After a wild weather day yesterday with two brief tornadoes in New England (Clinton, MA and Thompson, CT), and extensive flash flooding, all eyes now turn to tropical storm Henri. A hurricane watch is now posted for the Cape and Islands, southern Plymouth, southern Bristol County and much of southern RI and CT. A storm surge watch is in effect along the South Coast and across Cape Cod Bay too.
Henri becomes a hurricane over the next 24-48 hours as it moves west, then north.
Water temps are very warm off the Carolina and mid-Atlantic coast, and will provide fuel for strengthen as the upper-level winds become more conducive for development too.
While many times these storms curve out to sea, and New England is spared the worst impacts from the rain and wind, occasionally, that escape (out to sea) route gets blocked by a ridge of high pressure to our northeast. That forces these storms move up the east coast, toward New England. Unfortunately, that a ridge of high pressure blocks Henri from racing out to sea. In addition, as an upper-level low to the west influences it’s track, it’ll slow down in forward motion and move a bit northwest. Some of the models with the most strengthening are also the farthest west. If indeed that track is into Long Island vs. RI/MA, it would mitigate some of the highest wind/rain/surge impacts for central/eastern Mass, but still be an impactful storm.
Even if Henri weakens a bit as it approaches the coast, a slow down in motion/pull back toward the coast, can push a lot of water toward the south coast. Combine that with the fact tides are astronomically high, the potential for significant to major beach erosion and coastal flooding is high. Damaging storm surges and damaging wind gusts are the biggest concerns along the south coast. Coastal flooding could be significant too along the east coast, although winds won’t be as strong.
Flooding rains is a concern as the west side of the track will likely pick up 3-6″, isolated 8″ of rain. The ground is saturated, we’ve had a lot of rain this summer, and poor drainage areas and street flooding will happen quick in tropical downpours. Additionally, streams and small rivers will have to be watched for rapid rises when the heaviest rain falls. The exact track will determine who gets the worst wind and rain and storm surge ultimately, it’s too early for town to town specifics, but it’s a good idea to start making preps now. Pull the boat out of the water, check sump pumps and generators, and be prepared in case you lose power. The next couple of days are relative quiet for that aside from an isolated shower.