Although synoptically (large scale weather) speaking our pattern has shifted to a more active one, you wouldn't know it by stepping outside. A weak cold front came through last night and gave us our first precipitation since November 13th...but it was only a trace. Now are back to generally dry weather for Sunday, Monday and Tuesday before a storm threatens for midweek.
Tonight: Mostly cloudy early but becoming partly cloudy after 10 PM. There are ongoing snow showers across western Maine and northern New Hampshire and they will continue through most of the night across the higher terrain. Accumulation will be minimal, in the dusting-2" range but it's still worth mentioning. Meanwhile temperatures will drop to between 22-28 F statewide by late this evening. It COULD be a lot colder given the current air mass, but the fact that winds will stay gusty overnight will actually act to "mix up" the air aloft and keep us a bit warmer near the surface. West winds: 10-15 MPH.
Sunday: Mountain snow showers may linger through the first few hours of the morning but will quickly dry up by 11AM-Noon. After that look for mostly sunny skies along the coastline with a 50/50 mixture of sun and clouds further inland. Temperatures will be noticeably cooler when compared to Saturday; highs only reaching 35-40 in most spots with a strong west wind providing a bit of a windchill.
Monday: Similar to Sunday but perhaps with a bit more cloud cover due to a weak upper level disturbance moving through. (There could even be a few mountain snow flurries by the afternoon). High temperatures improve a bit to the upper 30s to low 40s.
After a sunny start to Tuesday clouds will increase rapidly by the afternoon in response to a developing low pressure system moving toward Maine.
And here's where Keith has to earn his keep for the first time in 2 weeks...
The computer models DO agree that there will be a weak low pressure system over the Carolinas on Tuesday afternoon. But what they DON'T agree on is the track of this low on Tuesday night/Wednesday.
The GFS model has the low swinging a bit more northeastward and bringing some moderate snow to the coast of Maine and some light snow to the interior. The Euro model (which meteorologists have been pre-teen-girl-1990s-boy-band-obsessed with ever since Sandy) shows a weaker low pressure system that moves almost due east, basically not impacting Maine at all.
Right now I lean towards the GFS a bit and think there will be a light snowfall along the coastline through midweek and the POTENTIAL for moderate snow if the track holds a bit more west. I don't see this being a big storm for Maine no matter how you slice it, but I don't think the system will go completely out to sea.
One of the main reasons is the "inverted trough theory" friends of mine at WSI developed. The concept is that if the computer models show a low pressure system offshore with an inverted trough (basically a spoke of energy sticking out from the storm in a northwest to southeast orientation), the storm will actually track further west than indicated. We aren't sure exactly why this is the case, but there is a good track record of success. And what does the GFS model show with this midweek storm? An inverted trough.
Stay with us on this one either way...it's still 4 days out.
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