DAYS 1-5 (JUNE 5-9)

Surface high pressure to the south and an upper high pressure area overhead combine to give us another bright, very warm day today. Saturday’s conditions continue summery, but we see an increase in both cloud cover and humidity with the approach of an upper trough and surface front from the northwest. This surface and upper pair will progress through our region from Saturday night through Sunday night, bringing a period of unsettled weather, shifting wind, and eventually introducing a cooler air mass. The process looks a little different than was outline on yesterday’s update, mainly due to the front’s timing being slower and the surface wave traveling along it, originally expected to result in a cloudier, cooler Sunday, now tracking a little further north and holding the front back before pulling it through during the second half of Sunday. This allows for some sunshine for a number of hours on Sunday in a warmer air mass, allowing temperatures to be warmer than they’d have been in the previously-expected scenario. This changes the precipitation style from more widespread and stratiform to more convective and showery. I realize I just tossed a lot of info at you, so if you’re still wondering when the best chances of showers and possible thunderstorms are this weekend, here is your breakdown. The first shot comes Saturday afternoon, mainly north of I-90, but only isolated showers or thunderstorms would develop with a pre-frontal trough moving quickly through the region. The remains of a more solid line of showers and storms to the north and west makes a run at the region Saturday evening, with the most likely impact of any remaining activity taking place after sunset, with decreasing coverage from northwest to southeast. Another round of two of showers and possible thunderstorms could take place during Sunday, with odds favoring the afternoon and early evening hours based on current expected timing. Given the quick changes in the forecast for how this system acts as it goes through our region, I’d pay close attention to the next couple updates just to make sure it doesn’t have any other surprises in store for us this weekend. High pressure builds in with cooler, drier weather Monday, then sinks to the south with a warmer Tuesday following that, along with continued fair weather.

TODAY: Sun often filtered by high clouds. Highs 77-84 South Coast, 85-92 elsewhere but can turn cooler near the shoreline. Wind W to SW up to 10 MPH with coastal sea breeze possible.

TONIGHT: Mostly clear. Fog patches overnight. Lows 58-65. Wind SW up to 10 MPH.

SATURDAY: Partly sunny. An isolated shower or thunderstorm possible west and north of Boston after midday. Highs 86-93 except 78-85 South Coast. Dew point 65+. Wind SW 5-15 MPH, higher gusts.

SATURDAY NIGHT: Variably cloudy. Patchy fog. A shower or thunderstorm possible. Lows 62-69. Dew point 60+. Wind SW under 10 MPH but could be gusty near any showers / storms.

SUNDAY: Variably cloudy. A couple showers and thunderstorms probable, especially afternoon to early evening. Highs 76-83. Dew point 60+. Wind variable 5-15 MPH, can be stronger near any storms.

SUNDAY NIGHT: A shower potential early, followed by clearing. Fog patches form in lower elevations late evening then dissipate overnight. Lows 53-60. Dew point falls through 50s. Wind NW to N up to 10 MPH.

MONDAY: Mostly sunny. Highs 62-69. Wind N to NE 5-15 MPH.

MONDAY NIGHT: Clear. Patchy fog lower elevation locations. Lows 48-55. Wind calm.

TUESDAY: Mostly sunny. Highs 72-79. Wind W up to 10 MPH but potential for coastal sea breezes.

DAYS 6-10 (JUNE 10-14)

While there is an “attempt” at blocking of the omega-style in the upper pattern, it doesn’t have the organization or strength as the previous version. The orientation is further east as well. This allows high pressure to sink south of us with a quick warm-up by the middle of next week before a trough brings a shower & thunderstorm threat about June 11. Late week expectations are for high pressure to return with fair weather, briefly cooler then warming up again. Obviously, confidence in this scenario lowers with time, so catch updates.

DAYS 11-15 (JUNE 15-19)

Moving through mid month and into the final days of astronomical spring, the large scale pattern indications are for a weak high pressure ridge near or just west of our region to allow a trough or two to swing through. The latter would bring brief unsettled weather threats while the former would keep the overall pattern dry and seasonably mild to warm. I can’t rule out a cooler shot if one of the disturbances is stronger or high pressure to the north sends cooler air down from Atlantic Canada, and I’ll watch for both.