Today will feature chilly temps and continued unsettled weather as a storm system lingers just off Cape Cod. The first round of precipitation associated with that system has moved well northeast of the area as of 6 AM so most of us are seeing either dry conditions or a very light drizzle. These conditions will remain in place over the next few hours before an upper level disturbance arrives around noon. Once that disturbance gets here, expect showers to develop again over the Maine coast and adjacent parts of the foothills. Showers will initially fall as rain (especially right near the coast) but as cold air surges in from New Brunswick, expect a changeover to snow. Minimal accumulations are expected but up to 1″ is possible where stronger snow showers linger. This band of snow showers will slowly drift southwest this evening, bringing some precipitation into southeastern NH by sunset. High temps will be quite chilly today, ranging from a little below 30 in the north to around 40 in far southwestern NH.
I wanted to end this post with a quick note about last night’s storms. They were, well, unexpected certainly by me and perhaps by a few others too. I took a look through some of the data I analyzed yesterday morning with the benefit of hindsight. Should it have been obvious that thunderstorms would occur? The answer is that based on available forecast model data, it wasn’t entirely obvious. There was a layer of instability forecast between 10,000 feet and 30,000 feet, but it was extremely weak. That type of instability would only support thunderstorms if there was a strong forcing mechanism to push air upwards independent of thunderstorm updrafts. With the storm responsible for producing last night’s precipitation decaying >500 miles to our west, it wasn’t clear that we’d be able to manage such robust upward motion. That said, in retrospect I think I should’ve mentioned the possibility for thunder in southern areas. Hopefully you enjoyed the surprise fireworks, I know I did despite the fact they highlighted a mistake of mine.
Stay home and stay healthy everyone.