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Weather Blog - Snow, Sleet, Freezing Rain, & Rain Will Be Heading Our Way As We Ring In The New Year

Snow Potential
Posted at 7:35 AM, Dec 31, 2020
and last updated 2020-12-31 10:37:58-05

Good morning bloggers,

Did you know that Kansas City has gone 322 days with only 1.1" of snow? That's right! It has only snowed 0.9" on October 26, and 0.2" two days ago on December 29 for a grand total of 1.1" since it snowed 3 inches on February 12, 2020. It also snowed 8.5" last January as the Chiefs were going on their big Super Bowl run. Earlier this week we "broke the ice" and broke through with over an inch of liquid precipitation which came in various precipitation types from snow, to sleet, to freezing rain. This second storm will again bring various precipitation types into the Kansas City region, and this is another tricky forecast.

Weather Questions:

  • When will the mixture of precipitation spread into our area and begin?
  • How much ice will fall where you live, and what will the impacts be?
  • How much snow will fall in your neighborhood?
  • Where will the heaviest snow band set up, and how much will fall in this band?

We will be answering these questions and more here in this blog, and on 41 Action News during our newscasts as this storm approaches. We will try to update this blog tonight as well if we see any major changes. The countdown is on to the end of 2020, which I think we are all ready to put behind us, and to the beginning of this storm. Let's take a look.

Here are maps of possible snowfall amounts, the amounts as I showed them on the air last night, and the ice forecast:

Snow Potential
Snow Potential
Ice Potential

The ice amount forecast is lower in the areas that are more likely going to experience snow. There is a very important threshold that leads to power outages. It takes at least 1/4" of ice accumulation for the tree branches and power lines to have too much weight on them, to where they will reach their breaking point. Here is an explanation of ice accumulation impacts:

Ice Accumulation Impacts

Right now, it appears a few spots south and east of Kansas City may be approaching that critical 1/2" ice accumulation level, and we will be monitoring this closely. If you live in these impact areas, please use social media to share your information with us. I will be asking for these reports on my twitter feed of @glezak, and you can follow me on my Facebook page, facebook.com/GaryLezak. We will be sharing some of your information, so thank you in advance for helping us track this storm.

Here is a forecast that I showed last night, valid late Friday morning. This shows KC in the snow, with the mixture of sleet and freezing rain, with ice accumulations to the east. The heavy snow band is indicated by looking at the white and pink areas right near KC, which will be heavy accumulating snow with big snowflakes:

Friday Morning Forecast

Here is the new data from this morning:

Upper Level Flow (500 mb level) Valid At Midnight, The First Moment Of 2021

The storm we are tracking will be going right over Dallas, TX this evening and then it likely takes a perfect path to place KC in the comma head of where the heaviest snow will be located.

The Storm Tracks Over Central Missouri

There are reasons why this forecast is quite difficult. One of the reasons is a likely development of rapid weakening of the storm system that will impact our region. The storm, as it gets ejected out, kicked out by the second system (diving into Mexico just like the lead storm did), will be rapidly weakening, and just 12 hours later it will be falling apart. If this happens faster, it could impact the comma head. Now, it doesn't look like it will fall apart until it produces our significant weather. The comma head looks like it will be strong as it passes overhead, and KC will be near the center of the band of precipitation on Friday. Take a look at the developing comma below:

The Comma Head Is Developing Over Oklahoma & Southern KS Early On New Year's Day

This map above is valid at 5 AM in the morning, and look at what happens just a few hours later on this same model:

9 AM New Year's NAM Model Forecast

The comma head is shown here, and it is centered near the north side of KC. This is just one model, but if it is at all close, then we would see sleet, rain, freezing rain early in the morning mix with and change to heavy snow. The snowfall rates could be 1 inch to 2 inches per hour. This 1"/hour to 2"/hour rate would effectively accumulate the snow significantly in the center of this band. Think about three hours of 1" to 2"/hour. That adds up to 3" to 6" in just those three hours. There is also a chance of thundersnow in this band. Thundersnow happens when thunderstorms form within the band, and it rarely happens, but it is not out of the question late Friday morning. Whether this storm produces lightning is something to monitor, but more importantly, where will this band line up.

Again, here is that snowfall map I showed, and some local amounts will likely be higher, within that band:

Snow Potential

Okay, so let me answer the questions:

  • When will the mixture of precipitation spread into our area and begin? It will begin after midnight, after we ring in the New Year!
  • How much ice will fall where you live, and what will the impacts be? Look at the maps. The most significant ice will be likely two counties southeast of KC, so around Warrensburg, Clinton, & Sedalia, MO. If it does not rise above 32 degrees, then there could be a big problem with power outages
  • How much snow will fall in your neighborhood? Right now I am expecting 2" to 5" near Kansas City on top of some ice. We will be identifying where the heavy band is setting up early tomorrow, and we will continue to update our forecast as this approaches. So, watch our newscasts today and tonight.
  • Where will the heaviest snow band set up, and how much will fall in this band? Right now, it looks like the band will be setting up within 30 miles of KC. It could be right over the city.

* One other question that just came up was the wind: There will likely be a brisk 10-25 mph wind from the north or northeast where it is snowing, and maybe a little bit less where it is freezing rain. This will cause some blowing and drifting of the snow from KC north and west, and may be an impact on the trees and power lines to the south and east. I am still analyzing this effect.

Okay, we will be monitoring this closely. Expect this storm to begin after we ring in the new year. Our team will be here on New Year's Day to keep you updated, so stay with 41 Action News and KSHB.com, and we'll keep you advised.

It will be a sunny New Year's Eve with increasing clouds later today as the storm approaches. Thank you for spending a few minutes of your day reading the Action Weather Blog. Happy New Year!

Gary