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Joe’s Weather Blog: Winter Storm Warning In Effect

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9PM Update:

Good evening…cold and blustery are the weather words tonight as temperatures have slowly dropped and/or held steady over the last 6 hours or so. We’re venturing down into the upper teens and it’s tough to imagine warming up more than 5-8° on Saturday…that means whatever falls will freeze one way or another.

The latest data is trickling in and for the KC area proper I see no reason to change my thinking of the last couple of days with accumulations…with that said there are some details I want to go through with you…

1) the worst of the storm for areas well south and southeast of the KC metro will be during the 1st part of the day tomorrow through lunch or so. Ice/sleet will be the most common precip type for Sedalia/Warrensburg/Clinton/Butler/Pleasanton etc…see the map below for additional details…this icing should create travel headaches down there from daybreak onwards…

2) the worst part of the storm (in the big picture of things) will be tomorrow afternoon and night for the KC Metro area and points westwards. There may be some areas of freezing rain/sleet tomorrow AM that will be patchy but yet may contribute to slick conditions for area roads especially from I-70 southwards. Check in with MB for radar updates tomorrow AM starting @ 7AM

3) concerning the snow situation…that will develop more towards very late in the day into the night as the entire atmosphere becomes more supportive of snow. This will be the timeframe of the most accumulating snow for the KC area…timing that would be early evening through 2AM or so. Again I think 2-5″ is still a good forecast for the KC metro area…as an average. Perhaps more leaning towards the higher numbers north of I-70. Sleet will be very prevalent before the switch to snow.

4) It’s becoming apparent that NW MO and NE KS may be the bullseye for the heaviest snowfall (we’ve come a long way with regards to that over the past 36 hours…originally they may have been mostly missed). 4-8″ looks more probable up there and I’m beginning to wonder IF maybe somebody chimes in with an isolated heavier amount towards the IA border. To complicate things up there, the winds will really be increasing SUN AM, especially from daybreak onwards..so what’s fallen will blow around I think creating some big headaches for snow removal and travel.

Here is a map I’ve cobbled together for you…MT has the accumulation ideas on the newscasts…Click on this image to make it larger.

wx

snow

I’ve been alluding for the last several days about the potential for near 0° weather for AM lows…and we may really make a run to that, if not below. TUE AM for areas up in north-central MO and towards NE MO (assuming a deep snowpack) may see lows tank to 10 below!

5) Longer range thoughts are cold as well with minor interludes of warmth. I see no change in this pattern of repeated cold shots every so often with minor warm-ups ahead of the fronts. The net effect will be below average temperatures to finish the month…and this will be turning into one cold December that we’ll feel into January I fear. Might want to start saving some extra pennies for the higher gas/electric bills coming down the pike. More on the longer range on Sunday.

6) You’d never know it from all this blogging this week…but I’m actually on vacation this week and weekend…so MB will handle the on-air duties for me…but since I live and breathe this stuff (especially during the winter ;) ) I’ll continue to update the blog, at least into Sunday. Maybe I’ll take a couple of blog day offs next week for the holiday.

7) There are always curve balls with these storms. Somebody gets more/less than what I think…it’s the nature of the beast…to be honest, if this thing comes 50-75 miles farther north or south, we get less/more snow in the KC area…you know the drill and we do our best.

8) Tomorrow I will have lots of live animations of the models etc for you to look over at any point during the day, including radar images/forecast radar plots etc. So check in often…and I’ll try and update the blog several times tomorrow. Just remember that 1st thing in the AM…before 10AM I may not have a new blog ready for you…let’s see how functional I get in the AM…since it’s going to be a long day/night tomorrow for the blog.

JL

6PM UPDATE…

All still going according to plan…bigger update coming tonight at around 10PM or so…after the new data comes in. I did want to emphasize the potential of some decent+ icing going on towards the south of KC. Travel may be rough towards the S/SE of the metro tomorrow…even here in KC we’ll need to watch for some lighter freezing rainfall during the AM days. Here is a forecast radar image for tomorrow @ 6AM…showing the area of concern…

ScreenHunter_32 Dec

Then by 9PM tomorrow night…here is what radar may look like…

ScreenHunter_33 Dec

A Winter Storm Warning is now in effect from Midnight through early Sunday AM…

ScreenHunter_34 Dec. 20 18.10

Winter storm warnings are indicated in PINK…Ice Storm warnings in PURPLE and Winter Weather Advisories are in lighter BLUE…

JL

NOON Update:

The models have come in this AM and they’re consolidating nicely which helps out a forecasters confidence. By the way the temperatures keep falling this early afternoon…down to 21° at 11AM. This is an issue tomorrow should anything fall from the sky at any point of the day…because of the freezing issue that could occur. More on that tonight…again though the main part of the storm is still slated for later tomorrow into tomorrow night.

Here is a look at some of the various model forecasts for snowfall…

More later today…have a great afternoon. Essentially no changes to my previous thinking based on this data…JL

++++++++++

Temperatures have dropped below 32° and I’m not hopeful that we’ll go above that for the rest of the day. As a matter of fact temperatures today may actually trail off a bit as the day goes along. The risk of freezing precipitation has now mostly ended…there is a bit of freezing mist out there but overall the rest of the day will be fine for traveling, shopping etc.

Let me briefly mention how I’ll be updating the blog today. I’ll do an update this AM around 11:30 or so…then another later this afternoon, after 4PM and a final update closer to 10PM tonight. Things should get a little better focused with the model data and the potential impacts mainly of the snow for tomorrow night into early Sunday AM.

So as I start the blog let’s go over the snow aspect first and cut right to the chase. There is still disagreement with how strong the disturbance will be as it zips through the region tomorrow night into early Sunday. There are also concerns about the specific path the disturbance will take…which is critical in determining who gets the heavier snowfall. At this point I still see no reason to waver about what I’m thinking for snowfall. It’s rare for us to get more than 2-5″ of snow in a wrap-around snow situation or what we technically call the “deformation zone”. Whatever happens will not last for that long…some 3-6 hours or so and that to argues for lower totals. There will be a dividing line, as is typical with these wrap-around snows…so some of you will get little to nothing and NOT have a “White Christmas” while some do get the headaches and the joys of snow on the ground (depends on your perspective I guess).

Now let’s backtrack a bit. The front as of 8AM has pushed through most of the region and is now into the Lakes area. Temperatures which have been dropping since midnight will be edging downwards for the rest of the day…as there is some pretty chilly air “advecting” or moving into the region as I type this.

Here is the 8AM temperatures (in RED) through the region….

sfc

So the cold air is here and really is going nowhere for the next few days.

Now let’s talk about the storm. It’s out there and doesn’t look that impressive yet and that’s because it hasn’t entrained moisture yet from the southern part of the country. The storm now is located in the northern reaches of Baja California and you can see it rotating on the water vapor loop this morning…

Notice ahead of the rotation a lot of sub-tropical moisture streaming through northern Mexico and Texas…as the storm near Baja moves eastwards it will start tapping into that moisture and fling it more northwards tomorrow. Keep in mind that moisture also has “warmer” air aloft associated with it…so tomorrow as we start to get into at least some light precipitation during the afternoon from south to north…the air above the surface will not allow snowflakes to wither form or if they did form, make it to the ground. The thing is though that our ground temperatures may be near or even below freezing for a good part of the day…so whatever falls may be more icy with perhaps a transition to liquid rain in the PM tomorrow. Typically however IF the temperatures during the daytime are 30-32° and we have freezing rain there aren’t too many problems aside from needing to scrape etc. So I think we should be in pretty good shape tomorrow for shopping/traveling for the most part in the KC area. There may be some additional freezing rain during the 1st part of the day towards the south of the KC area…from Marshall to Sedalia to Clinton to Butler to Pleasanton to Garnett and a little north of that line to the I-44 corridor that could create some road issues in the AM hours.

So essentially I’m expecting highs on Saturday to be somewhere in the 22-25° range (revised down) for the KC area with OK travel conditions for most of the day around KC proper. You may need to scrape a bit…and watch those untreated surfaces.

Then as we head towards tomorrow evening the storm that is now near Baja CA will eject northeastwards and move through MO from OK and SE KS. To the north of this track is where a band of moderate to potentially brief heavy snow set’s up and this will be our “snowstorm” for the KC area. If there has been any change of significance int he data over the past 24 hours (aside from the model movements of the storm itself and who gets snow and who misses out) it’s the speed of the system which is getting faster and faster. Indications are that most of the snow will be over with by 3AM Sunday morning. Remember a couple of days ago it looked like it could linger another 3+ hours and start a bit later in the night. So again, and I know I keep going back to this, the “snow window” is not long for the KC area. For snowlovers out there though what falls will stick right away so there will be little to no melting…I would expect road conditions to head downhill tomorrow night though 3AM Sunday morning.

The rub about all of this is what track does the ejecting storm take? Again a deviation of 50-100 miles (in the world of weather this is small) will pull the accumulating snow 50-100 miles in a different direction, whether that be north or south. For the most part though the modelling has shown this disturbance to take a favorable track for the I-35 corridor to be in the decent snow. When we talk about these “disturbances” for the most part I’m talking about what’s going on in the middle to upper part of the atmosphere. When we look at our modelling we look at the 500 mb level or about 18,000 feet up. Here is what one of our models, the NAM model does at that level. You can see the storm in the Baja area and follow the storms path as it ejects through MO.

You have to look carefully but you may notice how the storm “shears out” as it moves into the fast flow from TX through the Great Lakes…this too helps in the forecast in terms of giving me confidence in the “short” duration of the snow in the big picture.

So how does the model depict the various precipitation types for the region…this will give you an idea on the travel conditions through the US and the Plains over the next couple of days.

Now some of you may be thinking…well Joe this is great but I have no idea about the timing of all this in the animations above. Fair enough so let me help out with that. 12Z represents 6AM…18Z is Noon…00Z is 6PM…and 06Z is 12AM. There may be times when the models are updating and the map placers are blank…just come back to the blog in about 30 minutes and the data should be there. The great thing about that is that you’re seeing the exact same model data that we are and you get an idea about what we are thinking about and the models will automatically update for you throughout the day and night…so check back often. Who knows maybe you’ll get a sense of the ups and downs we go through when we try to figure out the fine details of snow forecasting.

Alright so you’ve read a lot of my thoughts and more as the day goes along will be written with additional maps as well. Here is where I stand…and it’s in the same place as where I was yesterday. I still think this is a 2-5″ event (yes I’m aware that there are higher forecast accumulations out there) and at this point I see no reason to alter my thoughts. The speed of the storm + the limited “snow window” are the driving mechanisms for me to think those higher totals may be too high. Don’t get me wrong…higher amounts are possible should things slow down by 3 hours…I just don’t feel like that will happen. My thoughts are that lighter snow totals will be realized towards the SE of the KC area…towards the Lakes region. There is potential for some higher totals 6″+ across north central MO into SE IA.

Timing: There is still a “warm wedge” of air aloft around even at 6PM tomorrow…so again I think at this point the sticking snow happens after that…but before 9PM. We may have a period of freezing rain or sleet before we transition to snow. All of this ends by 2AM, if not faster. Again back to that short window again. Could we get an hour or two of heavy snow…yes. That’s why I still don’t want to waver with my 2-5″ forecast.

Sunday will be a cold blustery day with highs around 15-20° and wind chills near 0° (revised downwards). There should be enough time for the plows to pile up the snow @ Arrowhead…so aside from that tailgating will be fine I think…although I could see how this should be a late arriving crowd. I still think lows will tank with the fresh snowcover MON-TUE AM and near zero lows are possible. What may prevent us from totally bottoming out TUE AM is a south wind that should kick in towards 12 AM TUE…typically that slows down the falling temperatures even with snow on the ground. Something to watch though.

Have a great day and bundle up…so much for the nice warm air of the past couple of days!

Joe

Now let’s get into

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