This has been a very wet fall in California. A big contrast with last year.
Los Angeles this week
Consider the differences from normal of the precipitation during the last month for the western U.S. (below).
Wow. Some parts of southern California have gotten 800% of normal precipitation! The entire state is considerably wetter than normal.
Many of the rivers are running MUCH higher than normal, as shown by the latest percentages below. Crazy high river levels over coastal southern California.
All are at or above normal. Over southern California, some are full.
Last year, had one of the driest Octobers through December on record in Southern California, which contributed to the LA wildfire in early January.
Some claimed this was the result of "climate change."
The atmosphere did not get the message. Consider the precipitation from October 1 through November 19 over the past 50 years. This year was the second wettest of the entire record!
This wet fall has led to the suppression of wildfires.
So far this has been a VERY low wildfire year in California....something that is being given little attention in the media.
Below are the statistics for wildfire acres year to date. So far in 2025, about 525,208 acres have burned compared to a fire-year average of 1,315,947.
That is only about 40% of the recent average.
So, why has California been so wet? The answer: a persistent trough of low pressure off its coast.
For example, here is the anomaly map (difference from normal) for the heights at 500 hPa pressure (think of pressure around 18,000 ft).
Purple and blue indicate lower than normal values....troughs of low pressure. Right off of California!
Thanks for this analysis. Could you explain why there’s such a dramatic transformation in the amount of rain in Washington during the month of November? It feels like it’s typically the wettest month of the year and the spigot is turned on relative to October.
ReplyDeleteOh that's easy, the sky is falling, we're in a horrible nasty drought and everybody is gonna dye of it sooner than later suffocating on dust and forest fire smoke.
DeleteBy this time of year, the north Pacific high that keeps us dry has lost most of its influence. The atmosphere is slightly warmer than in winter, so the systems that do come our way can hold onto more moisture. Interestingly, the biggest monthly increase in precipitation probability happens in October, where the chances of daily rain nearly double between Oct 1 and Halloween.
DeleteIn Bellingham, at least, the change in normal monthly mean precipitation from September to October is indeed the largest month-to-month difference of the year with normal mean October precipitation nearly double that of September. The change in monthly normal mean mean temperature between September and October is also the largest month-to-month difference of the year, as well, with October’s normal monthly mean temperature nearly 8 degrees cooler than September’s. Early autumn is without question the time of year that Western Washington’s weather regime undergoes its most dramatic shift.
DeleteInterestingly, while the month-to-month change in normal mean precipitation between April and May is less dramatic, the change in normal monthly mean temperature is the largest that occurs during the warmer months with May nearly 6 degrees warmer than April.
Western Washington’s official wet season officially begins October 1 and ends April 30.
IIRC, Cliff has previously blogged about the occurrence of the major seasonal temperature transitions in Western Washington.
I am confused by the use of the word "normal". It seems to me that you are using it instead of "average", which would seemingly be the more accurate word. for example you write, "What about the levels of the all-important California reservoirs? The answer is below. All are at or above normal". Isn't it true that all of the values are actually within "normal" variation? Is this some weather jargon that I am missing? thanks for your insightful reporting. I learn something every time.
DeleteGreat news for So Cal. Be on the lookout for a super bloom in the deserts next spring!
ReplyDeleteLooks like California is having a good year in terms of rainfall, lack of wildfires (excluding the LA fires in January...those were nothing short of awful), and water storage.
ReplyDeleteI grew up in Southern California. Wildfires are endemic there, the only question is how big will fire season be. The more rain SC gets, the more brush is available to burn. The size of the fires depend upon both the fuel load and how intense the Santa Ana winds are. The Santa Ana winds were very intense and the fuel load was very big, so there were massive fires last year.
ReplyDeleteIt's not rocket science, just climate.
The drought monitor appears to have responded accordingly.
ReplyDelete