Weather Watch

On that day, the wind fed the flames

It was windy, hot and dry on Oct. 20, 1991 at Alameda Naval Air Station near Oakland. We kept the cargo door open for the entire duration of our flight in our Navy H-3 Sea King helicopter as we practiced hovering near the Golden Gate Bridge.

On most days, hovering near the iconic, international orange-painted symbol of San Francisco meant keeping the helicopter pointed toward the Pacific Ocean as the persistent westerly (onshore) winds blew toward the inland valleys. However, on that Sunday morning, we kept the helicopter pointed to the East Bay as gusting easterly (offshore) winds buffeted our aircraft.

Reaching the end of a long Navy Reserve drill weekend — and wanting to see the 49ers game at Candlestick Park — we headed back to the base. We made our final approach to the runway and noticed smoke coming from the Oakland Hills.

A strong area of high pressure had developed over the Great Basin earlier that weekend and given rise to strong-to-gale-force northeasterly (offshore) winds. These winds produced scorching temperatures and bone-dry conditions, perfect for fire.

The wildfire that broke out that day became one of the nation’s deadliest and most destructive on record. The firestorm destroyed nearly 800 homes in the first hour. As the blaze spread westward, it produced its own atmospheric conditions, with fire whirls spinning upward as it consumed homes and eucalyptus trees.

Asphalt roads boiled as air temperatures reached an estimated 2,000 degrees. For the brave first responders and residents, it was hell on Earth.

Our helicopter squadron received a call for mutual assistance and launched out of Alameda, but tragically, we were only able to recover bodies. By the end, the fire jumped two freeways, destroyed more than 3,800 homes and killed 25 people.

The 20th anniversary of the Oakland Hills fire Thursday brought back some powerful and disturbing memories. Seeing firsthand what a terrible toll such disasters take on our communities brings into sharp focus the importance of first responders. I’m so appreciative of the work that our first responders do to keep our families and neighborhoods safe. We are all responsible to help them in every way we can.

Today’s weather report

Gusty northeasterly (offshore) winds early Saturday morning produced mild conditions with air temperatures reaching the mid-70s at Diablo Canyon at 3 a.m. due to adiabatic heating. However, the winds shifted out of the southeast (onshore) at 5 a.m. and air temperatures plummeted nearly 20 degrees in less than two hours.

San Luis Obispo reached 91 degrees at noon Saturday before the onshore winds cooled things off during the afternoon hours.

Like a seesaw with two people of the same weight at equal distances from the fulcrum, a delicate balance between the offshore and onshore winds will once again develop along the beaches of San Luis Obispo County today.

The beaches with the offshore winds will be clear and mild, while the beaches with the onshore winds will be overcast and cool. The surface charts and models are simply not indicating any strong pressure gradients today, making it difficult to forecast wind direction. We’ll probably have gentle southerly winds that will produce overcast and cool conditions along southwesterly facing beaches (Cayucos, Avila and Shell Beach), while the northwesterly facing beaches (Cambria, Morro Bay, Los Osos and Montaña De Oro State Park) will probably be clear. The westerly facing beaches (Pismo Beach and Oceano) will have periods of sunshine along with overcast.

Nevertheless, the coastal valleys and North County will see another spectacular fall day with plenty of sunshine and temperatures reaching the low 80s.

A weak trough of low pressure will cross Northern California on Monday and bring increasing coastal clouds with temperatures retreating back into the 60s and 70s.

Increasing northeasterly (offshore) winds will bring warmer temperatures and widespread clear skies Wednesday through Friday. These offshore winds will filter a very dry air mass across the Central Coast, allowing for cooler minimum temperatures at night and warmer temperatures during the day.

It continues to look like dry and mild weather will hold through the remainder of October and early November, with potential wet weather the second week of November.

Today’s surf report

The surface charts and models are not indicating any significant wind events along the Central Coast through the end of October. Consequently, short-period seas are not expected during this time frame.

This morning’s 2- to 4-foot northwesterly (310-degree deep-water) swell with a 7- to 9-second period will remain at this height and period through Monday morning.

A long northwesterly wind fetch in the Gulf of Alaska and gale force winds off the Northern California coastline will produce a 5- to 7-foot northwesterly (290-degree deep-water) swell with an 11- to 17-second period Monday evening along the Pecho Coast, increasing to 6 to 8 feet with an 8- to 15-second period Tuesday.

This northwesterly (290-degree deep-water) swell will decrease 5 to 7 feet (with an 11- to 13-second period Wednesday), further lowering to 3 to 4 feet (with an 8- to 11-second period) Thursday through Friday.

Increasing storm activity in the Gulf of Alaska may produce increasing northwesterly swell along the Pecho Coast in the Oct. 31 through Nov. 1 time frame.

Arriving from the Southern Hemisphere: A 1-foot Southern Hemisphere (185-degree deep-water) swell with an 18- to 20-second period is forecast along our coastline on Monday, increasing to 1 to 3 feet with a 16- to 18-second period Tuesday.

John Lindsey is a media relations representative for PG&E. He is also a local weather expert and has lived along the Central Coast for nearly 25 years. To subscribe to his daily weather forecast or ask him a question, email pgeweather@pge.com.

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