Sunday’s Storm Worries…Ice, Snow, Flooding

Happy Friday. I hope everyone enjoyed our taste of spring this week. Winter is about to make a return. No weather worries tonight or Saturday. Sunday is a different story. The National Weather Service has issued a winter storm watch for part of our area.

So far, Sheboygan, Fond du Lac, Dodge, Washington, Ozaukee, and Jefferson counties are included in this. However, there is a good chance the entire area will have a big mess. As happens so often, our area will be right on the dividing line between rain, freezing rain, and snow. The computer models all have  a strong low pressure center, but they are diverging on the eventual track. This is not unusual, especially when the low is still so far away in Southern California. Take a look at the various solutions.

The GFS has moved much farther south than its previous run. The European model is the farthest north solution. That would bring us mainly rain if it verified. If the RPM verifies this is the result:

You can see some substantial totals across the area with the heaviest north. Here is the timeline of what I expect at this point. The precipitation will begin as snow early Sunday morning. This will eventually mix with freezing rain from south to north. I’m quite concerned there will be a pocket of freezing rain that lasts much of the day. I think the greatest chance of this would be north of Milwaukee and west of the lake. There could be more than 1/4″ of ice in some locations in Washington, Waukesha, Dodge, and Jefferson counties. North of that, the precipitation will likely stay all snow. That is where more than 6″ are possible. The snow will have plenty of moisture. If the storm track deviates a little more to the north we may have to deal with flooding issues. As much as an inch of precipitation is possible. Most rivers are running high thanks to all the snowmelt this week.

So where does this storm work in terms of the LRC (Lezak Recurring Cycle)? I believe that this is the storm that moved through on December 31st and January 1st. If you go back and look at this storm, you are probably asking how are we going to get so much moisture? We only had a few hundredths of an inch the last cycle. The thing to remember in the New Year’s storm is that we hit the dry slot. The graphic below will show how much precipitation they had just to our south and there was more to the north as well.

The December 31st storm stayed north. That is why we warmed to the 50s. This time around it will be farther south, but I will be curious to see if the models trend farther north with time to more coincide with what happened the last cycle. You may recall this happened with the Groundhog Day blizzard. Stay tuned and have a safe weekend.

Mark

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3 Responses

  1. Just my opinion, but I believe yesterday matches up perfectly with December 31. The big surge of warmth and LP tracking well NW of us into Canada. I’d look to see if there was a storm that went through to our south around January 3. Especially if this trends to the south solutions.

    Which model runs did you use for that graphic? Up until today, the ECMWF was the furthest south and the GFS was north and now they end up flipped into their usual biased positions.

    What do you think the snow ratios will be with this? The surface temps have me thinking 8:1 or maybe even 6:1 like that early December 2009 storm that dropped snow so heavy, some trees completely bent down to the ground and then were subsequently frozen like that for a couple of months.

    • Hey, Daniel,

      The 500 mb features match very nicely from January 1 and Sunday’s storm. January 3rd was next to nothing. That was the beginning of our run of piddly snows. .02″ and .2″ snow.

      European is 12z this morning. Way farther north than earlier in the week. 18z GFS was much farther south. I’m hoping 0z runs will clarify a bit, but doubtful.
      Ratios will likely be no better than 8:1. Very wet and heavy snow.
      Thanks.
      Mark

  2. Good luck with this storm, Mark! These are so tough to predict!

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