SEATTLE — It’s an event stargazers have been looking forward too all month, and it’s finally almost here.

Unfortunately, the clouds are also rolling in, just in time to ruin the fun.

The first of two total lunar eclipses visible to Washington residents occurs Sunday and will turn May’s full flower moon blood red. It’s also a supermoon — depending on whom you ask.

Not everyone will see all three stages of the eclipse. People living in the eastern half of the country and all of South America will see every stage of the lunar eclipse, according to NASA. Here on the West Coast, we’ll still see the eclipse in its totality, but will miss other phases.

Here’s what to expect:

Moonrise is around 4:50 p.m. PST Sunday, but the partial eclipse starts at 7:28 p.m. PST. Again, Puget Sound will probably miss this portion of the event, but we will be able to see it during the totality, which peaks at 9:11 p.m. Totality will last about 1 hour and 25 minutes, ending at 10:36 p.m.

Unfortunately, the National Weather Service is predicting cloudy skies the night of the event. They’ve been wrong in the past (in fact, this whole week was supposed to be mostly cloudy, and we’ve had a fair share of sunny skies), but forecasters are pretty confident that, come Sunday night, most of Western Washington will be under some cloud cover, with a roughly 70 percent chance of scattered showers.

Lunar eclipses only happen during a full moon, when the moon is opposite the sun in its orbit of Earth. In a total lunar eclipse, the sun fully illuminates the face of the moon. During an eclipse, the entire moon enters the darkest part of Earth’s shadow.

In a penumbral eclipse, the moon passes through the outer part of Earth’s shadow, only slightly dimming the surface of the moon. In a partial eclipse, the moon enters Earth’s darkest shadow, the umbra, causing some of the moon to darken significantly.

“Blood moon” is a descriptive rather than technical astronomical term, though The Old Farmer’s Almanac says the phrase is “hyped” and that a fully eclipsed moon is orange, or copper-colored like a penny, but not blood red. The moon’s color at totality can also vary depending upon the amount of dust, volcanic ash or other particulate matter in the atmosphere, and because of cloud cover, according to Space.com.

Weather permitting, the lunar eclipse is worth staying up late to watch, even if it isn’t a supermoon.

“Supermoon” isn’t an astronomical term either, but rather one coined by astrologer Richard Nolle, who calls a full or new moon a supermoon when it is at 90 percent of its closest point, or perigee, to Earth. Under Nolle’s definition, four full moons meet supermoon criteria: a new or “stealth” moon on Jan. 14, full moons on June 14 and July 13, and a new moon on Dec. 23.

However, Fred Espenak, a retired NASA astrophysicist who worked at the Goddard Space Flight Center, uses slightly different criteria. He says the May flower moon is the first of four supermoons in 2022. He also counts the June 14 and July 13 full moons as supermoons. Unlike Nolle, Espenak says the Aug. 12 full moon will be a supermoon (bad news for Perseids meteor shower fans, because the supermoon and the peak of the summertime favorite coincide).

Although most often called the full flower moon, the May full moon is also known as the corn planting moon and the milk moon in the United States. In Asia, it is known as the Vesak Festival Moon because it corresponds with Buddha Jayanti or Buddha Purnima, a Buddhist holiday that marks the birth, enlightenment and death of Gautama Buddha.

The actual date of the Vesak festival depends on the calendar used in different countries and regions, but generally falls on or near the day of the May full moon.

If you miss the eclipse this month, the second 2022 total lunar eclipse on Nov. 8 will be visible across the Americas, Oceania and Asia.