Supermoon: Moon will appear larger than it has in 18 years Tonight

Are you ready for a “supermoon,” Seattle?

Cross your fingers extra tight, because there’s a chance the clouds will part and you’ll be in for an eyeful Saturday night.

That’s when the moon will be at perigee — the closest point in its orbit around the Earth. Perigee happens every month, but this time there’s something special going on: The moon will also be full.

That means we have all the making of a so-called “supermoon,” the largest the moon has appeared in the sky in nearly 20 years.

You might recall the “supermoon” received some attention last week, when it was erroneously blamed for causing a devastating earthquake in Japan. Besides bringing slightly higher-than-average tides, the celestial event won’t do much besides put on a good show, scientist say.

“The last full Moon so big and close to Earth occurred in March of 1993,” Geoff Chester of the US Naval Observatory said in a statement from NASA. “I’d say it’s worth a look.”

Don’t expect a “George Bailey lassos the moon” type experience; the perigee moon is still about 356,577 kilometers away. It’s about 14 percent larger and 30 percent brighter than an apogee moon (at its furthest point from the Earth).

But it might appear much bigger than it actually is, especially when viewed while low on the horizon.

NASA has this advice for sky watchers:

The best time to look is when the Moon is near the horizon. That is when illusion mixes with reality to produce a truly stunning view. For reasons not fully understood by astronomers or psychologists, low-hanging Moons look unnaturally large when they beam through trees, buildings and other foreground objects. On March 19th, why not let the “Moon illusion” amplify a full Moon that’s extra-big to begin with? The swollen orb rising in the east at sunset may seem so nearby, you can almost reach out and touch it.

So, what about that cloudy Seattle weather?

KOMO News meteorologist Scott Sistek reports that we might get lucky Saturday, with the forecast calling for partly cloudy skies.

Partly cloudy, after all, implies there will be at least some visibility.

For more on the “supermoon,” watch this video from NASA.