Tropical Storm Henri Poses An Increasing Threat To Southern New England On Sunday

Tropical Storm Henri seems to be gradually organizing and strengthening this afternoon and it’s likely to become a hurricane very soon. This storm needs to be watched EXTREMELY closely as it could either make a very close brush by or make a direct landfall in Southern New England on Sunday. Right now, Henri is currently tracking nearly due west and this westward track is likely to continue for the next couple of days. By Friday and certainly this weekend, the weather pattern around Henri is going to become extremely complex as that high pressure ridge moves a little to the east and an upper level trough of low pressure moves into the Ohio Valley. Two big questions still need to be answered with this upper level pattern. One is whether the trough of low pressure takes on a negatively tilted look, which would turn the upper level winds over New England into a southeast to northwest direction. Question number two is whether a blocking high pressure system builds over Atlantic Canada. The reason why these questions are so important is because if this does occur, it would lead to Henri moving nearly due north and even in a northwest direction causing it to make landfall in Southern New England. If that blocking high pressure system does not develop or if the upper level trough isn’t as strong as currently expected by some of the models, then Henri would likely escape and pass well south and east of New England. The current location of Henri and its potential track to the north and even possibly northwest is completely outside of climatology and would be a very unique track. On one hand, this makes me extremely skeptical that Henri will make it all the way into Southern New England like what some of the weather forecast guidance shows. Usually, tropical storm and hurricane hits in New England originate either near the Bahamas or are the long track Cape Verde storms & not a storm that originated near Bermuda. On the other hand, however, the upper air pattern signal for a very close brush or a direct impact from Henri in Southern New England looks legit to me. Saying that, remember that this is still 4 to 5 days away from potentially occurring and a lot can change in that time. There are things that I’ll be watching for – First is whether the south and west trend in the guidance continues as Henri moves into a more favorable environment. The stronger Henri gets, the more westward it’ll track before it turns back to the north. Second thing that I’m watching is whether the upper level trough of low pressure over the Ohio Valley remains oriented in a way (negative tilt) that allows it to capture Henri rather than kick it out into the open Atlantic. The third thing to watch is whether the blocking high pressure system over Atlantic Canada continues to be forecast. If all 3 things continue to show up, then the threat to all of Southern New England is likely to increase. Fortunately, we are going to see more data ingested into the model guidance with Henri. Reconnaissance flights have been scheduled to fly around Henri and special weather balloon soundings have been scheduled. I am hoping that this additional data will help to nail down a forecast track of Henri. Here are my recommendations for now – If you are reading this and live along the coast of Southern New England, especially the Cape/Islands or know of someone that lives along the Southern New England coast, it’s time to pull out those hurricane plans and review them. If you don’t have one, it may be a good idea to come up with one, just in case. For Western and Central Mass, the main threat should be extremely heavy rainfall if Henri does make landfall. This could lead to some big time flash flood problems. The wind threat looks low for now, however, there is that possibility for 40-60 mph wind gusts on Sunday, depending on the exact track of Henri. This, in turn, could lead to some power outage problems. One other bit of information – The full moon is on Sunday, just when Henri would be either making landfall in Southern New England or making its closest pass to Southern New England. This means that the tides will be above normal and thus the flood threat from very high surf and any storm surge would be exacerbated. I continue to watch Henri extremely closely and will continue to have frequent updates for you over the next few days.