The GFS giveth and the EURO taketh away.
Last Sunday all computer models agreed on a large Nor'easter this weekend. And then...they all proceeded to drop the idea on Monday, again on Tuesday and finally once again on Wednesday. I fought it for a while because I really liked the large scale setup for a storm, but yesterday I gave in and called the storm a likely miss.
Sure enough I wake up this morning and the GFS has a bomb of a storm right on top of Maine for Saturday night, but the EURO...eh a yawner of a system. Let the fun begin.
Today: Mostly sunny and pleasant. High temperatures in the upper 30s to low 40s with melting ongoing. (The melting is less about the temperature, more about the sun angle which is starting to become more powerful as we head towards spring).
Tonight: Clear early but clouds increase after midnight. Can't rule out a snow shower over western Maine and the mountains during the early morning hours on Friday as a weak system approaches. Overnight lows won't be that cold, between 23 and 30 F.
Friday: With a weak Alberta Clipper style system moving through look for mostly cloudy skies and scattered showers. The showers will be rain along the coastline and about 40 miles inland, but west of that look for snow showers with some light accumulation possible. Either way it's not a big deal as the moisture is very limited. High temperatures will be fairly mild, between 40 and 45 F, as southwest winds drag in some air from MA. (There are many jokes to be made there, but I won't make any of them since I'm from that lovely little state :-))
Saturday's forecast hinges completely on which computer model you buy this weekend. The EURO brings a weak little wave of snow through on Saturday afternoon/evening, amounting to a few inches of accumulation at worse and then we clear out for Sunday with a mixture of sun and clouds.
HOWEVER the GFS paints a completely different picture. It has clouds increasing on Saturday, but remaining dry, and then a large low pressure system develops offshore on Saturday night bringing snow to the state from very late night Saturday through Sunday afternoon. The GFS solution would result in widespread 6"+ totals with 10" possible in spots.
So what's going on here? Well there is an upper level disturbance (shortwave) moving from west to east across the Mid-Atlantic in both scenarios. There is also low pressure system moving up from North Carolina in both scenarios. So they agree on that much at least.
But here's where they differ: The EURO moves that shortwave quickly over Maine only to link up with that larger ocean storm over Cananda. So the EURO only hits us with the light snow from the shortwave itself, never the coastal low. Meanwhile the GFS is slower to push that shortwave along so it essentially stalls out and waits for the coastal low. Then they link up to the east of Maine creating dynamic forcing for snow right over our heads.
Who wins? As you know, I like the EURO more in general but we are in that foggy zone between the medium range (where EURO is king!) and short range (where the GFS scores better). To further complicate things they are both doing essentially the same thing with the atmosphere, one is just doing it a bit faster than the other. In the end I like some snow on Sunday, probably in the 3-6" range for most. It's a bit of a compromise solution because I don't look at either of these models and think "Well you can throw THAT forecast out." I like making strong calls when I have a strong feeling, but this isn't one of those situations.
They'll be some computer model watching over the 24 hours...if they can agree by tonight I'll let you know.