DAYS 1-5 (SEPTEMBER 21-25)

Today we see the departure of the system that moved in yesterday with mostly light rainfall (though the South Coast saw a bit heavier) as dry air put limits on the system’s ability to produce significant moisture. Clouds linger to start the day, and will break and clear at least partially, leaving a sun / cloud mix and a cool breeze, but nicer weather as we move through the day. Some clouds make a comeback tonight but clear out again on Tuesday – a day nice day for the final hours of summer. The autumnal equinox occurs at 8:05 p.m., marking the arrival of fall. We’re seeing the evolution of a blocking pattern, one not foreign to autumn, but more common in spring, as we move through this week. By midweek, a low pressure area forms to our south while sprawling high pressure is centered to our north. We’ll have to watch the track of that low very closely as it will determine the extent of impacts our area sees. A near certainty now is a persistent northeasterly air flow that will become pretty notable and build the seas, leading to a lot of rough surf and larger ocean swells that can result in coastal flooding / beach erosion by later this week. What’s less certain is how much rain will occur from the system. Many models bring a shield of rain across much of the region around Friday, but guidance often underestimates the influence of high pressure in a blocking pattern and also has been somewhat inconsistent with the track of low pressure, which may remain more elongated (flattened) to our south and never get that intense. If that is the case, the rain, while getting close or getting into southern areas at times, may never fully advance into our region. Important to follow updates as we move through the week…

TODAY: Cloudy start then a sun / cloud mix. Highs 61-68. Wind N to NE 5-15 MPH.

TONIGHT: Partly to mostly cloudy. Lows 47-54. Wind NE 5-15 MPH.

TUESDAY: Mostly cloudy to partly sunny. Highs 61-68. Wind NE to E 5-15 MPH, gusts above 20 MPH coastal and southern areas.

TUESDAY NIGHT: Partly cloudy. Lows 47-54. Wind E to NE 5-15 MPH, higher gusts coastal areas.

WEDNESDAY: Partly sunny. Highs 62-69. Wind NE 5-15 MPH but gusts up to 30 MPH in coastal areas especially to the south.

WEDNESDAY NIGHT / THURSDAY: Mostly cloudy. Lows 47-54. Highs 60-67. Wind NE 10-20 MPH, higher gusts especially coastal areas.

THURSDAY NIGHT / FRIDAY: Mostly cloudy. Rain chances favor the South Coast. Lows 46-53. Highs 60-67. Wind NE 10-20 MPH except stronger Cape Cod / South Coast and higher gusts in all locations.

DAYS 6-10 (SEPTEMBER 26-30)

The blocking pattern remains in place to start the period before weakening and transitioning back toward a zonal (west to east) flow. This means we need to watch for low pressure impact through the weekend (September 26-27). Lower confidence here but after this we should see a weakened or remnant version of low pressure move through with shower chances at mid period followed by dry weather later in the period. However this evolution is not certain so follow updates on trends for the final days of September.

DAYS 11-15 (OCTOBER 1-5)

Low to moderate confidence outlook that October opens up with a zonal flow, a shower chance at first, then fair weather, with a milder trend overall.