Weather Blog

What's the difference between...?

under the umbrella

Some weather terms may sound similar, but they actually have different meanings. It's supposed to make the forecast easier to understand, but for many, it just might cause more confusion.

Let's begin with one of the most confusing:

What's the difference between "rain" and "showers"?

You'd think they're the same but even though "showers" are indeed rain, there's a subtle but important distinction between the two as far as weather forecasts go.

When we call for "Rain" (as in, "Rain at Times", "a rainy day", "Occasional rain") is a more widespread event. Most, if not all, of the area will see rain and it'll last for a while.

"Showers" are more scattered. That usually means that not everyone will be getting wet at the same time.

It could be raining in Everett and Gig Harbor, but dry in Seattle and Arlington. Plus, showers tend to be much shorter in duration -- anywhere from a minute to an hour.

So when we say "rain changing to showers", it means a steady, widespread rain will switch to more hit-and miss rain pockets.

The graphic on the left shows a radar's depiction of "rain" while the one on the right is more "showery"

While I've got you here, there were a few other questions that popped up in recent blogs from commentors:

What's the difference between "partly sunny," "mostly cloudy," and "partly cloudy"?

The three are somewhat interchangeable. Usually "partly cloudy" is saved for a nighttime forecast since we can't use "sunny" there. All three can depict 30-70% cloud cover, but we tend to trend the "partly sunny" more toward the 30-50% cloud cover and "mostly cloudy" to 50-70% cloud cover, although there is no real exact science here.

For our forecasts, we tend to go partly sunny if the forecast trend is improving, and mostly cloudy if it's trending toward cloudy.

What's the difference between snow and sleet, freezing rain and flurries?

Snow is pretty obvious. Sleet is when a snowflake falls into a layer of warmer air, melts into rain, then reencounters cold air near the surface that freezes the drop into an ice pellet.

Freezing rain is almost the same as sleet, with one critical difference -- in this case, the cold air layer near the ground is much thinner, so the raindrop gets supercooled but not quite to ice yet, then it hits the ground and instantly freezes to the surface, creating a layer of ice. This is how we get those ice storms where stuff can get coated by 1/2-1" or more of ice.

Ice storms are devastating because not only does it make driving impossible, but the weight of ice on trees and power lines makes them easy to topple over. Big ice storms can knock out power to millions and make it very treacherous for crews to try and restore power.

Flurries are just the snow equivalent of drizzle -- Very fine snowflakes caused by weak cloud dynamics.

What's the difference between a "Watch" and a "Warning"?

You'll see these during the severe weather season in the fall and winter, but a "watch" simply means conditions are possible within the next 48 hours. A "Warning" means those conditions are imminent or already occurring.

So for example, a "High Wind Watch" means conditions show there is potential for high wind within the next 24-48 hours. A "High Wind Warning" would be issued if high winds are imminent or already occurring.