DAYS 1-5 (OCTOBER 20-24)

We enter the next unsettled weather episode today and stay in it through the weekend as we are in the zone of “weather evolution”, i.e., a complex system consisting of 3 parts (both upper level and lower level) interacting and joining forces. The end result is a powerful autumn low pressure area, but as previously stated, this end result doesn’t really take place until the system is beyond our latitude. We’ll see showers, focused to the west and more numerous later tonight, from one area of low pressure lifting northward along the coast into our region. Another round of more widespread showers occurs on Saturday as a frontal boundary and secondary low (to the primary one further northwest) get going while the main upper trough lifts through the region. As the upper trough goes “negative” (tilts to the left if you’re looking at it on a weather map), the surface low will deepen more rapidly over the Gulf of Maine while lifting toward Atlantic Canada. As this process goes on, we’ll dry out as the wind across the region shifts to the west behind the axis of surface low pressure. The old low becomes part of an elongated trough connected to the newer, stronger low, and as the process finishes up in our region, this trough axis will swing back to the southeast and cross the region later Sunday through Sunday night, bringing one more round of rain showers. The coverage on these showers will likely be highest across southern NH and northeastern MA, as they will be drying out as they head southeast, so coverage will likely drop as you go south and east. Regardless, the system has exited by early Monday, leaving us with a windy, chilly day, with fair weather (sun and passing clouds). High pressure then builds over the region for fair and more tranquil weather Monday night and Tuesday. This set-up should allow for a fairly widespread frost Tuesday morning.

TODAY: Early sun especially east central and northeastern MA to southeastern NH, otherwise clouds take over with isolated to scattered rain showers this afternoon, favoring areas west of the I-95 belt. Highs 60-67. Wind S 5-15 MPH.

TONIGHT: Mostly cloudy. Scattered to numerous rain showers likely, highest coverage west of I-95. Areas of fog. Lows 53-60. Wind SE 5-15 MPH becoming variable under 10 MPH.

SATURDAY: Cloudy. Areas of fog early. Periodic rain showers in the morning. Widespread rain showers in the afternoon. Highs 60-67. Wind variable up to 10 MPH early, then E 5-15 MPH, higher gusts along the coast, becoming variable again before shifting to W by evening.

SATURDAY NIGHT: Breaking clouds but still a passing rain shower possible in the evening. Lows 45-52. Wind W increasing to 10-20 MPH, higher gusts.

SUNDAY: Lots of clouds, breaks of sun. Rain shower chance is highest in southern NH then increases into northern MA later in the day. Highs 52-59. Wind W 10-20 MPH, higher gusts.

SUNDAY NIGHT: Mostly cloudy with widespread to numerous rain showers southern NH and northern MA becoming scattered to isolated as they push to the south during the evening. Clearing overnight. Lows 42-49. Wind NW 10-20 MPH, higher gusts possible.

MONDAY: Sun and passing clouds. Highs 52-59. Wind NW 10-20 MPH, gusty.

MONDAY NIGHT: Clear. Fog patches in lowest elevations and especially over lakes/ponds. Frost likely especially outside urban centers and away from the immediate shoreline. Lows 35-42, 28-35 in normal cold spots. Wind NW 5-15 MPH early, diminishing to calm.

TUESDAY: Sunny. Highs 56-63. Wind calm early, then SW up to 10 MPH.

DAYS 6-10 (OCTOBER 25-29)

High pressure shifts offshore providing fair weather and a mid-week warm-up. A frontal boundary should pass through the region at some point later in the week, with a much lower rain chance than previous systems, but a shift in wind bringing in cooler air from Canada around the final weekend of the month.

DAYS 11-15 (OCTOBER 30 – NOVEMBER 3)

Low confidence outlook but leaning toward high pressure providing fair weather the last couple days of October, and a trough / frontal system bringing some unsettled weather somewhere in the first couple days of November.