Ask the Meteorologist: Does a ring around the moon always mean rain, snow is coming?

On New Year's Eve and even Sunday night, some people in our area took note of the ring/halo around the moon. 

You'll often hear folks say "That means rain or snow is on the way." I've even heard "If you count the stars inside the ring, that's how many inches of snow you can expect."

Wives tales aside, let's talk about why these halos can sometimes be a harbinger of precipitation to come.

How does a lunar halo form?

When the moon's light passes through ice crystals in high-level cirrus clouds, that light gets bent. It gets bent at a specific angle of 22° relative to the viewer at ground level. 

This gives off a halo shape from our perspective. 

Oftentimes, you'll see these high-level cirrus clouds blowing off of storm systems away from us. At the top of a storm, the air diverges meaning that these clouds can stretch hundreds of miles.

While it sometimes will precede a storm, it's ultimately up to the storm's trajectory as to whether or not it comes here.

Where are the storm systems going this time around?

Interestingly enough, we can trace the Sunday night cloud cover back to the Pacific. Moisture feeding off the distant ocean was carried eastward by the winds around airplane cruising altitude (the jet stream). 

As far as snow, there's no shot of that happening here any time soon.

In fact, we're forecasting near-record warmth some days this coming week.

The snow remains locked in the Sierra Nevada, Cascades, Rockies and the northern tier of the Continental U.S. 

Will we ever see snow again?!

Patience, my snow-loving friends. The official start to winter was a little over two weeks ago. The game has just begun. 

Climatologically speaking, 68% of our snow (sampled between October and April) comes after mid-January. 

That said, our average snow per winter continues to decline in recent years. 

A little snow in...Hawaii?

What's interesting is that there is a Winter Storm Warning in effect for Mauna Kea and Mauna Loa in Hawaii.

Granted, those mountains peak over 13,000 feet above sea level, so it's not that rare for them to get snow. 

It's not like people sitting out at the beach are getting snowed on.

Have questions about the weather and how it works?

Send me an email with the subject line 'Ask the Meteorologist:' to cmichaels@wral.com.