Monday, Jan. 11, 2013
Another Winter Weather Advisory for the area. Yesterday turned out different than I expected as temperatures dropped much faster than I was expecting, so there were plenty of road problems in spite of the less than an inch (.8″) that was recorded at the airport.
Tonight’s situation is entirely different…we’ll be on the tail end of what is commonly called an Alberta Clipper that will move through the Great Lakes late tonight and tomorrow. There’s not usually too much to get excited about south of the clipper’s path, but this time may be a little different – at least the NWS seems to think so. Me, I’m not so sure, but I do think we’ll get something tomorrow morning.
This evening and early tomorrow morning, we’ll probably see what appears to be lots of snow on the radar, but don’t be fooled. High levels will be producing snow, but the lower level air is too dry for it to reach the ground. The result is called virga (falling precipitation that evaporates before reaching the ground). It looks good on the radar, but the result is disappointing to snow lovers.
That virga over night will be from a weak upper air disturbance preceding the primary clipper system. While it shouldn’t produce more than a few flakes of snow, it will serve to increase the low level moisture levels so that the primary system should have more chance to drop some snow.
As mentioned above, the major problems with the clipper will be far to our north, but the cold front trailing the system will come racing across Indiana and Kentucky tomorrow morning. While the atmosphere is very cold right now, it’s hard to squeeze much moisture into the air. But, it should be able produce a few hours of snow (probably between 6 and 10 A.M. in the Louisville area (earlier to our west and later to our east).
All the models I’ve seen are generating only small amounts of precipitation (less than .10″ liquid), so that doesn’t hint at much snow. Also, temperatures are expected to remain in the lower 30’s tonight, so the roads should be able to handle it pretty well.
With the Winter Weather Advisory, the Weather Service (and most of our media sycophants) is predicting 1″-3″ of snow. The indicators don’t look that strong to me. It’s possible that a few scattered snow showers could produce a few isolated swaths of 1″-2″ of snow (especially over southern Indiana). The vast majority of the area should see anywhere from a dusting to up to an inch of snow.