Yes, I am forecasting much higher than the NWS...hear me out

Needless to say, I was really surprised when I saw that the National Weather Service dropped our forecasted accumulations to 4-7"...and to be honest, I can't really find a good reason why they're doing that. I can agree with them that there will be some dry air to overcome at the onset of the storm, but since the heaviest snow is going to fall around 12 hours after the storm begins, I don't think the dry air will cut into accumulations much at all. They see a south trend with the precipitation shown by the forecast models, but I haven't seen any model move far enough south to knock us out of the 6-10" range. There has been a slight southward trend in the models over the last day or so, and seasonal trends support the storm moving a little further north than is currently depicted by the models (this last minute northward trend has happened to every storm this year that I can remember). Therefore, I'm really questioning why the National Weather Service dropped our totals, especially when the National Weather Service in Grand Rapids forecasts 6-10" to fall in the counties to the west of us, and 8-12" to fall in the counties to the southwest of us. I think that is a more realistic depiction of what will actually happen.

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Forecast Model Images:

NAM

This image of the NAM shows a heavy band of snow impacting the M-59 and I-94 corridors early Wednesday Morning:

This image of the NAM shows that band of snow affecting us in simulated radar form:

This image of the NAM shows storm total precipitation. It has moved south from yesterday, but if you read my discussion yesterday, you'll note that I was disregarding the NAM in the first place because it was too far north. It is simply moving into model consensus...

GFS

This image of the GFS shows moderate-to-heavy snowfall impacting all of SE Michigan early Wednesday morning. Note the tightly packed pressure gradient, which will result in very windy conditions which will blow the snow around, with the end result being huge snow drifts.

This image of the GFS shows storm total precipitation...note how similar it is to the NAM...

GGEM

This image of the GGEM shows moderate-to-heavy snowfall impacting all of SE Michgian early Wednesday morning.

This image of the GGEM show storm total precipitation...a bit drier than the NAM & GFS, but still has the dark blue over us, which equates to 6" minimum

ECMWF

Once again, no pics, but apparently it also is a bit drier than the NAM & GFS...still showing at least 6" of snow for us...

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Forecast Model Preference:

All models show a near-perfect storm track for SE Michigan to get heavy snows, there has been almost no change since yesterday. Models have basically stayed the same with precipitation (except for the NAM which went south to the model consensus). There is now a tight model consensus for where the heaviest precipitation will occur, which is south of I-696 and into NW Ohio. I have no preference on the track, for precipitation, I will use a blend of all four of the major models. Really, it's getting to the point in the storm where models become almost useless, and by tomorrow, we'll be nowcasting...

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Snow Map:

Once again, I am glad I used 15:1 snow-to-water ratios (for a further discussion on ratios, look at the discussions below), as it looks like these may not even be met. I always like to stay conservative on ratios, so for this map, I will stick to 13:1 ratios.

For Detroit south, I will assume they will get anywhere from 0.65-0.95" of water equivalent. With 13:1 ratios, this equates to anywhere from 8.45-12.35" of snow. I'll just round those down, for a forecast of 8-12". I still feel some areas with persistent heavier banding could get over a foot, so I will include the "Locally Higher" label.

From I-69 to Detroit, I will assume we get anywhere from 0.5-0.75" of water equivalent. With 13:1 ratios, this equates to anywhere from 6.5-9.75" of snow. To give myself some breathing room, I'll round the 6.5" down and the 9.75" up, for a forecast of 6-10". Come tomorrow morning, when I make my final prediction, I may shave an inch of the bottom or the top of the forecast, depending on nowcasting trends...

From I-69 up to Bay City, I will assume they will get anywhere from 0.3-0.5" of water equivalent. With 13:1 ratios, this equates to anywhere from 3.9-6.5" of snow. I'll round the 3.9" up to 4", and round the 6.5" up to 7" as I have a hard time believing amounts will diminish extremely quickly.

North of Bay City, I'll cut amounts just a little bit more due to the slight south trend, for 3-6". Due to enhancement from Lake Huron, I will not cut amounts in the Thumb, opting to keep them at 4-7".

This is reflected in the following snow map:

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Snow Day Chances:

My thinking still hasn't changed. It's early February, and we haven't had a snow day. Therefore, I feel anywhere from 5" on up gets us a snow day. In fact, due to the blowing and drifting of snow, 4" may do the trick. However, I still find the National Weather Service's forecast quite curious, and am still quite confident we end up with 6+" of snow.

Snow will start around noon tomorrow. This event will start slowly, but will pick up steam rapidly in the evening, with moderate-to-heavy snow falling after 8 p.m. tomorrow night and continuing on into the morning hours on Wednesday. Rush hour traffic will be severely impacted, as the road comission simply will not be able to keep up with the snow. Adding to the headache will be 20-30 mph winds that will cause near-whiteout conditions at times, and cause snow drifts up to 2' high, rendering some back roads nearly impassable. In fact, some weather outlets have hinted at gusts up to 40 mph as the storm departs. Considering all this, there is almost no doubt in my mind that we will have a snow day Wednesday. I have no reason not to raise the snow day grade to an "A" (near 100% chance of a snow day) for the first time this year. Everything looks set for our first snow day to occur on Wednesday. Hope everyone enjoys the storm.