WEST MICHIGAN -- After 60 plus degrees on Tuesday and a day filled with sunshine, a quick snap-back to winter will arrive Thursday. A very potent, moisture laden low pressure system with some excellent lift and upper level dynamics will track in to the lower Great Lakes. This system will bring the possibility of heavy rain (one inch or more), accumulating snow, and wind to West Michigan.
All of our forecast models have done a very poor job with the evolution and tracking of this system the past few days. It seems to be having issues resolving whether or not this system will phase (or merge) with another low coming in from the north/west. That means it's either under or over estimating the precipitation chances. As a result, snow accumulation maps from these models are all over the place. Take a look at some of them below: The first is the NAM, or North American Model. Way too high in my opinion for totals!
Next is the Canadian forecast model known as the GEM. Probably too light in many locations.
Below is our in house forecast model known as the RPM, or Rapid Precision Model. This one may make the most sense, but amounts may still be a bit high in areas. Note the bulls-eye it shows east of Grand Rapids. Somewhat consistent with the NAM.
The model below seems to be in left field. It's one of our long range American models called the GFS, or Global Forecast System. Note where it places the heaviest snow...well north. This one seems out to lunch.
The final model below is from the always publicized European, high resolution forecast model. This one has been somewhat consistent the past few days, but may be on the light side.
So what does all of this inconsistency mean? It's what we Meteorologists struggle with from time to time...what will actually happen. Clearly with all of our forecast models not agreeing, it's also tough for us to come to a accurate conclusion. That said, I believe we will see things begin as rain overnight and continue into Thursday early/mid morning. Some of the rain could be heavy, especially across our southern counties where another one inch or more may fall. The rain will eventually mix with/changeover to thick, wet, heavy, high-moisture content snow. I envision an accumulation of about 2" to 4" between I-96 and I-94, with lesser amounts north/west of Grand Rapids and along the Michigan/Indiana stateline with slightly warmer temperatures and more rain there.
Take a look at the track of this system. The image below is valid for 7 A.M. Thursday morning. Notice all green/yellow precipitation means steady to moderate rain...all liquid.
The next image is valid for noon on Thursday. Note the changeover to blue or snow. Darker blue denotes moderate/heavy snow.
If these two systems phase together and the upper level energy all play in, there may be some areas that see one inch snowfall rates per hour and a heavy swath of snow east of Grand Rapids of up to about six inches. Make sure to stay up on later forecasts! Get updates at www.fox17online.com/weather.