Accumulating Snow For Eastern Vermont; JRWeather Winter Weather Advisory In Effect

Local Update...
   Moderate Snow Accumulations Expected Across Eastern Vermont Through Sunday; JRWeather Winter Weather Advisory In Effect From 1AM Sunday Morning Until 1AM Monday Morning...


JRWeather WINTER WEATHER ADVISORY
     JRWeather Has Issued A Winter Weather Advisory For Essex, Caledonia, Orange, Windsor, and Windham Counties In Eastern Vermont From 1AM Sunday Morning, Until 1AM Monday Morning.

     A clipper system dropping out of Canada and Into the Great Lakes this evening will slow down, and take on a more easterly track. As this storm tracks east, a weak secondary area of low pressure will form off the Southern New England Coast, helping advect some Atlantic moisture into Eastern Vermont. The low will continue to trek northeast, and up into the Canadian Maritimes by Monday Morning.

     Light snow will develop overnight tonight and become heavier at times Late Sunday Morning and early afternoon. The snow will taper off overnight Sunday. Total snow accumulation by very early Monday Morning will range from 4-6 inches in the Advisory area, with locally higher amounts.

     A Winter Weather Advisory is issued when significant but not severe winter weather is imminent or occurring. In this case the the Winter Weather Advisory is for moderate accumulations of snow. Travel will become hazardous by early Sunday Morning, and continue to be hazardous throughout the day Sunday. Conditions should improve by Mid Monday Morning. Stay tuned for further updates.


DISCUSSION
     A clipper system moving out of Canada will result in the formation of a weak Coastal low, and resultant light snow across much of the region. This wont be a very impressive storm. Just some advisory snow accumulations across eastern Vermont, and near Advisory accumulations for the rest of the area.
     There is some question as to how much moisture the clipper will be able to hold, prior to the secondary low development. Question also exists as to where, and how fast the coastal low will develop. At this point though the heaviest snow appears to fall across eastern Vermont. If more moisture can get into the clipper, or the coastal low develops sooner, stronger, and/ or closer to the coast, then areas further west could pick up some advisory criteria snow amounts.
     The other big factor on how much snow will fall, is the snow to liquid ratio. The best way to explain this is, when we have a snowstorm, its still liquid moisture, the water droplets just freeze, and become snowflakes. So a 10:1 snow ratio would mean 10 inches of snow to 1 inch of liquid. If we received .60" of water equivalent, in a 10:1 ratio storm, this would be how much snow? 6 Inches.
     Now in the fall, and spring, snowstorms are usually a 10:1 ratio. But as we get into the colder months, they tend to be greater ratios, because its much colder, and the snow tends to be drier, and fluffier. So since we are in January, the climatological snow ratios are around 15:1, although its not uncommon to receive up to a 30:1 ratio during January and February, especially with the colder, drier clipper systems. So with all this said, models indicate a .25" to .50" of liquid across New Hampshire edging into Eastern Vermont. Snow ratios for this storm will be around 20:1 This would result in 5-10 inches of snow. But you have to think about the way these systems work, they tend to be a bit drier then what models depict. Although this one will be tricky, depending on when the link to Atlantic moisture occurs. So with that said I down played the liquid amounts to around .20" to .30" across eastern Vermont, resulting in 4-6 inches of snow. Across the remainder of Vermont and northern New York generally liquid amounts will range from .10" to .20", resulting in 2-4 inches of snow. If just the slightest deviation in how much moisture will fall, will result in significant changes to the snowcast. Just think if the Champlain Valley receives and additional .10" of liquid. Just a .10"! That would push them to 4-6 inch snow totals, which is advisory level. So we will keep a close eye on this storm system. Stay tuned for further updates. Updated maps below...


CLICK ON IMAGES TO ENLARGE!