Joe’s Weather Blog: Messy morning…messier start to 2021 (TUE-12/29)

Weather

We have a combination of snow and sleet as I start this blog today with snow coming down pretty good in spots and sleet as well. Roads are covered so accidents are starting to increase in the area this morning. Have an ice scraper ready to go today.

Winter storm warnings are in effect for northern MO. More snow is likely there than in the KC Metro area. Winter weather advisories are in effect for the Metro. Less snow but more sleet is likely within the Metro.

This will be problematic into the early afternoon as temperatures gradually work their way to above freezing. Then later today things will improve and tonight will be a wet night with needed moisture (rain) coming into the area.

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Forecast:

Today: Sleet>snow to freezing rain to rain as the early afternoon moves along. Temperatures gradually creeping up into the mid 30s by later this afternoon. Breezy as well.

Tonight: Rain, perhaps heavy at times into early Wednesday. Temperatures going up to 40-45° before falling before daybreak back to the lower 30s

Tomorrow: Rain ends before daybreak. Let’s watch for some refreezing just in case. Then variable clouds and seasonable with highs in the mid>upper 30s

Thursday: Partly cloudy and seasonable with highs in the upper 30s

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Discussion:

I was talking about this on the air last night…I wrote about this potential system about a week or so ago…and then on the 23rd identified the wave…yeah it was 5700(!) miles away. From the blog last Wednesday.

“So as near as I can tell the wave that may be the origins of this is out towards the north of Japan…off of Russia really. Only about 5,700 miles west of the KC area…give or take. It will be going through various incarnations as it comes through the northern Pacific”

Science is amazing.

The details obviously weren’t overly specific but we sort of had a feeling and indications that “something” could happen…and it would happen today or tomorrow or both. Well something is indeed happening.

We tracked it through the Aleutians…into the northern Pacific…towards southern CA where yesterday there were some good snows in the mountains and hail reports in the LA area. They got their best rain in months there which was a good thing for them.

The system though has created this broad area of lift which is what we’re dealing with right now…and why we’re seeing the outbreak of sleet and snow, with freezing rain to the south of KC as I start this blog this morning. This will continue through the morning with various intensity.

Temperatures to the south of here are warmer. The freezing line at the surface is towards Emporia this morning and will be slowly coming north this morning. In time it will pass through the Metro…and then we just get liquid rain from this.

The precipitation will lighten up considerably this afternoon and some may not get much of anything for awhile before picking up again tonight for about 6-8 hours through 4am or so tomorrow. That will be just rain in the KC area and we could see 1/2″ to 1″ from that alone. All very much needed.

Garry checked this one for me…it’s been over 109 days since the last time we had 3/4″ of moisture in one day. This may not do that though since we’re sort of splitting the system up into 2 calendar days. but regardless when you’ve had so little moisture for months…we need it for sure. You may not like the form of the moisture this morning…but the rain will be helpful.

The reason for the sleet…despite the surface temperatures below freezing is that the atmosphere is vertical. What happens here at the ground is also dictated but the temperatures and other parameters above us. There is a wedge of above 32° air a few thousand feet above us…this melts the snowflakes as they fall…then they refreeze into pellets. IF that layer of 32°+ air wasn’t there we’d have more snow this morning (i.e. parts of the Metro). When that layer is within KC you get these different precip types, like what we’re seeing this morning.

This next map shows the freezing line in dashed purple…so this whole wintry mess continues till that line passes north of the Metro.

That happens this afternoon.

As I mentioned this is really just broad lift being generated by a smaller scale system in the SW USA.

It’s sort of tough to even make out for now on the water vapor loop.

What will happen is that the remnants of this will drop into northern Mexico over the next couple of days then make a hard left turn and come up the State Line into central MO on Friday.

Let’s go up to about 18,000 feet or so and we can see the upper level storm in Mexico making the turn towards the north on Thursday.

It’s a unique track, as I’ve mentioned over the past few days. I don’t recall a similar type system in years around here.

What this means to us is that we’re going to see more wintery weather in the area later on Thursday night into Friday. Odds are favoring another sleet or freezing rain event with at least some snow towards the end. How much snow we get is tough to say…but odds are it may be more than what we’ve seen this morning.

Here is a look at the GFS ensembles…showing a lot of pink…indicating ice and sleet.

0Z is 6PMm Thursday…6Z is 12AM Friday…12Z is 6AM Friday…18Z is Noon Friday

What’s fascinating and frustrating for those who want snow and not ice…is that the temperatures above us, at close to 5,000 feet are going to be a LOT warmer than what’s happening here on the ground. That warmer air above us means there’s no way flakes can make it to the surface. Model data this morning shows temperatures at 5,000 feet or so close to 40-45° near the State Line on Friday morning. Yikes. The storm actually draws and wraps “milder” air up and around and pushes it back towards the west towards KC. Not something you see every day around here.

While that is happening above us the temperatures at the surface will be around 30-32°. So you can see we will likely do this whole thing again to ring in 2021.

So when we look at the vertical profile of the temperatures above us through time starting at Noon on Thursday and going every 6 hours from there (ending at noon Friday) we get something like this…

That darker blue to purple area shows above 32° air above us roughly from 3500 feet up to about 7500 feet…close to a mile in the vertical. No bueno for pure snow to fall. Then when the air cools down enough in that layer, after 9AM or so…then we get snow. How much of the system is still with us by then though remains to be seen. We may get A LOT of sleet and freezing rain from this and not too much snow.

I’d like to say that is so 2020…but now that will be so 2021 :)

The feature photo comes from @BlueSpringsWx via twitter.

The comment “The ice looks like glass fragments. No real form”

Joe

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