Our heavy snow band has developed as expected this morning and after passing through York County last night, most activity is now focused along the midcoast extending back through Lewiston. In this band expect near zero visibilities and very heavy snowfall on the order of 1-3″ per hour.
The heavy band will continue to slowly drift NE today bringing more snow to the midcoast. Attention will then turn to the upper low behind it which will likely touch off some snow squalls this afternoon.
As the upper low swings through, another round of heavy snow is likely this afternoon in the form of a line of snow squalls similar to summer thunderstorms (without the thunder). While the line that the HRRR depicts looks to be a reasonable interpretation of how things could unfold, I think they may be a tad more hit or miss. If one manages to find its way to you, expect a brief period of very heavy snow and low visibilities. Accumulations from these squalls will be light with a coating to an inch in the heaviest precip. Snow squall activity looks to be focused between 1 and 4 PM this afternoon followed by… you guessed it! More bitter cold winds and falling temps.
Revised snow map including what has already fallen. Should have stuck the original map… Oh well. Here’s what changed. I’ve been mentioning the uncertainty in this forecast for a while now and I’m glad I did because as with any storm, there are surprises.
Here’s yesterday’s GFS showing winds, temps, and moisture (RH) for about 5,000 feet up. Notice all the green indicating plentiful moisture. The idea that there would be plentiful moisture around allowing for precip to continue through the day as a new low formed offshore was supported by all the models and the forecast was good to go.
However, bust potential was mentioned for a reason. Anytime you get this Norlun trough type setup, there are surprises and as is par for the course, we got one. This map is the same model for the same time with the same parameters just from this morning. Notice the light greens and yellows working their way into the region. This indicates a dry slot which has shut off the steady precip over SW areas today.
Another storm is looking likely for the weekend and is looking warmer with a heavy wet snow possibly changing to rain for the coast. Our next threat for an all snow event arrives in the middle part of next week along with even more of the frigid temps we love so well.