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Laguna Beach

 Volume 14, Issue 52  |  July 1, 2022


Dennis’ Tidbits

By DENNIS McTIGHE

Here comes summer! 

Dennis 5On Father’s Day, the gloom took the day off. It was a beautiful day in the neighborhood with clear and sunny skies. Air and water temps were both 68 degrees with gentle breezes from the SW. Here comes summer!

How ordinary summer heat develops – given terrain and geographic situation, North American summers are bound to be hot. As the advancing sun drives back the polar air, the land is opened up to light and solar heat, and occupied by masses of warm moist air spun landward off the tropical ocean. With these rain-filled visitors come the tongues of dry desert air that flick northward out of Mexico and occasionally the hot winds called “chinooks” which howl down the Rockies’ eastern slopes.

Inequalities of atmospheric heating and cooling of moistness and aridity are regulated at middle latitudes by horizontal and vertical mixing. The mixing apparatus is the parade of cyclones (low pressure centers, or lows) and anticyclones (high pressure centers or highs) which lie at the heart of most weather, good or bad.

The cyclones and anticyclones drift in the mid-latitude westerlies, as the prevailing eastward-blowing winds follow a scalloped path around the Northern Hemisphere. The large-scale undulations of these winds may extend for thousands of miles and are called planetary waves. Their high-speed core is the jet stream which snakes across the continent some six-eight miles up, keeping mainly to the cool side of the highs and lows as they form and spin and die below it.

The strength of the jet stream varies and therefore, it rarely moves across a hemisphere as one continuous river of air. Generally, its segments span 1,000-3,000 miles with a width of 100-400 miles and a thickness of 3,000 ft. A jet stream’s winds can be as low as 50 knots or as high as 300. Frequently the jet stream wind speed settles between 100-150 knots.

The kind of weather predominating in an area over a period of time depends largely on the prevailing position and orientation of the jet stream. As the continent warms, the jet stream shifts northward along with the tracks of surface weather disturbances. Cyclones like the ones which brought April rains to the Gulf states bring June thundershowers to the Plains, and the humid spring of Georgia becomes the muggy summer of Illinois. These semi-regular alternations of instability and equilibrium, hot and cool, moist and dry, combine year-in and year-out to generate the average June to September climate for North America.

 In the next edition of Stu News Laguna, I’ll discuss how heat waves occur and the phenomenon known as “heat index.” I’ll try to forecast what kind of summer we can expect here in Lagunaville, which is a tough call. Incidentally, I had a little help from the latest edition of the Weather Almanac. Hope you had a good Happy Pop’s Day, and we’ll get together again on Friday. 

Until then ALOHA!

 

Shaena Stabler, President & CEO - Shaena@StuNewsLaguna.com

Lana Johnson, Editor - Lana@StuNewsLaguna.com

Tom Johnson, Publisher - Tom@StuNewsLaguna.com

Dianne Russell is our Associate Editor.

Michael Sterling is our Webmaster & Designer.

Mary Hurlbut and Scott Brashier are our photographers.

Alexis Amaradio, Dennis McTighe, Diane Armitage, Marrie Stone, Sara Hall, Suzie Harrison and Theresa Keegan are our writers and/or columnists.

In Memoriam - Stu Saffer and Barbara Diamond.

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