Good morning, I’m pressed for time this morning so this will likely be a two-part blog, a brief update then a second update with the morning model runs. I essentially see no significant changes from yesterday’s huge blog regarding the scenarios laid out.

Read that blog if you missed it!

Today there is a weak system giving us clouds. There may be a few flurries or snow showers somewhere out there but no accumulations are expected.

Temperatures today won’t be too bad, with highs in the lower to mid-40s; colder air comes in tonight.

Then the focus shifts to everything about the weekend.

Today: clouds and perhaps some sunshine during the afternoon. Highs in the low to mid-40s

Tonight: Turning chillier with variable clouds. Lows in the low to mid-20s

Tomorrow: Mostly sunny and cooler with highs in the low to mid-30s

Saturday: Clouds lower and thicken with a wintery mix of snow and perhaps some sleet developing later in the day into the overnight. Highs in the upper 20s. Light precipitate totals are expected.

Sunday: Wintry mix switches to heavy snow. Accumulations over 3-4″ are expected for most with northside areas likely over”6″—perhaps more than that (rather easily) depending in the switchover timing. More specifics perhaps later this morning and for some

Model data overnight hasn’t changed that much. There were some minor colder trends in the atmosphere, although the south side is still going to fight with that wintry mix of sleet and freezing rain well south Saturday night into Sunday morning.

Basically, IF this was an all-snow event and it still could be (very easily), we’d be looking at a likely 6-10″ system (which is somewhat rare for us, with some easily over 10″ as jackpot locations).

That IS on the table because I’m still not 100% convinced that this “warm” poke of air that will be supposedly nudging up to the I-70 corridor, give or take about 30 miles is going to happen.

Why is that? Because the track of the storm and many of the features that I like to follow is just so darn good right now in the data coming out.

Perhaps that’s playing out now in the data which has considerably shrunk the above-freezing layer on the south side from yesterday to today. It’s still there but it’s also a bit weaker, leading perhaps to more sleet.

We do know the heaviest part of this mess will come later Saturday evening into Saturday night and especially Sunday (where is maxes out during the morning into the early afternoon).

That will be the heaviest snow accumulation in the region as a whole.

I do feel somewhat confident that areas north of I-70 get the biggest totals, while areas south of I-70 get a bit less. This is based on the current path of the system and where it should end up.

We do know the winds will be a big factor on Sunday as well…gusts to 30 MPH are possible, leading to wind-blown snows in the region. This may not be a blizzard technically but near-blizzard conditions are very possible

We do know that the snow will likely end towards evening.

We do know that temperatures will likely be down into the teens and dropping on Sunday, and with winds sustained at 15 MPH, wind chills will be near to sub-zero.

LATE THURSDAY MORNING UPDATE

The morning computer runs of the GFS American model and the NAM model continue to show this elevated warm layer of air (meaning at least 32° or warmer) about 4,000 feet up… this continues to be an issue for big snow totals in areas that have bigger issues with sleet, and farther south, freezing rain. Where this elevated warm layer of air maintains itself longest will certainly lower potential snow totals.

So what am I talking about… take a look at this graphic below… this is off the NAM model for Lee’s Summit. For reference at the bottom is the time…0Z Sunday is 6PM Saturday then 6Z Sunday is 12AM Sunday and 12Z Sunday is 6AM Sunday etc.

So, flakes that form fall through that “warm” layer and melt. Likely refreeze as sleet when coming down to the ground, or freezing rain, which won’t be good if it doesn’t refreeze in time.

Again, this is for the south side… how about up towards KCI? And let’s switch models to the GFS. There are still elements of “warmth” in there (circled area). This is also more sleet up there than down south perhaps.

I CAN’T be confident about a HUGE storm in the METRO region until that “warm” layer is resolved one way or the other.

Let’s take this one step farther… suppose that we’re waiting for areas from I-70 southwards to transition fully to snow until 9AM Sunday. Then how does the model resolve that snow amount till the end…

From the GFS… this is a 10:1 snow ratio (10″ of snow for 1″ of liquid equivalent BUT with this part of the storm we may average the METRO liquid at around 4-7/10″ so hence that snow output. The snow ratios won’t be good (likely below 10:1) into Sunday AM… that cuts totals, then rapidly improve into Sunday mid-to-late morning from NW to SE through the Metro.

Now, it’s important to remember for areas farther north of the METRO this won’t be as big an issue with the transition part. So, higher totals than the graphic above are expected there… perhaps in excess of 8-10″. Areas farther south, and not that much farther south of Kansas City may only be in a 1-4″ range with more icing. 1/10″ to 1/3rd of a icy something, freezing rain and perhaps some sleet, is going to be more problematic down there it appears.

NOW ONE HUGE CAVEAT!

The storm in question is a lock BUT it’s still out here… in the eastern Pacific

It won’t be ashore till Friday night where it will then split in two pieces.

This is partly a reason why we see model gyrations within 48 hours of the storms arrival sometimes. It gets into a better and more data rich zone and incorporates additional weather balloon data.

What I will say though is aside from the vagaries (which are significant) with this elevated “warm” layer of air… the track of things has been extremely consistent. As I’ve lamented (if you want snow that is) it’s virtually perfect for big snows.

IF you don’t want the snow, which I’m sure is the majority of you… you want that elevated warm layer to be real and to last. That cuts the snow down and limits its duration. Negative to that thought process is it will increase the freezing rain potential south of the Metro.

So with all that said… the biggest snows may well end up towards the US 36 corridor area…and likely there will be 10″+ totals up there with jackpots over 12″ more likely than not for some communities.

That’s about 50+ miles away, so IF the southside is going to get into those bigger totals, things need to shift south in terms of the system overall. That would cut down the warm layer, keep that aspect farther south and bring that heavier snow band into the Metro area even moreso.

There is an opposite to that, more north of a track, and then we’re dealing with more ice/sleet than heavier snows until the real backside of the system. A lot of folks don’t like snow, but I think it’s fair to say NO ONE wants ice.

Bitterly cold air comes in during the day and we may tank to near 0° on Monday morning and then sub-zero early next week for lows. Depending on clouds early next week some areas could easily tank to 10 below with that snow on the ground and the Arctic air pouring in. More on that down the road.

NO big storms are expected for 10 days afterwards…although the temperatures will be going all over the place as Arctic air masses come in and then leave us.

Lastly, don’t discount the wind on Sunday making things more challenging with falling snow and bitterly cold temperatures.

The new EURO doesn’t really add/change what I’ve written in this update.

Brian with the feature photo.

Joe