Rain, Brief Surge of Warmth Incoming Before Thanksgiving Cool-Down in New England

Moving into tonight, a deep trough will move through the Great Lakes region and into southern Quebec on Wednesday. A surface low pressure system will move northeastward ahead of this trough. This system will likely move west of New England before lifting eastward through northernmost New England. This will make this system an inside runner, dragging its warm front across the region and resulting in a widespread plain rain storm.

Clouds will be on the increase and thicken through the day today, but a vast majority in New England won't see precipitation break out until after dark. Rainfall will move southwest to northeast through the night tonight, arriving in Connecticut and western Massachusetts first. Showers could break out this afternoon in these areas, but the storm will be battling dry air initially that could delay its arrival. The batch of steady, widespread rain will steadily push northeast through the night. The rain is unlikely to get very heavy at any time tonight.

Below: HRRR showing potential weather this evening (1st image) and overnight tonight (2nd image):

The widespread rain will come to an end for pretty much everyone by mid-morning. With that said, New England will remain in the system's warm sector through the day Wednesday. This will lead to generally unstable conditions, so scattered showers may still pop up throughout the day at times. Eastern Maine will see the most widespread rain activity during the day, as the storm (naturally) arrives later and exits later as it moves from southwest to northeast. Southeast Massachusetts and Rhode Island is another spot that may generally see more shower activity during the day tomorrow.

The system's cold front will push through New England later Wednesday through Thursday morning. This cold front may ignite another round of scattered rain and snow showers Wednesday evening through Thursday morning, but it is unlikely to be widespread or too organized. These showers will likely push out of New England from west to east through the morning hours on Thanksgiving.

Below: FV3 showing potential weather late Wednesday evening:

Overall, a widespread quarter to half of rain is likely across the entire region. There will generally be more rain the farther south in New England you go. Some frozen precipitation will eat into rainfall amounts across northernmost areas. With a strong warm front pushing north through New England during this time, temperatures will likely rise after sunset Tuesday, and continue to rise through the day Wednesday. The freezing altitude is expected to push well over 5,000 feet by early Wednesday morning, so all but the highest summits of the Presidential Range will be above freezing.

Temperatures Wednesday afternoon will likely push well into the 50s, with some areas likely making a run for the 60° mark, for central and southern New England. It will be cooler across the northern tier as the area may not fully get into the warm sector before the cold front passes. Temperatures here will likely stall in the 40s, and even maybe upper 30s for northern Maine.

The large-scale setup for Thanksgiving (and into Friday) will feature a mature upper-level low spinning across Quebec. This will result in broad cyclonic flow across the region. With the system's cold front having cleared New England by this time, cold air advection will be steadily ongoing. With that said, stronger cold air advection will likely hold off until later Thursday and peak on Friday. Broad cyclonic flow will support puffy cloud development on Thanksgiving and the potential for some quick, pop-up rain/snow showers. This will be most likely in the mountains.

With stronger cold air advection and an upper low remaining north of New England, upslope snow showers will likely be more prevalent across New England on Friday than they will be on Thanksgiving. More persistent activity is likely across the higher terrain (Greens, Whites and Berkshires, namely). Pop-up sprinkles or flurries will be possible anywhere in New England, however.

Below: RGEM showing potential weather Friday afternoon:

Gusts on Thanksgiving will likely be in the 20-30mph range for most. Friday will likely see more wind as cold air really pours in. Highs will struggle to reach 40° anywhere in the region, and northern areas remaining below freezing, in the 20s and low 30s. The breeze will add even more bite to the air, with 25-35mph gusts. Gusts will be strongest across southern New England on Friday and weakest across eastern Maine. Winds will gradually settle over the weekend, except for eastern Maine, who will see gustier conditions on Saturday as the overall setup shifts east.

High pressure is slated to move toward the region to start off the weekend. This would help bring an end to upslope snow shower activity. Overall, it appears to be a quiet weekend, with chilly temperatures. At this point, New England's next system is slated to approach later Sunday, but being a week out, this system could trend sooner or later over the coming days.

Looking at the longer range forecast, the highest confidence is in the potential for below average temperatures. Very cold air is poised to pour into the middle of the country after the holiday weekend. This air mass will, in all likelihood, migrate eastward to kick off December for New England. The air mass will probably moderate as it moves east, meaning it likely won't be as cold here as it will be in the Midwest, but cold temperatures to some extent will likely welcome us to meteorological winter.