By Reginald Stanley. Posted December 31, 2024, 4:37 AM.

The month of December 2024 will close with many WeatherCurrents stations having received no measurable precipitation, while other stations received less than 0.10 inches. This continues are trend of very dry weather that has persisted since the summer months across Southern California.

Season totals to-date for WeatherCurrents stations since July 1 are exceptionally below average for this time of the year, with all active WeatherCurrents stations standing with less than 1/2 inch of precipitation to-date, with the exception of Anza. Not even one storm has made it to the southern portion of California intact, which stands in stark contrast to Northern California, which has received substantial rainfall to-date. Precipitation events in Southern California so far have been limited to moisture-starved inside slider-type systems and marine layer drizzle events, separated by numerous Santa Ana Wind and offshore flow events. Responsible for this pattern is persistent, anomalous subtropical ridging over northern Baja California and the Southwest, which has been stubbornly in place since late Spring.

In Downtown Los Angeles, where precipitation records date back to 1877, the period from July to December in 2024 is the second-driest such period on record, with only 0.16 inches recorded there - just behind 0.12 inches recorded during the same period in 1962. In San Diego, with precipitation records dating back to 1870, the July to December period in 2024 is the driest such period on record there, with only 0.14 inches recorded since July. In second, the same period in 2017 saw 0.17 inches in San Diego - and ended up a very dry rainy season. Both rainy seasons did not see any significant rain in Southern California until January - and in 2017-2018's case, there was only one significant rainstorm of the season. The 1962-1963 season saw meaningful rains beginning in late January and February, and while the season finished below average in both Los Angeles and San Diego, a severely dry season was averted.

As of late December, computer forecast models continue to indicate dry conditions persisting for Southern California through at least the first third of January. The possibility of reaching even average seasonal rainfall is looking increasingly highly unlikely for the region, currently we are eagerly awaiting any hints of a change to a wetter pattern for Southern California in either late January, February or March. The dry conditions have contributed to worsened air quality for the region, and an increased number of Red Flag Warnings during wind events - greatly extending the region's fire season far beyond normal limits.