Joe’s Weather World: My Winter 2020-21 Forecast (TUE-11/24)

Weather

So once again…it’s the 3rd week of November and time for my winter weather forecast. The team and I released our ideas yesterday…and as we start this blog here is the zoom call that we did yesterday with that information and more!

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So with that out there and the team average being **17.3″** it’s time for me to dive a bit deeper for all you weather nerds out there for this exercise in likely wrongness. There I said it…wrongness. I don’t pretend for a second that I’m very good at this. Sometimes I feel better about a forecast than other times. Last year for example…my first thoughts were around 17-18″ or so…then at the last minute I decided that sounded too low…and boom went up to 20 whatever inches and the reality of the situation was that we had about 17″. It hasn’t been the 1st time I backed off or doubted myself and this endeavor and in the end wished I stuck with my original thoughts.

So let’s see if I can talk myself out of my original idea I’ve had stuck in my mind for the last few weeks shall we…

So first of all trying to predict how much snow one point in the KC Metro area will have, in this case KCI, which is the official reporting station for the KC Metro area, is a silly enough exercise. When we’ve seen numerous snows create a swath of snow from a dusting to over 6″…even some higher extremes in the area just adds to the silliness.

One then can say well…just use a range. That’s fine…but in my mind a 6 or 10″ range for the Metro or one spot seems like such a cop-out in my mind. IF I were to do that I would have a much better chance of being “right” when in reality it wouldn’t “feel” right. Hey I predicted 20-30″ of snow…we had 21″…I was right! Yeah…that doesn’t work for me at least.

It’s one point and that’s the way it goes…KCI here I come!

So with those preliminaries out of the way…when compiling a forecast for snow amounts…I look at history…stats (perhaps too much so…to my detriment)…ocean water temperatures including El Nino and La Nina set-ups…areas of drought or excessive moisture…climate change (yes this is now starting to factor into my forecasts to some extent)…what things are doing in the arctic regions…my thoughts about how various pressure patterns in the North Atlantic and Arctic will do…how the polar vortex may or may not buckle and dump cold air or tend to keep the worst of the cold bottled up in Canada and the Arctic region like last year…and a few other things such as some of the longer range models that go out for 30-120 days (usually not successfully) and whatever else I can look for.

From there…I guess. :)

OK FULL STOP. IF you don’t want to read anymore of my musings…I totally get it. I will leave you this image capture…from the very bottom of this blog.

You can now go about your day.

For the others though…let’s really get into the weeds. Bring a weed-whacker…pour yourself a large cup of coffee and come with me on what ended up to be about a 5 hour write-up. It could’ve gone longer really…there are about 3 other things I could’ve written about but after 3 evenings I was over it.

Here goes…

So before we dive in the deep end of things…let’s see where we have been. Take a look at the last 60 years of snow accumulations.

The solid black line is the 30 year moving average and it really hasn’t changed much in a while. We average around 19″ of snow locally. More towards northern MO and less towards the south of KC.

The last 30 years…

Really ALL over the place from 2012 onwards.

Finally the last 10 years showing that. We’ll always 2009-2010. THAT was a winter for the ages…numerous events with thundersnows…4 I think. Blizzards…incredible.

That’s what HAS happened. Now to the forecast reasoning.

So the 400 pound gorilla in the room this season is La Nina. For those not familiar with La Nina or El Nino…they are opposite of each other. La Nina is a cooling of the equatorial waters in the Pacific Ocean off the coast of South America all the way into the central Pacific. El Nino is a warming of the same waters.

This year we are in a La Nina…and it’s teetering into the moderate>strong range.

Let me show you…take a look at the worlds oceans…and now look of South America. See all that blue? The graphic shows the water temperatures in relation to “average”. The blues and greens represent cooler than average waters. The reds/oranges are warmer than average.

Here is a bit more of a close-up…

Water temperatures in the La Nina area are running roughly 1-3° below average.

Also important is the “staying power” of La Nina…and for that we look at the depth of the colder than average waters…and you can see that more clearly below.

See all the blue towards the top right…that colder water extends down some 100-200 meters or so. That’s almost 500 feet. It’s not going anywhere for awhile.

That means La Nina sticks around for at least a couple-few months. In time that water below will moderate and warm back to average and that warmer water will come towards the surface and eradicate the current La nina.

So La Nina is a lock…the Climate Predication Center has a “La Nina Advisory” up.

In the last week or so…perhaps there has been the slightest warming of these waters. Technically certain temperature parameters have to be over a consecutive 3 month period for us to figure exactly where we are but that overwhelming consensus is at the very least a high end weak La Nina set-up if not a downright moderate La Nina.

Model forecasts support this…

With us gradually coming out of La Nina towards the later winter and early spring.

There have been many La Nina winters over the years of various weak-moderate-strong tendencies for the particular winter.

This is from Jan Null…nice layout.

Weak and moderate La Ninas are the most common.

So let’s look at the stats…weak La Ninas and snow that following winter in KC.

1954-55: 20.2″

1964-65: 29.8″

1971-72: 10.4″

1983-84: 24.4″

1984-85: 26.4″

2000-01: 22.8″

2005-06: 13.4″

2008-09: 14.6″

2016-17: 4.9″ (gulp)

2017-18: 7.7″ (gulp x’s 2)

So IF you were just to average the weak La Ninas and snow in KC…of the 10 weak La Nina’s we get to about 17.5″ or so. Our long term average is around 18.8″ regardless of La Nina…El Nino…or nothing.

What about the moderate La Nina snows? Any indicators?

1955-56: 25.6″

1970-71: 20.5″

1995-96: 19.1″

2011-12: 3.9″ (our worst snow winter in KC history)

So I’m heading down the snowy primrose lane for 3 of those winters then I go off the cliff. It’s not even worth the averaging of them because they are so few years…only 4.

So what happens if instead the trends tilt towards a strong La Nina? There is some data that suggests that this indeed could happen. Now my feeling about these things is typically weak or moderate La Nina’s are interesting in the scheme of winter…but a strong version of either La Nina or it’s opposite catches my attention in a major way.

So let’s analyze the previous strong La Nina years.

1973-74: 13.9″

1975-76: 21.8″

1988-89: 6.9″

1998-99: 11.8″

1999-2000: 12.9″

2007-08: 24.1″

2010-11: 36.9″

So all over the place…remember that winter of 2010-11? That was a nasty cold winter and a reminder that winter still can deliver in these parts!

There actually has been some research regarding La Nina and snow totals…

The above is for all La Nina years…here is a breakout of weak vs strong La Ninas. Use the slider below…you can see that things get a bit dicey in strong La Ninas.

Why is La Nina important? Well because by itself there is data to indicate that certain weather patterns are more persistent through the winter season. This is the rough look at how the weather is affected by La Nina.

There is more of a likelihood of ridging off the western US with a dip in the average jet stream towards the OH Valley. See the dip?

And sure enough that’s the overall forecast from NOAA regarding this coming winter more or less.

Pretty standard stuff….and I hate it. Hey it may be right at the end…but here is the kicker…I think it’s WAYYYYYY to formulatic. This is standard forecast almost every La Nina…I’ve seen this forecast before…several times.

Look familiar? This is the winter forecast from 2017-18 for what then was another weak La nina winter.

I mean come on! Same forecast almost to a tee. OK maybe it’s a ridiculous coincidence. Let’s go back one more weak La Nina…2016-17

It may not be perfectly the same…but it’s a lot alike.

By the way the verification on the 2016-17 temperatures at least wasn’t terrible.

Although the northern Plains and NW part of the country wasn’t so great.

For grins…the 2017-18 reality.

Meh.

Hey this stuff is next to impossible…I get that but there has to be more.

So is there? I think so. Another thing I’m watching is what I’ve written about before. It’s referred to as the “blob”. This is an area of warmer than average waters…except this one is toward the northern Pacific Ocean…and in reality encompasses more territory than La Nina does. Yet most forecasters don’t have a clue. I really feel it has to have some connection to what’s coming. Perhaps in tandem with La Nina…or something else. The “blob” though has been a recurring feature over the past few fall seasons. Sometimes it stays persistent through the winter…other times because of strong and more frequent big Pacific storms…it erodes through the winter season as large waves churn the Pacific waters so much that the warm “blog” eventually evens out.

This blog has been a thing in mid November for the last few Novembers. I went through a bunch of sea data back to 1982…and can’t find a parallel between La Nina and the blob both happening together at least at the same time. Maybe something a pinch closer in 2013 but a stretch.

So what I’m trying to say is that basing a forecast strictly on La Nina is happening so A+B+C=whatever I think is not the greatest for me at least.

So what does the blob do? The warmer waters out there have a tendency to create ridging…or northward pushes of the jet stream. That creates a downstream effect of dips…where those dips tend to migrate are important. IF the dips migrate into the western 1/3rd of the country…that means we might have more of a tendency of seeing waves come out of the southwestern US…that can lead to more rain…snow…ice in the Plains. IF the average dip is pushed farther east…then this happens east of the KC area…we get cold…and get something but fewer big storms potential.

VERY important to remember that these might be trends…there are almost always exceptions to the rule and that’s what makes specific seasonal snow forecasting not a pleasant experience for me :).

See the chart below…over the last month or so there has definitely been a tendency, as we go up to about 18,000 feet or so…to see these “ridges” in about the area of the “blob” (the bottom 2 panels).

I dislike the area where the average dip is occurring (in blue) towards the Lakes and east to some extent. That isn’t thrilling to me at all for a decent snowy set-up that has some lasting qualities in it.

Model Data: Well. I’m writing this a week ahead of publishing my write-up…and gulp…the models aren’t very friendly into December. The European model for actual snow amounts (out to 46 days…through December is meh at best. This is from the run on the 16th. I’ll try and do a late add on the run from last night after.

Of the 50 or so members of the model run…a handful are somewhat optimistic. One member does have a snowstorm on Christmas though (the solid blue line on the bottom). The green lines are the average of all 50 or so members of the model run.

That’s about 3″ or so through the month.

Meanwhile the run that came out last night…that carries us through December…is a bit more optimistic.

To add to that…here are the super long range snow forecast that came out last night through the 1st week of January.

Then you look at the other long range model…showing some pretty mild looks to the 1st 2 weeks of December with perhaps a mid-month shot of colder air beyond…so it comes out to this.

and then there’s this from the same model…for the 3 months of DEC>FEB.

Not thrilling.

Hey you can still get some snows…and snow storms in a warm winter…a bit tougher at times and perhaps we fight the rain/snow/ice thing more this winter.

So the model data isn’t too exciting to me but it rarely is.

The EURO model showing snowfall anomalies into the winter is even less exciting for us. This is from Ben Knoll. and came out about a week ago.

Climate change:

So it’s a thing…and when you look into the arctic region…it’s really a thing. There is some data that suggests because of an increased reduction of sea ice in the Arctic region that weather patterns in the mid latitudes…like the USA are affected in different ways.

What does this mean? Well when the arctic gets warmer…and it is…

the potential of colder air being released/reorientated into mid latitudes increases during the winter season. By no means is that a 100% correlation though. Other things during the winter season can affect this release or not release of colder air US…especially into the central and eastern US.

What we do know though…at least over the last 50 years is that things are indeed changing…and the one season that is changing the most in MO and KS is the winter season.

and in KS

Meanwhile more focused on KC…and for the winter season which is defined as DEC>FEB…things are changing as well.

An overall warming from 1970 through last season. This isn’t a model…this is actual data. Things have changed, some 3.4° or so in the winter around here. That doesn’t mean you don’t get big cold shots or major snowstorms…it just means that things aren’t the same now. Most, if not all would agree to that I think.

Also of note…

So yeah…more above average days during the key winter months. You can see the variety…and again perhaps this just translates into “wetter” snows as opposed to “drier” snows. Or more rain/snow events together. Who knows…but the “bite” to winter has definitely lessened in the Metro over the past 50 years “on average”. Goodness knows back in the winter of 2009-10…there was more than enough “bite” for a full buffet.

Then there is the polar vortex. This was sort of a big deal last winter…and can be a big deal in the winter season. When the vortex is strong and wind currents up in the northern latitudes remain strong…colder air is more likely to remain “bottled up” with moderate incursions into the States.

When the polar vortex though is weaker and more susceptible to buckling…then things get more interesting. Buckles in the vortex allow colder air top be released into other areas of Canada and in time the USA. These buckles typically create big storms…because while the colder air comes south it runs into moisture and warmth the farther south it gets. Low pressure areas love temperature gradients…and when things come together they can really come together.

Last winter again was more of a stable polar vortex…this winter may be somewhat the same with perhaps some occasional buckling. I do see a path where we can indeed get some impressively cold shots of air into the Plains

Other indicators include facets referred to the NAO or North Atlantic Oscillation and the AO…the Arctic Oscillation. These are factors especially in seeing cold air patterns setting up ahead of time. The NAO has a positive and negative value.

Positive isn’t great for cold…negative is better

The Arctic Oscillation sort of works the same way…and when the two are in tandem one way or the other…it can be an important indicator to mildness or coldness.

There is pretty strong correlation to when we have a La Nina and when the AO goes negative to getting a cold pattern. The left side of the following maps show the C (meaning cold-La Nina) and the various AO phases…again you want a AO- (negative) to at least get something interesting on the table most times.

then you look for precip tendencies…

So you can see IF the AO trends positive for the winter…odds favor a less cold and drier pattern. IF near neutral it’s a warmer signal…and IF negative…maybe something can happen.

Trends this fall are mostly on the positive side…which isn’t great with some dips into the negative which is more favorable for snow.

There is some model data that goes out through the end of December that do indeed show nice negative dips.

Finally a look at the fall so far…mainly from a precipitation standpoint.

I’m writing this before the weekend rains…but as of Friday we’ve been very dry since 8/1.

Now maybe we shift a spot or two…but it’s been really dry.

The winter of 1937-38 had 16.1″

The winter of 1953-54 had 11.9″

and the winter of 1976-77 (that was cold too!) had 17.5″. If you want to throw in the winter of 1893-94….we had 24.5″

It’s not the greatest connection though in the big scheme of “snow” things but it sort of is in a very minor way somewhat guiding me a bit to my final forecast.

OK…so thousands of words later…this is what I’m thinking.

I do see the chance of having some colder air masses…perhaps well below average for a period of time…I’m struggling though in seeing anything that locks into place with the other things coming together at the right time…so that to me means no repeat of the memorable winters of the 2009-10…2010-11…2012-13 in terms of snow totals.

So that leaves me under 24″ or so…now let’s see where we go from there. IF this turns more into a moderate to strong La Nina…and IF we see mostly AO+/NAO+ conditions…I think I want to cut more…so that takes me to under 20″. Model data is overall pretty mild and somewhat dry. Now I’m trimming to under 18″. Remember 18.8″ is average. I also have increasing concerns of more than a random ice scenario or two setting up. We typically have one or two light glazings…I’m suspicious that we may have a bit more of an ice storm this season, compared to other seasons. Those types of events are headaches and frustrating because we’re “wasting” snow opportunities as well.

So in the end…here we go…

16.5″. It’s where I started in my head and where I’m finishing. I’m sticking to my 1st thought from a month ago. My feeling as well is IF I’m wrong…I may be too high?

Oh and I have early worries about a summer drought next season.

Done. Have a great winter and watch this blow up in my face.

Hope you enjoyed this crazy exercise. The feature photo is from Glen Briggs up in Trenton from yesterday!

Joe

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