Today, we’ll finally be getting rid of the upper-level low that has brought unsettled conditions to the region since Sunday. However, to do so, we’ll need a cold front to sweep through the region from north to south. That front will provide forcing for ascent for strong to severe thunderstorms especially in northeastern parts of the area this afternoon.
Before we get to the storms this afternoon, we’ll start off with widespread low clouds and fog this morning. Some of this fog is quite dense with visibilities of less than a quarter mile. Low clouds and fog will burn off over the next couple hours, leaving mostly sunny skies by noon.
That sunshine will push temps well above what they have been this week under the influence of the upper-level low. Highs will range from 75 in the mountains and along the coastline to near 90 along the coastal plain. Unfortunately, dew points will surge into the mid/upper 60s which means it will feel hot and muggy.
Any time a cold front slices through a hot and humid airmass, we start thinking about thunderstorms. This afternoon is no exception. Expect showers and storms to begin popping up over the mountains around 2-3 PM before moving southeast later in the afternoon. The central part of the region from Fryeburg to Belfast will be most unstable, and the best forcing for ascent (the initial upward nudge thunderstorms need to develop) will be found over eastern parts of the area. As a result, the best chance for strong thunderstorms will be found over central/eastern parts of the area from Penobscot Bay north into Somerset County and west towards the Lewiston/Farmington corridor.
This is generally consistent with model forecasts. That said, I also suspect we’ll see a few storms initiate from terrain forcing over the White Mountains before proceeding south-southwest into Oxford, Cumberland, and York counties. These won’t be as widespread as the storms farther east, but I think we’ll see at least one or two. Storms today will produce lightning, damaging winds, and heavy rain.
Cooler and drier weather arrives tomorrow.