Thursday, January 8, 2009

Stuff Falling From The Sky...

As I am writing this, we are seeing reports of all sorts of stuff coming down from the sky - and even some "unknown" precipitation forms (where it just falls and nobody saw which type it fell as). Freezing rain is being reported as of late in Sioux Falls at the airport, blowing snow in Mobridge, light snow in Aberdeen, and unknown in Huron (although earlier they reported some icy pellets). That's just from the 6pm readings! They've been like this all day.

Here's what we're looking for by the end of this system:

That up to 1" line is probably going to be switching around some, hence the lack of other wording by me in this map. It's been a tough forecast. Basically, what those of us on the southern fringes of this storm can expect is some form of frozen precip - likely ice pellets - to start. Then ice pellets switch to freezing drizzle as warmer air flows way above us. Then it all changes to some light snow afterward. During all of this the best chances for heavier precipitation will be moving toward the East. Most snow should be in NE South Dakota and into North Dakota and portions of central Minnesota.

We're keeping an eye on some precipitation showing up on radar as well - some of it is showing up as heavy precipitation.

What we're trying to figure out is whether or not those heavier-looking bands are actually rain, freezing rain, or snow. Based on the height of the radar beam at that distance and the freezing level it is possible we're seeing "bright banding," or an effect when snow partially melts and shows up as a big raindrop.

That's it for this update - we'll update again as necessary. Have a great & safe night!

~KDLT Meteorologist Aaron Shaffer

2 comments:

Anonymous said...

Can you get your bright banding stuff in the fall too or just winter?

KDLT Weather said...

Yup! You sure can. It actually probably happens more in the fall or spring just because that's when we get a colder rain more often. The reason we mention that is because that's where the freezing level is closer to the ground. If the melting is happening at the same height as the radar beam, the snowflake that would normally fall as either light snow or drizzle "looks" like a larger raindrop as it melts and has a thin layer of water surrounding it.

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