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12 FOUR SEASONS BREEZE | OCTOBER 2021 "Understanding the Weather" – A Series by Mel Zeldin, Retired Meteorologist With the current drought and severe fires affecting California, many people ask me about the upcoming fall and winter season. While weather forecasting relies on current information, computer models, and other tools to forecast for Southern California, looking ahead some six months in advance is more challenging. For these projections, I turn to the National Climate Prediction Center, where experts rely on a number of factors to look that far into the future. The most important of these is sea surface temperatures. (For a discussion of sea surface temperatures and the El Niño and La Niña phenomena, please see the weather article in last November's Breeze.) For the upcoming season, both temperature and precipitation outlooks are shown for the conterminous United States for the fall months, October through December (Figures 1 and 2), and also for the winter months, January through March 2022 (Figures 3 and 4). The fall outlooks show a 40%-50% probability of above-average temperatures and a 30%-40% probability of below-normal precipitation for the Southern California area. For the winter outlooks, there continues to be about a 40% chance of above- normal temperatures and above 40% probability for below-normal precipitation. It should be noted, however, that last year's extremely dry winter was associated with a very strong La Niña sea surface temperature pattern. This year, though a La Niña pattern is expected again, it is forecast to be weaker than last year. Hence, while precipitation is expected to be below normal, it will not be as severe as the last rainy season. So, slightly more precipitation than last year would be expected. And that is a tiny bit of good news. Fall & Winter Weather Outlook Fig. 1. Temperature Outlook: October, November, December 2021 Fig. 3. Temperature Outlook: January, February, March 2022 Fig. 4. Precipitation Outlook: January, February, March 2022 Fig. 2. Precipitation Outlook: October, November, December 2021 (a tiny bit of good news)

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