Snow is on the way for all of southeast Michigan! It should start snowing during the late afternoon on Friday and will last until early Saturday morning. The expected snow totals for Lower Michigan is shown below. The forecast is for 3 -5 inches from the Michigan/Ohio border north to about 696 or M59, then 2-4 inches from M59 to I69, and 1-3 inches north of I69. It is possible that the snow totals could increase or decrease depending on the path of the system and its strength as it moves through our region, but I am going to give a case for us achieving the higher end of the snow totals.
Forecasted snow total
First, let’s look at the NAM model. The image below shows the NAM forecasted surface map for Saturday at 1am. The left image is the 7am NAM model run and the right image is the 1pm NAM model run. Looking at the left image, the center of the surface low is positioned in southwest Kentucky. This puts the system further away from Michigan which would keep heaviest precipitation from reaching central Lower Michigan. However, the 1pm NAM surface map on the right has the center of the low pressure system in north central Kentucky. This slight shift of the low closer to Michigan can play a big role on the amount of snow.
Comparison of NAM model runs 7am (left) and 1pm (right). Click image to make it larger. This result of this shift can be seen below. The left image is the total precipitation forecast from the 7am NAM model and the right image is from the 1pm NAM model run. You can see that the northern shift of the surface low causes higher forecasted snow totals for most of Lower Michigan.
NAM forecasted precipitation totals. Click image to make it larger.
It is good to look for consistency between weather models to increase confidence in what they are showing. If only one model shows a trend happening, then confidence is low and that model is considered to be the outlier, but if a few models show the same trend then it is something to watch. The image below shows the GFS forecasted surface map and 6 hour precipitation total for 7am (left) and 1pm (right). The GFS also shows a shift to the north of the center of the surface low. Even better, the 1pm GFS and NAM both forecast the center of the surface low to be positioned in north central Kentucky. The 7am NAM and GFS had the surface low in different states. This consistency in the 1pm model run is a good sign.
Comparison of GFS model runs 7am (left) and 1pm (right). Click image to make it larger.
So the forecast of 2-4 and 3-5 for most of Southeast Michigan sounds about right but I would argue that we could expect the higher end. Only time will tell if I am correct. The image below shows the forecasted precipitation total expected for Thursday evening until Sunday evening. Our area is in the 0.25 – 0.50 inch range, and with a 10:1 snow ratio, that is 2.5-5 inches. I did see a mention that we could get a 11:1 or 14:1 ratio which would be 2.75-5.5 or 3.5-7 inches!
Forecasted precipitation totals. Image courtesy of HPC.
I will write a final posting Friday afternoon to confirm the forecasted snow totals.
Chris
