Second, Sunday

Another storm system will move in quickly right behind the storm tomorrow. This one has more energy out west right now, and will rotate into the midwest, with surface low pressure moving across the central plains Saturday morning. 500mb vorticity max wraps around the east side of the negative tilting H5 low Saturday night. High pressure to our north will be weakening and retreating. This will allow the deepening surface low pressure to cut north to the Great Lakes. Secondary low pressure will develop inside the benchmark Sunday morning and rapidly strengthen with energy transfer from the primary low.

High pressure will still be present enough to reinforce cold air for at least interior New England. Right now precipitation type issues are certain for the I95 corridor where snow changing to a wintry mix, and rain is likely, before changing back to snow Sunday night. NW of I95, into central MA, a wintry mix is likely Sunday, with another round of significant ice accretion possible for some of the same areas devastated last week. This will have to be watched carefully. In Keene, current model forecast thicknesses suggest precipitation should stay all snow.

QPF looks like a general .5+" across all of New England, with highest amounts towards the north. In Keene, looking at .8" to 1.0" for water equivalent right now. If the secondary low gets going earlier, could be talking about more. Right now we may get an hour or two of wrap around precipitation Sunday night, but if the low can develop / strengthen quicker, back end snows could be more significant.

Current forecast for snowfall Sunday into Sunday night: 7" to 12"

In addition to snow, the rapid deepening of the secondary low could develop a very tight pressure gradient across northern New England. Blowing and drifting snow will be possible Sunday night into Monday down into southern NH with even blizzard conditions possible further north.