More Fun; Blame Me!

We’ve got a few small events coming, along with some bitter cold over the weekend, and then a potential for a higher-impact winter storm (and potential change over to rain) for next week… the last of which you can blame me.

Rehashing the Tues Snow, one last time:
First, amazing to see the difference with the last storm between the “high-elevation” Piedmont snowfall and areas south and east, which got next to nothing… bummed it wasn’t more widespread. I have noticed over recent years the Piedmont “influence” has become more pronounced as we get more and more of these marginal snow events, with temperatures often hovering in the lower 30s. I did some looking a while back, and I discovered what I think is the main answer for the difference. Yeah, the Piedmont is farther inland, more north and west, and it’s higher up. But being 500-1000′ up doesn’t make that big a deal with respect to the temperature… you lose ~ 3.5°F for every 1000′ you go up in a saturated atmosphere (one producing rain and snow)… so really, the Piedmont elevation will shave roughly 2-3°F. I think it has more to do with what I read from the folks up out of SUNY/Albany: falling snow typically will melt after descending ~1,000′ through above-freezing temperatures (assuming it’s not 60°F, of course). Basically, the Piedmont elevation allows these areas to “meet” the snow before it finishes melting in marginal events. At least that’s my take. The slightly colder air and more north/west locale add to the chances for maintaining snow, but for this last event, it really seemed almost entirely contingent on elevation once you got north of VA/DC.

Next up: Friday. Cold front will blast through, producing a period of light snow or snow showers as it approached Friday eve. Not a big deal, but if you’re out on Friday be aware we could see snow coat the roads.

Saturday: Some models show a band of lake-effect snow showers setting up over nrn MD as the wind trajectory coming into nrn potions of the region comes off Lake Huron, Lake Superior, and Lake Erie. We’ve seen this before… if you can line up these 3 lakes in our upwind trajectory, we can see a band of accumulating lake-effect snow. Given (1) how cold the air rushing in is and (2) the lakes aren’t frozen, this is worth mentioning. Could be enough to even coat the ground (though with the wind and increasingly cold, dry air, it won’t last)

Monday/Tuesday: Blame me. I have the U.S. Drought Monitor duty over the next 2 weeks. In the past, I have had a litany of things interrupt my shift, including snow storms (more than once), a tropical storm, a furlough, an earthquake, and a Papal visit. That leaves pyroclastic flow and earth’s magnetic field swap on the list… or, just tap into my greatest hits. Naturally, models show a storm approaching from the southwest Monday, then moving overhead (or nearby) Monday night into Tuesday. This would get us a period of moderate snow Monday into Monday eve, then changing to rain Tuesday. At least that’s how this looks now. The models are targeting the heavy snow more to the west as the low is expected to track more inland, but some snow/ice appear likely before the changeover, and it could be a moderate to heavy before the change over.

Again, this last one’s all on me. Sorry!

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