No change to rainy weather pattern in days ahead

New England has recorded precipitation somewhere in the six-state region for 11 days in a row, and the Boston area for 10 days in a row, and that streak isn’t ending anytime soon.

The culprit is a persistent and recurring weather pattern that is rooted in the jet stream winds aloft – the storm-steering wind, high in the sky, that flows like a river through the upper atmosphere and determines the track of storms, separating cold air to the north from warm to the south. That jet stream pattern has featured a continued “trough,” or dip in the jet stream, from the Great Lakes to the Northeast, with multiple storms slowing as they enter that persistent trough.

The result continues to be areas of showers, rain and thunder that blossom across the Northeast, punctuated by breaks of sunshine, but that sun only serves to warm the land beneath a cold sky aloft, creating sufficient contrast to lead to yet more cloud and shower development. With no meaningful change to the jet stream pattern, this also means no meaningful change to the weather pattern, with rain in the forecast at least somewhere in New England on each of the next 10 days in our exclusive First Alert 10-day forecast! 

Of course, not all showery days are created equal, and both the areal coverage and intensity of showers will vary from one day to the next, largely driven by the proximity of the slow-moving storms, surface and aloft, to New England. Our weather setup Monday features the storm to our west, dropping steadiest rain in western Pennsylvania and New York, but the counter-clockwise flow of air around the storm center encourages a southerly wind through New England, which blows in milder air with highs near 80, increasingly humid air during the afternoon, a few isolated showers in that increasingly moist air, and increased pollution with some modicum of lingering wildfire smoke, reducing air quality to moderate. 

As the slow-moving storm draws closer, the southerly wind will bring more moisture Monday evening and night for increasing showers and a period of rain dropping around a quarter of an inch of rain for many, then breaking into scattered showers on Tuesday. At the surface, a weak area of low pressure will shift the wind Tuesday to blow from the northeast from northern Massachusetts and point north, meaning much cooler temperatures than Monday, while areas south of the Mass. Turnpike are likely to reach the 70s again. 

Even as early morning showers drift north out of southern New England and into the North Country, plenty of atmospheric energy aloft is likely to touch off at least some scattered showers again during the afternoon in central and southern New England. The center of the jet stream level storm will move over New England slowly Wednesday, raising the chance not only for clusters of afternoon showers, but also thunderstorms, owing to the pool of cold air aloft associated with the disturbance.

Amazingly, a new disturbance should drop into the jet stream trough over the Northeast Thursday through Saturday, continuing the chance of scattered showers with embedded thunder possible especially on Friday afternoon, then yet another – albeit weaker – disturbance arrives Sunday into early next week. If enough distance develops between disturbances, New England may see a dry day to break the showery streak, and while Father’s Day Sunday is the most likely day for that to happen, our First Alert Team wouldn’t bet the farm on it – chances are good a shower will develop for at least some of New England that day, too. 

On the bright side, lawns are staying green at this time of year when the strongest sun angle of our calendar year often scorches grass during dry stretches, and temperatures remain comfortable all the way through the 10-day with 70s on most days, and 60s on cooler days.