The first two weeks of May in Coeur d’Alene were the driest since records were kept beginning in 1895. There was not a drop of rain during the first 14 days of the month, but 0.05 inches fell on the 15th. Then, our weather pattern changed as a potent storm system brought rain and cooler temperatures to the region beginning last Thursday and continued into the weekend.
As of late Saturday, nearly 2 inches of rain fell this month at Cliff’s station in northwestern Coeur d’Alene in 61 hours. That pushes our seasonal total to around 14.50 inches. Our normal to date is just over 11 inches. However, we’re behind last year, when 15.62 inches was measured.
This same storm system also brought significant rainfall to California. Many stations received more than double their normal May rainfall from one storm. This type of system is not very common at this time of year as conditions normally dry out as the Golden State moves into the late spring. The moisture is good, as it will also enhance some of the foliage in the area. Unfortunately, when conditions do dry out in June, the odds of more wildfires go up. Let’s hope that California and the rest of the western U.S., as well as western Canada, does not see a repeat of the huge fire seasons of the last two summers.
The arrival of this western storm was near the “full moon” on May 18. And, this particular full moon was also known as a “Blue Moon.” When most of us think of a Blue Moon, it’s a month that contains two full moons. However, based upon an old almanac (the Maine Farmers’ Almanac, which is no longer in circulation) the meaning for a Blue Moon is different.
According to the Farmers’ Almanac, the other type of a Blue Moon is a “Seasonal Blue Moon.” As a lunar cycle, full moon to full moon, is approximately 29.5 days, there are occasions when one year will have 13 full moons rather than 12. During each season of winter, spring, summer and fall, we will usually observe three full moons. However, there are occasions when there will be four full moons during a season.
For 2019, based up on the Maine Almanac’s version of a Blue Moon, we will have four full moons during this spring season. The first one occurred on March 20, with the second on April 19. The one on May 18, the third, was the Blue Moon. The last full moon of the spring season will occur on June 17.
During the 19th and early 20th centuries, the Maine Farmers’ Almanac listed all the Blue Moon dates. This was the standard definition for a Blue Moon until there was a misinterpretation in the March 1946 issue of Sky and Telescope. James Hugh Pruett wrote an article, “Once in a Blue Moon,” and referenced a Blue Moon as a second full moon in a month. Pruett inadvertently simplified the definition from the Maine Farmers’ Almanac by stating, “Seven times in 19 years there were — and still are — 13 full moons in a year. This gives 11 months with one full moon each and one with two. This second in a month, so I interpret it, was called Blue Moon.”
For 34 years, this definition of Blue Moon was rarely mentioned. Then, in 1980, a popular NPR show called “StarDate” used the Blue Moon event as two full moons in a month. After that, this new definition became more recognized.
By the way, it’s very rare to see the moon with a shade of blue. However, when there are big volcanic eruptions, there were reports of seeing an actual blue moon due to the tremendous dust and ash sent high into the atmosphere. For nearly two years, people observed a blue moon after the massive eruption of Krakatoa in 1883. There were instances of blue moons caused by the Mount St. Helens eruption in 1980 and Mount Pinatubo in 1991.
Blue moons have also been seen when there have been large forest fires. In September 1950, a major fire in Alberta, Canada, the particles in the sky helped to create the bluish color.
Our next “seasonal” Blue Moon will occur on Aug. 22, 2021, while the following “calendar” Blue Moon will occur on Oct. 31, 2020.
In terms of our local weather, more showers are expected off-and-on through the end of the month that should push us close to the 2.37 inch normal for May. More wet weather is likely in early June.
Later in June, we should turn to the dry and warmer side. Although, Cliff and I do see another dry summer season, it probably won’t be as rainless as the ones over the past two years based on the projected sea-surface temperature patterns.
As is often the case, July should be our driest month with wetter conditions expected later in August and September.
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Contact Randy Mann at firstname.lastname@example.org