A note from the Doc: The references to planets and constellations on this site are not astrological in nature, merely the clearest way to reference these positions and angles. For more, please read: Astrology or Astronomy »
An observable planetary movement pattern connected to the fluctuations in the polar jet stream is the passage of a planet through a particular longitude. In the basics section of Doc Weather the article on the lunar passage is a simple example of this dynamic. In that article, as the Moon passes by the longitude of North America it can be seen that air masses that have been stationed in a particular longitude will respond to the passage of the Moon by moving in the direction of the lunar passage in the exact time frame of the transit. The motion in longitude of a planet transiting a given longitude is often coincident with the motion in longitude of a stationary air mass in that longitude. It is a kind of tidal effect in the air that is readily observable.
Related to this passage in longitude is an accompanying movement in latitude of a transiting planet. The rapid motions of the Moon make it's longitudinal passage perceptible. At the same time however, the Moon is also moving in latitude as it passes the West Coast of the United States. The same is true for any other planet, except that the other planets are moving much more slowly than the Moon. To see the effects of slower planets a reference is needed. The Sun moving in longitude and latitude is a good planet to study for these influences. In the first figure we can see why.
This image shows the path of the Sun in its yearly apparent movement projected down onto the surface of the Earth. For information about the projection technique behind this idea please refer to the article projective fields . In the chart the green wave-form represents the apparent path of the Sun as it moves from the northern hemisphere into the southern hemisphere and back again in the course of a year. The Sun moves one degree of longitude in one day as it travels from west to east across the equatorial regions. From figure 1 it can be seen that the path also goes above and below the equator. The place where the Sun crosses from the southern hemisphere into the northern hemisphere is labeled as the vernal point. For the solar year this is an important position. The Sun crossing this point signals the reference point of the yearly rhythms for the northern hemisphere. For half of the year the solar track is below the equator and for half of the year the solar track is above the equator. With the vernal point in the longitude of England it can be seen that the solar zenith point of Northern Hemisphere summer, puts the position of the Sun at the summer solstice in the sign of Gemini over the Mid East (the twins of Gemini are the Tigris and Euphrates). The nadir of latitude of the solar cycle puts the position of the Sun at the winter solstice in the sign of Sagittarius over the West Coast of the United States.
It can be seen in this figure that this motion of the Sun, while it is constant in its daily longitude increments, is not constant in its daily latitude increments. At the solstices the daily one- degree motion in longitude is only accompanied by a few seconds of latitudinal motion. This is the source of the term solstice or sol (sun) stice (stays). At the spring and fall equinoxes the solar motion in longitude is accompanied by a degree in latitudinal motion every few days. From the chart we can see that the Sun in approaching the West Coast is declining in latitude towards the solstice point. This declining motion gives its name to the position of the Sun in latitude with reference to the equator. The Sun's position above or below the equator is reckoned in degrees of declination (declining latitude).
The last element that this chart depicts is the name of the green line itself, the ecliptic. This name comes from the bi-annual concentric meeting of the Sun and Moon along the orbital path of the Sun. Every six months the orbits of the two planets provide for the eclipsing of the Sun and Moon. For more information about this please refer to the article drought and lunar eclipses
Since the path of the Sun above and below the equator is the place where the eclipses happen it is called the ecliptic. So we could say now that the ecliptic of the Sun is a wave in time revealing the interaction of the longitude and latitude or the forward motion and the declination of the Sun.
In the amazing wisdom of the cosmos all of the other planets also move in longitude and declination throughout the year. In these motions they are following the path of the Sun. This means that a planet transiting the Pacific will have a tendency to be moving south in its declination just like the Sun. The complexities of the Moon make its motions in declination difficult to easily understand. These motions will be the focus of a future Doc Weather article. For now however it is useful to track the declination of Mercury as it approaches the West Coast of the United States. Doing this reveals an amazing coincidence of polar jet stream oscillations related to the motions in declination of Mercury as it passes the coast.
In this image we can see the daily paths of the polar jet stream in the Eastern Pacific between December 3rd and December 23rd of 2002. These paths are taken from daily records in the newspaper. It can be seen that the polar jet stream was very active in California but not so active in the Pacific Northwest. This is a southerly path for the jet stream bringing rains and storms to the south. At that time Mercury was crossing the West Coast at its most southerly declination of 25° S latitude. We might say that this coincidence proves nothing and that the southerly placed jet during the southerly declination transit of Mercury was purely coincidental.
To address that let's look at the period just before Mercury went into its southernmost declination. Figure 3 shows the daily jet stream paths in the Eastern Pacific from November 17th to December 3rd, this is the period for the two and a half weeks just prior to the situation depicted in the previous chart. We can see that the polar jet stream avoids the southerly latitudes and is centered in the Pacific Northwest. Even though the jet can sometimes be seen moving to a low-latitude to the east of Hawaii, the prevailing motion is to the northeast as it approaches the coast. Mercury at this time was in the longitude of Hawaii making its way eastward into the coast and it was not at its most southerly declination. As soon as it reached 25° declination on the third of December 2002 the polar jet stream shifted to the south (figure 2) and stayed there during the entire southerly passage and only returned to the north once Mercury had left its lowest point in transit.
Just so that we don't think that this was just a random relationship let's look at the year before these events, 2001. Figure 4 shows the period from December 3rd to December 13th 2001. Mercury was moving rapidly during this year as it approached the coast. It was moving about 1.5° a day in longitude. As a result of this fast motion in longitude, the period of its approach to the most southerly declination was only about ten days long. Figure 4 depicts the polar jet stream motion in the Eastern Pacific during the time of the approach to maximum declination. It is a bit more turbulent than the approach picture in figure 2 but the same tendency towards moving into the Pacific Northwest is present in these jet tracks.
In figure 5 we see the jet tracks in the Eastern Pacific during 2001 at the time that Mercury was at its most southerly declination at 25° S latitude. The turbulence of the rapid transit into the coast is evident but the unmistakable signature of the southerly placed jet stream is overwhelmingly present except for one days travel into the northwest.
In figure 6 we see the positions of the jet stream during the first half of November 2004.The period of Mercury's approach to lowest declination started on the11th of November and the period of its entrance into lowest declination began on the 17th. The early period is depicted in blue lines. We see the now familiar pattern of motion into the Pacific Northwest. The red lines depict the daily jet stream curves starting on the 16th of November the day of the entrance into most southerly declination, until the 23rd of November. The only red curve that goes through the Pacific Northwest is the curve for the 16th , the day of the shift. Otherwise the splitting of the jet stream by the Mercury entrance into its most southerly declination is precisely depicted by the jet tracks from these two consecutive time periods.
Mercury ran out of maximum southern declination on the 29th of November. During the maximum southerly declination period we can see that the southerly jet was aimed at Texas. This pattern brought strong storms to that area. However, on November 27th Mercury went retrograde between Hawaii and the West Coast. It is often the case that when Mercury is retrograde in this area the polar jet stream tends to split into a northern branch and a southern branch. The northern branch steers storms into the PNW and the southern branch steers storms into southern California and the desert South West. This track then puts storm energies into the Denver area. From there the storms track eastward across the Gulf Coast bringing rains to that area. This is an el Nino signature and should dominate the weather patterns for the southern High Plains through the New Year.
The retrograde motion continues into December, as Mercury goes retrograde back through Sagittarius putting it in the longitude of Hawaii in the middle of December where it again goes direct on the 20th. This means that Mercury this year can make another run at the West Coast. However, the second time around the maximum declination will only amount to 23° of latitude. It will be interesting to see if this shallower track will pull down the jet once again into Texas or will the track be more northerly through California. The period of this motion is between January 10th and January 25th 2005. Mercury will then be at 23° S latitude rather than 25° S latitude. Let's watch and see what happens.