This article was updated Tuesday with additional details on what to expect on the West Coast and a viewing map.

If you glance skyward during the predawn hours Wednesday and the moon is bathed in an eerie red glow, don’t be alarmed. Parts of the western United States will be treated to a total lunar eclipse early in the morning, while skywatchers coast to coast can enjoy a bright full moon.

Some are even calling it a “super flower blood moon,” making reference to its apparent size in the sky, the abundance of blooms at this time of year and the color the moon will turn during the eclipse.

Eclipses occur when one celestial object blocks another, casting a shadow known as an “umbra.” During a solar eclipse, the moon passes between the Earth and the sun, plunging our planet’s landscape into a nocturnal darkness. Lunar eclipses, which are much more widely seen, result when Earth blocks sunlight from reaching the moon.

Not all of the sunlight is intercepted, though; some passes through Earth’s atmosphere and is cast in a bronzed auburn light over the moon’s surface. It’s the same effect that leads to sunrises and sunsets appearing red on Earth.

If you live in New England, you’re out of luck when it comes to the eclipse. You’ll still see a full moon — one that some are calling a “supermoon” since it is marginally closer to Earth and therefore appears marginally brighter and larger — but it will set before the total eclipse begins.

In Boston, Earth’s penumbra, or more diffuse, broad shadow (which is very faint), will nick the left side of the moon beginning at 4:47 a.m., but the moon will set at 5:16 a.m. Eastern time, nearly two hours before the total eclipse is slated to start. New York and Philadelphia will be in a similar boat.

Washington and Baltimore are right on the cusp and will witness the umbra, or darkest part of Earth’s shadow, make contact with the edge of the moon before it sets. It still won’t be anything to write home about; in D.C., for instance, the partial eclipse begins just three minutes before the moon sinks below the horizon at 5:47 a.m.

Chicago, Nashville, Indianapolis, Charlotte, Miami, New Orleans and Minneapolis will see varying degrees of coverage from a partial lunar eclipse, with Earth’s curved shadow taking a bite out of the moon. But they still won’t get to witness the moon turn red, since it will set before totality begins at 6:11 a.m. Central time (5:11 a.m. Mountain time).

All of Texas, western Louisiana, southwestern Arkansas and the High Plains westward will experience some degree of totality. The farther west you go, the higher the eclipse will be in the sky. In Dallas, for instance, the moon will be just 1.2 degrees above the horizon during maximum eclipse at 6:18 a.m.; in San Francisco, totality peaks at 4:18 a.m., when the moon is 15.3 degrees above the horizontal.

The West Coast will be best positioned to witness the full eclipse, since totality will occur when the moon is still high in the sky and daylight hasn’t yet arrived. Totality begins at 4:11 a.m. and lasts until 4:25 a.m. The brevity of totality means that, if you give yourself a roughly half-hour window, you’ll be able to see the entire process unfold — the edge of the Earth’s shadow finally sweep to the upper right edge of and engulf the moon, the moon turn red, and the shadow begin exiting from the left.

You’ll want to look to the southwest. In Seattle, the moon will be about 8 degrees above the horizon. That will make for great photo-ops. The moon also appears largest to the naked eye when it’s near the horizon.

Viewing outlook

Weather will be a concern in some areas, particularly over the Intermountain West, where a large batch of mid- to high-level cloud could prove a viewing obstacle.

Overnight thunderstorms could deposit some cloud cover along and east of Interstate 35 in Texas, Oklahoma and Kansas as well; those clouds will have a sharp western cutoff though as dry air surges in behind the storms.

Much of California, the Great Basin of Nevada and interior parts of Washington and Oregon are looking good, though areas near the coast are a bit more iffy. Along the immediate shoreline, fog will be a problem, limiting viewing chances.

In the “iffy” zones, it will all depend whether gaps in the cloud cover cooperate during the brief window of totality.

In the East, only a partial eclipse will be visible, weather permitting, and the weather should feature cloud cover in the Ohio Valley and patches of clouds from the Carolinas to Georgia. There will be some breaks and clear skies in the Appalachians, but where exactly is uncertain.

The 14 minutes of totality in the West is very fleeting for a total lunar eclipse. On June 27, 2018, a total lunar eclipse lasted nearly 43 minutes, due in part to it being a “micromoon,” or a moon that appears extra small because of its distance from Earth, meaning it could spend longer in Earth’s shadow.

Total solar eclipses, however, can last no more than 7 minutes 31 seconds and seldom persist beyond 3 minutes.

If you live on the cusp of totality for Wednesday morning’s eclipse, as will be the case for Oklahoma City, Wichita, areas east of Dallas and Houston, Lake Charles, La., and west of Lincoln, Neb., you’ll have a unique opportunity to experience firsthand the lineup that makes full moons and eclipses possible. To the southwest, the fully eclipsed moon will be setting at precisely the time the sun rises.

In Grand Island, Neb., the sun will rise at 6:07 a.m., the eclipse will reach totality at 6:09 a.m. and the moon will set at 6:11 a.m. You’ll see the morning sunrise in the east, appearing red thanks to the light’s lengthy passage through Earth’s atmosphere, as well as the moon in the southwest bathed in that peachy light. Pollutants in Earth’s atmosphere may darken it a bit.

While the Northeast U.S. won’t see much from this particular eclipse, much of the Northeast, Great Lakes and Mid-Atlantic regions will be treated to a separate partial solar eclipse at sunrise on June 10, during which a fiery amber crescent will hang in the sky.