Nor’easter To Bring Heavy Rains, High Winds Possible Flooding To Southern New England

BOSTON (CBS) – And away we go! It seems that nor’easter season has begun. Late October often serves as a “warm up” for the impending winter storm season. You can almost set your seasonal clock by it.  The list of big storms in the last two weeks of October in Boston is nearly endless.

Just in the last 4 years:

• Halloween Eve, 2020: 4.3” of snow in Boston, a record for the date
• October 17, 2019: A storm so deep and powerful Boston recorded its lowest barometric pressure ever for the month of October
• October 27, 2018: A wet and windy nor’easter
• October 29-30, 2017: Another case of bombogenesis with massive wind damage and hundreds of thousands without power

And then of course how could we forget…

• October 2012, Hurricane Sandy
• October 2011, Snowtober
• October 1991, The Perfect Storm

Year after year, October serves up some of the best weather New England has to offer for the first three weeks and then hits us with a reminder that winter is coming.

And that brings us to 2021 and our first nor’easter of the young season.

After one of the wettest summers ever in the Boston area, October has been spectacular. Plentiful sunshine, low humidity and 23 straight days at or above average temperatures to start the month. And, right on cue, the last week of October arrives with not one but two big East Coast storms and days of rain and wind.

Our primary concern with the Tuesday/Wednesday nor’easter is by far the wind. Sure, we will likely get several inches of rain, but likely not enough for any massive flooding. We certainly have had plenty of practice dealing with street flooding since the start of summer here in southern New England.

The wind with this event could reach 70 mph in parts of extreme southeastern Massachusetts and could easily top 50 mph across the rest of Eastern Massachusetts. The effects of the wind and the damage caused are often exacerbated in October with many leaves still on the trees. Picture each leaf as a mini sail capturing the wind from the nor’easter and helping to sway the limbs and trees.

There’s a big difference between 50-70mph wind in October and say November or December when the leaves are all on the ground. Think back to the amount of damage caused in 2011 in the “Snowtober” storm. That was also preceded by a mild stretch and therefore many leaves remained on the trees.  There won’t be any snow with the storm, but there will still likely be quite a bit of tree damage and power outages.

Some good news – the tides are astronomically very low during this storm. Had it been the reverse, we would have been looking at a major coastal flooding problem given the long fetch and duration of the northeast winds.

Having said this, even though we are in the low portion of the tide cycle, there still is likely to be some minor flooding and splashover at the typical prone areas.

TIMELINE:

Overnight Monday night through Tuesday morning.

• Still waiting on the storm.
• Periods of rain, mostly light
• Winds out of the east-southeast, generally 10-20 mph at the coast
• No travel issues expected

Tuesday afternoon

• Storm arrives
• Rain becomes steadier with a heavier band likely rotating south to north through the afternoon and PM commute
• Winds increase hour by hour, steady out of the northeast 15-35mph with gusts to 50+mph along the coastline after 4 p.m. and 20-40 mph inland after 4 p.m.
• PM commute Tuesday expected to be very wet, some street flooding possible especially south of Boston

Tuesday evening/overnight

• The peak of the storm
• Heaviest rain lifts north and now is centered along and north of the Mass Pike. A total of 1-3” of rain possible in the overnight hours in those areas.
• Strong, damaging northeast winds all night long.
• Peak gusts 60-70 mph over Coastal Plymouth county, Cape Cod and the Islands
• 50-65 mph in most of Eastern MA, inside Route 128, strongest right at the coastline
• 30-50 mph inland from I-495 north and west
• Expecting dozens of reports of trees and limbs down and numerous power outages
• Very poor travel overnight, lots of flooded roadways and rain coming in sideways near the coast

Wednesday morning

• Storm winding down, winds still damaging
• The heaviest rainfall will exit by 7-9 a.m. (likely north of Boston) and the rest of the morning will feature lighter showers and drizzle
• The winds will continue to be damaging through Wednesday morning. No significant let up yet. Same gusts as above (overnight).

Wind damage can also be incremental…the longer you experience damaging winds, the more damage you get as the hours wear on. I fully expect the reports of downed trees, limbs and outages to continue through Wednesday morning.

The Wednesday morning commute will improve from a water standpoint with most of the street flooding subsiding. However, with the wind staying active, many of the streets will be littered with downed limbs and leaves

Wednesday PM and beyond

• Finally we start to get some improvement
• The rain is essentially done, just left with scattered pockets of light showers and drizzle

By late Wednesday afternoon the winds will have peaked and will gradually (slowly) come down with each passing hour. By 8 p.m. Wednesday, coastal gusts should peak out around 40 mph and inland between 20-30 mph.

Beyond that, things quiet down Thursday and Friday. The winds remain a bit busy Thursday near the Coast but below damaging thresholds.

Then our attention turns to the next storm, in part, the remnants from the storm that has been battering the West Coast over the last few days. Right now it doesn’t appear to be anywhere near as strong or concerning as storm No. 1. More on that storm later this week.

As always, we urge that you stay tuned for updates before and during the storm on WBZ-TV, CBSBoston.com and CBSN Boston

Click here for Westford snow storm data and past totals or select “Winter Snowfall“ under “Pages” on the left hand side.

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