Upgrade: 4-6" of Snow With Locally Higher Amounts

A good consensus has formed between all of the forecast models with regards to the position, timing, and strength of our upper level low. I have a relatively high confidence in my accumulation forecast, as only nowcasting features need to be worked out with the storm. These features will determine which areas will receive the "locally higher amounts".

Anyways, the last remaining forecast model with a southern track, the GFS, jumped into agreement with the rest of the models with this morning's run. I therefore have a good deal of confidence with my forecasted track of this system. The upper level low is currently located in South Dakota. I expect it to dig down to around the St. Louis area, before turning east-northeast and moving through Central Illinois, Central Indiana, and Central/Northern Ohio.

In addition, this morning's models came in more robust w/ regards to precipitation. The GFS, which also was the driest of the models, bumped up our QPF by .1 - .2 inches, putting it more in line with the NAM w/ regards to precipitation amounts (the NAM is still the wetter of the two forecast models, but not by much).

Comparison: Old GFS Precip Amounts (Top) vs. New GFS Precip Amounts (Bottom). Note that this is the driest model. The third picture is of the wettest model, the NAM.



So what does this all mean for us? Well, firstly, it means I have greater confidence that portions of SE Michigan will receive 4-6" of snow. Also, due to the northward trend in the forecast models w/ regards to the precipitation shield, I will move the 4-6" of snow area up to around the I-69 corridor. North of there, there will be a fairly sharp cutoff in snow totals, but there is a very good agreement among the forecast models that we will be in the main band of snow.

In addition, I will include some areas in a "locally higher amounts" shading. First, I will include areas near the Ohio Border in this shading because they will be closer to the low pressure system. Second, I will include the "hills" of SE Michigan (eastern Livingston County, western/northern Oakland County) in this shading. The reasoning for this is twofold. First, some of the higher-resolution forecast models such as the NMM show a heavier band of snow setting up between the I-96 and I-69 corridors. Secondly, the areas on higher ground usually do well in long-lasting, moderate snowfall events, which tomorrow's event will be. Therefore I think a good compromise is including the "hills" of SE Michigan in this shading. I don't expect to see too many areas get over 6", but there will likely be some isolated amounts of over 6" in those shaded areas.

Heavier band of snow shown by the NMM's simulated radar at 11 p.m. tomorrow night

Anyways, I am expecting snow to start around 1 p.m. tomorrow and end around 4 a.m. Thursday Morning. Snow won't be particularly heavy, but it will be steady. This will make the Thursday Evening and Friday Morning commutes a mess, especially because temperatures may be low enough to render road salt partially ineffective. So, now to the part everyone is waiting for: what does this mean for our snow day chances?

It definitely increases them. I said earlier that if I had to bump forecasts into the 6" range, a snow day would definitely become possible. And it is, especially since there will not be time to plow all the back roads. I still think that there is a chance that our area in the hills sees the higher end of totals (5-6"), but everyone around us sees lower totals (4-5"), so no one calls a snow day. But it is January, and we haven't seen a snow day yet, so it could happen. Also, there's a chance that a persistent band of heavier snow sets up over us and we get higher than 6". All in all it will likely lead to the first legitimate shot at a snow day tomorrow night, and I will raise to the snow day grade to a "C" (around 50/50, could break either way based on nowcasting trends).

For now, I'll leave you with my forecasted snowfall map. Unless there are any major updates, I anticipate making my snow day prediction between 8:00 and 9:00 tomorrow night.