David Middlecamp

🌊🌡️ An Extraordinary Ocean Temperature Record: Nearly 50 Years in the Making! Something remarkable has happened beneath the waves along California’s Central Coast. This October, Station 19-10, a subtidal seawater temperature monitoring station in Patton Cove, south of the Diablo Canyon Power Plant, recorded an astonishing 69.53°F at a depth of about 10 feet! That's the warmest seawater temperature recorded at this location since monitoring began in 1976, nearly half a century ago! To put this extraordinary reading in perspective, the previous record was 67.7°F, set in September 2015 during another very strong El Niño event. This October's reading shattered that record by nearly 2°F. Even more remarkable, the average annual seawater temperature here is just 55.3°F. During autumn, temperatures typically reach their seasonal maximum, averaging around 62.5°F. This October's reading was a staggering 7°F above that typical seasonal maximum! 🥶 From Bone-Chilling Cold to Record-Breaking Warmth 🌡️ This station's historical temperature records tell a fascinating story about the extraordinary variability of our coastal ocean. During April 2008, relentless gale-force northwesterly winds drove intense coastal upwelling, bringing exceptionally cold, nutrient-rich water from the ocean's depths toward the surface. On April 22, 2008, Station 19-10 recorded a bone-chilling 47.35°F! That month, the Diablo Canyon Ocean Lab measured an average seawater temperature of just 49.52°F, the coldest April average in its records dating back to 1976. Now, compare that icy 47.35°F reading with this October's remarkable 69.53°F. That's a difference of more than 22°F at the very same monitoring station! 🔬 A Little Personal History Beneath the Waves For 31 years, I worked at Diablo Canyon Power Plant, where one of my responsibilities involved monitoring seawater temperatures along the beautiful, rugged Pecho Coast as part of the plant's environmental monitoring program. This fascinating work relied on electronic, waterproof temperature recorders, some about the size of a large Sharpie, secured inside protective steel canisters at fixed locations in the intertidal and subtidal zones. Every few months, marine biologists would venture into the rocky tide pools to exchange the recorders. During the summer, some of the lowest tides occurred in the darkness before dawn. I still remember those remarkable conditions: scientists working by flashlight or moonlight, navigating slippery rocks as waves crashed nearby. Occasionally, bioluminescent plankton illuminated the water, creating an almost otherworldly experience along this remote coastline. The team returned the recovered instruments to the Diablo Canyon Ocean Lab, where they downloaded, checked, and archived the temperature measurements. Since 1976, this extraordinary monitoring program has produced millions of temperature measurements, including more than 800,000 observations from Station 19-10 alone. That remarkable continuity is what makes this October's new record so meaningful. We're not comparing just a few years of measurements. We're comparing nearly five decades of observations at the same location. 🌎 What's Behind This Extraordinary Warmth? The unusually warm seawater is consistent with reduced coastal upwelling and the arrival of anomalously warm water (Kevin Wave) moving northward along the California coast, associated with the ongoing very strong El Niño condition and climate change. These conditions can dramatically alter seawater temperatures, coastal sea levels, marine ecosystems, and even the weather we experience along the Central Coast. For someone who has spent more than 35 years studying the weather and oceanographic conditions along California's Central Coast, this is a truly remarkable observation. Perhaps most importantly, this record reminds us why long-term environmental monitoring matters. Without the dedication of generations of marine biologists, oceanographers, and technicians who have maintained these instruments since 1976, we might never have recognized just how extraordinary this event really is. 🌊 Nearly 50 years of observations. More than 800,000 temperature measurements. And now, a new record of 69.53°F! The ocean is telling us an extraordinary story, and thankfully, we've been listening since 1976. I took this photo of Frankie Mellow and Randy Price on horseback near Patton Cove, where station 19-10 is located. – at Los Osos, CA

Not to alarm anyone, but to raise awareness and encourage preparedness for what could be an exceptionally stormy winter across California. As the late, great Rea Strange of Pacific Weather Analysis often said, one of the most reliable indicators of a wet weather pattern for California is the development of strong, persistent upper-level westerlies stretching across the North Pacific Ocean. In my more than 35 years of forecasting weather along California's Central Coast, I've learned to pay particular attention when upper-air charts and numerical weather models indicate the development of a powerful, persistent Pacific jet stream. In fact, I consider this one of the most important atmospheric indicators of a potentially wet and stormy winter for California, especially during a very strong El Niño condition. The latest projections from the European Centre for Medium-Range Weather Forecasts (ECMWF) suggest that an exceptionally powerful subtropical jet stream could develop across the Pacific Ocean and extend across much of the United States this winter and into early spring. Remarkably, these projections indicate the potential for record-strength subtropical jet-stream winds extending from California to Florida. If these long-range ECMWF projections verify, we could be looking at a remarkably active winter storm pattern, with the potential for well-above-normal precipitation across portions of California, particularly from late December through January, February, and March. Of course, there is an important distinction between favorable atmospheric conditions and actual rainfall. These are long-range projections, not guarantees. Even during powerful El Niño events, California's precipitation can vary considerably depending on the position of the jet stream/storm tracks and other atmospheric influences. Nevertheless, the potential development of such an unusually strong and persistent Pacific jet stream is a significant atmospheric signal that deserves our attention. My message is not one of alarm, but of awareness and preparedness. Now is an excellent time to clear drainage systems, inspect roofs and gutters, review emergency plans, and prepare for the possibility of an unusually wet and stormy winter. Please visit ReadySLO.org for preparedness, emergency, and recovery information. I'll continue closely monitoring the upper-air patterns and numerical weather models as we approach the heart of California's rainy season. Special thanks to meteorologist Ben Noll for sharing this ECMWF analysis and highlighting the potential significance of this developing atmospheric pattern. – at Los Osos, CA