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Dennis’ Local Almanac

By DENNIS McTIGHE

The highs and lows of January tides

At our latitude, today, Tuesday, Jan. 9, the sun will set at 5 p.m., 19 minutes later than our earliest sunsets of the year – which occurred from December 8-11. Our sunrise still occurs at its latest time at our latitude until January 13 at 6:58 a.m. For the remainder of the month, we will gain one-two minutes per day of sunlight. At month’s end, our sunrise will be around 6:46 a.m. and our sunset around 5:14 p.m.

The highest and lowest tides of the winter usually occur in December and January during the time of the full or new moon. The swing between high and low tide can be as much as nine feet on occasion.

This upcoming Thursday and Friday, we’ll see a spread of 8.7 feet here in Laguna – and other beaches in Orange County – when the new moon happens on the January 11. The King Tides, as they’re called, occur in the morning in the winter (somewhere between 8 and 9 a.m.)  and the evening in the summer (between 8 and 9 p.m.) with the following super low tide occurring about 7 to 7.5 hours later.

To our south, San Diego beaches will see a greater swing – up to eight feet or more during these episodes. The Hawaiian Islands only see a swing of about two or three feet on the average while at the other end of the scale, The Bay of Fundy in Nova Scotia, Canada, can see a spread as much as 50 or 60 feet during the new or the full moon.

Those of us who live in hilly areas or mountainous areas like Southern California are aware that the weather they experience is often different from that of surrounding areas. Annual rainfall totals can vary significantly in just a short distance from town to town. However, rainfall amounts can be consistent in a region that is relatively flat over an area of many miles – like the plains.

This is what orography is, the effect of those hills and mountains on weather. As the wind blows over the ocean, it picks up moisture from evaporation. If the air is then blown onshore, it is forced to rise when it reaches the hills. As it does it cools and allows condensation to take place which causes the formation of clouds from which precipitation falls.

Most rain falls on the hilltops or the windward side of the hills, the side facing the ocean, and so the onshore winds carry this moisture. As the air descends on the lee or sheltered side of the hills it warms; evaporation takes place, and the air dries so little rain falls. This results in the leeward sides experiencing much drier conditions than the windward sides.

It is possible for hills and mountains to produce clouds by themselves. Some mountains develop lenticular clouds which are formed by locally rising air which condenses as it rises over the top of the hill. This air cannot rise farther, however, and so the winds then “bounce” downstream of the mountain. These lenticular clouds do not move along with the wind but instead appear stationary. They form as the air rises and dissolve as the air descends, hence the apparent stationary effect that resembles a flying saucer in its appearance. I witnessed a triple layered such cloud just above the top of Mount Shasta up in Northern California a few years back.

Finally, it froze the other night out in the canyon at 31 degrees with a chilly 36 here in town.

Have a great week, ALOHA!

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