Tides and the Weather | |
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Forecasting weather patterns with an almanacOrbiting celestial bodies follow elliptical paths around their parent bodies, in general. Each year, as the earth orbit's the sun, it makes it's close approach to the sun (perhelion) on January 3rd and is farthest from the sun (aphelion) on July 4th; while the moon comes close to the earth (perigee) every 27.5 days.
 Note that this "Perigee Period" is two days shorter than the lunation period (from new moon to new moon), so that if the new moon coincides with the perigee one month, they are more and more out of sync on suceeding months,
 until finally the perigee is coinciding with the full moon. The result is that the perigee and syzygee coincide every 206 days, when the moon's major axis is directed toward the sun. [These numbers are averages which will vary slightly over time.]
 Due to the 8.86 year precession rate of the moon's major axis, every seventh or eighth close pass is also a new or full moon, bringing the moon even closer to the earth and resulting in the High Tides of the Year (on a 206 day scheduel, alternately at new and full moons).
 [Note that tidal peaks that occur near January 3 are exaggerated by the fact that the Earth is close to the sun at that time (in the Northern Hemisphere), and the highest tides (in the Northern Hemisphere), in general, occur close to this time when the sun's gravitational effect on the earth maximizes each year.] It has been suggested that this combination of circumstances represents not only the highest tides, but also times of increased probabiltiy of meteorological disturbances, such as Storms and Flooding events, the nature of which depends upon the season during which the peak occurs.
Notice, in the calculator below, that the lunar perigee will coincide very closely with the new moon on Decemebr 12, of 2004. If you look at 2005, you will see that the two will also coincide on January 10th, and that the lunar distance will measure 356571 km on that date; that being the fifth closest perigee in 30 years (1982-2012).
Fergus J. Wood on Tidal FlodingI would like to acknowledge a debt to Fergus Wood, Phd., a former Research Associate at National Ocean Survey (and later NOAA), and the author of "THE STRATEGIC ROLE OF PERIGEAN SPRING TIDES IN NAUTICAL HISTORY AND NORTH AMERICAN COASTAL FLOODING, 1635-1976", published by NOAA in 1978. Wood, an expert on tidal phenomena, noted that the tides themselves are not the problem, but that the problem arises when out-sized tides are accompanied by strong onshore winds. Wood pointed out that while we cannot predict whether strong onshore winds will occur within several days of unusually high tides, "The seemingly above-average frequency of such concurrent events raises the question whether some interrelationship between respective astronomical and meteorological phenomena might exist which has not yet been established". What I have done is to apply Wood's method to meteorological events in general, suggesting that high tides have an effect on the levels of precipitation in-land as well as along the shore lines. Wood goes on to say that "A certain statistical relationship also seems to hold between the most severe cases of tidal flooding and the second or third alignment of a given perigee-syzygy series. Repeated flooding events often occur within consecutive anomalistic months." [By "anomalistic months" we mean the period between the moon's close approach to the earth, which we pointed out earlier is 27.5 days.] Going back to the perigee calculator, we see that the first alignment of this winter's perigee-syzygee series will occur on December 12th, 2004, followed by Jan. 10, 2005, Feb. 7-8, then March 8-10. Applying Wood's formula, we might expect repeated storm events at these times, with the most severe occuring in January and February of 2005. [Note that this implies an early onset of wintery precipitation and an early spring. Take a look at the perigee calculator for 2006 and see that the perigee will coincide with the syzygee later in the winter season that year, implying a later winter onset and spring.]
Inferior Conjunction of MercuryIn several years of watching for "some interrelationship between respective astronomical and meteorological phenomena", I have come to notice the tendency of the inferior conjunction of the Mercury with the Sun (when Mercury pases between the Earth and the Sun) to exacerbated meteorological conditions, especially if it coincides with a syzygy (new or full moon), as it did in April this year. The conjunction occured on the 17th and the new moon (a partial solar eclipse) on the 19th, accompanied by a series of tornadoes in the mid-western United States. This December the conjunction occurs on the 10th, just prior to the perigee-syzygy event of the 12th! I personally expect that to produce the first big winter this year.
Tides and Seimic ActivityWood sent a copy of his book to the U.S. Geological Survey with a comment about possible tide/quake connnection. On pages 201-203, Wood points out that during six centuries (1635-1976), the greatest tidal force exerted on the Earth by the Sun and Moon was January 4, 1912. On that date the Earth-Sun distance was at a minimum (perihelion); the moment of the Full Moon was only 6.5 minutes away from an extreme minimum perigee. Only two quakes are listed for California/Nevada during 1912-1913, with the strongest of these hitting near the California-Nevada border, close to Bishop (about 5.5M), which occurred on January 4, 1912, the day of the maximum tidal forces in six centuries. Today a geologist named Jim Berkland has a web site dedicated to the subject of tide-based earthquake predictions.
Mt. St. HelensIn 1980, the perigee and syzygy coincided at the new moons in March, April and May; the earthquakes at Mt. St. Helens began in March. Looking at a Farmer's Alamanac (as well as an ephemeris) I noticed that the new moons in May and June were the same days when the earth was going to pass between the planets Uranus (May 14) and Neptune (June 12). I contacted a friend at a local TV station and arranged to produce an early Sunday morning segment where I spelled out the reasons why I believed that these two days would be the most likely times for the mountain to finally erupt. As it turned out, the initial eruption occured on May 18th (killing 65 people after the "red zone", which had been closed, was re-opened), with a secondary eruption occuring a week later (May 25th), while another big eruption occured on June 12th!
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