Snow? What snow?

It is almost 9pm on Thursday evening, and taking a look at the local temperatures, it is still above freezing in most of the Metro Detroit area.  The map below shows current temperatures for Michigan and its surrounding states.  You can see that the temperatures in the circle are in the mid to upper 30s, but if you look to the west from the Lansing area to Lake Michigan, temperatures range from the low to upper 20s.  Even further west the temperatures are in the upper teens.  This shows that pretty cold air is moving into our area which will change any rain to all snow most likely sometime before midnight.  By looking in central Ohio you can get a good idea on where the cold front is.  The temperature in Columbus Ohio is 31F but the temperature in Dayton Ohio is 20F.  That is a 11F difference in about 70 miles.  So it is easy to see that the cold air is making its way into southeast Michigan.

 The image represents current temperatures.  Click on the image to make it bigger.  Courtesy of NWS.

Looking at the radar below, most of the precipitation is to our west and north.    Also, the center of the low pressure system is currently positioned in southeast Michigan.  The center of the low being positioned in our area is bad for the following reason.  The air around the center of a low pressure system moves in a counterclockwise direction.  If you look at the radar, you will see this by watching the precipitation move counterclockwise.  With mature storm systems like this one, dry air from higher levels start to sink on the western edge of the upper level wave, and as it sinks, it gets caught up in the counterclockwise circulation.  This causes the drier air to move towards the center of the low pressure system, which is in southeast Michigan.  The term for this is a dry slot.  This dry slot is strong enough to prevent precipitation from forming and that is why it is not raining or snowing right now.  The center of the low pressure system will eventually move off to the east, bringing in colder and moist air behind it, but this is not expected to occur until around sometime after midnight.  Because of this, we can expect even lower totals for the Metro Detroit area.  I would guess around an inch if we are lucky.  Further north from about Saginaw towards Midland, the dry air will move in but it won’t last very long.  Therefore, they are expected to get 3-5 inches of snow.  Towards Lake Michigan, they can get 6-12 inches.  

 This is the current radar.  Courtesy of NWS.

One last thing…below is a good example of the bubble.  There are winter storm warnings and winter weather advisories in the entire Great Lakes region except for southeast Michigan.  This is what the bubble does.  It blocks snow from reaching where I am.

 This image represents the bubble.  Courtesy of NWS.

The bubble isn’t a real weather term, but sometimes I think it is.  Only one or two people will know what I am talking about!

Chris