Monsoon's Forecast and Weekend Storm Outlook
Whew! That was some storm on Sunday and Monday: more than an inch of rain fell in most places, and the wind wrought havoc, causing downed limbs and power outages all over the place. In the Susquehanna basin, where nearly two inches fell, flood warnings in nearby counties remain in effect until late Wednesday. If this had been snow, some places could have been looking at more than a foot.
Speaking of which…
It’s still 72 hours out from the weekend snow event, but if everything falls right, we could be in for significant snowfall. Here’s my preliminary call, to be updated later this week as more information comes in:
The low tonight will get down into the mid 20s with diminishing winds.
Wednesday will be cooler with plenty of sunshine; the high will struggle to reach 40. Low in the mid 20s.
On Thursday we’ll see similar conditions, but some clouds will move through in the afternoon and evening, which may be accompanied by a passing snow shower. No biggie. High 41, low 20.
Friday will be partly sunny and markedly colder to start; the high will reach only 29. If we do get snow, it will not begin until 5 or 6pm. Right now I’m looking at a period of heavy snow overnight Friday into Saturday afternoon, bookended on Friday evening and Saturday evening by flurries and light snow.
Snow ratios with this storm could be impressive, with the temperature in the teens during the bulk of the storm.
[In brief, snow ratio refers to the amount of liquid precipitation equivalent to the snowfall. For example, with a pretty typical snow ratio of 10:1, ten inches of snow would be produced from roughly one inch of liquid. A “wet” snow has a lower snow ratio; a “dry” or fluffy snow has a higher snow ratio. For this storm, ratios would be in the range of 15:1 or 20:1, and so far model runs suggest that between three-quarters of an inch and one inch of moisture will fall. So, as those of you who are math whizzes have already figured out: that’s in the range of 12 to 20 inches of snow.]
This is all very preliminary, and the models don’t all agree on this solution. The track could be farther south (and some indications suggest this could happen) and give us fairly little, instead whomping the Philadelphia region and points south. The system could fail to tap into sufficient moisture as expected and give us lighter stuff.
This moisture--which will be centered over Texas and Oklahoma on Thursday night--could give us a significant snowstorm on Friday night into Saturday.
Right now, it’s looking good for fairly heavy, visibility-reducing, plan-cancelling snow on Friday evening, overnight into Saturday afternoon. Best chance right now for us in Berks and northern Lancaster Counties is somewhere in the range of eight inches, maybe ten. (Obviously, given the projected timing, this wouldn't affect school schedules.) Stay tuned for updates!