3. Bryan,
      Practically, reanalyses can't change. They are based on data assembled for NWP, and it's quite a lot of computation. No-one is going to re-run it because of data that may arrive or change after the forecast period is past.

    4. Nick,
      Yes, I understand they don't change every month and that is one of the things I like about them. I was just complaining about the constantly changing TLT and GHCN-based GMST estimates. I read the link you provided to the NCAR Climate Data Guide discussion about reanalysis strengths and limitations. They are certainly not perfect, but at least since 2010 for CFSR and since 2002 for ERAI the latest generations look very impressive. The next generation, like the upcoming ERA5 and potentially the based on coming GFS replacement, should be even better.
      NOAA to develop new global weather model

      I have to agree with you that going back in time prior to 1979 is probably not worth the trouble for reanalysis, although I was impressed at how well the monthly NCEP/NCAR R1 compares versus NCEI for the 1960's and 1970's.

  3. Yes, the pole thing has escaped the Arctic this week and is running around North Texas. We'll have that varmint back across the Red River within the week.