Today will feature strong to severe thunderstorms in the afternoon and evening as an approaching disturbance aloft stirs up our extremely warm and humid airmass.
This morning, sunshine will dominate the area ahead of the cold front we’ll be tracking this afternoon. Daytime heating from the strong early-June sun will push temps into the mid to upper 80s for most with some 70s along the Midcoast and some low 90s in the usual SW NH warm spots. With dew points rising into the mid 60s, most spots will feel like temps are in the low to mid 90s.
This warm and humid air, aside from being miserably uncomfortable, is volatile fuel for thunderstorms. An approaching disturbance aloft will provide the necessary nudge for storm development over the mountains in two rounds this afternoon. The first round will be more scattered and will kick off around 1-3 PM in the mountains before moving towards the coast around 3-5 PM. These cells will likely be discrete which means they could produce hail and maybe even a brief tornado in addition to lightning, heavy rain, and gusty winds.
Another round of storms will develop early in the evening over the mountains before heading towards the coast around sunset. This round will most likely be organized into a line of storms better at producing damaging winds than hail.
Since the disturbance responsible for today’s storms will be dropping in from Canada, the best shot at thunderstorms will be north of a Portland-Lebanon NH line. Points south and west just won’t get enough of a prod to jumpstart storm development despite the abundance of thunderstorm fuel.
Not everyone will see storms today and of those that do, not everyone will see damaging wind gusts, but the atmosphere is set up to be supportive of winds strong enough to knock down trees and powerlines in the stronger cells. Make sure you keep an eye to the sky if you’re out and about this afternoon and have a way of receiving warning information if one is issued for your area.