Cold air damming likely to affect outcome
I am going to get right out ahead of this now and say that the cold is likely going to prove me and other forecasters wrong once again. Guidance does a very poor job handling it. I know this. I hammer that point home often in my discussions. I took the bait, and I will pay for taking the hook.
Looking over observations, Aroostook County was at or below zero at the 7 AM recording point. The Isle of Shoals and Portland weather buoys were in the mid-20s. The cold air is damming, and it does not appear to go down without a fight.
Guidance is beginning to catch onto this idea. The 9z (4 AM) HRRR model is showing a later time for the southwest coast to rise above freezing. This means more snow will fall before the changeover to rain.
It could be 4 PM this afternoon or later before the entire coast sees liquid. Given the projected track of the storm, eastern Maine has a better chance of seeing rain move further inland than western areas.
Due to the trend, I have modified the snowfall map accordingly. The higher amounts in the mountains and north is for higher elevations. Areas along Route 2, Lewiston and Waterville can expect a half a foot. Shoreline areas will be on the low end. I am thinking 3-4" for Portland, Augusta, and Bangor. DownEast areas along the Airline can expect 2" or so before the changeover.
I am not afraid to admit my errors. Models fooled me on this one. I will make adjustments.
I will update later today.