Stay Weather Aware Tuesday

Joe’s Weather Blog: So what happened with the snow? (WED-12/19)

Good morning…a weak wind shift is going to move through the area overnight…and will usher in a return to more seasonable conditions for a couple of days. Yes, after today the 50s are done, but they will come back before the end of the year…and while there may be a few showers out there, perhaps more so on the MO side…I’m not expecting much from this next system locally. There will be a bigger system to track next week…but once again we may not be in the right place for any significant snow. There is a system on Sunday to watch…just in case but again it may not have enough to do much for us locally.



  • Forecast:

Today: Variable clouds and mild with highs in the 50s

Tonight: A few showers possible with lows in the 30s

Thursday: Blustery and cooler with highs near 40°

Friday: Chilly but really average with lows near 20-25° and highs near 40°



  • Discussion:

My twitter feed is rather busy with folks talking about a lot of cold coming…and trying to connect this to something called a sudden stratospheric warming event. Oh boy.

This is somewhat a new discussion over the past few years…and while I find it somewhat interesting…once again some weather folks are putting WAYYYYY too many eggs into a basket that frankly has a lot of holes in it, especially how it relates to what happens in the Plains region.

Let’s backtrack.

What exactly is this? It’s somewhat complicated and it means that we have to go wayyyy up in the atmosphere to explain. Put your thinking caps on…

I think to try and keep this from getting to deep in the woods…let’s start by looking at the atmosphere as a whole…from the ground up to the edge of space.

We live in the Troposphere…the bottom 30,000 feet or so of the atmosphere.

In reality the troposphere varies in height from the equator where it might be closer to about 65,000 feet thick to the the Poles region where it might only be about 23,000 feet thick. Air is warmest down towards the surface and coldest at the edge of the troposphere. We can actually monitor the altitude of where the change happens by the launch of the weather balloons. How? The temperatures actually start to go up when you pass into the stratosphere. For example…the sounding this morning from the balloon launch in Topeka…note the red line (temperature) and how it jolts to the right way up there…that’s around 33,000 feet up. From that jolt right and upwards we’re into the stratosphere.

Above the troposphere is the stratosphere and that’s where this discussion about changes up there towards the far northern latitudes begins. The air up there is VERY dry and contains VERY little water vapor. The air up there is roughly 1000 times thinner than the air at the surface and that’s a reason why planes fly up there…less resistance!

So what does all this have to do with how some are talking about a big trend towards cold weather.

Come up to the northern latitudes with me…and now we’re going up to the upper reaches of the stratosphere…but for the polar regions…it’s actually not that high up compared to the height of it in the Plains…it’s getting complicated now.

Way up there…both in latitude and altitude the weather also changes sometimes…mostly from a temperature standpoint. Way up there there can be huge variations in temperatures, especially in the winter months. These variations can and do alter the weather at the surface days ahead of time. The thinking is that you can create a forecast days ahead by monitoring the situation in the stratosphere and perhaps there is a telegraph to the future.

In particular we look for sudden warmings…or as we refer to it SSW’s or Sudden Stratospheric Warmings. During this events the temperatures can swing some 50°C…almost 100°F way up! These changes actually reverberate through the atmosphere and depending on the changes can actually alter the jet stream below the stratosphere. Now we’re talking more my language.

The thing is…this is somewhat new research…we’ve known about them for a long time…but are now trying to figure out the connection to the delivery of cold air into the States…or often into other parts of the northern hemisphere. Europe and Asia especially.

Well some in the weather world are buzzing about a potential SSW event coming over the next 10 days or so…and given the research..indicating that there could be effects in parts of the world days to weeks afterwards.

This is all well and good BUT and this is a big BUT…there are conflicting pieces of information about how this effects the States…and especially how this effects the Plains.

You can see the change happening…take for example today…and again we’re way up towards the North Pole…you can see the States towards the lower right.

Note the -75 to -80° region towards Greenland.

Now lets jump into the future…same tippy top part of the stratosphere.

Note some of the changes..the core of the cold way up there has shifted more towards Europe. Winds up at that level typically circulate from the west to the east. Now when a SSW event occurs…these winds REVERSE and that’s a key to the effects down the road. This reversal  in time propagates downwards and weaken the jet stream. This allows for the release of colder air up across the northern latitudes to come southwards…not all the time though and certainly not for any one place all the time.

There is obviously a connection the the POLAR VORTEX with all of this! These tippy top winds blowing from west to east help keep the stratospheric polar vortex together…which affects the tropospheric POLAR VORTEX…yes there are two of them in different levels of the atmosphere!

What happens with one can effect the lower (tropospheric one). The devil is in the details though.

Will it affect us? Maybe…maybe not. There is somewhat more of a correlation for the eastern US and Europe to be more affected that us in the Plains…and it typically can take about 10 more days for this to actually come together. So data today indicates that an SSW event could occur by the end of 2018…then add 10 days for everything to percolate down to the jet stream and PERHAPS there is impactful cold coming after 1/10…perhaps!

There is some great information here! Click on the link to get some nice and more detailed explainers about all this…I tried to detail some ideas but now this blog is getting way too long…and too complicated I think.

Until then though…it appears to be nothing but transient cold air shots through the end of the year for us in the Plains I think.

So about the title of the blog…do you realize that IF it wasn’t for the blizzard in November…we’d have about 2-3″ of snow as a total so far…and here we are with about 1/2″ in December…and not a lot coming any time soon. Snow lovers would about be thinking…well here we go again.

There is a weak system to watch for Sunday…it will be fighting some dry air closer to the surface and upwards to about 7,000 feet or so but maybe we can get something from that and then beyond that…the Christmas Eve system looks to be more of a drizzle storm than anything else unless there is a big southwards shift. That is still the only hope locally for a White Christmas.

As I told you more than a week ago…I’m still holding at a 5% chance…I haven’t changed this at all since I first issued it last Tuesday. I’ve been tempted to go up a bit…but there were always issues for NOT changing.

Let’s see if there are last minute changes though…we’re still 5-6 days away! It should be very MUCH noted that the afternoon that the EURO is throwing a Hail Mary and bringing a system in that could create snow Christmas Eve snow.

There is another system towards the end of the year to watch as well but that may run toward the northern Plains region and bring even warmer air to us for a few days after Christmas before we turn colder towards the end of the year.

Our feature photo comes from @TwistedSkiesWx of a neat sun pillar this morning!

Joe

 

 

 

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