Winter Storm Monday Night into Tuesday

Monday, January 26 -- 8:00AM

Winter Storm Warning effective from 6PM Monday until 6PM Tuesday...

Greetings, one and all!

All indications are that we are in store for a 2 phased Winter Storm that should dump between 4"-8" inches on the STL area. The weather models have been consistent in advertising this event for the last 5 days or so, only differing in the timing and track of the storm. The models are pretty closely aligned now.

The "good" details:

• Plenty of cold air in place from the ground levels to the upper atmosphere. All you have had to do is poke your head outside for the last few days to know this is true.
  
• Abundant moisture from the Gulf of Mexico. This should actually create a warm air "wedge" in the column of cold air, creating a period of sleet.
  
• 2 phased storm. First phase should begin this evening -- and be the bigger of the two phases -- dumping 3-5" on our area. Phase 2 should begin Tuesday morning and bring us another 1-3"
• High snow-to-water ratio of 15:1. This will be a powdery type of snow. It won't take a lot of moisture to get a good amount of snow.
  
• The timing of this storm is perfect if one is interested in School closings. The main thrust of the storm will be overnight tonight, with a reinforcement of snow tomorrow morning hampering the efforts to get the roads in good shape for drivers.

The details that worry me:

• St. Louis and St. Charles counties are part of the line that form the northern limit of the Winter Storm Warning. The counties north of us are only under a lower-threat "Winter Weather Advisory." So we are not exactly in the "bullseye" area of this system. Wih a storm that approaches us from the Southwest U.S., the worry is that there is always a tight "snow gradient," meaning that some place will get 8 inches of snow, but 30 miles north of this point will not even get a flake. That could happen to us here, though I don't think it will.
  
• This should be a long-lived storm system. That can be both good and bad. If you have only light snow for 24 straight hours, road crews can cope with that. So hopefully the scenario plays out as forecasted, with a two pronged snow attack.
• This is not exactly the "Storm of the Century" here. Don't look for a Day After Tomorrow scenario. There will not be widespread pillaging by Norse Vikings as the local TV weather people tend to portray. This will be a nice-sized storm, but nothing crazy.

My prediction is this: 6 inches of snow, and widespread school closings.

So break out those tobaggons, and think snow!

I will update this blog as necessary.

-WD

Winter Storm Watch Sunday night thru Monday

Saturday, December 13 -- 4:00PM

Winter Storm Watch from Sunday 6PM to Monday 4PM...

All signs still pointing to a significant Ice Storm for our region for late Sunday night into Monday. To be honest, I have a hard time believing some of the numbers being thrown at us. For instance, tomorrow's high temperature will likely break 60 degrees, and then the cold front is supposed to pass, and the temperature will plunge into the 20s by Monday morning. A 40 degree drop? That's not exactly unprecedented, but we will need every last bit of that temperature drop to get the expected ice accumulations. If the temperature "only" drops 35 degrees instead of 40, then this will just be cold rain.

Predicting the effects of an Ice Storm is tricky business. Forecast models are pretty poor at anticipating how cold the air will REALLY be. To give you an idea, since Sunday's high temperature will be around 60 degrees, for us to get significant ice accumulations Monday morning, the temperature actually needs to fall into the lower 20s (say, 22F) during the rain event to overcome that prior warm air presence. Yes, yes, I realize water freezes at 32 degrees. But entropy is at work here. Ever notice that if you put a glass of water into a freezer it doesn't immediately freeze? Same thing.

Then again....

Interested if schools will be closed? My guess is the following scenario will play out:

• This Ice Storm scenario will "mostly" come true. Come early Monday morning, the temperature will be around 27, and freezing rain will be accumulating as ice on the ground. At 4AM or so, we will have a light glaze, and forecasts will be dire
• By 6AM, it will still be moderately raining, with the temperature around 25, grassy areas will be covered with ice, but streets will be only slightly bad. School district officials will envision kiddies standing at bus stops, covered in ice as if Frozone from The Incredibles had sprayed an Ice Ray their way. The school officials will hit the panic button, and there will be widespread school closings.
• By noon-time, most of those school officials will walk outside, see that there is no ice on the streets, scratch their heads and say, "We called off school for some cold RAIN?!?"

The margins for error are razor thin here. Just a few degrees either way will make a huge difference. But if I was a betting man, I would say there is a 60-70% chance of widespread school closings, and for a very short period of time Monday morning, those decisions to close schools will seem justified. What worries me is come mid-day Monday, a lot of school officials will be second guessing their decisions.

Remember, weather fans, there is nothing I want to see more than a thick sheet of ice covering everything, to the point that I need to break out my ice skates to take the dog outside. I am just not convinced we will get those extra 5 degrees.

-WD