12 Hour Forecast Snow Accumulations- SPC SREF

Hour 36

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Afternoon Snowstorm Update

Amounts for Chicago have risen to 4-12 inches, with the GFS and NAM at opposite ends, respectively. The Chicago NWS Office is going for 4-8 inches, so we will have to see. Model update this afternoon.

5-7 Inches of Snow Possible for Chicago, Illinois

Up to 9 inches of snow is possible per the 18z NAM, but the NAM has been known to over-estimate snowfall amounts. Here's what the models think, all engraved on graphs.

SREF Ensembles

The SREF has never been too adventurous with this snowstorm, so I would bet on the models above the model average. But we will have to see, as every ensemble has their right to their own forecasts.

Models

The models are showing a range from 1-5 inches. This is not the accumulation, but rather accumulation with compaction- that is, snowfall compressed on the ground after all is set and done. Here's the snowfall without compression- what we classify as the actual accumulation.

As you can see, accumulations without the compression are higher, with the NAM reaching into the 8 inch range. Below is what models we think are correct in accumulation forecasts:

We are thinking 3-6 inch accumulations right now. This is for Chicago, and the most affected areas will actually be the northern suburbs within Illinois. In the whole inter-state snowfall accumulations, Wisconsin may get a foot of snow.

1/10/12

Henry Margusity, Accuweather Meteorolgist, posted a Facebook status indicating that the Northeast had a HUGE storm Presidents Day 1979 due to a La Nina to El Niño scenario. As of right now, I could see that as a possibility, but ENSO temperatures seem to tell a better, more accurate indicator of whether a Nina or Niño is in effect. Regardless, it will be something to watch.