DAYS 1-5 (SEPTEMBER 30 – OCTOBER 4)

On this final day of September and first day of the weekend we’ll remain under the cloud canopy of low pressure located to the south of New England, but the wet weather associated with it will be confined mostly to areas south of I-90 to start the day, with a drying trend as the day goes on. The clouds will begin to thin out and break from northwest to southeast as we get into the afternoon, but probably not enough for any appreciable sun, only some partial sun in areas well to the north and west of Boston. Complete clearing takes place during the nighttime hours though, albeit slowly, as the low pressure area finally starts to pull further out to sea. October arrives and the weekend wraps up Sunday with a very different day. We’ll have lots of sun, some fair weather clouds, and pleasant air as high pressure builds in. This high pressure area will then be in control of the weather the early to middle portion of next week with sunny, mild days, and clear, cool nights.

TODAY: Overcast through early afternoon with periods of rain favoring areas south of I-90. Clouds thin and break especially north and west of Boston later in the day where a glimpse of sun is possible. Highs 58-65. Wind NE 5-15 MPH.

TONIGHT: Slow clearing northwest to southeast. Patchy low elevation fog. Lows 45-52. Wind N up to 10 MPH.

SUNDAY: Early fog patches dissipate otherwise sunny to partly cloudy. Highs 68-75. Wind variable up to 10 MPH.

SUNDAY NIGHT: Clear except ground fog patches forming. Lows 48-55. Wind variable under 10 MPH.

MONDAY: Sunny. Highs 69-76. Wind W up to 10 MPH.

MONDAY NIGHT: Clear. Ground fog patches interior lower elevations. Lows 47-54. Wind NW under 10 MPH.

TUESDAY: Sunny. Highs 72-79. Wind NW up to 10 MPH.

TUESDAY NIGHT: Clear. Ground fog patches interior lower elevations. Lows 47-54. Wind NW under 10 MPH.

WEDNESDAY: Sunny. Highs 71-78. Wind N up to 10 MPH.

DAYS 6-10 (OCTOBER 5-9)

Dry weather and above normal temperatures to start the period with high pressure in control, but as high pressure slips to the east a southerly air flow increases the humidity and cloud cover ahead of a cold front, set to pass through the region sometime during October 7. A shorter-duration rain shower threat would accompany this. This will be followed by a cool air mass from Canada along with some gusty wind at least initially. A secondary push of cool air may arrive at the end of the period.

DAYS 11-15 (OCTOBER 10-14)

A little more confident now in calling for a drier pattern with high pressure in control much of the time, and a cool start followed by a milder trend.

DAYS 1-5 (SEPTEMBER 29 – OCTOBER 3)

And one more bout of unsettled weather will squeeze in just before the door closes on September. Once again low pressure to our south will be the culprit, and with the help of an upper trough swinging through the region, we’ll see an inverted trough extending northward from low pressure first bring a showery rain to the region today, focused on areas south and west of Boston. Heaviest rainfall with this portion of the event is likely to occur southwest of the WHW forecast area, focused on western CT to the NYC area. As low pressure starts to organize to our south and drift northeastward, the rain area will shift to a more general one focused from the I-90 belt southward, depositing the most significant amounts in the South Coast region tonight while some lighter amounts fall further north, ranging down to hardly any at all once you get to northeastern MA / southern NH. High pressure begins a push southward as the upper and surface lows begin their exit during Saturday midday on, so we’ll start to see improvement at that point, from north to south, with the rain last to end later in the day along the South Coast, especially Cape Cod. Sunshine will start to return from north to south, but may run out of time before reaching the South Coast. It will finish clearing out there during the night though, and this will set the region up for a very nice finish to the weekend on Sunday, with abundant sun, some fair weather clouds, and comfortable air. High pressure then has complete control with fair, milder weather early next week.

TODAY: Mostly cloudy. Rain showers move in from the south during the day, favoring southern and western areas. Highs 60-67. Wind E 5-15 MPH.

TONIGHT: Cloudy. Periods of rain evening, becoming steadier overnight, heaviest near and south of I-90. Patchy fog developing overnight. Lows 50-57. Wind E-NE up to 10 MPH.

SATURDAY: Cloudy start including a chance of additional rain especially from the I-90 belt southward, then rain exits and clouds break for sun north to south midday on, but clouds likely linger along the South Coast for longer. Highs 58-65. Wind NE-N 5-15 MPH.

SATURDAY NIGHT: Clear except foggy areas low elevations. Lows 45-52. Wind N under 10 MPH.

SUNDAY: Early fog patches dissipate otherwise sunny to partly cloudy. Highs 68-75. Wind variable up to 10 MPH.

SUNDAY NIGHT: Clear except ground fog patches forming. Lows 48-55. Wind variable under 10 MPH.

MONDAY: Sunny. Highs 69-76. Wind W up to 10 MPH.

MONDAY NIGHT: Clear. Lows 50-57. Wind NW under 10 MPH.

TUESDAY: Sunny. Highs 70-77. Wind NW up to 10 MPH.

DAYS 6-10 (OCTOBER 4-8)

Dry weather and above normal temperatures continue as high pressure maintains control of the weather through mid period, then looking ahead a frontal boundary and trough swing through with showers followed by a Canadian cool shot to end the period, based on current expected timing.

DAYS 11-15 (OCTOBER 9-13)

The trend is still there for stronger Canadian high pressure in control more often and less opportunity for low pressure to the south to impact the region. With slight hesitation I lean in this direction as a drier pattern with variable temperatures from a front or two passing by in a westerly flow aloft.

DAYS 1-5 (SEPTEMBER 28 – OCTOBER 2)

High pressure will hang on with fair weather today, but we’ll see another day of filtered sun, first from lingering high altitude wildfire smoke from Canada, then the arrival of additional high clouds in advance of our next round of unsettled weather. As the upper winds turn more southerly tonight into Friday, we’ll see the smoke be pushed away just in time for the clouds to thicken up. Additionally, early this morning and again tonight we’ll see some patches of low clouds and radiation fog from the light wind and radiational cooling. Eventually later Friday, lower clouds will make an appearance from the ocean on an east to northeast wind as the low levels moisten up. The biggest question to answer: How much impact from low pressure to our south? I think an inverted trough helps bring the most pronounced axis of moisture, initially in the form of showery rain, into the Hudson Valley and western New England, mostly to the west of the WHW forecast area, with a lighter and more scattered rainfall pattern to the east as we move through Friday. And then as an upper trough swings into the region it helps organize a surface low to our south, close enough for a more stratiform rain event, but far enough so that the best coverage of this will be from the I-90 belt southward, with the greatest threat for highest rain amounts in the South Coast region. I’m also still optimistic that despite a potentially cloudy and wet (especially to the south) start to Saturday, the low will begin to wheel away significantly enough so that the weather improves markedly from midday on. I still have to refine the details in the forecast after I’m more certain of this, which I will do on tomorrow morning’s update. And this is how September comes to a close, with another bout of unsettled weather. Ironically as October opens, we’ll see high pressure begin to dominate and we enter a stretch of dry and milder weather starting on Sunday and beyond.

TODAY: Areas of low clouds and fog dissipating by mid morning, otherwise smoke-filtered sunshine. Increasing high clouds later in the afternoon. Highs 62-69. Wind N up to 10 MPH shifting to E.

TONIGHT: High-altitude smoke exits as clouds increase. Patchy ground fog. Lows 47-54. Wind E under 10 MPH.

FRIDAY: Mostly cloudy. Rain showers move in from the south during the day, favoring southern and western areas. Highs 60-67. Wind E 5-15 MPH.

FRIDAY NIGHT: Cloudy. Chance of rain, favoring areas near and south of I-90. Patchy fog. Lows 50-57. Wind E-NE up to 10 MPH.

SATURDAY: Cloudy start including a chance of additional rain mainly from the I-90 belt southward, then rain exits and clouds break for sun north to south midday on, but clouds likely linger along the South Coast for longer. Highs 58-65. Wind NE-N 5-15 MPH.

SATURDAY NIGHT: Clear except foggy areas low elevations. Lows 45-52. Wind N under 10 MPH.

SUNDAY: Early fog patches dissipate otherwise sunny. Highs 68-75. Wind variable up to 10 MPH.

SUNDAY NIGHT: Clear except ground fog patches forming. Lows 48-55. Wind variable under 10 MPH.

MONDAY: Sunny. Highs 69-76. Wind W up to 10 MPH.

DAYS 6-10 (OCTOBER 3-7)

Several days of dry weather and above normal temperatures with high pressure dominating the region at the surface and aloft. Late-period approach of frontal system and trough returns the chance of unsettled weather to the region.

DAYS 11-15 (OCTOBER 8-12)

A little trend in the medium range guidance for a little stronger high pressure from the north and an upper trough near or east of the region with low pressure pushed further south than previously depicted. This would be a mostly dry but cooler pattern. A little hesitant to jump on this as a lasting pattern but more as a shot of cool air early in the period followed by a moderation. Will monitor guidance trends.

DAYS 1-5 (SEPTEMBER 27 – OCTOBER 1)

At dawn this morning, temperature ranged widely from the upper 30s across interior lower elevations to the lower 60s on the outer part of Cape Cod. As sunshine dominates the landscape today under high pressure, the temperature will even off across the region as they rise significantly from the chilly inland lows and rise modestly from the mild coastal area lows, so that these areas will have a fairly similar high temp in the middle 60s. Outside of those details, the general idea is nice weather is finally here and will be with us today and tomorrow under the influence of high pressure. One thing about our sunshine though, it will be filtered at times by additional high altitude wildfire smoke from Canada as their long fire season goes on. Additionally, we’re still in “that pattern”, which means we have to keep an eye on something that can turn the weather unsettled to prevent a longer stretch of fair weather. Once again we’ll be keeping an eye on low pressure sitting south of New England as a low pressure trough swings eastward from the Great Lakes and Ohio Valley late this week. This trough will help develop that low which will have an inverted trough with it extending northward as if it’s trying to grab onto New England. There is some variety in the guidance we look at as to how this feature is going to behave and impact our region, but right now it looks like it will at least give us more cloudiness from Friday to early Saturday, and at least the chance of a period of wet weather favoring areas south of I-90 with highest chance in the South Coast region. Some fine-tuning is obviously needed in the short term and I’ll have a more detailed breakdown of this on the next update. I am pretty confident though that this episode will not mimic the coverage and length of time of the last one – this being a much shorter-lived bout. High pressure builds in again for the return of fair weather as we move through the weekend.

TODAY: Mostly sunny. Highs 61-68. Wind N up to 10 MPH.

TONIGHT: Mostly clear. Patchy ground fog interior low elevations. Lows 47-54, 40-47 in some lower elevation locations. Wind N under 10 MPH.

THURSDAY: Mostly sunny. Highs 63-70. Wind N-NE up to 10 MPH.

THURSDAY NIGHT: Mostly clear early, then clouds return later. Patchy ground fog interior low elevations. Lows 48-55. Wind variable under 10 MPH.

FRIDAY: Mostly cloudy. Chance of rain by late in the day, favoring southern areas. Highs 60-67. Wind E 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy. Chance of rain, favoring areas south of I-90. Patchy fog in valleys, swamps, and bogs. Lows 50-57. Wind SE under 10 MPH.

SATURDAY: Clouds give way to sun. Highs 65-72. Wind E up to 10 MPH.

SATURDAY NIGHT: Clear except foggy areas low elevations. Lows 45-52. Wind calm.

SUNDAY: Early fog patches dissipate otherwise sunny. Highs 68-75. Wind variable up to 10 MPH.

DAYS 6-10 (OCTOBER 2-6)

A little more confident in a drier weather pattern during early October. Temperatures variable, starting out above normal then dropping back toward normal after a cold front delivers a Canadian air mass mid period.

DAYS 11-15 (OCTOBER 7-11)

The large scale pattern still maintains the tendency for high pressure to our north and low pressure to our south, and while the trend remains for the high to exert more influence and our pattern to stay on the drier side, we still remain vulnerable to a northward push of low pressure from the south bringing a period of wetter weather at some point. Temperatures near to above normal.

DAYS 1-5 (SEPTEMBER 26-30)

We’ve gotten rid of the low pressure area, formerly Ophelia, that plagued the area with more rain at times the last 3 days, but today we keep a lot of clouds from a northeasterly air flow supplying low level moisture while a disturbance rides over the top of that across the region. High pressure builds in for midweek with fair weather and finally plenty of sunshine, but we may have a stop at a proverbial weather toll booth on Friday as that low pressure hanging around to our south nudges northward enough to bring at least a mostly cloudy sky and possibly some wet weather into the region. With luck, and I think luck will be on our side, we’ll see the high pressure to the north re-establish control and push that out of here in time for the start of the weekend on Saturday, which is also the final day of the month.

TODAY: Lots of clouds. Partial sun develops later. A sprinkle or patch of drizzle possible. Highs 59-66. Wind NE 5-15 MPH.

TONIGHT: Clearing. Lows 45-52 except 37-44 some interior low elevations. Wind N under 10 MPH.

WEDNESDAY: Mostly sunny. Highs 60-67. Wind N up to 10 MPH.

WEDNESDAY NIGHT: Mostly clear. Patchy ground fog interior low elevations. Lows 47-54. Wind N under 10 MPH.

THURSDAY: Mostly sunny. Highs 63-70. Wind N-NE up to 10 MPH.

THURSDAY NIGHT: Mostly clear early, then clouds return later. Patchy ground fog interior low elevations. Lows 48-55. Wind variable under 10 MPH.

FRIDAY: Mostly cloudy. Chance of rain, favoring southern areas. Highs 60-67. Wind E 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy. Chance of rain in the evening. Patchy fog. Lows 50-57. Wind SE under 10 MPH.

SATURDAY: Sun/cloud mix. Highs 65-72. Wind SE up to 10 MPH.

DAYS 6-10 (OCTOBER 1-5)

No big changes here. Still optimistic that high pressure dominates with a drier pattern and a seasonable to mild temperature trend for the first few days of the month, then a weak cold front from Canada bringing in cooler air later in the period. All the while we watch the tendency for low pressure to hang around to our south and hope it stays down there this time…

DAYS 11-15 (OCTOBER 6-10)

Cautious optimism continues about a continued drier pattern with temperatures near to slightly above normal, but somewhat variable. Still we’ll be in a pattern that needs us to eye low pressure to our south at times.

DAYS 1-5 (SEPTEMBER 25-29)

One more day. Just one more day. …for now… So here we are still in the midst of another stretch of unsettled weather like so many we’ve seen in the past few months. This one which started during the weekend stretches through today as the remains of what was TS Ophelia pass just to our south as an elongating, weak area of low pressure. This feature will still cause rain in the region today, with the focus of it in the I-90 belt southward, though lighter rain can and likely will occur to the north of there in at least patchy form until as late as mid afternoon. After this we will finally see a steadier push southeastward of the rain area, which will exit off the South Coast this evening. While we start to feel the influence of Canadian high pressure building toward the region tonight and Tuesday, we’re going to have a northeasterly air flow, and one more upper disturbance swinging through too, so I still think we’ll see only partial clearing tonight and a lot of clouds hanging around Tuesday. I can’t rule out a sprinkle or patch of drizzle with the combination of the disturbance and the northeasterly air flow, but for the most part, once we get rid of today’s rainfall, it’s dry. High pressure builds right over the region by midweek with fabulous weather. Once we get to Friday, we’ll already be eyeing disturbed weather hanging around to our south, but so far the indications are stronger this time that it will remain to the south and high pressure will hold it off…

TODAY: Overcast through mid afternoon with periods of rain, steadiest I-90 belt southward. Clouds start to thin/break north and west with rain ending northwest to southeast late in the day. Highs 58-65. Wind NE 5-15 MPH.

TONIGHT: Partial clearing. Lows 47-54. Wind NE 5-15 MPH.

TUESDAY: Lots of clouds / partial sun. A sprinkle or patch of drizzle possible. Highs 59-66. Wind NE 5-15 MPH, higher gusts possible.

TUESDAY NIGHT: Clearing. Lows 45-52. Wind N 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 60-67. Wind N up to 10 MPH.

WEDNESDAY NIGHT: Mostly clear. Patchy ground fog interior low elevations. Lows 47-54. Wind N under 10 MPH.

THURSDAY: Mostly sunny. Highs 63-70. Wind N-NE up to 10 MPH.

THURSDAY NIGHT: Mostly clear. Patchy ground fog interior low elevations. Lows 48-55. Wind variable under 10 MPH.

FRIDAY: Partly sunny. Highs 63-70, coolest coast. Wind E 5-15 MPH.

DAYS 6-10 (SEPTEMBER 30 – OCTOBER 4)

Optimistic route being taken with this outlook in the thought that high pressure will maintain control of the weather with an extended dry stretch and temperatures near to a little above normal. Sometime toward the end of the period a cold front from eastern Canada may deliver cooler air but with only a brief shower threat. Can things go “wrong” with this outlook? Yes, because the large scale pattern is still one that leaves us needing to keep an eye out to our south for things potentially missed by guidance.

DAYS 11-15 (OCTOBER 5-9)

Cautious optimism about a continued drier pattern with temperatures near to slightly above normal, but somewhat variable.

DAYS 1-5 (SEPTEMBER 24-28)

We sit in the lull between part 1 and part 2 of our latest stretch of unsettled weather to open autumn. The advanced moisture plume associated with Ophelia – which made a NC landfall as a strong TS and has since weakened, become post-tropical, and drifting northward – put up a battle against dry air eventually getting most of the region into the rain area during Saturday. The next moisture plume, more directly associated with the remnant low, will overspread our region slowly as the day goes on today, peak tonight and early Monday, then get pushed out from northwest to southeast as Monday ages, finally exiting via the South Coast by the evening hours. Upper level low pressure swings across the region Tuesday, but fairly uneventfully other than some additional cloudiness, and then finally high pressure builds in with a stretch of dry weather beginning at midweek.

TODAY: Cloudy. Areas of drizzle and fog. Periods of showers and rain redeveloping from southwest to northeast during the afternoon hours. Highs 57-64, coolest eastern coastal areas. Wind NE 5-15 MPH.

TONIGHT: Cloudy. Areas of drizzle and fog. Rain becoming most widespread. Lows 50-57. Wind NE-N 5-15 MPH.

MONDAY: Cloudy through mid afternoon with rain gradually diminishing northwest to southeast. Breaking clouds / partial clearing later in the day but may never reach the South Coast. Highs 60-67. Wind N 10-20 MPH.

MONDAY NIGHT: Variably cloudy. Lows 50-57. Wind N 5-15 MPH and gusty.

TUESDAY: Lots of clouds – intervals of sun. Highs 60-67. Wind N 10-20 MPH and gusty.

TUESDAY NIGHT: Clearing. Lows 46-53. Wind N 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 60-67. Wind N 5-15 MPH.

WEDNESDAY NIGHT: Mostly clear. Patchy ground fog interior low elevations. Lows 47-54. Wind N under 10 MPH.

THURSDAY: Mostly sunny. Highs 63-70. Wind N-NE up to 10 MPH.

DAYS 6-10 (SEPTEMBER 29 – OCTOBER 3)

High pressure will provide fair weather for the final 2 days of September along with warming temperatures. The first couple days of October are vulnerable to low pressure getting close again from the south with potential unsettled weather, but should move out again by the end of the period. That part of the forecast remains low confidence.

DAYS 11-15 (OCTOBER 4-8)

Overall outlook is fairly dry with high pressure again in general control. Temperatures near to slightly above normal.

DAYS 1-5 (SEPTEMBER 23-27)

Autumn arrived at 2:50 a.m. with the equinox occurring, and our new season will get underway with something familiar – an unsettled weekend. However, today is not going to be a washed-out day for a good part of the WHW forecast area, and the reason is one that was outline previously as this tough forecast was being formulated over the last handful of days. Coming to pass is the source of dry air at mid levels born of “confluent flow” between high pressure in east central Canada and a low pressure trough to its east. This drying effect is pronounced in northeastern New England, i.e., Maine, with that dry air being transported southward into southern New England just as a rain shield, far in advance of Ophelia (a named system set to make landfall in NC). Basically, the forecast for “part 1” of the event today is the same: Rain shield to the South Coast early morning, then slowly advancing northward as the day goes along, but struggling to do so against dry air. The most solid rain shield will remain south of I-90 and the steadiest rain will indeed be closer to the South Coast. Once you get north of I-90, as the rain tries to move in there, it will be eroded by the dry air being supplied from Maine (a-yeahp), and once you are around the MA/NH border, you may not see anything more than sprinkly very light rain which struggles to even dampen the ground. By the time it even gets up there, the dry air still holding on and the tailing off of the initial rain plume will just clear the region of any rainfall this evening, with just patchy drizzle becoming more likely due to a persistent northeast flow from the Atlantic. Even that will take all day to get its act together, so I’m not expecting a lot in the way of low clouds/drizzle until after dark, and first closer to the eastern coastal areas before it can penetrate inland. Meanwhile, Ophelia will have gone inland in the Southeast and the low will rapidly weaken and start to dissipate, also losing any tropical characteristics. The remnant low will then emerge off the Mid Atlantic Coast and travel south of New England later Sunday and early Monday, when we have our best chance of rainfall across the region. When this is all done, I expect 1 to 2 inch rainfall amounts along the South Coast, dropping off to around 1/2 inch in the I-90 belt and less as you go north from there, again with a good amount of that coming in part 2, especially northern areas. High pressure from Canada will push the wet weather out of here during Monday, though I’m not sure how much clearing we might see later Monday. Will revisit and refine that tomorrow. Also, we still have an upper disturbance that has to swing through the region Tuesday which may also result in a fair amount of cloud cover, but only a remote chance of a light shower, remote enough that I still don’t have it in my forecast. Finally, dry, bright, cool weather arrives by Wednesday as the high pressure area in southern Canada takes full control.

TODAY: Cloudy. Rain South Coast all day, advancing northward with time. Highs 60-67, coolest eastern coast. Wind NE 5-15 MPH, higher gusts likely especially Cape Cod.

TONIGHT: Cloudy. Any lingering rain ends / dissipates. Areas of drizzle/fog overnight favoring eastern coastal locations. Lows 52-59. Wind NE 5-15 MPH, higher gusts near the South Coast.

SUNDAY: Cloudy. Areas of drizzle and fog. Periods of rain. Highs 57-64, coolest eastern coastal areas. Wind NE 5-15 MPH.

SUNDAY NIGHT: Cloudy. Areas of drizzle and fog. Periods of rain, again favoring southern areas. Lows 50-57. Wind NE-N 5-15 MPH.

MONDAY: Mainly cloudy morning with periods of rain, best chance south and east. Partial sun may develop afternoon. Highs 60-67. Wind N 10-20 MPH.

MONDAY NIGHT: Variably cloudy. Lows 50-57. Wind N 5-15 MPH and gusty.

TUESDAY: Lots of clouds – intervals of sun. Highs 60-67. Wind N 10-20 MPH and gusty.

TUESDAY NIGHT: Clearing. Lows 46-53. Wind N 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 60-67. Wind N 5-15 MPH.

DAYS 6-10 (SEPTEMBER 28 – OCTOBER 2)

High pressure will provide fair weather for the final 3 days of September as we see a gradual temperature moderation. The end of the period may see low pressure trying to push back toward our region from the south, introducing the possibility of unsettled weather, but this is a low confidence outlook at this point.

DAYS 11-15 (OCTOBER 3-7)

Potentially unsettled start to the period followed by a drier trend again. Temperatures near to slightly above normal.

DAYS 1-5 (SEPTEMBER 22-26)

High pressure remains in control with another day of very nice weather for the final full day of astronomical summer. Autumn arrives at 2:50 a.m. Saturday with the vernal equinox (the moment the sun is directly over the equator on its journey to the southern hemisphere, where its their first day of spring). For the weekend, we turn our attention to a moisture plume associated with low pressure well to our south. While this low center, which may acquire enough tropical characteristics to be named, drifts to the coast of NC where it moves onshore there, its associated moisture plume elongates northward in a southerly flow aloft and makes a charge at southern New England. At the same time, an amplified higher latitude pattern with a high pressure ridge in east central Canada and a deepening low pressure trough further east in Canada will create a road block of sorts for the moisture / storm to the south. One surface high (the one governing today’s weather) will slide to the southeast and leave a little weakness in the pressure field to aid in the rain’s northward progress as we get to early Saturday, but as this is happening a second surface high to the northwest of it will begin pushing toward New England. So now you see the set-up for a tough day 2 forecast – just how fast and how far north does the rain push before it gets obliterated by dry air supplied by the systems to our north? Earlier onset / best chance of steadiest rain and most amounts will be the South Coast region, while the further north you go the onset time, ability to maintain steady rain, and ability to generate measurable rain drops off quickly, as well as the amount of time this can occur, because by Saturday evening the dry air to the north should already be in the process of slicing right into the rain area. On regional radar it will look somewhat like the rain splits in two with one area drifting into NY while another peels off to the east off Cape Cod. Either way you see it, we have a dry interlude where it rained, and continued dryness in any areas the rain never quite reaches. The greatest chance for the latter are places from around the MA/NH border into NH where it may only sprinkle lightly or not rain at all from the initial push of rain. All during this, with high pressure to the north and low pressure well south southwest of our region, we’ll set up a cool northeasterly air flow with below normal temperatures for the weekend. Patches of drizzle can evolve eventually, favoring the east-facing coastal communities where the wind will be directly off the ocean. This is most likely to happen later Saturday night into Sunday. During Sunday and Sunday night, and into early Monday, what remains from the low to the south will make its way northward through the Mid Atlantic, and then as a remnant low into the waters south of New England. It’s during this time when our region can see additional periods of rain along with continued areas of drizzle and some developing fog, though the gusty wind that had developed especially along the South Coast during Saturday will ease off some, because low pressure will be much weaker. Eventually, the stronger features to our north will push that remnant low away later Monday, but we still have to wait for upper level low pressure to cross the region through Tuesday. This means Monday would probably remain generally cloudy even if it starts to dry out in terms of rain chances, and Tuesday would be day that if any sun was to shine, it would help trigger lots of clouds, but I think the air would be dry enough to prevent much shower activity from developing. Those days will also feature a continuation of below normal temperatures for the early days of autumn. Also, the wind that had eased off a little Sunday would pick back up again as the pressure gradient tightened up behind now-regorganizing low pressure and the high to the north and west.

TODAY: Sunshine becomes filtered through an increasing shield of high clouds. Highs 66-73, coolest coast. Wind variable becoming E up to 10 MPH.

TONIGHT: High overcast. Low elevation ground fog patches. Lows 47-54. Wind E under 10 MPH, calm in some low elevations.

SATURDAY: Overcast may be thin enough for some sun in the morning-midday especially north of I-90 otherwise thickening overcast with time. Rain likely South Coast, tries to push north but very slowly and may struggle to get to areas north of I-90 doing so only as patchy and light. Highs 61-68 with a cool-down to under 60 especially near east-facing shores by late in the day. Wind E to NE 5-15 MPH but 15-25 MPH South Coast including late-day higher gusts around Cape Cod.

SATURDAY NIGHT: Cloudy. Any lingering rain ends / dissipates. Areas of drizzle/fog overnight favoring eastern coastal locations. Lows 52-59. Wind NE 5-15 MPH, higher gusts near the South Coast.

SUNDAY: Cloudy. Areas of drizzle and fog. Periods of rain, favoring the South Coast to I-90 region. Chance of rain at times further to the north. Highs 58-65, coolest eastern coastal areas. Wind NE 5-15 MPH.

SUNDAY NIGHT: Cloudy. Areas of drizzle and fog. Periods of rain, again favoring southern areas. Lows 50-57. Wind NE-N 5-15 MPH.

MONDAY: Mainly cloudy. Best chance of rain southeastern areas morning. Highs 60-67. Wind N 10-20 MPH, a few higher gusts possible.

MONDAY NIGHT: Breaking clouds. Lows 50-57. Wind N 5-15 MPH and gusty.

TUESDAY: Lots of clouds – intervals of sun. Highs 60-67. Wind NW 10-20 MPH and gusty.

DAYS 6-10 (SEPTEMBER 27 – OCTOBER 1)

High pressure builds in from Canada with a stretch of dry weather from mid week to at last the start of the weekend (September 30), but may have to watch to our south once again for low pressure threatening the region with rain by the end of the period (October 1).

DAYS 11-15 (OCTOBER 2-6)

General pattern should feature high pressure to our north and the tendency for additional low pressure to our south, leaving our region somewhat vulnerable to battle zone unsettled weather, but my continued leaning is that high pressure to the north will be close enough / strong enough to keep us drier more often than wet.

DAYS 1-5 (SEPTEMBER 21-25)

High pressure hangs on through Friday with fair and pleasant September weather for the last 2 days of summer, but while this is going on, east-facing and south-facing shores will have high rip current risks due to distant Hurricane Nigel’s long-period swell, so keep that in mind if you have plans to be at the coast and in the water. Meanwhile, subtropical low pressure will develop and organize off the US Southeast Coast and drift north to northwest toward the coastline late this week. Its northern rain shield will make a run at southern New England, but I’m still of the meteorological opinion that guidance is over-forecasting the scope and aggressiveness of this rain shield, and while I’ve introduced a lot of cloudiness to the forecast for both weekend days, I don’t think the rain is going to blast into the region and wash out Saturday. I think some of it gets to the South Coast especially Cape Cod, but much of it runs into dry air in place and gets obliterated, and then peels off to the east, waiting for a weaker version of low pressure, which has interacted with the coastline now for many hours, to come drifting northward to bring some wet weather to the region on Sunday. After that, it will get shoved southeastward Monday by high pressure in Canada, though an upper level disturbance swinging through will result in lingering clouds and the chance of some lingering showers that day, if all goes as I expect it to. Reminder: Fall arrives with the autumnal equinox at 2:50 a.m. Saturday.

TODAY: Sunny. Highs 68-75, coolest coast. Wind NE up to 10 MPH.

TONIGHT: Mostly clear. Ground fog patches low elevations. Lows 47-54. Wind variable under 10 MPH.

FRIDAY: Mostly sunny. Highs 67-74, coolest coast. Wind variable up to 10 MPH with coastal sea breezes.

FRIDAY NIGHT: High clouds increase. Ground fog patches low elevations. Lows 48-55. Wind calm.

SATURDAY: High overcast, except thicker/lower overcast may bring some rain to South Coast / Cape Cod region. Highs 66-73. Wind E 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Patchy fog. Lows 53-60. Wind E up to 10 MPH.

SUNDAY: Cloudy. Chance of rain, favoring the South Coast but possible anywhere. Highs 62-69. Wind E 5-15 MPH.

SUNDAY NIGHT: Mostly cloudy. Lingering showers and/or drizzle. Patchy fog. Lows 55-62. Wind E to N up to 10 MPH.

MONDAY: Lots of clouds. A possible shower. Highs 65-72. Wind N 5-15 MPH.

DAYS 6-10 (SEPTEMBER 26-30)

High pressure builds in from Canada with a stretch of generally fair weather during the middle of next week with near to below normal temperatures, then a moderating trend when a disturbance may swing into the region with some unsettled weather toward the end of the period, but less confident of that.

DAYS 11-15 (OCTOBER 1-5)

October’s early days show hints of weak westerly flow over our region, but a Rex block type set-up with high pressure dominating eastern Canada while low pressure hangs out to our south. This leaves the region vulnerable to battle zone unsettled weather, but for now my initial leaning is that high pressure to the north will be close enough / strong enough to keep us mainly fair. Long way to go to sort out the early October weather…

DAYS 1-5 (SEPTEMBER 20-24)

The next 3 days (through Friday) will be dominated by high pressure with fair weather with mild days and cool nights. Late in the week we’ll be watching the development of a low pressure area near the US Southeast Coast. Most guidance tries to push this low somewhat to the north over the weekend, but takes its rain shield more vigorously north, now early enough to arrive sometime on Saturday. But that’s not necessarily my forecast just yet. I’ve seen a very similar set-up be handled incorrectly by medium range guidance before, with the computer simulation taking the rain shield too quickly and too solidly north, when in reality the high pressure area holds stronger and dry air associated with it gives the rain area a buzz cut, and a deflection. I’m leaning toward this scenario at the moment, which if it is the case, we’ll salvage Saturday mainly dry around the region, despite increased cloud cover, and then Sunday would be the day with a higher rain chance as the low pressure area, now weakening, got closer to the region. Fine-tuning of this outlook will take place as needed through the week. One thing that is not uncertain – fall arrives at 2:50 a.m. Saturday with the occurrence of the autumnal equinox.

TODAY: Mostly sunny. Highs 69-76. Wind NW-N up to 10 MPH, turning NE in some eastern coastal areas.

TONIGHT: Clear. Ground fog patches low elevations. Lows 47-54, coolest low elevations inland. Wind N under 10 MPH.

THURSDAY: Sunny. Highs 68-75, coolest coast. Wind NE up to 10 MPH.

THURSDAY NIGHT: Mostly clear. Ground fog patches low elevations. Lows 48-55. Wind variable under 10 MPH.

FRIDAY: Mostly sunny. Highs 67-74, coolest coast. Wind variable up to 10 MPH with coastal sea breezes.

FRIDAY NIGHT: High clouds increase. Ground fog patches low elevations. Lows 48-55. Wind calm.

SATURDAY: High overcast, may thicken up enough for some rain near the South Coast or Cape Cod. Highs 66-73. Wind E 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Patchy fog. Lows 53-60. Wind E up to 10 MPH.

SUNDAY: Cloudy. Chance of rain, favoring the South Coast. Highs 62-69. Wind E 5-15 MPH.

DAYS 6-10 (SEPTEMBER 25-29)

If my scenario works out as expected, high pressure to the north pushes surface low pressure to the southeast of our area but an upper low means lots of clouds and maybe a few showers around on September 25 before the high pressure area takes over with another stretch of dry weather. Temperatures would cool down early period and warm up again later.

DAYS 11-15 (SEPTEMBER 30 – OCTOBER 4)

Guidance is divergent out this far, but the general pattern to me looks weak hybrid – a bit of a zonal (west to east) flow over our region but still a tendency to see high pressure to the north of the region and low pressure to the south of the region, which can always set up potential battle zones. Leaning toward a drier pattern with no major temperatures swings to end September and begin October.

DAYS 1-5 (SEPTEMBER 19-23)

Down the home stretch of summer 2023, and in an ironically symbolic way, we’re not going to see wet weather, but another stretch of dry weather similar to the holiday weekends that opened and closed the “summer vacation season”. High pressure will build toward and into the region today and sit around through late this week, keeping it fair, dry, and pleasant. Today will be a breezy day behind yesterday’s low pressure area and ahead of the approaching high center, but a weaker gradient will mean lighter winds but also coastal sea breeze for the balance of the week. We may see an increase in cloud cover later Saturday ahead of low pressure to our south, but at this point in time I’m not thinking that system will move fast enough to get here sooner, so I expect fair weather to start the weekend too. Saturday is the first day of autumn with an early morning equinox occurrence.

TODAY: Sun and patchy clouds. Highs 70-77. Wind W-NW 5-15 MPH.

TONIGHT: Mostly clear. Lows 50-57. Wind NW up to 10 MPH.

WEDNESDAY: Mostly sunny. Highs 69-76. Wind NW-N up to 10 MPH, turning NE in some eastern coastal areas.

WEDNESDAY NIGHT: Clear. Ground fog patches low elevations. Lows 47-54, coolest low elevations inland. Wind N under 10 MPH.

THURSDAY: Sunny. Highs 68-75, coolest coast. Wind NE up to 10 MPH.

THURSDAY NIGHT: Mostly clear. Ground fog patches low elevations. Lows 48-55. Wind variable under 10 MPH.

FRIDAY: Mostly sunny. Highs 67-74, coolest coast. Wind variable up to 10 MPH with coastal sea breezes.

FRIDAY NIGHT: Mostly clear. Ground fog patches low elevations. Lows 48-55. Wind calm.

SATURDAY: Partly cloudy. Highs 66-73. Wind E 5-15 MPH.

DAYS 6-10 (SEPTEMBER 24-28)

Clouds, higher humidity, and rain chances September 24-26 depending on how far north low pressure to our south gets against high pressure to the north. The high should win out again with dry weather returning late period.

DAYS 11-15 (SEPTEMBER 29 – OCTOBER 3)

Zonal (west to east) flow pattern expected. Watch for a frontal system swinging through about September 30 with the best shot of wet weather. Otherwise, the pattern looks fairly dry. Warmest early in the period, cool shot following the frontal system.

DAYS 1-5 (SEPTEMBER 18-22)

The final 5 days of summer will contain one rainy Monday and 4 nice days. We’ll get the nasty day out of the way first as low pressure tracks just offshore today. This track is a little bit of good news though. Even though we don’t “need” any rain right now, and this looks like a healthy 1 to 2 inch rainfall for most of the region, a band of potentially 2+ inch rainfall will stay south and east of areas that were hit hardest by recent flash flooding. An offshore low track prevents a warm sector from coming onto land in southeastern New England, greatly reducing the threat of damaging wind gusts from thunderstorms, with now only some embedded thunder possible from more elevated convection – not typically the kind that will produce hail and/or wind damage. Also, this system will not carry much wind with it – just a little gusty along the coast / Cape Cod, but not really any damage. Despite that though, we do have to watch for a few vulnerable/weakened trees from recent rain and wind, so I can’t 100% rule out isolated power outages due to any that might succumb. Conditions improve tonight as low pressure pulls away, and then from Tuesday through Friday we’re governed by high pressure with fair weather – cool nights and mild days, with a slight warming trend as the week goes along. Enjoy that!

TODAY: Cloudy. Rain overspreads the region early and continues all day. Heaviest rain and possible embedded thunder, mostly to the east of I-95. Highs 63-70. Wind SE 5-15 MPH, a few higher gusts around the South Coast.

TONIGHT: Cloudy evening with rain ending and patches of fog developing. One more quick shower or thunderstorm may occur mainly near and north of I-90 late evening. Breaking clouds but areas of fog continuing overnight. Lows 55-62. Wind variable to W up to 10 MPH.

TUESDAY: Sun/cloud mix. Highs 67-74. Wind NW 5-15 MPH.

TUESDAY NIGHT: Mostly clear. Lows 50-57. Wind NW up to 10 MPH.

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

WEDNESDAY NIGHT: Clear. Ground fog patches low elevations. Lows 47-54, coolest low elevations inland. Wind N under 10 MPH.

THURSDAY: Sunny. Highs 67-74, coolest coast. Wind calm then NE up to 10 MPH.

THURSDAY NIGHT: Mostly clear. Ground fog patches low elevations. Lows 50-57. Wind variable under 10 MPH.

FRIDAY: Mostly sunny. Highs 70-77, coolest coast. Wind variable up to 10 MPH with coastal sea breezes.

DAYS 6-10 (SEPTEMBER 23-27)

Dry weather hangs on into the weekend for the first day of autumn September 23, but we’ll then be vulnerable to the return of cloudiness, higher humidity, and a rainfall threat September 24-26 as one low pressure area approaches and moves in from the south, and a second one arrives from the west on its heels. Dry, cooler weather should end the period as the unsettled weather pushes away.

DAYS 11-15 (SEPTEMBER 28 – OCTOBER 2)

Dry weather for the most part with a return of a zonal flow pattern, but around mid period a disturbance may bring some showers through the region. No big storms or extreme temperatures are indicated.

DAYS 1-5 (SEPTEMBER 17-21)

The last Sunday of summer will be a splendid one with a cool start, a nice warm-up, dry air, and lots of blue sky with a few decorative clouds around as high pressure builds in from the west. It’s a small high though and won’t be around long. You’ll notice higher clouds approaching from the southwest later in the day ahead of our next system, set to put an exclamation point on the wet summer season on Monday with another bout of unsettled weather. This system will consist of a vigorous upper level trough swinging through from west to east while a pretty decent surface low gets going and passes over or just offshore of southeastern New England by Monday night. While the event starts with some bands of showers and rain in morning hours of Monday it will consolidate into a pretty solid rain area Monday afternoon and evening, along with some potential embedded thunderstorms. The latter is most likely to occur close to the track of the surface low – i.e., RI and southeastern MA, where I can’t rule out an isolated severe storm or two with the potential for damaging wind gusts and/or hail. That will be one thing to eye closely with this system, as well as the healthy rainfall delivery, which can impact areas already hit by flash flooding recently, as well as creating some flooding issues in other areas. That said, I do not expect this event to rival what happened one week ago, so that’s some good news. The other good news is the system doesn’t hang around. It moves out quickly. And following it is a long stretch of dry weather beginning on Tuesday as high pressure builds in both surface and aloft…

TODAY: Mostly sunny. Highs 68-75. Wind NW 5-15 MPH.

TONIGHT: Increasing clouds. Showers possible pre-dawn. Lows 52-59. Wind W to variable to SE up to 10 MPH.

MONDAY: Cloudy. Areas of showers in the morning. Widespread rain in the afternoon with possible embedded thunderstorms late-day near South Coast. Highs 63-70. Wind SE 5-15 MPH.

MONDAY NIGHT: Cloudy with widespread showers likely and a chance of thunderstorms in the evening. Breaking clouds overnight with patchy fog. Lows 52-59. Wind SE to SW 5-15 MPH with higher gusts, shifting to NW.

TUESDAY: Sun/cloud mix. Highs 67-74. Wind NW 5-15 MPH.

TUESDAY NIGHT: Mostly clear. Lows 50-57. Wind NW up to 10 MPH.

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

WEDNESDAY NIGHT: Clear. Ground fog patches low elevations. Lows 47-54, coolest low elevations inland. Wind N under 10 MPH.

THURSDAY: Sunny. Highs 70-77, coolest coast. Wind calm then NE up to 10 MPH.

DAYS 6-10 (SEPTEMBER 22-26)

High pressure hangs on into late week with fair and slightly warmer weather. The September 24-26 period is vulnerable to the return of clouds, higher humidity, and the chance of wet weather as we watch low pressure moving up along the Atlantic Coast. Doesn’t look, at this range, to be a strong storm of any kind.

DAYS 11-15 (SEPTEMBER 27 – OCTOBER 1)

Dry weather for the most part with a return of a zonal flow pattern, but around mid period a disturbance may bring some showers through the region. No big storms or extreme temperatures are indicated.

DAYS 1-5 (SEPTEMBER 16-20)

Lee is now a post-tropical cyclone as of 5 a.m. with maximum sustained winds around the center still at category 1 hurricane level (80 MPH). Lee will continue to weaken but remains a powerful storm as it approaches Nova Scotia on a northward track where landfall will take place near or just west of Argyle today. Thereafter, Lee curves back to the northeast and accelerates through Atlantic Canada. For us, we have a windy and in some areas wet start to the day. The steadiest rain band worked from the coastal plain in to the I-495 belt overnight, with the heaviest rainfall over Cape Cod. This rain band, the only one to impact the area, is already in the process of starting to decay as Lee now moves away, and dry air continues to erode the rain band. With surface dew points ranging from the middle 40s in the western portion of the WHW forecast area to the middle 50s along the coast, you can see that Lee’s rain is indeed fighting rather dry air in place. Surface temperatures are mostly in the upper 50s to lower 60s (a few middle 60s over Cape Cod area) as of early morning, and combined with a gusty north to northwest wind, it doesn’t feel “tropical” at all, but rather autumnal – like it would during the passage of a coastal or offshore storm during the autumn (yes it’s still technically summer, but close enough). Anyway, the worst of our weather is now, as I write and post this update. From here on, improvement, while starting slowly, will happen steadily as we move through the day and this evening, with first the rain band eroding and departing northeastward, and then the clouds thinning and breaking basically from southwest to northeast, and most areas will see sun later. That colorful sunset that I prognosticated can take place if there are still enough clouds in the sky for the setting sun to shine onto the bottom of, much like the region saw last evening. I do think it’s a strong possibility. Later tonight the clouds vanish, and we are set up for a very nice day on Sunday, the final weekend day of astronomical summer, with plenty of sunshine, some decorative fair weather clouds, warm air but low humidity, and a pleasant breeze. But as has been the theme for so much of the summer, that doesn’t last long, as the next trough swings in from the west Monday with another showery day. With ground still somewhat saturated and some areas still recovering from recent severe flash flooding, it should be noted that the rainfall from Monday’s system can be enough to result in some additional flooding, but I expect that it would be far less severe than the event that preceded it by 1 week. High pressure builds toward the region Tuesday and Wednesday with fair, dry weather returning.

TODAY: Cloudy through midday including rain likely Cape Cod and a chance of rain eastern MA & NH Seacoast, then increasing sun especially western areas during the afternoon and maybe into eastern areas later on. Highs 66-73. Wind N to NW 10-20 MPH with gusts 25 MPH or higher inland, 15-25 MPH with gusts 35 MPH or higher coastal plain, and 25-35 MPH with gusts 45 MPH or higher immediate coast, strongest gusts Cape Cod and Nantucket as well as tip of Cape Ann, gradually diminishing in all areas afternoon.

TONIGHT: Clearing. Lows 51-58. Wind NW 5-15 MPH.

SUNDAY: Mostly sunny. Highs 68-75. Wind NW 5-15 MPH.

SUNDAY NIGHT: Increasing clouds. Lows 50-57. Wind W up to 10 MPH.

MONDAY: Mostly cloudy. Showers likely. Highs 67-74. Wind variable becoming SE 5-15 MPH.

MONDAY NIGHT: Cloudy with showers likely and a chance of thunderstorms in the evening. Breaking clouds overnight with patchy fog. Lows 52-59. Wind SE to SW 5-15 MPH with higher gusts, shifting to N.

TUESDAY: Sun/cloud mix. Highs 67-74. Wind NW 5-15 MPH.

TUESDAY NIGHT: Mostly clear. Lows 50-57. Wind NW up to 10 MPH.

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

DAYS 6-10 (SEPTEMBER 21-25)

High pressure will continue to dominate the weather with fair weather through the day of the autumnal equinox on September 23. The end of the period may turn unsettled with the arrival of moisture from the south bringing clouds and a rain chance.

DAYS 11-15 (SEPTEMBER 26-30)

Overall a dry pattern with high pressure in control, but a disturbance from the west may bring the next shower chance before the end of this period. Temperatures near to above normal.