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No Snow! Really?!?!?!

Good Saturday bloggers,

Today will make the 15th straight day below freezing. This is not that unusual considering it occurred during the end of December and early January. What is odd is that we have had just 2.2″ of snow (0.9″, 0.8″ and 0.1″ in the two snows,on the Plaza where we measure for the snowflake contest)  during this cold stretch and we have a system for Sunday that is going to produce rain, huh?

Where is the snow? Why is it so hard for it to snow in KC? I don’t care what the year, or what the LRC is for the season, the set up for Sunday should be an easy 3″ to 6″ snowstorm. Here we are one day before the storm, firmly in Arctic air, and by Sunday morning we will still be 30°-32°, but for some reason the air from 1000 to 5000 feet surges above freezing overnight, so that any precipitation that falls from the sky will be liquid. I can see this happening if we were in just southwest flow, but an actual upper low drops right over Kansas from the northwest, a perfect track for our region to see snow. When this upper low moves by, why does the air column not cool enough for snow?  I have asked these questions, and to be perfectly honest, I do not have a great answer. It is just this year’s pattern I guess.  It shouldn’t be so hard.

When we made our winter forecast and Gary forecast 21″ of snow and I forecast 19.5″ of snow, this was one of the storm systems that we calculated into the forecast. It is the part of the pattern that occurred October 7-11. So, when we lose this chance of snow, it puts our winter snow forecast in jeopardy and we will have to rely on another storm over producing. And we know, that is not going to be an easy task.

So, here we are, in Arctic air with a chance of rain and freezing rain. It is what it is, so let’s go through the weather timeline.

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Here is the set up from Saturday morning with an Arctic high over southeast Minnesota, bringing lows to near -20 in northeast Iowa and Minnesota. We were around 10° with a cold east-northeast wind.

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We are in a Winter Weather Advisory for Sunday morning as the Arctic air is retreating while rain is increasing. If the rain falls with temperatures 30°-34° for even 5-10 minutes, then all surfaces will become quite slick. In this situation, even if temperatures are above freezing by a few degrees the rain may still freeze on contact as it has been below freezing for 15 straight days and there will be a lag of 1-2 hours between air temperatures warming above 32° and the surfaces warming above 32°.

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Here is how we have the different precipitation types. During the winter all precipitation usually starts as snowflakes in the clouds. Then, as the snowflakes fall to Earth they will encounter a variety of temperatures.

If the snowflakes fall and it is below freezing all the way to the surface you get snow.

If the snowflakes fall into a large layer of above freezing temperatures that extends all the way to the surface, the snowflakes melt to rain and stay liquid on contact with the ground.

If the snowflakes fall into a large layer of above freezing temperatures they will melt to rain drops, but if the temperature near the surface is below freezing, then the water will freeze on contact with the ground, creating a glaze of ice, freezing rain. This can make things extremely slick in just a few minutes of the rain starting. This is what we may be facing Sunday morning.

If the snowflakes fall into a layer above freezing they once again will melt to a rain drop. But, if the rain drops encounter a thicker layer of below freezing air before reaching the surface, the rain drops can re-freeze and become ice pellets, or sleet. This is my least favorite precipitation type as it is hard to see when it falls and it takes hours and hours of sleet to accumulate to 1/2″ to an 1″.

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Now, let’s go through the weekend weather and time out this next storm system.

SATURDAY AFTERNOON: It will be mostly sunny with highs in the mid to upper 20s and wind chill values in the teens. This includes the big Chiefs playoff game. There is NO reason they should not win their first home playoff game since 1994!

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SATURDAY EVENING: Temperatures may drop to the low and mid 20s with wind chill values between 5° and 15°, including the end of the game. It will still be dry.

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SUNDAY 4 AM: Temperatures will be on the rise to near freezing as light rain and freezing rain develop to the southwest. It should still be dry in KC.

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SUNDAY 4-7 AM: This is the period where we have the most concern for icing as it will be dark with temperatures around freezing and the surfaces will likely be even colder. So, any rain that falls will freeze on contact and this would create a glaze of ice within minutes of the onset of the rain. You can go from dry to a skating rink in 5-10 minutes or less.

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SUNDAY 7-11 AM: It is during this time when we will see the temperatures rise enough to make this all rain. Some surfaces, especially on the north side of buildings may still see ice as they will be naturally colder due to never seeing sunlight this time of year. Also, the NAM (only model to do this) insists on temperatures barely above 32° which would mean the slick conditions would persist. We lean with the warming up just enough to melt any ice.

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SUNDAY AFTERNOON AND EVENING: The rain will move away with temperatures likely in the mid 30s. Total rainfall will be a trace to .05″ northwest to near .50″ in the Ozarks. This means the KC area has the chance to see .05″ t0  .25″, perhaps a bit more. It is not much, but we will take what we can get.

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MONDAY MORNING: The drying conditions Sunday night will not be that good as the sky clears by morning. This will allow lows to drop to 25°-30° and if there is any leftover water/dampness it could freeze and become black ice. The amount of black ice will depend on how much rain we receive.

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Well, at least we have a storm system to track and there is another interesting set up Wednesday-Thursday as a storm system comes in from California, followed by a second weaker system and Arctic blast. Maybe we can get 1″ of snow out of all of that!

Have a great weekend and GO CHIEFS!

Jeff Penner

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