BASIC PATTERN:
Large Scale Pattern -
- November appears to be a transitional month between anomalously dry conditions to the beginning of near normal precipitation for central and N California and Sierras. Southern California continues anomalously dry and warm in November.
- For December, we continue the transition to wetter than normal in central and N portions of California. Southern California continues to remain with near normal rain at best. There is a chance for some above normal rainfall developing in west Santa Barbara and San Luis Obispo Counties, as rains begin to increase in the mid to latter parts of Dec. The IVTinit pattern is shifting to favor some more frequent rains and wetter regime to develop in central and N California.
- Latest CFSv2 model solutions and the GFS (first 15 days of the forecast period from today) start to show some support for more rains into Northern California but associated with warmer than normal conditions indicating a tendency for atmospheric river conditions in NW and N California and Oregon.
- The sea surface temperature anomaly maps have continued to show a robust El Nino pattern along the Peru-Ecuador coast and westward along the equator out to about 170W. Therefore, a classic El Nino pattern continues in place, with a colder than normal sea surface developing in Indonesia to North Australia.
- Precipitation trends in longer range, up through Feb 2024: A change to above normal precipitation in December 2023, January 2024, and continuing in February 2024. The trend in the NMME short term climate forecast for late winter 2024 suggest that we approach the end of the anomalously wet period around the beginning of March 2024. March appears to return to warmer and drier than normal conditions.
- Potential dates of wet periods in Central-N Calif: Nov 2-3,5-7, 15, 19-21,22-30, ~Dec 1-6. The best indicator for mountain snows appears to be in January 2024, with temperature across California Near normal (for Jan), and precipitation above normal across the state.
FORECASTS FOR CALIFORNIA
Forecast for Northern California:
NORCAL Precipitation: Nov 2-5,6-7, 11-14, 17-22,24-30, Dec 2-6
NORCAL WARM/HOT SPELLS: Nov 1, 9-10, 16 and 31-Dec 1
NORCAL COLD OF FROST: Nov 2-7, 11-14, 17-30 and Dec 2-6
Forecast for Central California:
Central Calif Precipitation: Nov 3-5, 7, 12-14, 18-22, 25-30 and Dec 3-6
Central Calif WARM SPELLS: Nov 1-2, 9-11, 16-17, 31 and 26.
Central Calif COOL/COLD SPELLS: Nov 7-9, 19-21, 23-29 and Dec 1-2
Forecast for S California:
SOCAL RAINS: Nov 21-22, 27, 30 and Dec 5-6
SOCAL WARM TO HOT SPELLS: Nov 5-8, 12-14, 24-26 and Dec 1-3.
SOCAL COLD OR FROST SPELLS: Nov 22-24, 28-29, 30-31 and Dec 5-6
Central Sierra Nevada Precipitation for 1-30 Sep 2023:
Main dates of rains or showers and/or snow...
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The listings of dates normally included for hot and cold spells, and precipitation are approximate. They are based on our CFSDaily and CFSDailyAI products; and present expected trends in precipitation and temperature (FoxCFSDailyAI) to 5km. Our system gives some consideration to terrain and coastal influence. We consider the CFSv2 one of the better ways to represent basic weather down in the sub-monthly time scale beyond the 15ñday GFS or monthly maps from CFSv2 or NMME.
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Southern California Deserts Outlook:
Troughing Dates: Above dates may contain some showers as well as gusty winds.
Looking Ahead — Longer Range Outlook 3-31 Dec. 2023
N and Central California and Sierras:
The El Nino pattern gets started in December, after a mid November period of maximum rainfall.
The El Nino precipitation pattern appears to be in place in Dec before the holiday period.
So a more consistent El Nino pattern sets up near and west of the California coast from mid Dec onward into January.
S California: Above normal temperatures recur for most of Nov. Cool periods coincide with the November rainy periods and the Thanksgiving holidays. Wet conditions continue in Dec as El Nino develops.
NOTES ON THE SEASONAL OUTLOOK FOR THE PERIOD JAN 1 ñ—Mar 31
We include the CFSv2 outlook maps for the period Dec 1 - Feb 28, 2024. The CFSv2 shows above normal precipitation for California as a whole during the entire period from Dec 1 ñ Feb 28. We extend that wet precipitation anomaly through first 10-15 days of Mar 2024. Heaviest rains are indicated for N half of California, where the positive rainfall anomaly coincides with the time of active winter storms, i.e. Dec - Mar. Exceptions are: SOCAL where only near normal rainfall is forecasted for Nov and Dec by the CFSv2 model.
(Terms and Definitions Used In This Weather Outlook)
Figures: Alan Fox
Text: Zane Stephens, Fox Weather, LLC,
Copyright © 2023 Fox Weather, LLC