Uncle...
A new month may be about to start...but nothing seems to be changing. Our stormy Winter pattern isn't quitting this week and we are in for potentially three storms this week.
A dramatic baroclinic zone is fueling storm formation in the middle of the country where two storms are forming. The first one will pass by tomorrow producing a solid fluffy swath of warm advection snow. The QPF is expected to be a little over .5" liquid which with a normal 10:1 ratio would be around 6" but I expect fluff with this one due to lingering arctic-like air, good moisture and lift in the best snowgrowth zone. This will put most of the area in a 6-9" swath. The 850mb 0C line sneaks up into extreme SE Mass so some rain will limit amouths...3-6 Plymouth and Bristol Counties and 1-3" SE Mass. Storm one will be in here first thing tomorrow morning between 6-8AM.
Storm two will be more powerful...not only warm air advection precip but it will also have upper level support to supply additional lift. This will come in first thing Wednesday morning. Storm one will be able to erode some of the low level cold so it will make it easier for mixing to work farther up from the south so far up that I expect sleet to make it up into Boston Wednesday midday. North and west of Boston it should remain mostly snow and fluff will once again play a role in amounts. South and east of the city sleet and freezing rain will make for some very icy conditions. There will be a really nice cold high to our north...in a good spot...so it should be able to dam the cold in at the surface and a big ice threat exists south of Boston...right now the thinking is southern Plymouth and Bristol counties...farther north sleet should be the predominate mixer. Snow amounts with the second storm look much more difficult due to the mixing but NW of Boston over a foot is likely in Northern Worcester County and the Monadnock region of NH and Southern Vermont...amounts will taper to 6-9" in Boston and much less over SE areas. In fact, it is quite possible that Boston gets more snow tomorrow than on Wednesday.
In the end, Boston still looks to receive 12+" of new snow with the NW suburbs getting 20+".
