DAYS 1-5 (JUNE 21-25)
In case you forgot, summer officially arrives today – solstice 10:57 a.m.! Early this morning a blanket of stratus clouds covers the rising sun from the Merrimack Valley northward, save for a few breaks in the overcast, while a veil of high clouds filters it somewhat along the South Coast, and some stratus patches have also made their way into MA East Coast locations, with a few more patches of stratus in northwestern RI and northeastern CT too. The patchy stratus will dissipate as the high-angle sun rises into the sky, and the more extensive stratus deck to the north will initially be fed by the eastern MA stratus which can increase for a while into mid morning, but otherwise will begin break up before undergoing a transformation into diurnal cumulus clouds as morning becomes afternoon. The onshore flow should eventually prevent these from forming over the coastal plain. Some of the cumulus may grow enough to produce a few showers over the interior higher elevations from southwestern NH through central MA and perhaps as far southeast as northwestern RI, but these will quickly dissipate with the setting sun. With high pressure sliding into the waters to our east, a light east to southeast air flow will allow additional patches of stratus to form tonight as the aforementioned shield of high clouds to the south starts a northward trend. That cloud area, associated with low pressure and a warm front to our south, will thicken as the day goes along Thursday, but right now I expect any of the showers associated with the warm front to struggle against dry air and hold off until late evening or overnight / early hours of Friday. That front will continue a slow northward push and Friday, once prognosticated by model guidance to be a summery day with sunshine and highs of 90+ will actually end up as a mainly cloudy day in the 70s with rain showers. Our weekend is so-so as it stands now. I think the warm front does lift northward through the region by Saturday, with both days at least having a shot of 80+ in all but immediate coastal areas, especially the South Coast, where a southerly air flow will keep those locations sub-80 for high temps. Higher humidity will be noticeable, as we haven’t had much of it so far. Also, it’ll be unsettled, not in the way it was last weekend with upper level and surface low pressure plaguing the region, but this time just from pop up showers and possible thunderstorms, which will become more numerous on Sunday as a cold front slowly approaches from the west…
TODAY: Sun/cloud variety. A pop up shower possible southwestern NH, central MA, and northwestern RI this afternoon. Highs 70-77, coolest coast. Wind E up to 10 MPH.
TONIGHT: Partly to mostly cloudy. Lows 55-62. Wind ESE up to 10 MPH.
THURSDAY: Partly to mostly cloudy. Highs 70-77, coolest coast. Wind SE up to 10 MPH.
THURSDAY NIGHT: Mostly cloudy. Showers possible in southern areas especially South Coast. Lows 60-67. Wind SW up to 10 MPH.
FRIDAY: Mostly cloudy. Scattered showers. Highs 72-79, coolest South Coast. Dew point nearing 60. Wind SE-S 5-15 MPH.
FRIDAY NIGHT: Mostly cloudy. Scattered showers evening. Lows 62-69. Dew point near 60. Wind S up to 10 MPH.
SATURDAY: Partly sunny. Isolated to scattered showers and thunderstorms. Highs 77-84. Dew point 60+. Wind S 5-15 MPH.
SATURDAY NIGHT: Variably cloudy. Isolated showers. Patchy fog forming. Lows 62-69. Dew point 60+. Wind S up to 10 MPH.
SUNDAY: Mostly cloudy. Scattered to numerous showers and thunderstorms. Highs 75-82. Dew point 60+. Wind S 5-15 MPH.
DAYS 6-10 (JUNE 26-30)
Upper level low pressure lifts from the Great Lakes through southeastern Canada, and we’ll be in a southerly air flow with a slow-moving frontal boundary the first part of next week with periodic showers/thunderstorms. This system loses grip with improving weather by later in the week. Temperatures below to near normal.
DAYS 11-15 (JULY 1-5)
There’s a lot of uncertainty in this forecast for the early days of July. Oftentimes it can be really hard to see a persistent pattern just vanish, and I don’t think we’ll see that, but I also don’t think it’ll be as unsettled as previously. I see a few hints that a Rex-type block may return. We have to watch eastern Canada for high pressure, which if strong enough, can trend the region drier but also prevent significant heat. If such a high is too far north, unsettled weather can sneak in as there will still be a tendency for upper level troughing in the Great Lakes to Mid Atlantic, and if, though less likely, the high ended up pushing further south, the door could open up for hotter weather. I see that final “option” as least likely though. Will monitor and give this outlook a better shot in the coming days. For now, I’d lean toward a drier overall pattern with temperatures below to near normal.