Cool, Damp Weekend for New England Before Warmer Weather Next Week

As of Saturday morning, New England's weekend nor'easter is pushing through western portions of southern New England. A very pronounced dry slot has developed to the east of the center of the storm. Mostly dry conditions will likely persist into the afternoon for eastern Massachusetts, Rhode Island and southern New Hampshire, outside of a few showers or thunderstorms. On the north and west side of the storm, rain will fill in and fall steadily through much of the day.

Below: HRRR showing potential weather early this afternoon:

The storm is playing as expected as these setups tend to produce their heaviest and most widespread rainfall on their north and west sides. On the west side of the system, cooler conditions will prevail, which will favor a longer period of steady rainfall. Areas on the east side look to get within the system's warm sector, which would result in rain becoming more scattered in nature.

Areas on the west side tend to see more stratiform rain (which is rain that's generally continuous and uniform) while the east side will tend to see more convective rain (which results in brief scattered downpours between longer periods of lighter showers or dry conditions, caused by warm air rising along a warm front). Within the warm sector, breaks of sun will even be possible in the afternoon. Areas within the warm sector could see a few thunderstorms pop up as well.

As the system races northward, areas that saw a break in the rainfall early in the afternoon will likely see more numerous showers wrap back around the system late in the afternoon or evening. While that occurs, western New England will likely continue to see steady rainfall, which is expected through the entire day. Vermont in particular will likely see an all-day washout. In the evening, the pronounced dry slot will likely have pushed into Maine, bringing a drier evening to the state before showers fire back up for the overnight.

Below: HRRR showing potential weather this evening:

The highest rain totals will be just to the west of the storm track. The storm still looks to drop a good 1-2 inches across westernmost New England, centered over Vermont. A half inch to inch is likely across the coastal plain. Some terrain enhancement is possible within the Green Mountains, bringing localized higher amounts as well. Like last week's storm, this would have been another big snowstorm had it blown through a few months ago.

The overall flooding threat remains on the lower end. Rainfall totals have trended up for western New England, which has introduced the possibility of scattered and localized flash flooding. The phasing of the southern and northern stream troughs will enhance the band of heaviest rainfall over western New England. The Weather Prediction Center has placed much of Vermont in the “slight” category (level 2 of 4) for excessive rainfall. Despite the uptick in rainfall totals, river flooding is still not expected.

While the nor'easter will lift north and east by Saturday night, the upper-level, cutoff low will linger just to the north through Sunday, resulting in continued cool conditions with plenty of clouds and some showers. With the low to the north, the best chance for some lingering showers on Sunday will be across the northern tier of New England. A cool flow will be present behind a cold front and northwest flow.

After this system passes, a gradual warm-up to summer-like temperatures continues to look likely through next week. New England's trough will shift well offshore and allow for a period of expansive ridging to New England's south and east. This will result in a very warm and mainly dry flow.

With high pressure offshore, sea breezes may keep the coasts a notch cooler, but widespread 80s continue to look likely for the middle of next week away from the coasts. The one issue that could derail this is if the ridge pinches off the departing trough and creates a new cutoff low. This outcome is becoming increasingly less likely as confidence builds on the warm-up, but it's not 100% locked in quite yet.