Oct 25, 2016 11:51 PM
NH1 First Alert Weather: Another Round Of Rain Ahead, Some Mountain Snow
NH1 Chief Meteorologist
Cyclonic flow over our heads remains in place Wednesday as low pressure very gradually departs. The result will likely be another gusty and cool day along with a few scattered snow showers in the north. Sunny to Partly sunny skies can be expected with highs in the middle 40's. Warmer temps will be closer to the coast, with the coldest air in N & W New Hampshire.
High pressure builds in Wednesday night allowing for decent radiational cooling, especially in the south and west which should bring temperatures down into the 20s for many locales. After a cold start on Thursday, The ridge of high pressure will move rapidly east of the area Thursday as low pressure approaches from the west. Clouds will be increasing with skies becoming mostly cloudy with cool onshore flow keeping highs in the Lwr-mid 40's. A warm front will approach later in the day with showers arriving in the later afternoon. The Berkshires, portions of Vermont will see a burst of snow and some minor snow accumulations.
Our models are in good agreement with a low over Ohio Valley early Thursday morning moving northeast over Lakes Erie and Ontario as it weakens...with a secondary low developing and intensifying Thursday night and Friday in the Gulf of Maine. This will lead to a cold rain across much of the area Thursday afternoon through Friday.
The precipitation should gradually spread northeastward from southwest New Hampshire during the day Thursday and become heavy Thursday night into Friday. The precipitation may start as a little wet snow well away from the coast. Across the higher elevations of the mountains, several inches of snow are possible before a changeover to rain. In lower elevations of the mountains, surface temperatures will be critical to any snow and may depend on the amount of warming that occurs during the day Thursday before the precipitation arrives.
After a rainy Friday, with the heaviest rain happening in the morning...The low will be departing Saturday as a very weak ridge of high pressure crosses the area. Partly sunny skies expected with highs in the Lwr 50's. Warm advection on the back side of the ridge will bring more clouds into the region late Saturday with the threat of rain for Saturday night through Monday morning as another area of low pressure moves east. That is one possibility. There is low confidence on weekend forecast right now. There is a weaker solution which could happen with a few showers Saturday afternoon, evening...and a breezy drying NW wind on Sunday with building high pressure Sunday. We will have a better handle on the weekend outlook I am sure tonight at 5 PM. High pressure will move into the area for early next week with more seasonal air for this time of year. In terms of precipitation, models are currently showing about an inch in most areas for the Thursday through Friday with the possibility for Saturday night through Monday morning. For now, I am choosing to lean a bit more optimistic with weekend outlook until I see more agreement with the models.