Wednesday August 5 2020 Forecast

7:30AM

DAYS 1-5 (AUGUST 5-9)

The impact from TS Isaias speaks for itself today in the power outages and damage (mainly downed trees and tree limbs) to clean up. Largely, the system behaved about as expected, with top wind gusts in the expected range. A good deal of the strongest wind not only came with the main convective line that passed through late in the day, but after it as well, as the storm was rapidly transitioning to post tropical, which expands its wind field. But in terms of sensible weather, that is now beyond us, and we look ahead. Today will be a warm and somewhat humid day and a weak trough moving through from the west may set off a shower or 2, but look for a generally rain-free day. High pressure builds in Thursday, centered north of the region it will provide a broad onshore flow and comfortable air. This high retreats as a low pressure disturbance passes south of the region Friday, but close enough to bring cloudiness and a shower threat. I’ve expected this shower threat to favor the South Coast region, but looking things over this morning make me believe the high may retreat enough that at least a minor shower threat exists anywhere in the region. This will be pushed back out of here Saturday as the high pressure area drifts back to the south, though it may take some time, and even as it dries out, we may set up some sea breeze convergence enough to pop a few afternoon showers on Saturday. High pressure will be in firm control with great August weather on Sunday.

TODAY: Sun and passing clouds. Slight risk of a passing shower. Moderately humid. Highs 82-89. Wind W 5-15 MPH, a few higher gusts.

TONIGHT: Clearing. Lows 62-69. Wind W up to 10 MPH.

THURSDAY: Sunny to partly cloudy. Highs 78-85, coolest coastal areas. Wind variable up to 10 MPH becoming NE-E 5-15 MPH.

THURSDAY NIGHT: Increasing clouds. Lows 60-67. Wind E to SE under 10 MPH.

FRIDAY: Mostly cloudy. Isolated to scattered showers. Highs 76-83, coolest coast. Wind E-SE up to 10 MPH.

FRIDAY NIGHT: Mostly cloudy. Risk of showers, favoring the South Coast. Lows 61-68. Wind SE up to 10 MPH.

SATURDAY: Early clouds and a shower risk South Coast, otherwise partly to mostly sunny but the slight risk of a pop up afternoon shower favoring southern and eastern areas. Highs 78-85, coolest coast. Wind variable up to 10 MPH with developing sea breezes.

SATURDAY NIGHT: Clearing. Lows 60-67. Wind variable up to 10 MPH.

SUNDAY: Mostly sunny. Highs 80-87, cooler some coastal areas. Wind variable up to 10 MPH with coastal sea breezes.

DAYS 6-10 (AUGUST 10-14)

High pressure shifts to the south with an increase in humidity and a risk of showers/t-storms during the August 10-13 period, highest risk around August 12-13 with a frontal boundary in the region. High pressure builds in with drier weather to end the period.

DAYS 11-15 (AUGUST 15-19)

A warm front may push through early in the period with cloudiness and perhaps a shower as high pressure retreats to the northeast. Look for a flat ridge of high pressure mainly south of the region and a jet stream to the north which would be a warm to hot pattern with mainly dry weather here. Will have to watch a frontal boundary to the north.

Tuesday August 4 2020 Forecast

7:42AM

DAYS 1-5 (AUGUST 4-8)

As far as “action” goes, this forecast is front-end-loaded. Today and this evening will be our impacts from Isaias. The thinking has not really changed since yesterday. While the system, according to NHC, returned to hurricane strength before making landfall in SC yesterday and moving up across the eastern Carolinas overnight, it has weakened to a tropical storm and will continue to slowly weaken while at the same time starting to undergo transition to a post-tropical system (or return to a cold core low pressure area) as it tracks north northeastward all the while accelerating. This track will take the center of the low across NJ, southeastern NY, and far western to northwestern New England during this evening. It’s known, but I will remind you, that the wind field around these systems tends to expand as the storm loses tropical characteristics. Another general rule of thumb is that the heaviest rainfall amounts occur west of the center with a more showery/windy eastern side of a northward-moving storm system. All these rules generally apply here. I think it’s important to note that the absolute strongest wind gust potential will be coming as what appears to be a single band of convective rainfall (downpours & possible thunder) sweeps across the region from southwest to northeast early this evening. Yes it will be breezy to windy before it and after it, but those convective cells are what can bring down your strongest winds to the surface, and therefore can be where you find the most significant pockets of wind damage. These systems also bring their own wind sheer along with them and those convective cells can easily rotate, sometimes enough to produce brief and (relatively) weak tornadoes. It goes without saying that even “weak” tornadoes can cause significant localized damage. So we will need to be on the watch for this. But as quickly as the maximum part of this event will be underway for us, it will be gone, and the overnight hours will feature less wind, but still a gusty breeze, and an opportunity to look at the stars and moon as the sky clears. With the low in eastern Canada and moving rapidly away on Wednesday, expect a rather nice summer day here on Wednesday. If there is any damage cleanup to be done it can proceed without any further weather issues. High pressure builds in, centered just to the north of the region, with a nice day, air temperature modified by an easterly wind flow, on Thursday. A frontal boundary not too far to the south will edge northward far enough on Friday for more cloudiness, and maybe a bit of South Coast shower activity. This may linger into early Saturday before high pressure wins the battle and clouds retreat for a nice start to the second weekend of August.

TODAY (THROUGH EARLY AFTERNOON): Mostly cloudy. Passing rain showers possible. Increasingly humid. Highs 76-83. Wind SE-S 5-15 MPH except increasing to 15-25 MPH late afternoon, strongest South Coast.

MID AFTERNOON / EARLY EVENING (ABOUT 3PM TO ABOUT 7PM): A band of showers, some heavy, and a risk of thunder, moving southwest to northeast across the region. Very humid. Temperatures cooling slightly to 70-77. Wind SE-SSW sustained 15-25 MPH interior and 25-35 MPH coast. Maximum wind gust potential generally 45-60 MPH, favoring coastal and higher elevations, but can occur in isolated locations interior with any heavier showers/storms.

TONIGHT: Partly cloudy to mostly clear. Humid. Lows 65-72. Wind SW 10-20 MPH, higher gusts.

WEDNESDAY: Sun and passing clouds. Less humid. Highs 82-89. Wind W 10-20 MPH and gusty early, diminishing to 5-15 MPH.

WEDNESDAY NIGHT: Clear. Lows 62-69. Wind W up to 10 MPH.

THURSDAY: Sunny to partly cloudy. Highs 80-87, but turning cooler in some coastal areas during the afternoon. Wind variable up to 10 MPH with coastal sea breezes.

THURSDAY NIGHT: Increasing clouds. Lows 60-67. Wind E to SE under 10 MPH.

FRIDAY: Mostly cloudy. Slight risk of showers South Coast. Highs 77-84, coolest coast. Wind SE up to 10 MPH.

FRIDAY NIGHT: Mostly cloudy. Risk of showers South Coast. Lows 63-70. Wind SE up to 10 MPH.

SATURDAY: Early clouds and a shower risk South Coast, otherwise partly to mostly sunny. Highs 78-85, coolest coast. Wind NE 5-15 MPH.

DAYS 6-10 (AUGUST 9-13)

High pressure brings fair and warm weather August 9, then shifts to the south with an increase in humidity and a risk of showers/t-storms during the August 10-13 period, highest risk around August 12-13 with a frontal boundary in the region.

DAYS 11-15 (AUGUST 14-18)

This looks like a mostly dry period with high pressure centered north of the region at first, keeping temperatures moderate, then high pressure shifting to the south later as upper level high pressure builds, increasing the chance of hotter weather returning.

Monday August 3 2020 Forecast

7:29AM

DAYS 1-5 (AUGUST 3-7)

August in New England. The sun angle may not be as high as it was in June and July, but we’re still in the midst of summer and we get some of our best “summer weather” around this time of year. And some of that will indeed take place during this 5 day period, but there will be a couple of “less-nice” days as well. We start with a hot and day today in a humid southwesterly air flow ahead of a trough, that will pass by and dry the air out a bit with a wind shift to west. Humidity will start to rise again later tonight and Tuesday as another trough approaches from the west – the very trough of low pressure that will steer a weakening Tropical Storm Isaias up (mostly just inland) along the East Coast today and Tuesday, the center passing just west of the WHW forecast area, probably between the Connecticut & Hudson Rivers Tuesday night. This track keeps much of the rainfall in advance of the system light and patchy with only an embedded heavier shower possible during the day, and the main storm impact will be a band or two of showers / downpours (possible thunder) Tuesday evening, also when the strongest wind will occur. We’re not going to see any widespread damaging winds from this – it will be too far west and too weak, but gusts in the 40 to 50 MPH range are definitely possible, favoring the South Coast. This system exits overnight, and by the time the sun comes up it’ll be a memory except for a gusty westerly breeze, transporting some drier air into the region behind it. Wednesday will be a very nice summer day, despite some forecasts you may have seen to the contrary. High pressure builds in for a nice Thursday too, but this high will be centered a bit north of the region and during Friday, a frontal boundary and weak disturbance to the south will be close enough for some cloudiness, but probably no rain except possibly a few South Coast showers.

TODAY: Mostly sunny to partly cloudy. A very slight risk of isolated showers or thunderstorms central MA and southwestern NH. Humid. Highs 80-87 South Coast, 87-94 elsewhere. Wind SW 5-15 MPH, higher gusts.

TONIGHT: Partly to mostly cloudy. Risk of a shower or thunderstorm late evening and overnight, favoring areas southwest and west of Boston. Humid. Lows 67-74. Wind S 5-15 MPH, higher gusts possible.

TUESDAY: Mostly cloudy. Episodes of showers, a few of which may be heavy. Slight risk of a thunderstorm. Humid. Highs 78-85. Wind S 10-20 MPH, gusts 25-40 MPH possible especially by late in the day favoring the South Coast.

TUESDAY NIGHT: Mostly cloudy evening with showers likely, a few downpours probable, and a risk of thunderstorms. Clearing overnight. Humid. Lows 67-74. Wind S 15-25 MPH with gusts 35-45 MPH favoring the South Coast and higher elevations evening, shifting to SW 10-20 MPH with higher gusts overnight.

WEDNESDAY: Sun and passing clouds. Less humid. Highs 81-88. Wind W 10-20 MPH and gusty early, diminishing to 5-15 MPH.

WEDNESDAY NIGHT: Clear. Lows 62-69. Wind W up to 10 MPH.

THURSDAY: Sunny to partly cloudy. Highs 80-87, but turning cooler in some coastal areas during the afternoon. Wind variable up to 10 MPH with coastal sea breezes.

THURSDAY NIGHT: Increasing clouds. Lows 60-67. Wind E to SE under 10 MPH.

FRIDAY: Mostly cloudy. Slight risk of showers South Coast. Highs 77-84, coolest coast. Wind SE up to 10 MPH.

DAYS 6-10 (AUGUST 8-12)

High pressure drifts back to the south providing fair weather for the August 8-9 weekend. High pressure then shifts south of the region with an increase in humidity and a slight risk of showers and thunderstorms August 10-12, maybe highest around the end of the period as a frontal boundary arrives.

DAYS 11-15 (AUGUST 13-17)

Weak blocking pattern – high pressure north and low pressure south, probably with this region influenced more by high pressure with dry weather, but a more persistent northeast to east air flow keeping heat at bay. Still not the highest amount of confidence on this forecast. A high pressure area that shifts to the south, which may happen later in the period, could quickly open the door to a shot of heat.

Sunday August 2 2020 Forecast

8:34AM

DAYS 1-5 ( AUGUST 2-6)

While today will not be as sunny as yesterday was, we’re still not looking at a bad summer day, with partial sun eventually losing the battle to clouds, and only the minimal risk that a few showers work into areas outside of and around I-495 mid to late afternoon. This will be taking place as a warm front approaches the region. This front will cross the region tonight when there is a better risk of showers and even a few isolated thunderstorms. While our parameters are not ideal for severe weather, it’s important to keep an eye out for any isolated storm that can gets its act together, as they can produce isolated damage. The front will be by the region by Monday, which will be a very warm to hot and humid summer day with a southwesterly air flow. Other than the remote risk for a pop up shower or thunderstorm again mainly outside of I-495 later in the day, Monday should be a rain-free day. Then we can turn our attention toward Isaias, currently a tropical storm, and forecast by NHC to remain one for the duration of its run up the East Coast toward our region. We can discuss the impacts from Florida to the Mid Atlantic in the comments section of this blog over the next couple days. I will focus on its impacts here for the purposes of this discussion. Best guess now is we have a weakening tropical storm, getting ready to transition to post tropical, center passing west of the Boston area, possibly as far west as near the NY border with CT/MA very early Wednesday. Typically, this set-up would produce a couple periods of rain or showers, not too heavy, initially, with that timing most likely during the day Tuesday, and a band or 2 of heavier tropical showers (possibly some thunder), that timing likely Tuesday night into the pre-dawn hours of Wednesday. As always, the right flank of a system like this creates its own wind shear, and that can be enough for a brief weak tornado in some of the convective showers. This will be a very low risk but as you have heard many times, if it’s a non-zero risk it is worth paying attention to. Except for a gusty westerly breeze Wednesday morning, the system will be a memory by then, with a nice day behind the departed system. High pressure will build in with another nice day expected Thursday.

TODAY: Mostly cloudy. Scattered mid to late afternoon showers and possible thunderstorms, mainly west of to around the I-495 belt. More humid. Highs 78-85, coolest coastal areas. Wind SE up to 10 MPH.

TONIGHT: Variably cloudy. Risk of showers. Slight risk of a thunderstorm. Humid. Lows 65-72. Wind S up to 10 MPH.

MONDAY: Mostly sunny to partly cloudy. Isolated showers and thunderstorms possible late-day, mainly outside the I-495 belt. Humid. Highs 86-93, cooler South Coast. Wind S-SW 5-15 MPH.

MONDAY NIGHT: Variably cloudy. Slight risk of a shower or thunderstorm. Humid. Lows 65-72. Wind variable 5-15 MPH.

TUESDAY: Mostly cloudy. A few episodes of rain or showers likely. Humid. Highs 75-82, coolest coastal areas. Wind SE-S 5-15 MPH.

TUESDAY NIGHT: Mostly cloudy. Showers likely. Slight risk of thunderstorms that may contain locally strong wind gusts. Humid. Lows 65-72. Wind SE-S 15-25 MPH, higher gusts coastal areas, especially South Coast.

WEDNESDAY: Mostly sunny to partly cloudy. Moderately humid. Highs 83-90. Wind W-SW 10-20 MPH, higher gusts during the morning then diminishing during the afternoon.

WEDNESDAY NIGHT: Clear. Lows 60-67. Wind SW up to 10 MPH.

THURSDAY: Mostly sunny. Highs 80-87, coolest coast. Wind variable up to 10 MPH with coastal sea breezes.

DAYS 6-10 (AUGUST 7-11)

A frontal boundary to the south will get close enough for some cloudiness Friday but no more than a risk of showers near the South Coast. High pressure should win out for fair weather, seasonable temperatures, coolest coast, and moderate humidity over the August 8-9 weekend. A disturbance brings higher humidity and a risk of showers / thunderstorms August 10-11 but too far away to know any detail.

DAYS 11-15 (AUGUST 12-16)

A weak block may form in the atmosphere (low pressure to south, high pressure to north in upper levels). This promotes surface high pressure to the north with a general maritime air flow (northeast to east) at the surface. With time high pressure would probably drift southward and keep the region dry with a late-period warm-up.

Saturday August 1 2020 Forecast

8:04AM

DAYS 1-5 ( AUGUST 1-5)

First of August, and first the weekend for discussion. Your pick of the weekend is today, which will feature plenty of sunshine and moderate humidity, light winds and coastal sea breezes. The only “thing” to watch for is the remote risk that enough lift is provided by a sea breeze boundary near or inland from the South Coast to pop an afternoon shower or two. This is a low risk and I would not cancel any outdoor plans over it. Sunday starts with sunshine but clouds will become dominant as the day goes on, this due to a warm front approaching the region. This front may generate a few showers as well, but for now it appears we will get through the majority of the day rain-free, with shower activity most possible late-day and mostly to the west. Some heavier thunderstorms will likely have formed west of the WHW forecast area closer to the warm front during the afternoon of Sunday, and if that is the case, we’ll have to watch for a couple of them trying to survive their way into portions of the region sometime Sunday night. Once the front passes, the humidity spikes and the heat returns for Monday, which will feature a risk for a few showers and storms popping up later in the day mainly well west and northwest of Boston well in advance of a cold front. This cold front will serve as a running board for tropical moisture heading northward up the Atlantic Coast in advance of Isaias, forecast to be a Category 1 Hurricane as it moves out of the Bahamas and parallels the coast of Florida over the weekend, then continuing its re-curve as it weakens to a tropical storm, center staying offshore of Georgia and South Carolina Monday, accelerating and probably moving over eastern North Carolina Monday night and continuing to accelerate while moving northeastward along (anywhere from just inland to just offshore of) the Middle Atlantic Coast Tuesday., at which time we may see tropical showers become more widespread along the front ahead of the system. With the typical track uncertainty to be taken into account, the current official forecast track brings the center of Isaias as a tropical storm, transitioning to post tropical, across southeastern New England late Tuesday night / very early Wednesday, at which time any rain and wind impact would be at maximum. We won’t know the details on either of these until we’re a little bit closer to the event, so the forecast below will reflect the forecast track, but expect tweaks to be made! Either way, expect rapid improvement as the system accelerates away so that Wednesday ends up as a very nice day.

TODAY: Mostly sunny to partly cloudy. Slight risk of isolated showers just inland from the South Coast during the afternoon. Highs 80-87. Wind variable up to 10 MPH with sea breezes.

TONIGHT: Clear. Lows 61-68. Wind variable under 10 MPH.

SUNDAY: Increasing clouds. Risk of mid to late afternoon showers, mainly west of the I-495 belt. More humid. Highs 78-85, coolest coastal areas. Wind SE up to 10 MPH.

SUNDAY NIGHT: Variably cloudy. Risk of showers. Slight risk of a thunderstorm. Humid. Lows 65-72. Wind S up to 10 MPH.

MONDAY: Partly sunny. Isolated showers and thunderstorms possible late-day, mainly outside the I-495 belt. Humid. Highs 86-93, cooler South Coast. Wind S-SW 5-15 MPH.

MONDAY NIGHT: Variably cloudy. Slight risk of a shower or thunderstorm. Humid. Lows 65-72. Wind variable 5-15 MPH.

TUESDAY: Mostly cloudy. Increasing risk for showers and a slight risk of thunderstorms. Humid. Highs 73-80, coolest coastal areas. Wind S-SE 5-15 MPH.

TUESDAY NIGHT: Cloudy. Widespread showers or rain likely. Chance of thunderstorms. Humid. Lows 65-72. Wind variable 15-30 MPH with potential stronger gusts, direction to be determined by the exact track of Isaias.

WEDNESDAY: Mostly sunny to partly cloudy. Humid. Highs 83-90. Wind W-SW 5-15 MPH, higher gusts.

DAYS 6-10 (AUGUST 6-10)

Most of this period should feature nice August weather. A frontal boundary may be close enough for at least some cloudiness and possibly a few showers around August 7 with another disturbance near the end of the period, but overall the majority of the time looks rain-free, but typically humid and warm.

DAYS 11-15 (AUGUST 11-15)

A weak block may form in the atmosphere (low pressure to south, high pressure to north in upper levels). This promotes surface high pressure to the north with a general maritime air flow (northeast to east) at the surface. Whether this persists the entire period is unclear. The general idea would be mostly dry weather but a lack of significant heat with this pattern. It’s also a low confidence forecast.

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