DAYS 1-5 (SEPTEMBER 20-24)

The final two full summer days and one mostly summer day won’t have a lot of summer feel to them as we are now in a cooler pattern. We felt that cooler air arrive yesterday after a couple warmer days prior. Today’s an unsettled but not totally washed out day. Dry air does the chomp-down on rain as it tries to push in from the west in response to a disturbance moving in ahead of a frontal boundary, but while many of the model precipitation depictions showed a wash-out by late morning on, we won’t really see a whole lot of steady rainfall until the system has moved about half way through our region and is entering its back half, and that will mainly occur late this afternoon and early this evening, and rainfall amounts should and likely will be lower than most guidance indicated. Previous thoughts were for a slower evolution of this part of the system with wetter weather for Monday, but I’ve shifted this as it does appear that frontal boundary will push things far enough east and south to set us up for a mainly dry Monday. This is when high pressure becomes established to our north and low pressure evolves to our south in a blocking set-up. We then watch to see if low pressure can get close enough to push any additional rain into our region through the middle of the coming week. I think it will be held mostly to the south, but can be close enough at times so that its cloud shield limits sunshine, particularly Tuesday and Thursday (as it looks now). The autumnal equinox marks the start of fall at 8:05 p.m. on Tuesday.

TODAY: Mostly cloudy. Rain chances favor west and south of Boston afternoon. Highs 65-72. Wind SE up to 10 MPH.

TONIGHT: Cloudy with some rain in the evening then breaking clouds but patchy fog forming overnight. Lows 53-60. Wind E 5-15 MPH shifting to N under 10 MPH.

MONDAY: Clouds and areas of fog early, then a sun / cloud mix. Highs 61-68. Wind N to NE 5-15 MPH.

MONDAY NIGHT: Partly cloudy. Lows 47-54. Wind NE 5-15 MPH.

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

TUESDAY NIGHT: Mostly to 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 to E 10-20 MPH, higher gusts especially coastal areas.

DAYS 6-10 (SEPTEMBER 25-29)

Blocking pattern remains in place. Watching battle between high pressure to north and low pressure to south. Leaning toward the high winning the battle but low pressure may get close enough for some wet weather in southern areas particularly during the second part of this period based on current thinking. Temperatures near to slightly below normal. A long-lasting fetch of east to northeast wind will likely create rough surf and large swells along the coast many of these days.

DAYS 11-15 (SEPTEMBER 30 – OCTOBER 4)

A mid period rain chance flanked by drier weather episodes. Temperatures variable but mostly near normal.