Good morning bloggers,
We are in the middle of the longest cold stretch of the season. These aren't the coldest temperatures but this will be the first time this season we will have gone more than three days in a row below freezing. More on this statistic later in the week. First of all there has been a lot of talk about snowfall accumulation and this set up just is not quite coming together yet.
The stage is set for a minor accumulation of snow, but the actors (ingredients) are not quite ready to perform. Here are the factors:
- Upper level storm (500 mb level)
- Baroclinic zone (850 mb level)
- Surface cyclone
- Jet stream dynamics
Let’s look at each of these ingredients:
Ingredient #1: Upper level storm. For Kansas City to have a major winter storm system we usually must have an organized upper level storm system. We look at the 500 mb flow (around 18,000 feet up) to find these features. There is one coming our way, ejecting out of the southwestern trough, but it is forecast to stretch out as the entire upper level flow becomes very positively tilted. Where this upper level storm tracks tonight as it shears and stretches out will decide who gets a nice band of snow. Look below at the forecast 500 mb map valid Tuesday morning. You can see the positively tilted trough (black dashed line), the vorticity maximum (center of the strongest upper level disturbance ejecting out, and the PVA (positive vorticity advection) spreading into southeast Nebraska and Iowa. This will likely continue to form bands of snow to our north. Let's see where this tracks, and if it ejects out a bit stronger. If it does come out slightly stronger, then the 850 mb low could still be generated.

Ingredient #2: This is the most impressive feature right now and is the feature that will help produce the ice storm to our southeast. There is a strong temperature contrast (baroclinic zone) just above the surface at the 850 mb level. Look at the map below. All we need is for ingredient #1 above to be just oriented a bit differently and we would have a wave form at the 850 mb level which would produce a more organized area of snow. This isn't forecast to happen, and it is something we will be playing very close attention to.

Ingredient #3: There is a weak inverted trough at the surface but other than this reflection we just don’t have any surface forcing which is a problem. A surface storm is forming over Texas but we are deep into the cold air and it just isn't a major factor for our local area.
Ingredient #4: Jet stream dynamics. There is a jet streak associated with an ejecting wave with ingredient #1 above, but we are never really in a great spot for lifting from jet dynamics. The best stream dynamics will likely be to our northwest late tonight and then well off to our southeast on Tuesday.
This is close to coming together and just a minor change and we could have a more substantial storm on our hands. We are currently predicting 1 to 2 inches of snow by noon Tuesday. We will be tracking these developments on NBC Action News tonight as the storm approaches tonight at 5, 6, and 10 PM. And, then meteorologist Brett Anthony will keep you updated beginning at 5 AM Tuesday.
Gary