Our Report on the JAMSTEC Three-Season Forecast – Can be Compared to the NOAA Outlook – Posted on October 5, 2024
The Japan Agency for Marine-Earth Science and Technology, or JAMSTEC, is a Japanese national research institute for marine-earth science and technology
From the JAMSTEC Discussion:
“The latest observations show that there are weak signs of a La Niña. However, the SINTEX-F ensemble mean predicts that a La Niña Modoki will develop in the boreal autumn and persist into the boreal winter, although there is a large uncertainty in the timing and amplitude of the event.”
Although it is a World forecast, it includes a forecast for North America since North America is part of the World. One might try to compare it to the NOAA Outlook we published recently which can be accessed HERE.
First, we take a look at the forecasted sea surface temperature anomalies (SSTA). JAMSTEC starts by forecasting the SSTA and Nino 3.4 Index on the first day of the month and from there it usually takes their models about two weeks to produce their seasonal forecast. I received it from JAMSTEC on September 25 which was much later than when NOAA issued their Seasonal Update this month. The JAMSTEC model runs are based on conditions as of September 1, 2024. The NOAA Seasonal Outlook is based on conditions closer to the time when it was issued.
We do not have a full three-season forecast from JAMSTEC this month. We have forecast maps for OND, DJF and MAM so it is really an eight-month forecast as OND and DJF overlap a bit. For each of these three-month Outlooks, I also show the corresponding NOAA Precipitation Outlook for comparison purposes. The two are remarkably similar which is very unusual.
We also have single-month JAMASTEC forecasts for October through March 2025. I have a single-month outlook for October from NOAA but not single-month outlooks for the other five months so I could not show those comparisons.
Let’s take a look.
| This shows their forecast of sea surface temperature anomalies at three points in time. Blue is a cold anomaly and is associated with La Nina if it occurs in the Nino 3.4 measurement areas in the Pacific along the Equator. The cool anomaly along the Equator is somewhat further west than usual which gives it the Modoki characteristics.
The U.S. funded some of the Modoki research but for some reason declines to mention it in their seasonal outlook discussions. In the OND image above, look at that blob of cool (anomaly) water to the west along the Equator. Thus the La Nina has Modoki characteristics that impact the Walker circulation. I have written about that before. It raises questions about the reliability of our current approach to thinking about the ENSO Cycle. This is covered in another article that can be accessed HERE. Of interest also is the neutrally cold water just off the West Coast of the U.S. and the warm water between Africa and the north coast of South America which can support tropical storms and hurricanes. NOAA publishes a similar SSTA analysis. It can be accessed HERE. JAMSTEC uses the same definition of Normal (climatology) as NOAA. JAMSTEC does a better job at characterizing La Ninas and El Ninos than NOAA. JAMSTEC provides me with a lot of other information that I do not include in my articles to keep them to a manageable size for readers. That material is the atmospheric pressure patterns. |