Western US weather expert

Sundowner Winds-A Little Weather Lesson

7/15/2006, 11:03:41 PM

Just a little warning before you read on. You may have an educational experience today.

At times, we meteorologists use weather terms that are quite familiar to us but may not be to the general public. The last two days a Sundowner wind has occurred along the south coast of Santa Barbara County. So I thought this would be a great opportunity to explain what a Sundowner wind is.

A Sundowner wind is a warming, downslope wind that occasionally occurs along the south coast of Santa Barbara County. It can occur at anytime of year, or at anytime of day. But Sundowners are most prevalent in the late spring and early summer with their greatest frequency during the late afternoon and early nighttime hours, thus the reference to the sun going down.

These warming winds occur as a strong north-south pressure gradient develops between the central coast of California and the Los Angeles Basin. This pressure gradient, at times aided by strong winds aloft, cause gusty north winds to blow over the Santa Ynez mountain range that descends to the coast and beaches. This katabatic wind warms and dries out the air as it descends the mountains and displaces the usually cool, moist air at the coast. When the wind is funneled through the passes and coastal canyons it can cause wind gusts of tropical storm of hurricane force. Two cities, Goleta and Montecito, are places where the strongest winds can usually be found.

Large temperature rises occurs as these winds develop. In fact, Sundowners are responsible for the hottest weather in the city of Santa Barbara. The all time record high of 109 occurred on June 27, 1990 during a Sundowner event.

Firefighters are always on guard when a Sundowner is forecast. The combination of strong winds and very dry, hot air can cause a small fire to become a monster in a short period of time. In fact, the Paint fire on June 27, 1990 burned 5,000 acres in just three hours destroying 427 homes.

A Sundowner surfaced in Santa Barbara Wednesday, causing the temperature to skyrocket to 92, one of the hottest temperatures in California outside of the deserts. Another Sundowner is likely this evening into tonight with winds of 25 to 50 mph, while causing significant warming for a time.

Be ready for the pop quiz on Sundowners tomorrow.

Until then,

Ken

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

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Western US weather expert