First, let’s cut right to today’s temperatures: highs 45-60, coolest northern mountains, warmest far southern New England. With that out of the way, let’s dive into details with the system making its way here.
This system is a combination of a low near the Great Lakes and the remnants of Hurricane Patricia.
Rain will begin making its way into New England, from southwest to northeast, late this morning through mid-evening. By late evening the rain should have overspread the region; expect the worst of the storm to be between 1-7 AM Thursday morning, in time for the start of the Thursday rush hour. Rain will taper to scattered showers through midday Thursday, with the event being all done by late evening Thursday.
Expect a widespread 1-2″ of rain, with 2-3″ in localized spots. The rain will be heavy at times, which may lead to localized ponding of water; high PWATs (highly moist atmosphere) – and these are very high PWATs for late October!! – will allow for this heavy rain, and high vertical velocities at times support this. The heaviest rain will occur between 1-7 AM Thursday, when the combination of high PWATs and high vertical velocities, among other favorable aspects, will exist. Rain will taper to scattered showers around midday Thursday.
With screaming winds aloft, some of these will mix down to the surface; expect winds becoming southeast with gusts mostly up to 40 mph in the lower elevations inland with localized gusts to 60 mph; and gusts mainly to 50-55 mph with isolated gusts to 60 mph at the coast and in the mountains. This may be enough to knock down some small tree limbs, blow around very loose lawn furniture, maybe even take down a weak power line (this would be most likely caused by a tree limb/branch though); and will likely cause a big mess in your yard, bringing down the foliage (raking season!) as well as lots of sticks. There may be higher gusts within embedded thunderstorms (see “Severe” section).
With high shear and high helicity in place, especially at the low levels, there will be a severe weather threat for Thursday morning. Limiting factors here will be mostly unimpressive instability; however it may be good enough to fire off a few embedded thunderstorms. With that high shear/low CAPE setup potential along with good helicity, we may see some isolated wind gusts 60-70 mph in a scattered thunderstorm or two. A weak/brief tornado is not out of the question. This threat will continue to evolve as we get closer; stay tuned for my update later today. In recap, expect the potential for an isolated severe thunderstorm.
Minor to moderate coastal flooding is likely at the high tides today and tonight, due to the recent full moon, strong SE winds and this low pressure. Coastal flood advisories are in effect for the SNE coast as well as the NH coast for today’s midday high tide and a coastal flood advisory is out for the SNE coast for tonight, while NH and Maine’s coastlines are under a coastal flood watch for that timeframe.
Another update coming some time this afternoon or evening – half day of school in Dracut today.
Enjoy your Wednesday morning!