Good Thursday morning. Thanks for checking out the weather blog today.
True to form yesterday, snow flakes were flying in many areas above 2000-feet late yesterday, and accumulating up around 3000' and above. An inch or two came down on the ski slopes, and we're not quite done yet for flurries either.
Today's set-up is pretty tame in terms of commuting weather, but the chill is on. This will be the first of three successive nights with frost and freeze potentials across the tri-state. By the time we hit Saturday morning, the official frost/freeze program should end for most counties, signaling the end of the growing season (though anyone who watched our noon show yesterday learned from John Marra that there's definitely still things you can plant this time of year ;-)
Things get more interesting later in the day, as a weak disturbance passes just to our south. Given the cold pool of air in town, this holds promise for more flakes.
The image at left shows shaded areas of projected precipitation along with the temperatures at the 850mb level (about 5000-feet). I've put in a dashed oval in there to indicate where those temperatures are in the -8 / -9 Celsius range. That's some pretty cold air for October. Normally for me, a -5 or lower is good enough to go with for anticipating snowflakes, even in the river valleys. Certainly it's a green-light for snow from November onward. The only hangup that creeps in would be the climatalogically mild ground temperatures that would mix with the near-surface air to keep things wet instead of frozen. Nevertheless, with the right-hand map in mind, I would not be surprised to see wet snow at the 1500-foot level on the grassy hilltops, and perhaps even lower seeing flakes in the air. Now keep in mind the model is not projecting a lot of precip overall, so this is a mainly miss / sometimes hit scenario. Elevated areas see the best odds, as those ski slopes can get additional light accumulations out of this. Those places typically see snowfall in October, so that shouldn't be out of the realm for them. In fact, this represents the latest early season snowfall in the last three years for terrain above 3500-feet.
The next item of discussion are those cold morning temperatures. As you know, frost and freeze watches and warnings have been posted, and will gradually come off the grid once the first good freeze occurs (this ends the official growing season and with it the need for additional frost/freeze advisories). Here are the GFS anticipated low temperatures in the coming days:
Sub-freezing temperatures are in the mix each day through to Saturday, though Saturday morning itself figures to be the coldest because of the additional radiational cooling that comes through clearing skies. The other days feature a cold stirring breeze and waves of cloud cover. Not necessarily reassuring despite its marginal effect of keeping us slightly warmer :-)
Have a great day everyone!