Snow Chances & Arctic Air Watch

***Watch WISN 12 News all weekend for the latest weather information!***

Thank you for stopping by the Weather Watch 12 blog! If you watched any of our WISN 12 newscasts in the past day or so, or read the previous blog entry you are well aware that some big weather changes are ahead this week.

A more active pattern will bring a couple precipitation chances to the area, and potentially the coldest air of the season!

Let’s first discuss the chance of snow for later Monday and Tuesday. By Monday low pressure will be moving from the Plains to near the Missouri/Arkansas border. As the low stays to our south, the winds in southeast Wisconsin will turn to the east, or off Lake Michigan. With east winds and just enough cold air in place, some light lake effect snow showers could develop Monday afternoon or evening.

Below is our in-house high resolution computer model for 7pm Monday. The light blue in southeast Wisconsin near Milwaukee is light snow. Also of note is the wind bards, showing fairly light easterly winds.

The main snows at this time will be over the Plains and western areas of the Midwest.

As the surface low moves east, some of that general light snow will spread east and slide over our area on Tuesday. Along with the light snow, there could be some additional lake enhancement or lake effect as winds will stay either east or northeast on Tuesday.

The snow should be enough to bring some accumulation to our area, we’ll start putting actual numbers on the potential as we get a little closer to Tuesday. I think the heaviest snows with this weather maker will once again miss our area.

Snow chance #2 will arrive with a stronger storm in the Friday-Saturday timeframe. This will likely be a major storm for someone in the Midwest. But keep in mind the last time this storm moved through, the main surface low stayed northwest of our area back around November 25-26.

One thing looks certain, a surge of very cold air will pour in on the backside of the system. That is why I’m issuing an ‘Arctic Air Watch’ for next weekend. This means I’m watching for what will likely be the coldest air of the season to arrive.

Below is a surface map from the 18Z GFS for next Saturday night. The map also includes the 850mb temperatures(about 1500 meters above the ground) which are indicated in blue. This would have an 850mb temp of around -19C in Milwaukee! Also of note is the strong high pressure area dropping in from the Plains.

Here is another view of the cold, the map below is also the 18Z GFS next Saturday night, but it only shows the 850mb temperatures. It is color coded, and the colors in our area are generally not welcomed by many! Just click on the map to enlarge.

Right now it is tough to put forecast numbers on the arctic blast, because if we pick up a few inches of snow this week the cold blast would be even colder in southeastern Wisconsin. At the very least highs should fall into the teens, or even single digits in spots. This push of cold will fall in line with the first punch of cold air to hit the area back on November 26-27, or roughly 50 days ago come next Sunday-Monday.

The pattern is changing, and a true surge of arctic air looks likely to arrive next weekend. For more on the exciting week ahead check out WISN 12 News all weekend!

Have a great Sunday!

Jeremy Nelson

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4 Responses

  1. It will be interesting to see how the cold shot plays out because the long term models do love to exaggerate cold (and hot) spells.

    • Daniel,

      With the knowledge of the LRC and what happened in late November on the dates I listed I’m confident this will be a pretty good shot of cold air. Now the question is how much snow can we get on the ground before the cold hits?

      Jeremy

  2. Jeremy,

    I know you said it’s hard to predict at this point, but if we had 4-6″ on the ground by next week, would negative double digit temperatures in spots be quite possible if the cold followed the path that the LRC suggests?

  3. It looks like another storm is tracking along the Gulf Coast, bringing snow and freezing rain to the South, and it looks like we could have another Nor’easter brewing. What storm does this storm line up to?

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