DAYS 1-5 (SEPTEMBER 17-21)

The cold front that crawled across our region late Wednesday and Thursday is washing out near the South Coast today, never really having delivered much dry air, and now we have an established onshore air flow for today and tonight as low pressure organizes off the US Mid Atlantic Coast and heads north then northeastward. A combination of moisture from this low and the old frontal boundary keeps the chance of showers near the South Coast, especially Cape Cod and the Islands, for a while today, but the bulk of the moisture from this low will be passing southeast of New England through early Saturday. The low itself is acquiring tropical characteristics and will likely become a tropical depression and eventually a tropical storm as it makes its trek over the water off the coast. This has some indirect impact on our weekend, sending higher swells and rough surf back to the coast, increasing rip current risk for late-season beach visits. Use caution if planning to be in the water, especially Sunday. As for our weekend weather, drier air will start to move in as that low moves away during Saturday, but a weakening cold front will also be moving across the region from the northeast Saturday evening. It looks like most of the shower activity with this front will stay to the north of our area. High pressure then builds in during Sunday through early next week, the center of it probably staying just north to east of the region, with fair weather being the result.

TODAY: Mostly cloudy. Scattered showers Cape Cod and Islands region mainly this morning. Patchy drizzle possible eastern coastal locations. Highs 67-74. Wind E 5-15 MPH.

TONIGHT: Mostly cloudy. Foggy areas. Lows 60-67. Wind NE under 10 MPH.

SATURDAY: Mostly cloudy start with areas of fog, then increasing sun especially away from the coast. Highs 68-75. Wind N 5-15 MPH.

SATURDAY NIGHT: Variably cloudy. A passing shower possible mid to late evening. Lows 55-62. Wind NW up to 10 MPH.

SUNDAY: Mostly sunny. Highs 70-77. Wind NW 5-15 MPH.

SUNDAY NIGHT: Clear. Areas of ground fog in lower elevations. Lows 53-60. Wind calm.

MONDAY: Sunny. Highs 72-79, coolest coast. Wind variable to E 10 MPH.

MONDAY NIGHT: Clear. Areas of ground fog in lower elevations. Lows 53-60. Wind calm.

TUESDAY: Sunny. Highs 73-80, coolest coast. Wind SE up to 10 MPH.

DAYS 6-10 (SEPTEMBER 22-26)

High pressure shifts offshore by the beginning of this period with a warm start to the period. The next weather questions to answer will be the timing of a trough / cold front from the west, which I think comes through sometime September 23 with an opportunity for showers, before drier and cooler air comes in behind that for September 24 before it warms up September 25. Will watch for the approach of the next weather system with wet weather chances for the very end of the period, though it may be slow enough to allow our region to get through the September 25-26 weekend rain-free.

DAYS 11-15 (SEPTEMBER 27 – OCTOBER 1)

Wet weather may start this period before a shot of dry and cooler air, a quick warm-up, more unsettled weather, then another shot of cool air to end September and start October. While timing is lower confidence the confidence is higher for an overall west-to-east pattern being the cause of the changeable weather.

C-19 Chat Post – September 17 2021

DAYS 1-5 (SEPTEMBER 16-20)

A slow moving cold front is now across RI and southeastern MA and crawling to the southeast, and will come to a stop and lose its identity over the next 24 hours. Before that happens, some energy moving across our region, combined with the contrasts created by the frontal boundary, continue to produce a fairly decent area of showers and embedded thunderstorms in the vicinity of the boundary, and lighter scattered showers to the northwest. This activity will gradually diminish during the day. Clouds will hang around though for the remainder of today, tonight, and through Friday. We will also be watching low pressure to the south of New England which will be moving north to northeast, staying offshore, but close enough to possibly toss some bands of shower activity into the region at times Friday and Friday night. The low should pull far enough to the northeast so that drier air is drawn in during Saturday with improving weather, but cannot rule out a few pop up showers from leftover instability. High pressure builds in with fair, warming weather Sunday and Monday.

TODAY: Cloudy with scattered to numerous showers including embedded thunderstorms favoring RI and southeastern MA during this morning. Mostly cloudy with a chance of a few showers this afternoon. Highs 68-75. Wind NE 5-15 MPH.

TONIGHT: Mostly cloudy. Areas of fog. Chance of showers. Lows 60-67. Wind NE 5-15 MPH.

FRIDAY: Cloudy. Chance of showers. Highs 68-75. Wind NE 5-15 MPH.

FRIDAY NIGHT: Cloudy. Chance of showers evening. Areas of fog. Lows 58-65. Wind NE 5-15 MPH.

SATURDAY: Mostly cloudy to partly sunny. Isolated midday and afternoon showers possible. Highs 66-73. Wind NE to N 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. Lows 55-62. Wind NW under 10 MPH.

SUNDAY: Mostly sunny. Highs 70-77. Wind NW 5-15 MPH.

SUNDAY NIGHT: Clear. Areas of ground fog in lower elevations. Lows 53-60. Wind calm.

MONDAY: Sunny. Highs 73-80. Wind variable up to 10 MPH.

DAYS 6-10 (SEPTEMBER 21-25)

High pressure is expected to bring dry weather and above normal temperatures to the region September 21-22. Current indications are that a trough and cold front will pass through from west to east sometime September 23 with a shower threat, followed by another area of high pressure building in with more fair weather for the end of the period.

DAYS 11-15 (SEPTEMBER 26-30)

General west-to-east flow. Expected timing of disturbances with passing shower threats September 26 and 29. A brief shot of cooler air follows the first one and a sharper shot of chilly air may follow the second one to end the month.

C-19 Chat Post – September 16 2021

DAYS 1-5 (SEPTEMBER 15-19)

A warm front is pushing through the region early this morning and will open the door for a late-season summer blast of warmth and humidity today with a gusty wind to go along with it. A cold front will be approaching later in the day but won’t get here until the late night hours tonight into the early morning hours of Thursday. A line or two of thunderstorms spawned by the front will be quite strong to our northwest and west later in the day, but will be on a weakening trend as it enters the northwestern part of the WHW forecast area by this evening. We’ll have to keep an eye on it still for a few surviving stronger cells and some gusty winds, but I think the more powerful severe potential will have been lost in a lot of the activity by the time it gets here. The remnants of this line and the spawning of newer showers as the front crosses the region overnight will bring the shower chance to most areas. The front will hang up near the South Coast and wash out, its remnants pushing back to the north during Thursday as the focus for some scattered shower activity in the region with lots of clouds lingering. Low pressure to the south may develop into a tropical depression or even minimal tropical storm as it makes a run at our region on Friday, but the trends continue to be for the bulk of this system to pass southeast of our area. It still brings the threat of some rainfall for a portion of Friday, but it doesn’t look like a widespread heavy rainfall event. I still like the trend for the weekend. Improvement is expected Saturday as the low pulls away, and a great late summer day is expected Sunday as high pressure builds in.

TODAY: Mostly cloudy start, then partly sunny. Highs 80-87. Humid – dew point upper 60s to near 70. Wind S increasing to 10-20 MPH, higher gusts.

TONIGHT: Variably cloudy. Showers likely and a chance of thunderstorms. Areas of fog overnight. Lows 63-70. Humid – dew point above 60. Wind SW 5-15 MPH with higher gusts becoming variable.

THURSDAY: Mostly cloudy. Scattered showers and thunderstorms especially RI and southeastern MA during early and mid morning. Isolated showers possible thereafter. Highs 69-74. Wind N to NE 5-15 MPH.

THURSDAY NIGHT: Variably cloudy evening. Mostly cloudy with areas of fog overnight. Lows 58-65. Wind NE to E up to 10 MPH.

FRIDAY: Cloudy. Chance of rain. Highs 67-74. Wind E 5-15 MPH.

FRIDAY NIGHT: Cloudy. Chance of rain evening. Areas of fog. Lows 58-65. Wind E to NE 5-15 MPH.

SATURDAY: Mostly cloudy to partly sunny. Highs 66-73. Wind NE to N 5-15 MPH.

SATURDAY NIGHT: Partly cloudy. Lows 55-62. Wind NW under 10 MPH.

SUNDAY: Mostly sunny. Highs 70-77. Wind NW 5-15 MPH.

DAYS 6-10 (SEPTEMBER 20-24)

High pressure is expected to bring dry weather and above normal temperatures to the region September 20-22. A trough approaching from the west brings an increased chance of shower activity later in the period.

DAYS 11-15 (SEPTEMBER 25-29)

A transition to a stronger westerly flow will start to take place, but we will have to keep an eye on potential tropical activity off or near the East Coast. Temperature departure from normal expected to be above but may turn sharply cooler at the very end of the period.

C-19 Chat Post – September 15 2021

DAYS 1-5 (SEPTEMBER 14-18)

A weak area of high pressure to the north today is enough to provide some nice weather. The warm front approaching from the southwest doesn’t have a solid area of cloudiness with it, instead being the focus of clusters of showers and thunderstorms in a fairly narrow zone southwest of New England. This frontal boundary will move across our region overnight / early Wednesday with the chance of a few showers and a thunderstorm along it, but not a solid area of rainfall. It will introduce a gusty southwesterly wind and high humidity for Wednesday, a day that will have the feel of summer with a sun/cloud mix. A cold front approaching from the northwest parented by low pressure moving eastward to our north will be timed late enough that I still think we escape a severe weather threat. We likely see general showers and thunderstorms moving in Wednesday night, in weakening form, that had been much stronger to the west during the day. The frontal boundary will then slog its way across the WHW forecast area early Thursday with additional showers possible, and while the boundary itself never gets that far beyond us, we may see enough dry air work in for some partial improvement Thursday afternoon. It’s at that time our attention will turn to low pressure to the south. While this system may become a tropical depression or even minimal tropical storm, it doesn’t concern me just for being a potential tropical entity, as it doesn’t look like it would turn into a formidable system with wind and torrential rainfall. However, it will contain tropical moisture, and its track should be close enough to at least bring some rainfall into the region during Friday. There are still some differences of output across models as to how much rain gets in here and with the track of the system itself, and also its speed of movement. I remain optimistic at this time that it does move far enough to the north, and far enough to the east, that drier air is drawn into our region as early as Saturday for improving weather in time for the weekend, but a slower and/or further west system would change this outlook, so it’s low confidence at the time.

TODAY: Mostly sunny to partly cloudy. Highs 70-77. Wind variable to E up to 10 MPH.

TONIGHT: Partly to mostly cloudy. Chance of a shower or thunderstorm overnight. Lows 60-67. Wind SE up to 10 MPH shifting to SW.

WEDNESDAY: Partly sunny. Highs 78-85. Humid – dew point upper 60s. Wind SW 10-20 MPH, higher gusts.

WEDNESDAY NIGHT: Variably cloudy. Chance of showers/thunderstorms. Lows 63-70. Wind SW 5-15 MPH becoming variable.

THURSDAY: Mostly cloudy. Chance of showers especially in the morning. Highs 70-77. Wind variable 5-15 MPH becoming NE.

THURSDAY NIGHT: Partly to mostly cloudy. Lows 58-65. Wind NE to E up to 10 MPH.

FRIDAY: Cloudy. Chance of rain. Highs 67-74. Wind E 5-15 MPH.

FRIDAY NIGHT: Cloudy. Chance of rain evening. Areas of fog. Lows 58-65. Wind E to NE 5-15 MPH.

SATURDAY: Mostly cloudy to partly sunny. Highs 66-73. Wind NE to N 5-15 MPH.

DAYS 6-10 (SEPTEMBER 19-23)

High pressure builds in with a dry stretch of weather early to mid period, along with a warming trend. A trough and frontal system from the west brings the chance of unsettled weather back by later in the period.

DAYS 11-15 (SEPTEMBER 24-28)

General west-to-east flow resumes with up and down temperatures and limited shower chances but still need to watch the western tropical Atlantic for potentially putting a system somewhere near or off the East Coast.

C-19 Chat Post – September 14 2021

DAYS 1-5 (SEPTEMBER 13-17)

An unsettled stretch of weather is at hand. This part of the forecast is a little more pessimistic sounding than I had been during the last few updates. First, the pre-dawn hours today featured a fast-moving batch of thunderstorms crossing southern NH and northern MA from west to east, a little complex of storms that was fairly well-forecast by short-range guidance. The last little hang back tail, a small meso-scale low pressure area, is crossing Metro Boston as of 7 a.m. in the form of showers and a couple downpours, but this will all be offshore very soon and other than one additional shower or two coming eastward across similar areas into mid morning, today is going to feature improvement and a nice afternoon. The small bubble of high pressure bringing the drier air in will be centered to our north as it moves to the east and the wind will shift to the east Tuesday ahead of an approaching warm front, with more clouds returning. This warm front brings the chance of showers Tuesday night and introduces warm and humid air to the region for Wednesday, a day we’ll have to watch for a shower and thunderstorm threat as a cold front approaches. I still feel the timing of this front may be late enough that we may escape the potential for stronger storms as the activity will arrive during the evening and night, but it will be something to keep an eye on. Different from my previous forecast is a more unsettled look for Thursday and Friday as the front doesn’t really get that far to the south and east before coming to a halt, and the low pressure area that I alluded to for next weekend is expected to organize and have an impact sooner than that on Friday, so lots of clouds and occasional wet weather can be expected later in the week as well, with the wettest day expected to be Friday as it stands now.

TODAY: Mostly cloudy start with additional showers especially MA and southern NH into mid morning, then sun and passing clouds. Highs 72-79. Wind variable becoming NW 5-15 MPH.

TONIGHT: Mostly clear. Fog patches in lower elevations. Lows 55-62. Wind NW under 10 MPH becoming variable.

TUESDAY: Sunshine followed by increasing clouds. Highs 68-75. Wind variable becoming E up to 10 MPH.

TUESDAY NIGHT: Cloudy. Chance of showers. Lows 58-65. Wind SE up to 10 MPH.

WEDNESDAY: Partly sunny. Highs 78-85. Humid – dew point upper 60s. Wind SW 10-20 MPH.

WEDNESDAY NIGHT: Variably cloudy. Chance of showers/thunderstorms. Lows 63-70. Wind SW 5-15 MPH becoming variable.

THURSDAY: Mostly cloudy. Chance of showers. Highs 70-77. Wind variable 5-15 MPH.

THURSDAY NIGHT: Mostly cloudy. Showers likely. Patchy fog. Lows 60-67. Wind variable to E 5-15 MPH.

FRIDAY: Cloudy. Chance of rain. Highs 67-74. Wind E 5-15 MPH.

DAYS 6-10 (SEPTEMBER 18-22)

With the earlier arrival of low pressure and things not too bogged down I am a little more optimistic today about the weather for next weekend (September 18-19) with improving conditions. After that high pressure may park off the Atlantic Coast for a warmer interlude while we again watch moisture to the south, but this is a very low confidence forecast.

DAYS 11-15 (SEPTEMBER 23-27)

General west-to-east flow resumes with up and down temperatures and limited shower chances but still need to watch the western tropical Atlantic for potentially putting a system somewhere near or off the East Coast.

C-19 Chat Post – September 13 2021