A cold front currently in place across the Canadian border marks the dividing line from summer to fall. Clouds have been thickening with spotty light showers and sprinkles falling tonight in advance of this front. Saturday had highs near 80 with winds from the SW. By Sunday, winds will be shifting to the NW with a noticeable cooler breeze.
By dawn on Sunday, the cold front will lie across SNH. Plenty of morning clouds will still be in place. It may still trigger a few early morning light showers especially at the coast. By noon, the cold front will be pushing off the coast, with cooler drier more stable air following in for the afternoon with a breezy NW wind which will pick up during the mid afternoon hours. Skies will increase with sunshine from N-S during the afternoon with highs ranging from 70-76 degrees. Warmer temps will be found south of Boston and in SE MA.
Unseasonal cooler air will be steered in from Canada Sunday night with building high pressure. Lows will drop into the lwr-mid 40’s overnight with diminishing wind. Some colder unsheltered valleys may even drop into the 30’s by dawn on Monday. So expect a chilly start at the bus stop! Bright sunshine is expected Monday with high pressure directly overhead. Highs will remain cool holding mainly in the 60’s to near 70 with a definite feel of fall in the air.
As the high pulls off the coast, warmer SW winds will begin to develop. Tuesday will see more in the way of clouds as a warm front approaches, with warmer overriding the cooler air at the ground. There may be few early showers in advance of the front. Highs will climb back into the mid-upper 70s with a brighter afternoon. Behind this front, strong warm air advection along with SW winds at the surface will push temps well into the 80’s nearing 90 by Wednesday with partly sunny skies. The increasing heat will come with humidity with dewpoints climbing to near 70. This airmass will have many of us seeking cool places for relief. A definite feel of summer. There is the potential for a few late day scattered storms, bit they should be mostly confined to the far N & W.
Thursday will be the day of the front and the day with the most instability. The atmosphere will be juiced with high moisture at the surface, a cold front pushing through, and energized upper level winds. The ingredients are there for the potential for some strong to possibly severe weather on Thursday. The only question is the amount of sun we see. Clouds could inhibit instability. But if Partly sunny skies greet the morning, expect the potential for strong/severe storms in the afternoon. Highs will still range from 80-85 degrees.
Once this front pushes off the coast, it is back to the fall-like airmass with falling dewpoints and more comfortable air coming back in from Canada. Friday will see highs in the mid 70’s. near 70 on Saturday with more sunshine. A touch of frost may be in place early Saturday and early Sunday in sheltered N & W valley locations with the cool air once again moving back in as we continue the transition to late summer and early fall.
And of course, the tropics still remain very quiet. If we do not get a hurricane in the Atlantic basin by Sept. 11th, it will be the quietest start to a hurricane season since the beginning of satellite history which began in 1967. Impressive and odd all at the same time, considering all the catastrophe talk that was thrown about after Hurricane Sandy. We have not had a major hurricane make landfall on the US coastline since hurricane Wilma in the record breaking 2005 season. A prolonged drought from major land falling storms. It makes you wonder about all the claims from so called “experts” about what they really know about how these storms will behave in the future. I think the best way to know your future is to know the past! So despite the quiet start to this season, history shows…it only takes one storm to change our lives…and there is still plenty of time left on the calendar for a storm to ride up the east coast. Preparation for these storms is critical for those most vulnerable at the coastline.