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KANSAS CITY, Mo. — I mentioned Thursday night, after such a great day yesterday with highs near 60 degrees in spots, that I was fighting trying to predict the snow accumulations to the inch on Saturday. I wasn’t even sure how warm we’d be Friday (40s? 50s?). We are setting the stage for a rather interesting overnight, where conditions will be varied in timing the snow changeover and the amount of snow that may accumulate in the Kansas City region.

It’s becoming a bit more clear that there are going to be areas that exceed 3 inches of snow in the Kansas City area, while areas may struggle to get to 3 inches. I increased some of my top-end numbers last night by 1 inch or so to accommodate these ideas for the late shows last night. And I will tell you, as I told our viewers last night, remember that the accumulations are a range.

Some may see a bigger number on the TV screen and become convinced that that is the forecast while ignoring the lower number next to it. They get mad if the higher-end number fails but the lower end number is accurate. It’s a range. Why?

Think of it this way: If Overland Park got 2/10 inch of rain, and Olathe got 4/10 inch of rain, no one would really care at all. It can vary that much within a city, and even within a few blocks. We show this all the time when showing you the rain gauges through the region. Now when converting this to snow, you can get a 1 to 2-inch variation from the same amounts of moisture. Again, this is range of accumulations.

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Forecast:

Today: Cloudy with perhaps a few patches of rain showers, but overall not too bad. Breezy in the afternoon. Mild too, with highs near 50 degrees. Some may be close to 55 degrees, especially south of Kansas City.

Tonight: Initially rain is an issue. The timing of the switch/mix to snow and conversion is close to midnight on the north and west sides of the region, while the rain may not covert to snow until after 3 a.m. on the south and southeast sides of Kansas City. That conversion in important for final amounts. Temperatures at midnight will be the high for the day. By daybreak, we should be tanking through the lower 20s or so. Increasing overnight winds.

Saturday: Snow ending towards 10 a.m.-Noon. Windy and very cold with near-zero wind chills. Temperatures in the mid-20s or so in the afternoon with cloudy skies.

Sunday: Variable clouds and chilly with highs in the low-to-mid-30s. We should be fine for the game in the evening.

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Discussion:

Yeah, this is going to be a headache to track Friday night and early Saturday morning. Surface temperatures will impact changing road conditions overnight. Conditions will vary considerably for awhile from Lee’s Summit to Platte City. And if you take a trip around the 435 loop from west to east around the Kansas City area, you may well encounter moderate snow on one side of the loop with moderate rain on the other side of the loop.

Good luck trying to forecast snow accumulations in that environoment.

There hasn’t been a lot of change in the data really. Friday, we’ll have southeast/south winds and clouds all day, but yet another mild day. We’re starting in the upper 30s this morning. Some of the short-term model data suggests temperatures pop into the mid-50s in the afternoon. For example: here is a look at the HRRR model, which has been aggressive with this for the last 24-plus hours for today.

3 p.m. Forecast temps

Let’s say this is close: 50-55 degrees on the north side, 55-near 60 degrees on the south side of Kansas City.

Right off the bat, things have to drop about 20-30 degrees in about nine hours for accumulating snow.

That is going to be a process in and of itself. Here is an idea of where we may be for temperatures at the surface at midnight.

Midnight Temps

All of the metro is still 40-45 degrees. That won’t work for snow at all. Aloft through 3,000 feet or so, it’s still above freezing.

These are the temperatures at 3,000 feet or so in °C. Everything to the east and south of the grayish color is above 32°F

Hence at midnight we have this idea for rain/snow.

Midnight rain/snow forecast

Where it’s snowing, it may be snowing pretty hard, and the same for the rain situation. The metro though is still solidly in the rain.

Then by 3 a.m.

It should be snowing pretty good from Interstate 70 north and roughly from I-35 west. Look on the south side: still waiting, or perhaps mixing. This model shows the rain snow transition taking an excruciating 3 hours to go from KCI to Lee’s Summit. That will affect snow totals in the end.

The storm itself, because of its structure is drawing in warm air on the east side, then wrapping that “warm” air into and around it. This is one big reason why we’re going to have a problem with the transition to snow overnight for a few hours. Since the storm in uniquely moving from north to south, we end up with this weird setup.

You can see the warm air wrapping around the area with the circulation of the system as we go up a few thousand feet or so.

The heaviest snows will last 1-4 hours after the transition before things lighten up. You can only get so much snow in that timeframe.

At least off the HRRR model, we get this idea:

Basically widespread 2-4 inches for the Metro. A LOT of this will have to happen between 3-8 a.m. IF there is a further delay in the transition, especially on the south side and off towards the east and southeast of the metro, that could be a real push because while it may snow hard, it won’t for a long enough time to get to the 4-inch high-end forecast. Hence the RANGE!

Meanwhile for areas where the snow happens faster, it snows harder and for longer, so I won’t be shocked to see a 5-inch total somewhere, perhaps west of the State Line.

So why this weirdness? Well it’s because of the storms structure. There is a feature that we refer to as an “inverted trough” that is in play. We do get these every year multiple times, BUT this time this feature is very pronounced and important. There is a large temperature gradient from east to west through the inverted trough. It shows up in the surface maps and is even more pronounced when going up to 3,000 feet in the wind fields up there.

Since it’s playoff weekend, I sketched the inverted trough line with football laces. Winds are howling west of the laces with plunging cold air, and east of the laces it’s warm air coming up from the south (at least it’s above-freezing air).

That inverted trough is moving southwards, so the air in northern Missouri is coming southwards on its heels where it is cold enough to support snow. This north-to-south movement (and it’s not rapid) means the agonizing wait on the south and southeast side for the rain to switch over.

The kicker to all this is where we transition from rain to snow. The snow may come down hard for 1-3 hours or so, then the issue is how fast does it stick, etc. How do the roads hold up, how fast does the slushy to snowy accumulation happen with this, then how fast does the temperature fall. Do we get a setup for a flash freeze in the AM because of this forecast for temps by 8 a.m. It may not be that terrible on the roads through 3 a.m., perhaps a bit longer on the south side.

Near 20 degrees on the north side is problematic for the roads as whatever slush and snow is on them will freeze up depending on the road-treatment situation.

OK let’s try and recap this hot mess.

  1. Snow transition likely between 1-2 a.m. through 4 a.m. from north to south side of Kansas City. Varied weather through the metro in that time frame!
  2. Roads likely aren’t terrible, just wet to increasing slushy, for at least an hour or two after the transition. So late night travel won’t be terrible. Use common sense with the changing conditions but road temperatures may help us out a bit.
  3. Roads should worsen from north to south between 2-5 a.m.
  4. Areas southeast of Kansas City may have quick snows but less totals before daybreak
  5. I think MOST of the viewing area gets at least 1 to 2 inches of snow.
  6. Temperatures tank before daybreak. Whatever is on the ground may freeze up to some extent.
  7. Wind chills are near zero to 10 degrees for most of the morning and afternoon tomorrow.
  8. Winds gust to 30 mph in the AM and then 20 mph in the PM.
  9. IF there isn’t a heavy band of snow for a couple of hours in your location, you will likely be closer to 1 inch or so.
  10. IF you get that heavier band of snow for a bit longer (1-3 hours), amounts may exceed 3 inches.
  11. I get the sneaky suspicion that someone, perhaps on the west or northwest side of the metro may see over 4 inches (localized).
  12. Highest amounts still appear to be northeastern Missouri, over 5 inches widespread.
  13. IF the transition happens faster than I think, we could add 1 inch. If slower, I think take off 1 inch.
  14. With this inverted trough setup there will be winners for snow amounts and losers for amounts. Favored winners on west and northwest and favored losers for snow wanters are south and southeast with lower totals.

OK that should do it for today. Critical updates on FOX 4 News at Noon, 5, 6, 9 and 10 p.m.

The feature photo is from Matthew Smith.

Joe