Late-Season Nor'Easter Arrives in New England

Today's nor'easter has taken shape off the coast of the Mid-Atlantic Thursday morning. The system's upper-level low remains back across western New York. As the surface low slowly moves northeast toward Cape Cod today, showers will fill in and become heavier from south to north through the afternoon. It will likely take until Friday morning for rain to overspread much of Maine while the rest of New England sees rainfall throughout today and into tonight.

The bulk of the storm for most will occur this afternoon and evening. The storm will likely reach its maximum intensity overnight tonight as the center of the system crosses near Cape Cod. Several hours of a soaking rainfall is likely for southern and central New England from around noon to around midnight tonight.

Below: HRRR showing potential weather around mid-afternoon today (1st image) and overnight tonight (2nd image):

Widespread rain will likely break apart rather quickly heading into the daylight hours Friday. Around sunrise Friday, the system will likely be once again reduced to scattered showers with the most numerous showers over Maine. The system will be slow to exit, with scattered showers hanging around across New England through Saturday. The drying trend will be a very gradual one with this system, but looks to mostly wrap up by Sunday.

Below: HRRR showing potential weather Friday morning:

Overall, recent trends have pushed the center of the storm a bit farther east. The storm looks to cross New England around Nantucket or the Outer Cape before travelling into the Gulf of Maine and eventually across eastern Maine. This tick to the east does slightly lower rainfall amounts across western New England.

Still, a widespread 1-3 inches of rain remains likely through Saturday for southern and central New England. Amounts of 2 to 3 inches will be more likely the closer you get to the eastern Massachusetts coastline. Amounts will taper moving northward in New England due to drier air and high pressure eating away at the rain as it tries to move in.

Being a nor'easter, gusty winds are also likely with this system. At this point, wind gusts don't look to be overly high, but 40-50mph gusts will be possible, mainly for eastern Massachusetts. Winds of this strength with the trees now fully leafed would cause higher impacts than a similar storm with bare trees in the winter. Winds will dwindle moving away from the coastline. A wind advisory has been posted only for the immediate coastline.

With a strong northeasterly flow, thick clouds and steady rain, afternoon highs will struggle to rise very much at all from morning lows, which will be pretty chilly as is, given the time of year. Many areas will likely struggle quite a bit to reach into the 50s. Daily record cold high temperatures for May 22nd are in the mid 40s to low 50s region-wide. Some of these records are likely to fall. Concord, NH and Portland, ME are interesting ones to watch as both of these cities have record cold highs in the low 50s for May 22. Both cities will really struggle to reach the 50° mark this afternoon.

These very chilly temperatures will help set up the possibility for some late-May snow across the higher elevations of northern New England. It's possible snow levels may drop to as low as 1,500 feet above sea level for a time this evening and into the overnight hours. Accumulating snow should still be limited to the highest mountain summits of Vermont and New Hampshire. Wednesday night and Thursday night will continue to be very chilly as well. The record latest observed snowfall for mountainous counties in New England are all in late May or June.

Below: HRRR showing potential weather late this evening with snowfall potentially developing at elevation across the southern Greens, Whites, Monadnocks and maybe even Berkshires:

This system involves a primary low moving inland through New England with a secondary low forming off the Mid-Atlantic coast and moving northeast over New England's coast. The secondary low will strengthen as the primary low transfers energy to the coastal low. This is a very winter-like storm setup and would result in a widespread snowstorm if this was a few months ago.

The driving easterly wind will create the possibility of some minor coastal flooding as well, mainly across eastern facing shores of Massachusetts. While astronomical tides aren't high, they are high enough where a strong easterly wind could create pockets of minor flooding issues. A coastal flood advisory has been posted for the entire southern New England coast. Overall, a bullet was dodged in regards to coastal impacts as tides remain on the lower end. If this storm came during astronomical high tides, this impact would have been a much different story.

Below: Wind direction and speed this evening around high tide:

The system will keep broad cyclonic flow over New England on Saturday, resulting in plenty of clouds, scattered showers and continued cool temperatures. By Sunday, ridging and high pressure will begin to build in from the west, allowing for drier weather and moderating temperatures. By the middle of next week, the next system will approach, but could get suppressed south of New England.