Thump of Snow Today for Northern New England; Watching This Weekend

Precipitation chances will increase from west to east beginning this morning in the mid to late morning hours. This will steadily spread east through the afternoon hours. Precipitation will reach northern New England first, with the low pressure system moving north of New England. Rain and snow showers may not arrive in southern New England until the afternoon.

Below: HRRR showing potential weather around mid-afternoon today (1st image) and late this evening (2nd image):

The fast-moving nature of the system will be the biggest limiting factor for snowfall, with a widespread 1-3 inches across interior New England. A zone of 3-6 inches will be likely across the Green and White Mountains, as well as northernmost Maine. Overall, guidance seems to be trending a bit colder, which is not a surprise given models almost always underestimate how stubborn cold air can be to scour out in these setups ahead of time. This may allow for mixing or freezing rain to occur farther south across southern New Hampshire and northern Massachusetts for a time.

The jackpot zone will likely be the southern Green Mountains and the White Mountains. These areas will stand the best chance to see 4-8+ inches of snow. These areas will also likely pick up additional snowfall Thursday when an upslope snow shower event begins in the wake of this system. Winter weather advisories have been upgraded to winter storm warnings for southern Vermont. Winter weather advisories were also moved south a level in Maine to account for the colder trend.

Overall, this will be an elevation-based snow event, with a deep warm layer across the lower terrain and gradually becoming colder moving up in elevation. Places like the northern Worcester Hills, Monadnocks and Litchfield Hills may stand to pick up a quick inch or two before warmer air becomes deeper and a switch to a rain/snow mix or plain rain occurs or precipitation ends out-wright.

This will be a quick-moving system with a majority of New England done with precipitation by midnight Thursday. With that said, the upper-level low will remain to the north of New England. This will aid in creating broad-cyclonic flow and an upslope snow shower event for the northern New England mountains on Thursday and potentially into Friday. This will help to tack on additional snow totals for the mountains and ski resorts.

Elsewhere, the drier air mass should prevail, but broad cyclonic flow will still promote breezy conditions with puffy cloud development in the afternoons. Friday will certainly be colder than Thursday as cold air advection continues behind the system. Highs on Thursday may be seen in the morning with temperatures falling through the afternoon. This will depend on the timing of the cold front.

Heading into this weekend, the next northern stream system in this parade will pass to the north of New England (or through northern New England). Another system may begin to take shape off the coast of the Mid-Atlantic at the same time. The level of interaction between these two systems will ultimately determine what plays out.

Should these systems interact more, the system to the south would be pulled farther north, and a more widespread, accumulating snow would occur. Should these systems leave each other alone, the southern system would likely get suppressed south of New England, with only lighter and scattered snow showers from the northern stream occurring.

Guidance has been flip-flopping on these scenarios all week. Over the past 12 hours, the general trend has been toward a better chance of minimal interaction and a low-impact system. With that said, we're still in the flip-flopping stage, and guidance will need to hold this trend of decreasing chances for a more impactful storm through the day today before confidence begins to increase.

It's very possible the system trends right back north again. Just last night, things looked like they may have been heading in this direction before the overnight guidance. There's also the "in-between" scenario, which would see the storm come close enough to bring only southernmost New England accumulating snow.