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Here We Go Again: Heavy Rain, Wind & Coastal Flooding Incoming: Impacts, Timing

Storm number three of the week is on the way. The storm is currently in the deep south, near Arkansas. The system will shoot northeast the day today and arrive in New England for tonight. With the storm once again passing well inland, New England is placed on the warm side, allowing for another soaking rain and wind event. Like Tuesday to Wednesday, an initial thump of snow is expected. Major coastal flooding is also a possibility.



ALERTS




TIMING


This storm will arrive later in the day than Wednesday's storm did. Precipitation will likely enter into western New England around midnight and quickly begin to spread northeast during the early morning hours. The worst of the storm will take place during the early morning hours for most. By around sunrise, heavy rain will likely be falling across southern and central New England with snow north of Lake Winnipesaukee and across the Green Mountains.


Expected weather at midnight (1st image) and around dawn Saturday 2nd image):


By midday, the storm will be winding down to just scattered showers for most of New England. Maine will be seeing their heaviest rain and snow at this time as the storm continues its quick exit. The Saturday midday high tide could bring significant coastal flooding. By the evening, the storm will be gone and scattered showers will be reduced to northern Maine along with typical upslope snow showers in the Green and White Mountains.


Expected weather around noon (1st image) and Saturday evening (2nd image):



RAIN


There won't be quite as much moisture in the atmosphere for this storm to work with than the last one, but the amount of moisture will still be well above what is typical for winter. With that said, rainfall amounts won't be as impressive with this storm as Wednesday's, but a widespread 1-2 inches is likely across southern and central New England. Rhode Island will stand the best chance of reaching or exceeding two inches.



This rain will add to rivers that flooded and are running high from earlier in the week. As of Friday morning, seven river gauges remain at flood stage in southern New England, including the Pawtuxet River in Rhode Island, which remains at moderate flood stage. A new bout of river flooding is likely by Saturday afternoon in southern New England, despite the lack of snowmelt this time around.


Heading into northern New England, flooding isn't nearly as much of a concern. With lesser rainfall, more snowfall across the mountains and a lack of snowmelt across southern New Hampshire, Maine and Vermont, rivers in these areas are expected to handle the incoming rain without too much of an issue. Some poor drainage and street flooding will remain possible, however.



SNOW


Similar to Wednesday, a front end thump of snow is likely before a changeover to rain occurs from south to north as warm, southern air surges into the region. The White Mountains are again looking to be the jackpot zone, but with less moisture in the atmosphere and a faster moving storm, amounts will be lighter. There is just a 30% chance at the moment that snowfall will exceed 8 inches across the White Mountains.



WIND


The wind threat will basically be a toned-down version of what occurred on Wednesday. The storm will be slightly weaker and the flow in the low-level jet (winds at about 2,500 feet above sea level) will be less than Wednesday. The low-level jet will see winds of up to 90mph, but, as was the case on Wednesday, a temperature inversion will likely prevent the strongest of winds from reaching the ground.


We mentioned this on Wednesday, and because of this fact, power outage numbers were not as high as some expected. A temperature inversion is basically a warmer layer of air above the surface that can act as sort of a barrier that stops the strongest winds from reaching the ground. With this in mind, gusts up to 60mph will be possible along the coast, with scattered gusts of 30-50mph inland.



This setup once again favors a downslope wind event across the western slopes of the Green and White Mountains. Winds may be more easterly in these areas then they were on Wednesday, which would better support a western downslope event. All said, the Green and White Mountains,as well as the Berkshires to an extent,could see gusts of 50-60mph with isolated gusts to 65mph. Vermont will likely see the kind of outage numbers they saw on Wednesday.





COASTAL FLOODING


You can read a more detailed coastal flooding forecast here. The following is a more brief overview


A significant, potentially historic coastal flooding event is possible for northern New England around the Saturday midday high tide. After coastal flooding reached significant levels on Wednesday, forecasts for New Hampshire and Maine come very close to, or exceed those levels on Saturday. A surge of 2.5-3.5 feet will likely occur a few hours before high tide. With such a fast moving storm, even small changes in the expected timing could have big impacts on the extent of flooding, for better or worse.


Major coastal flooding is possible in Hampton, NH and Portland, ME, two areas that were hit very hard on Wednesday with erosion and damage. Moderate coastal flooding will be possible across the rest of the northern New England coastline as well as New England's south coast. Eastern Massachusetts is still expected to fare the best with minor flooding and potentially isolated pockets of moderate flooding.


Portland, Maine reached their third highest tide on record on Wednesday and Saturday's high tide is currently forecast to exceed that and reach 14.1 feet. This would close in on the all-time record high tide for the city, which was set during the Blizzard of 78. Hampton is forecast to be right at where they were on Wednesday. Images and videos of what occurred on Wednesday may paint a good picture of what to expect on Saturday.




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