Good Old Fashioned Nor'easter...
Not sure if you recall some of the blogs from last week when we were saying that this storm seemed easier to call than the Norlun event last weekend...well it's true. More or less a classic set-up...storm system rolling up from the Gulf of Mexico and energy diving in from the west inducing rapid cyclogenesis off the Mid-Atlantic and eventually our coastal waters. The track of the intensifying low should pass very close to Nantucket early Wednesday morning then onto Nova Scotia by Wednesday night. This is a good snow track for us...in fact I love the position and track of the 850mb low for the Boston to Providence coridoor...the strongest low level jet and associated overrunning in the cold air should occur about 50 miles from the center which is pretty close to the PVD to BOS line...gotta love it snow lovers! The meat of the storm should hold off until 06Z or maybe even slightly after even though some flurries and light snow will probably be floating in around midnight we are looking at a 3AM to 3PM Wednesday meat of the storm. I kind of hate the fact that we just had a blizzard because everything will pale in comparison to that...widespread wind and coastal flooding...18" plus...but this is going to be a solid thumping! While we won't reach blizzard criteria...blizzard-like conditions are possible at times during the height of the storm Wednesday morning. We won't, however, have the coastal issues...tides are at their astronomical lows for the month thankfully!
I need to address mixing...this is the one wildcard that could change our very confident thinking nearly 36 hours out. First and foremost I'd really like to see a stronger high pressure cell to our north...it's going to be relatively weak...so I'm not confident on true ageostrophic flow. With that said, there will be plenty of cold to draw on from all directions (except the water obviously)...in fact high temps tomorrow won't get to 32 in most locals...we are looking at highs in the upper 20s to near 30. With the current track, as the storm gets closer, a flow of air off the water will turn snow and or sleet to rain over Nantucket and likely the Mid and Outer Cape with, at the very least, heavier wet snow for the Upper Cape and South Shore which would keep ratios much lower in those parts so amounts will range from 3-6" in the rainy areas to 6-10" in the wet snow zone close to the coast. For the rest of us, I see it either side of a foot...more precip in Boston than in Worcester but the snow consistency will be totally different...lower ratio (10 or 12 to 1) in Boston...higher ratio (20:1) in Worcester...so totals should be similar. Also, some of our model members have been showing a more western solution to the track which would obviously allow for a warmer solution...that is a trend we will be watching and at the moment is really the largest concern we have for this forecast not verifying.
