Snow Saturday Morning

Southeast Michigan will receive 1-3 inches of snow tomorrow morning into the early afternoon as a clipper system quickly moves through northern Lower Michigan.

In the upper-levels, there is a shortwave trough that is currently positioned over northwest Minnesota.  To its east is a surface low that along with the shortwave will move into northern Lower Michigan by Saturday morning.  The two images below show the shortwave trough and the forecasted track of the surface low.

 The above image shows the 500mb upper-level shortwave trough over northern Minnesota.  Image courtesy of NWS.

The above image shows the surface map and the forecasted track of the surface low pressure system.  Image courtesy of HPC.

There will be a decent amount of moisture with this system.  The image below shows the 850mb mixing ratio which measures the amount of water vapor inside a parcel of air.  It is determined by taking the mass of water vapor inside an air parcel divided by the mass of the dry air inside the same air parcel.  The image shows there is a surge of moisture with mixing ratios as high as 2g/kg.  In the summer this isn’t a very high number, but it does the job during the winter.

 The above image shows the 850mb mixing ratio.  Image courtesy of TwisterData.com

A mid-level dry slot is forecasted to move in over Michigan about six hours after the snow begins, thus bringing the steady snowfall to an end.  This can be seen on the 700mb relative humidity image below.  

 

The above image shows the 700mb relative humidity.  Image courtesy of TwisterData.com

Finally, the last image shows the total expected precipitation for the day Saturday.  Southeast Michigan is in the 0.10 to 0.25 range, and with temperatures in the mid to upper 20s during the morning hours, we can use a snow ratio of about 12:1 which gives us:

            12:1 is 0.10 * 12 = 1.2 to 0.25 * 12 = 3.0 (1.2 to 3.0 inches)

 

The above image shows forecasted precipitation total for Saturday.  Image courtesy of HPC.

After Saturday, the next chance for measureable snow is Monday night into Tuesday.  This storm needs to be closely monitored as it has the potential to give us active weather.