NOTE

Today’s blog update is about 7 hours later than typically, and despite the ongoing storm system, very little has changed with my ongoing discussion and forecast. Because of that, I am using a copy / paste / edit of yesterday’s blog with necessary omissions and adjustments to serve as today’s update. Sunday’s update will be a fully re-written one.

DAYS 1-5 (SEPTEMBER 26-30)

Our block-driven storm is underway and will continue to impact our region through Monday before we see it exit and a shift to a much calmer set-up as we reach the final couple days of the month. But make no mistake. Despite the “slow start” to this storm, which, by the way, was anticipated, it will still pack quite a punch in the overall sense, particularly for coastal areas which see strongest winds and impacts from heavy surf and resultant flooding in prone areas. Even inland, strong wind gusts can take down some tree limbs, compromised whole trees, and result in power outages. Low pressure intensifies south of New England while blocked by high pressure to the north. The upper low associated with the surface low will capture it and it will take a track westward, south of Long Island, entering the NJ / Delmarva area by later Sunday, before looping and coming back to the east northeast as a weakening low, crossing far southeastern New England Monday night and exiting during the early hours of Tuesday. This will be followed by high pressure building in toward the middle of next week with fair and milder weather, favorable for post-storm cleanup / recovery operations.

A summary of expected impacts from the storm: Rough surf and elevated tides in coastal areas, enhanced by astronomical higher tides due to the full moon. We’re just beyond the midday high today, but high tides late tonight, Sunday midday, late Sunday night, and even Monday’s cycles can see minor to moderate flooding in prone areas. Wind gusts will be strong enough for isolated to scattered pockets of tree damage (and some property damage), with strongest gusts along the coast and in higher elevations. See numbers in the detailed forecast below. Timeline remains the same in the steadiest rain occurring Sunday / Monday but as the winds start to slacken, especially Monday. Much calmer conditions are expected thereafter. Rainfall amounts for the entire event (through Monday night): 1-3 inches with pockets of 3-6 inches. Some of this is banded so there can be fairly significant rainfall gradients over relatively short distances.

TODAY: Cloudy with areas of rain and bands of heavier downpours including a thunderstorm chance, though clouds can thin / break enough for brief sun here and there. Highs 59-66. Wind NE 15-30 MPH with gusts 35-45 MPH inland, 25-40 MPH with gusts 45-60 MPH coast.

TONIGHT / SUNDAY: Overcast but a few breaks in the clouds can occur in some locations. Showery rain, heavy at times. Slight chance of thunderstorms. Temperatures generally 56-63. Wind NE (may shift more E at times), 15-30 MPH inland with gusts around 40 MPH, 25-40 MPH coast with gusts 45-55 MPH and isolated gusts as high 60-65 MPH (Blue Hill and exposed coastal areas), starting to diminish later Sunday.

SUNDAY NIGHT / MONDAY: Cloudy. Periodic rain. Lows 53-60. Highs 60-67. Wind NE 10-20 MPH inland, 15-30 MPH coast, higher gusts continue.

MONDAY NIGHT: Mostly cloudy. Rain tapers to showers the ends. Areas of fog. Lows 52-59. Wind N diminishing to under 10 MPH.

TUESDAY: Mostly cloudy to partly sunny. Highs 63-70. Wind W up to 10 MPH.

TUESDAY NIGHT: Partly cloudy. Patchy fog. Lows 50-57. Wind SW up to 10 MPH.

WEDNESDAY: Mostly sunny. Highs 68-75. Wind S 5-15 MPH.

DAYS 6-10 (OCTOBER 1-5)

Fair, warm October 1 daytime with a shower chance that night. Fair, mild October 2-3. Rain chance later in the period as the pattern which will be more zonal will take a low pressure system this way from the Midwest.

DAYS 11-15 (OCTOBER 5-9)

Zonal flow pattern. A couple systems can bring shower threats but overall pattern is dry, seasonable to mild.