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 »
The present pattern of extreme heat on the West Coast is similar to other record cycles. In 1996 a similar stretch of triple digit temperatures occurred in July from much the same sources. The climatology of these events is the placement of a persistent high-pressure area over the inter-mountain west. The clockwise circulation around the high brings warm air off of the continent and into the central valley of California.
In 1996 the position of the anomalous high was over Western Canada. In the chart the disturbance diamond is placed over the desert Southwest. The high is keying off of the two 72° jet curves that are over British Columbia. The section of the curves that was active in the cycle was in the northwest quadrant of the disturbance diamond. The counterpoint of rhythms in the movements between the lunar node and Jupiter at that time firmly established the high for the period between July 6th and July 15th. Temperatures soared in the central valley and the coast range as the high pressure in the high desert pushed back through the passes in the Sierras and filled the central valley with high pressure. This high pushed the marine layer away from the coast allowing temperatures to move upwards for a record nine days.
In the second chart it can be seen that the placement of the disturbance diamond is very similar to 1996. This is a chart for the current site of the disturbance diamond that is contributing to the extreme heat wave now in progress on the West Coast and the High Plains. The disturbance diamond in this chart is placed slightly more to the west than in the previous chart. The active jet curves around this disturbance diamond are to the northeast of the diamond. Saturn, the lunar node and Mars (now approaching the eclipse points over the western Pacific) are active in establishing the persistent high pressure. The high-pressure coupled with a strong American Monsoon from the Sonoran desert has allowed moisture normally designated for the Colorado plateau to stream into the circulation around the stagnant high. This has brought morning cloudiness, general mugginess to the central valley of California and the threat of thunderstorms in the upland areas. While rare, this monsoon influence is not totally unexpected since these conditions accompanied the 1996 heat wave also.
The persistent high over the west should start breaking down in the end of July as Mars becomes more aggressive in oscillating the values on the western pair of eclipse points. The Mars influence should keep the atmosphere unsettled well into August changing the general mood of the circulation from the stuck high pressure of the present to a more fluid regime for the beginning of August onward. It looks like the unusual heat wave will not have a repeat in the later parts of the summer but instead the possible threat of rain in September will have people shaking their heads at the crazy state of the weather. These types of erratic and extreme shifts are normal when the disturbance diamond is in your longitude as it is for the West Coast this summer.