The energy we need to be tracking is still over the Pacific and will be moving over California Tomorrow morning. So models are still trying to get the right data on how to handle the overall set up. By Tomorrow and Tuesday, we will have better data coming in and we will start to have more confidence in the amounts and if this will be a significant significant storm.
By Wednesday, we will have a mid-latitude low pressure center that will be occluding across the midwestern part of the United States. Here is where the storm will peak in intensity and produce blizzard conditions over the upper midwest for a time. Upper level ridging in place across southern Canada with high pressure over the Canadian border will supply plenty of cold air into pattern ahead of this incoming moisture. Early wed morning, 850 temps are -12 to -20 over Northern New England and Canada. Cold air will filter south with NE winds to create a damming effect. Picture a cold dome sliding south. Approaching moisture will run into the dome, lift and precipitation will fall into that cold dome of air as snow.
I am expecting snow spread into New England Wednesday, latest 18 Z runs of GFS are colder and juiced. GFS is printing out between a .50-1" of precipitation...alot falling as snow. The Nam has and even colder look. The Euro is the coldest of them all. So it is with high confidence that we are predicting snow. The question this far out is how much? Also the exact track will determine how much mixing with rain. The GFS has the 0 line push to the Mass Pike Early Thursday morning, with some Warm air advection and rain mixing in at the south coast. While the Euro has the 0 line not even able to push to Long Island. A colder, all snow solution but with a heavier stronger high supplying dry air which may supply have a weakening stringing out effect.
It is still unknown if there will be enough energy to support cyclogenesis offshore. It is hard to say if the energy is going to be able to transfer from the Great Lakes to the coast at just the right time if at all. Such a system though might ramp up precipitation totals even further from New York City, NY to Boston, MA. Those details should will come soon. Right now, we need to let this all settle in for an interesting and challenging bit of weather for the midweek. One thing looks increasingly likely. This will likely be a long duration event, with several impulses riding along the boundary established between the strong damming high pressure over Canada and the weakening low to the west...and possible a strengthening low to our south. There will be ample moisture and cold to work with. Snow is likely...but how much still is remains unclear. Having any confidence in forecasts this far out this winter has proven foolish. We have seen how much things can change within 24 hours.
New England has the best chance for accumulating snowfall. Along and north of the Pike will likely be in the best snow growth regions for substantial accumulations..track dependent of course. If everything comes together just right... some areas could see up to 6 inches of snow or more...but let's just rest on this for now.
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