The upper-level low that has been in our region for awhile will finally move off to the east, allowing for an upper-level ridge to build over the Great Lakes today and into Monday. This will bring in an area of high pressure that will keep southeast Michigan dry with partly to mostly sunny skies today and Monday. This ridge will not stay for very long though due to an upper-level trough moving in from the west that will arrive on Tuesday. This upper-level trough will produce a surface low in the Tennessee Valley that is forecasted to track up through eastern Ohio and into northern Pennsylvania before combining with another surface low along the east coast over the Atlantic Ocean.
Before the surface low phases with the surface low traveling up the east coast, it could bring some accumulating snow to our region. The important factors involved include how close to Michigan will the surface low track and how much moisture will the system have to play with?
The image below is from the NAM Sunday 12z model run and it shows the surface low (circled in blue) getting as close as the northern Ohio/Pennsylvania border before combining with the surface low to its east (circled in orange).
Image courtesy of PSU Ewall
The surface low is forecasted to be a modest 1012mb when it’s the closest to Michigan which isn’t very strong, but it’s enough to produce some snow. The image below shows the amount of precipitation expected based on the NAM model from 7pm Tuesday evening to 1am Wednesday morning.
Image courtesy of College of DuPage
This shows about 0.1 to 0.175 of an inch of precipitation which translates to about 1-1.75 inches of snow. If you combined all the precipitation images from the NAM model run, it looks that about 2 inches of snow can be expected.
The GFS model run has the surface low in about the same position as the NAM model run shown above, but it keeps the precipitation more to the south as shown below.
Image courtesy of College of DuPage
This image shows the amount of precipitation expected between 1pm Tuesday and 7pm Tuesday. The differences with the GFS model are that it expects the system to move into our region a bit faster than the NAM and it also expects the bulk of the precipitation to stay further to the south. The map above shows the bulk of the precipitation will be from about Wayne County southward to the Ohio border with about an inch during this time period. The further north you go, the less snow you can expect. The total snow expected based on the GFS model is about 1-2 inches, with more snow expected further south.
The total of snow expected could change slightly depending on the final track of the low pressure system and if it strengthens more than the models are currently showing, but as of today around 2 inches looks like a good average forecast for southeast Michigan. Also, if the snow does come earlier in the day as suggested by the GFS model, then it could end up being a messy and slow commute home from work Tuesday evening.
It will then stay relatively quiet the rest of the work week until another opportunity of snow arrives on Saturday. Before today, this system was looking much more promising than it does right now, but I wouldn’t rule out the chances for accumulating snow yet. An upper-level low will drop through central Canada but it will not drop very far south into the U.S. This will cause the developing surface low to take an unfavorable northern track across northern Minnesota into UP of Michigan before occluding and moving northward into Canada. As the surface low passes, it will bring a cold front through the area that looked to have the potential of dropping several inches over our region, but now it is looking more like another 1-2 inch system. I will keep an eye on this over the week and will do another posting in the next day or two to update on any changes for both snow potentials.
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