Joe’s Weather Blog: Ice storm potential for Kansas City area. Snowstorm for others (WED-12/30)

Weather Blog

One aspect of the winter storm is done…the second and potentially now third aspect awaits. The second one is the potential doozy for Kansas City. The third would be adding insult to injury: Adding snow to an ice encrusted city on top of snow that falls on the ice to begin with.

Yesterday, there were close to 20,000 customers without power in northern Missouri mostly. This morning, there are still about 4,500 scattered around Missouri. The reason why I’m so concerned about ice potential in Kansas City doing something more is that we’re going to get more ice than northern Missouri, and we’re going to have more wind as well. That is a bad recipe for power lines and that is what has me so concerned right now.

If this turns into more sleet, ice pellets bounce of power lines with no issues. If this turns into more snow, that would be better, but ice is not good for anyone, and that’s what I’m most concerned about when looking at the data for the last couple of days and the reason why I’m raising the flag about this potential.

Last night, I showed the potential for at least 1/4″ of ice and mentioned that data was supporting almost double that for Kansas City. Less southeast with more snow northwest of Kansas City. That hasn’t changed in the overnight data. Again it’s concerning to me.

A Winter Storm Watch has been issued for the region. It doesn’t include far northwest Missouri but I won’t be surprised if some of those counties are added in later today.

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Forecast:

Today: Variable clouds and seasonable with highs in the mid 30s

Tonight: Clearing out. Watch for some freezing fog potential as well. Lows in the teens

Tomorrow: Partly cloudy with increasing overnight clouds and ice developing towards 12AM Friday morning. Highs in the upper 30s

Friday: Ice to sleet to snow. Significant ice accumulations are likely with decent snow accumulations possible on the backside of this. Right now I’m thinking 1-4″ of snow on top of 1/3rd+” of ice. Temperatures will be around or just below 31°. A bad day.

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Discussion:

Got to admit…started feeling like Paul Revere last night regarding the icing potential in the Kansas City area. At least the data is still screaming at me that this potential is the greatest locally. It’s an ice storm set-up.

Obviously depending on where the storm exactly goes will determine whether we can get a faster switch to snow…and perhaps if we can start at 33 or 34° early Friday morning, that too can diminish the icing. So there are some ways out of this to not get the worst impacts from the icing. But I said this last night, and I’ll reiterate it now, I’m concerned about the trends and the amounts of potential ice.

How can we get ice? The issue is that were setting up in the atmosphere for a long period of freezing rain…look below. See the freezing rain area…that is going to be our atmospheric set-up for Friday early morning into the mid-morning it appears. In time we should transition farther to the right in the diagram below. How quickly will determine how much snow we get.

Data overnight and again this morning shows that the surface will be around 32°. IF we can get a couple of more degrees on the positive side, that would greatly cut the ice build-up. That’s all it would take to help the cause. IF we can warm up a bit more tomorrow…let’s say into the lower 40s and IF we can get the clouds to come in fast tomorrow night before we drop off…there is a path that we could be 32-35° at the outset.

The problem with that thinking is that the dew points will be lower…and when whatever starts to fall, we’ll cool the air down a few degrees thanks to evaporation…and that brings those surface temperatures closer to or just below 32°.

The next way out of this to some extent is because the air above us will be likely so warm…up at 4-6,000 feet perhaps into the lower 40s…maybe the warmer rain drops help to bring the near surface air up a couple of degrees. It’s a stretch but I’ve seen it happen before. Typically with an ice storm, the air above us isn’t as warm as what the data shows as potential right now.

The next way of playing devil’s advocate for ice storm potential is the overall “weirdness” of the storm and the path it’s taking. Farther south or southeast with a track brings a better set-up closer to the I-35 corridor. Farther north and west with the storm track can actually try to bring a transition to liquid rain closer to I-35. These options are on the table, but right now are less likely.

Another thing about this: the potential of thunder freezing rain and/or thunder sleet. I mentioned this on the air last night to get ahead of this. Weird storms do weird things. Yesterday in a much weaker set-up, there were numerous reports of thunder heavy snow in Iowa and even into Illinois. That makes me go hmmmm. There will be heavy snows in southwest Texas with this, that is somewhat rare for them. That too makes me go hmmm. Texas itself will have a snowstorm…that makes me go hmmmm. Weird storms do weird things. We’re going to be in the area of the system Friday morning where lift will be maximized. We’re also going to be in an area where the air way above us will be fanning out in different directions. This creates areas of stronger lift. That makes me go hmmmm.

Let me show you what I’m referring too…let’s go way up to about 30,000 feet or so…

I wanted to highlight the winds for you…and in particular the flow closer to Kansas City with the purple arrows. Notice how the air is “fanning out” in our area. When the air does this at that level (or around that area), the air below that has to rise up to replace the air being fanned out. That creates more lift and allows whatever is happening precipitation-wise to get a bit of a boost in production. Another avenue for increasing the amount of whatever is falling. In addition to being in the right place within the storms circulation.

The issue is exactly WHAT will be produced.

There will be ice (freezing rain) for at least 6 hours I think. There are various tidbits that suggest we may be able to sneak some liquid rain into at least the south side of the metro Friday morning for a bit of time. That would be helpful.

My concern in the length of freezing rain before, let’s say 8 a.m. or so Friday. We could be looking at 6-8 hours worth. Precipitation totals for the region through 8 a.m. show this.

Now this is NOT all ice for all places. There will be a rain component to this, especially south of US 50 as a broad delineation line reducing the icing accumulations there tremendously.

IF that is all ice in the Kansas City area…that “liquid” equivalent is about 1/2″>3/4″ BUT that won’t be all accumulated ice on trees and power lines. What’s interesting about ice accumulation is slower is worse…harder is better. I know that sounds counter intuitive.

When freezing rain is coming down harder, it actually drips off exposed power lines/tree branches to some extent. When it comes down slower, it has an easier time accumulating on those same surfaces. So while the data points to heavy precipitations accumulations, you have to significantly cut those totals for ICE accumulations.

That though is still about 1/4″-1/3″+ of ice…that’s what the folks in northern Missouri saw yesterday knocking out power lines for some, especially in Buchanon County. That’s why I’m concerned. Oh and to add a bit of insult to this…there will be wind as well…and that too is a bad combination. 20-35 MPH winds are possible as this unfolds Friday morning.

Now we get to the vital part. How much longer does the freezing rain go beyond let’s say 6-9 a.m. Friday. Do we switchover to sleet and snow? How long does that transition take? Model data shows a fast wiping away of the “warm” layer above us creating this freezing rain problem in the KC area. Look what happens between 6 a.m. and 10 a.m at 5,000 feet or so. Use the slider to go right and left. Right is 6 a.m. and left is 10 a.m.

5,000 foot temperatures in °C. +5 is the lwoer 40s at that level! Look to the south of Downtown…+8!

Then colder air at that level comes up from the southwest (!) and by 10 a.m. we’re converting over to sleet and/or snow and in time over to all snow.

How quickly that snow switch happens determines our accumulation…we could get less that 2″ from the conversion time…especially IF we’re waiting till after 12 p.m…or we could get over 2″ of snow…if it happens quicker in the morning.

It does appear areas north and west of the KC area towards northwest Missouri and northeast Kansas are setting up for 3-6″ of snow and slop with this data.

So let’s wrap up…

Keys to the forecast:

  1. How long do we keep the freezing rain going.? Longer duration…bigger ice storm and the problems with power lines for some areas
  2. Can we switch for a few hours over to liquid rain in the Metro Friday morning?
  3. When do we switch to snow and for how long? 1-4″ is possible depending on the timing of the switch
  4. Areas north and west are more favored for better snow totals
  5. Areas south and east are more favored to be mostly rain with perhaps some light icing…down towards Sedalia and Clinton into southern Kansas
  6. Do we get additional boosts of precipitation coming down because of any convective elements somewhere in the viewing area?
  7. Will there be added insult with some quick hitting light snow on Saturday?
  8. The exact track of the system Friday and Saturday play a role in who gets what
  9. About 10 other things

As mentioned, a Winter Storm Watch is up for the region. Odds are something will be extended or issued into northeast Kansas and Northwest Missouri too at some point.

Start thinking about having your cell phone fully charged and/or plugged in Thursday night before you go to bed to be on the safe side.

Our feature photo comes from Sharon Graeff up in Osborn, Mo. last evening. Shows you what ice can do.

Joe

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