Thursday, December 2, 2010

First accumulating snow

Looks like the first accumulating snowfall will glance the area over the weekend. Here in northern Illinois is looks like things will kick off late at night on Friday and carry into the day on Saturday.

Yesterday morning the models decided to go bonkers with snowfall amounts suggesting upwards of 10 inches, but have since calmed down to a more realistic scenario. Main killing factor seems to be the weakening trend with the H5 wave. Rather than the more amplified solution projected yesterday morning, a more subtle feature should sweep into the area and rapidly lose it's definition as it pushes over the area. This lack of upper level support seems to be the main instigator in the lesser snow totals. Initially as the dendritic zone becomes saturated it will remain above the more favorable omega layer, but over time into Saturday morning it should lower into a more favorable layer. Even with upper level support lacking this should instigate a period of fairly heavy snowfall over northern Illinois around sunrise.

It won't be the most organized system, but with a fairly dry snow things could accumulate quickly. Winds won't be overly strong, but again a dry powdery snow will let things blow around in rural areas through Sunday. Given QPF totals from around 0.3-0.5" and a dry snow ratio beginning around 12:1 and increasing upwards of 18:1 by Saturday morning, maximum totals of around 4-5 inches seem plausible in a narrow band. With large model spreads even only 36-48 hours out and the system not even onshore yet, nailing down the area of heaviest snow totals is pointless.

As is typical with me, I'm fairly excited about the first snow of the year. I'm generally okay with snow until about the end of January. By February as things start thawing out, I start getting that "February itch" to get out chasing and am about ready for frozen things to stop falling out of the sky, unless they're golf ball sized chunks of ice hitting my windshield as I search for tornadoes. So mother nature, you've got two months to get in all the winter storms you want so use your time wisely.

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