Oct 19, 2016 10:38 PM
NH1 First Alert Weather: Showery Outlook, Windy Weekend
NH1 Chief Meteorologist
High pressure is parked off the coast Thursday morning, providing enough dry air to allow for at least a little sunshine this morning. As the high moves east into the Canadian Maritimes it will set up an easterly flow over most of New England and make for a much cooler day compared to Wednesday. As the upper trough approaches from the west it will spread cloud cover in from the west, initially just high clouds but lowering through the day. The combination of cloud cover, cooler temperatures aloft, and an onshore low level wind will keep temperatures in the 50's and Lwr 60's though the day. Oddly enough, this will be very close to normal high temperatures for this time of year. As clouds thicken through the day, eventually some showers may spread in during the afternoon, mainly in northern and western areas along a sharpening frontal boundary near the Canadian border.
The onshore wind will provide increasing low level moisture and clouds, but for the most part the more substantial rain should hold off. Some areas of rain and drizzle will be more likely Thursday evening, and the potential for some heavier rain into early Friday morning as a warm front begins lift north into New Hampshire. Temperatures do not cool very much Thursday night with low temperatures in the upper 40s to low 50s
A deep, long wave trough continues to dig over the Ohio Valley during the extended portion of the forecast. As energy drops into the base of the trough, the system continues to back and deepen with an area of low pressure developing over PA Friday night. This allows a deepening storm to occur along the southern New England coastline early Saturday morning. Rain will enter the region Friday and become more widespread Friday night into Saturday morning. We will have to watch for localized bands of heavier rainfall. The eventual track this low takes will play a large part in the upcoming wind and where the heaviest rain falls this weekend. I would expect a fairly ugly day Saturday with rain eventually ending during the afternoon. This weekend will turn from Rainy to Windy.
As the low begins to lift out of New England, gusty low level wind in excess of 40 knots will develop as the system departs central and northern New England on Saturday and early Sunday. Winds will pick up Saturday afternoon-evening. All areas will receive strong wind gusts by Sunday. Downed trees and power outages will be possible this weekend with WNW gusts 30-50 mph. Areas with peak foliage will likely be stripped of some of their leaves.
A significant shot of cooler air will enter the region late this weekend and early next week with high temperatures falling into the 40's and Lwr 50's for high temperatures.