We’re starting the day with gray skies in the area and temperatures in the 30s this morning. I’m not expecting much of a warm-up today, and that will be setting the stage for our likely first accumulating snows overnight into early Tuesday morning.

This won’t be a big snowstorm, but it may be an issue for tomorrow morning especially. The seasons first accumulating snows are always problematic it seems and depending on various road treatments, etc… sometimes more problematic than others.

So you may want to see how things are faring in the morning tomorrow before you head out.

Whatever snows we do get, and some may see a couple of inches worth, should quickly melt tomorrow, especially on the roads. So aside from some morning issues we should be in better shape in the afternoon.

The overall cold pattern though will remain and get reinforcements over the coming week. Wednesday/Friday and Saturday look to get even a bit colder. There are still signals of a Thanksgiving week moderation in the big picture, especially towards the Holiday itself.

Let’s dive in…

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Forecast

Today: Cloudy with perhaps a few isolated rain showers later this afternoon. Highs in the lower 40s

Tonight: IF there are any rain drops it will change to sticking snow, however, the snow accumulations may wait till well after dark. If you have evening plans you should be OK. Sticking snow likely overnight into near daybreak tomorrow. Lows near 30°

Tomorrow: Any flakes end quickly in the morning, then brighter skies in the afternoon with highs well into the 30s

Wednesday: Another shot of some pretty cold air coming in… temperatures may struggle to get to 32°. There might be a flurry or two as well.

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Discussion

In yesterday’s Sunday special snow blog we went through the playout of today and I’m really not changing too much in terms of my thoughts about how the day is going to play out at this point.

I’m still wondering when the actual first accumulations will begin as there are multiple layers of dry air in the atmosphere above us today and to our south now that need to be saturated. This is going to likely take time as the afternoon moves along.

There may be a pocket here or there that gets some rain drops, but they should be fleeting as the lift really doesn’t get going in the atmosphere till this evening.

The lift is important because the morning balloon launches show what I was expecting yesterday: Dry air.

For example, here is the balloon report from central OK this morning. The green lines are the dew points and the red lines are the temperatures as the balloon goes up to about 18,000 feet. Notice where the lines are together, that means the air is saturated. Where they’re farther apart means the air is drier and in some cases really dry.

Very little saturation (so far)

Here is Topeka’s report.

Lots of dry air in this case below 10,000 feet.

That is going to take time to saturate today and into this evening as well. We need to introduce moisture and lift below 10,000 feet to saturate the atmosphere. As the evening moves along that will happen, but it will take time.

As a matter of fact I’m thinking radar may start looking active, but the reality on the ground may be just some drizzle or flurries as a lot of the falling precipitation, at least initially, is being evaporated in the dry air beneath the cloud bases. We call this virga.

The morning run of the RAP model, similar to the HRRR model and updated every three hours, shows this nicely. For the purpose of this discussion the green areas below are the humidity of the atmosphere at various altitudes… notice the “lack of green” below the 700 mb level. That is roughly 10,000 feet aloft.

16Z is 10AM…20Z is 2PM…00Z is 6PM…4Z is 10PM

As we get to 6PM we’re starting to see more saturation and finally between 8-10PM we should be seeing more consistent flakes. This is for KCI, the one for Olathe on the south side, saturates just a bit quicker

You get the point though. It’s going to take a bit of time for things to come together.

This isn’t unusual given the dry cold air mass that has to get replaced by a more moist air mass and given the weak areas of lift moving through and setting the precipitation off. This is common for us.

Eventually though the air will support falling snow to the surface tonight.

Now the next issue for me is seeing how much “liquid” the atmosphere can crank out and then convert that over to snow. Some model data yesterday, as it usually does 24+ hours away from an event, was too generous with the amounts it cranked out. Today the data suggests anywhere from roughly .15″ to about .25″ of total precipitation.

IF all of this was snow, we’d get 1-3″ as a starting point to the forecast based on roughly a 10:1 snow ratio…1″ of liquid equals 10″ of snow.

Let’s allow for some initial evaporation of this and perhaps a brief period, although the later this waits in the evening the less raindrops will fall, of rain drops. So maybe slice that total by a few hundredths… so let’s say .12 to .22″ of liquid.

Now we’re more in line for 1-2″ or so and that seems reasonable to me at this point in things.

This mornings weather map is showing snow breaking out and accumulating across western KS.

9AM surface map with temperatures in red and highlighted areas reporting snow.

There are some reports of moderate to heavy snow in the OK Panhandle (3 and 4 stars)

Our storm this morning is moving through the Texas Panhandle so those heavier areas of snow are connected to the disturbance.

The storm in the middle of the atmosphere will move towards the region this evening and overnight.

As we go up to about 18,000 feet to track this, notice the little kink in the lines below. The wave we’re following is toward western TX.

It’s not the greatest, nor strongest. It is there though and that’s our snow for overnight.

With temperatures today in the lower 40s or so, the pavement will remain 32°+ into the late evening hours. So that’s why if you do have evening plans, based on the data this morning, you should be just fine… perhaps some wet roads.

Overnight as we start to see an increase in the snow, and there may be some moderate areas of snow developing for a few hours. The untreated roads should get at least some slush on them and perhaps get snow-covered.

Treated roads may not be that bad, but since this majority of the snow is at night, just use some common sense and watch for changing road conditions.

Again these first snows can create more problems, even though they’re not big “snowstorms” per say.

Here are some forecast radar snapshots.

For 6PM:

For 9PM:

and for 1AM:

Odds are at 9PM and 1AM that green is really snow too.

Note the snow sort of develops from the south to the north. A lot of this will be falling while most are sleeping

Things wind down towards daybreak.

A winter weather advisory is up for most of the area. The counties in purple are involved as of now. Really most of the viewing area aside from a county here or there.

Again for most, under 2″ seems right. There may be a pocket here or there that could do better. We’ll nowcast that tonight for the 9/10 PM shows as the snow bands start coming together better and approach the region.

The feature photo is from Lesa Wardrip

Joe