NOAA Updates their Mid-Month Forecast for December 2024 on November 30, 2024 – Major Changes. – Posted on December 2, 2024

December 2, 2024Posted inweatherNo Comments

At the end of every month, NOAA updates its Outlook for the following month which in this case is December of 2024. We are reporting on that tonight. In this article, I refer to December 2024 as “The New Month”.

There have been significant changes in the Outlook for the new month and these are addressed in the NOAA Discussion so it is well worth reading.  We provided the prior Mid-Month Outlook for the new month for comparison. It is easy to see the substantial changes in the weather outlook by comparing the Mid-Month and Updated Maps. My comments are in a box.

The article includes the Drought Outlook for the new month. NOAA also adjusted the previously issued three-month Drought Outlook to reflect the changes in the new month’s Drought Outlook. We also provide the Week 2/3 Tropical Outlook for the World. The Tropical Outlet includes both direct and indirect potential impacts to the Southern Tier of CONUS. We also include a whole set of forecasts for parts of the new month. These are both useful and provide a crosscheck on the validity of the new month’s Outlook. The whole should be equal to the sum of its parts.

The best way to understand the updated outlook for the new month is to view the maps and read the NOAA discussion. I have highlighted the key statements in the NOAA Discussion.

I am going to start with graphics that show the updated Outlook for the new month and the earlier Mid-Month Outlook for the new month. This is followed by a graphic that shows both the Updated Outlook for the new month and the previously issued three-month outlook for the three-month period that includes the new month. So you get the full picture in three graphics.

Here is the updated Outlook for December 2024.

For Comparison Purposes, Here is the earlier Mid-Month Outlook for November

It is important to remember that the maps show deviations from the current definition of normal which is the period 1991 through 2020.  So this is not a forecast of the absolute value of temperature or precipitation but the change from what is defined as normal or to use the technical term climatology.

It is a substantial change from what was issued on November 21, 2024. Remember, it is the first set of maps that are the current outlook for December which is the new month.  One expects some changes  10 days later. However, the changes to the updated new month Outlook are very significant.  This then gives us some reason to question the (November 21, 2024) three-month NDJ temperature and precipitation Outlooks which are shown in the following graphic.

NOAA provided a combination of the Updated Outlook for the New Month and the Three-Month Outlook.

The top pair of maps are again the Updated Outlook for the new month. There is a temperature map and a precipitation map. The bottom row shows the three-month outlooks which includes the new month. I think the outlook maps are self-explanatory.

To the extent that one can rely on a forecast, we would conclude that January and February will be very different than December. You can subtract December from the three-month Outlook and divide by two to get a combined January/February Outlook.

However given the major change in the new Outlook outlook from what was issued on November 21,  2024, we might not trust the three-month Outlook issued on November 21, 2024. Something to think about. But the major factor is the projected slower onset of La Nina. Thus this change may be consistent with the pattern the NOAA has been predicting although they have been playing catch-up.

I am still not convinced that there will be a La Nina Winter. Thus I am somewhat skeptical about the NOAA Outlooks.

Some readers may need to click “Read More” to read the rest of the article.  Some will feel that they have enough information. But there is a lot more information in the rest of this article.