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The Spokesman-Review Newspaper
Spokane, Washington  Est. May 19, 1883

Moon appears to affect weather

Randy Mann Correspondent

Last week, I mentioned that many of my long-term forecasts are based on lunar cycles. Much of this research was put together by Idaho climatologist Cliff Harris, who has found that particular phases of the moon will often produce certain types of weather patterns.

Have you ever noticed that much of our coldest weather in the winter and our hottest temperatures in the summer occur near a full moon? Our major change that led to the record snows and frigid temperatures began during that full cycle of mid-December. During January’s full moon cycle several weeks ago, areas east of the Rockies observed the record cold and snow while the Inland Northwest went to the dry side.

No one will contest the fact that the tides are created because the Earth and the moon are attracted to each other like magnets. The gravitational pull of the full moon results in high tides that are higher and low tides that are lower. If the moon can affect “tides of the water,” then why not alter “tides of the air”?

From our research, the upper-level jet stream winds tend to become more meridional, or north-to-south during a full moon and new moon lunar phase. High-pressure systems will often intensify, bringing our region the hot weather in the summer and frigid temperatures in the winter. During that same cycle, low-pressure areas also become stronger, which often leads to bigger storms.

When we’re in a first quarter or last quarter cycle, the jet stream will often become more zonal, or west-to-east. Although we can see active weather during a first quarter or last quarter lunar phase, conditions are generally milder and drier. Storms moving in from the Pacific Ocean will typically fall apart by the time they enter our region.

The best chance for moisture is during a new-moon lunar phase. Conditions tend to become milder and much wetter. Storm systems seem to intensify during these occasions. This was the case for this new moon lunar phase as snow increased on Tuesday in the Inland Northwest.

Of course, there are other factors that determine a long-term forecast. Sea-surface temperatures, sunspot activity and other short and long-term climatological cycles will shape our weather pattern. Moon phases seem to play a significant role and we noticed they follow our formula about 70 percent of the time.

As of early Tuesday, Spokane International Airport has slightly over 80 inches of snow. The second half of this harsh winter season will likely see much less snow than the first. It’s possible that we may still challenge the all-time record of 93.5 inches set in 1949-50. Regardless, the combined winters of 2007-08 and 2008-09 will be the snowiest across parts of our region in recorded history.

Contact Randy Mann at randy@longrangeweather.com.