DAYS 1-5 (MAY 16-20)

A weak trough of low pressure will cross the region during the day today, and while the majority of the day and possibly all of the day will be rain-free in most of the region, there will be some varying amounts of cloudiness and some scattered shower activity developing with the passage of the disturbance. A cold front will cross the region from north to south Monday, another focus for some shower activity, and possibly even a thunderstorm. This leads to a stretch of fair weather starting Tuesday through midweek, along with a warming trend with high pressure building over the region both at the surface and aloft. However this opens the door to sea breezes, and by the end of the period we will have to keep an eye out for one of those can-be-sneaky back-door cold fronts that are often not picked out by medium range guidance.

TODAY: Variably cloudy. Isolated to scattered showers and possible thunderstorms midday-afternoon. Highs 70-77 except cooler in some coastal areas. Wind SW up to 10 MPH except light sea breezes developing in coastal locations.

TONIGHT: Variably cloudy. Lows 48-55. Wind W under 10 MPH.

MONDAY: Variably cloudy. Scattered afternoon showers and thunderstorms. Highs 66-73 except cooler in some coastal areas. Wind N up to 10 MPH with coastal sea breezes.

MONDAY NIGHT: Partly cloudy. Lows 46-53. Wind variable under 10 MPH.

TUESDAY: Mostly sunny. Highs 65-72 coast, 73-80 inland. Wind S up to 10 MPH with coastal sea breezes.

TUESDAY NIGHT: Mostly clear. Lows 50-57. Wind SW under 10 MPH.

WEDNESDAY: Mostly sunny. Highs 78-85 except 70-77 South Coast and 63-70 Cape Cod. Wind SW 5-15 MPH.

WEDNESDAY NIGHT: Mostly clear. Lows 53-60. Wind SW under 10 MPH.

THURSDAY: Partly cloudy. Highs 77-84 except cooler in coastal areas and possibly cooler all areas later in the day. Wind SW to variable 5-15 MPH may turn NE later in the day.

DAYS 6-10 (MAY 21-25)

High pressure aloft likely remains dominant early in the period but more high pressure at the surface to the north likely means cooler than previous days. Watch for low pressure from the west which may bring a shot at wet weather later in the period (May 24-25).

DAYS 11-15 (MAY 26-30)

Overall pattern looks dry and mild, but ocean’s influence likely keeps coastal areas cooler some of these days.

C-19 Chat Post – May 16 2021

DAYS 1-5 (MAY 15-19)

It’s time to make a few adjustments to the forecast, and they are generally good ones if you want more days with nice weather. Not that I had a forecast of bad weather every day – far from that. But today the shower threat comes out of the outlook as the atmosphere looks stable enough to prevent them. We’ll just see some cloud patches and otherwise lots of sun, with once again warmest weather away from the immediate shoreline. Sunday and Monday will be the days that feature the chance of pop up showers, and even a few thunderstorms, as we’ll have a couple disturbances drifting across the region with colder air aloft and a more unstable atmosphere. But neither of these days will be “rainy”. You will just have to watch for developing and passing showers especially during the afternoon hours each day. Anybody who does experience a shower or thunderstorm can see a briefly heavy downpour, but these will be isolated. When we get to Tuesday and Wednesday, high pressure dominates at the surface and aloft and you can expect fair weather, and that hint we started to see of rather warm weather last week for this period of time will indeed come to be, with many areas not having hit 80 yet doing so by Wednesday. There will be exceptions, of course – probably Cape Cod and the Islands…

TODAY: Sunny to partly cloudy. Highs 73-80 but cooler some coastal areas. Wind variable up to 10 MPH with light sea breezes in coastal locations.

TONIGHT: Clear to partly cloudy. Lows 52-59. Wind S under 10 MPH.

SUNDAY: Partly sunny. Scattered afternoon showers and thunderstorms. Highs 70-77 except cooler in some coastal areas. Wind SW up to 10 MPH except light sea breezes developing in coastal locations.

SUNDAY NIGHT: Partly cloudy. Lows 48-55. Wind W under 10 MPH.

MONDAY: Partly cloudy. Isolated afternoon showers and thunderstorms. Highs 66-73 except cooler in some coastal areas. Wind N up to 10 MPH with coastal sea breezes.

MONDAY NIGHT: Partly cloudy. Lows 46-53. Wind variable under 10 MPH.

TUESDAY: Mostly sunny. Highs 65-72 coast, 73-80 inland. Wind S up to 10 MPH with coastal sea breezes.

TUESDAY NIGHT: Mostly clear. Lows 50-57. Wind SW under 10 MPH.

WEDNESDAY: Mostly sunny. Highs 78-85 except 70-77 South Coast and 63-70 Cape Cod. Wind SW 5-15 MPH.

DAYS 6-10 (MAY 20-24)

While high pressure aloft, centered west of the area, brings generally dry weather early to mid period, the region will be vulnerable to the passage of a back door cold front and influence from high pressure in far eastern Canada, which would cool the region down especially in coastal areas. The transition out of that cool-down toward an attempted warm-up could bring some rainfall by the end of the period.

DAYS 11-15 (MAY 25-29)

Trend back to drier. Any warm up may be thwarted by another cooler air mass from eastern Canada. Too early to really pick out details but the general pattern from the previous period will still be in place as it appears.

C-19 Chat Post – May 15 2021

DAYS 1-5 (MAY 14-18)

Yesterday’s diurnal development of cumulus clouds did occur as expected, and the heaviest clouds were along a sea breeze boundary not far from the eastern coastline. Some larger clouds were also seen initially over the hilly terrain of southwestern NH and central MA in the late morning and midday with the help of the hills forcing the air upward. None of the clouds really built up enough for any showers yesterday, and any that did try to produce a few drops did not see them reach the ground due to the dry air in place. Today, we have a similar set-up but with a little more “oomph” available. This means that some of the clouds may pop enough to produce showers. Watch hilly areas and near any sea breeze boundary for the best chance. Also, if these occur late enough in the day, rainbows are possible as any showers exit to the east. Then sun must be below 45 degrees for most to be able to see a rainbow, with the bow being lower to the horizon when the sun is higher and taller rainbows occurring as the sun sinks toward the horizon. Anyway something to watch for! The weekend will be ok – not perfect, but not bad! We will have a couple disturbances coming by with more clouds, but still some sunshine, and both days run risk of seeing a few showers pop up. A frontal boundary and disturbance passing by to the south may bring more cloudiness early next week but any rainfall should stay to the south.

TODAY: Mostly sunny start, then partly sunny midday and afternoon with isolated to scattered afternoon showers. Highs 70-77 but cooler in some coastal areas. Wind NW up to 10 MPH but with some coastal sea breezes.

TONIGHT: Partly cloudy. Lows 48-55. Wind variable up to 10 MPH.

SATURDAY: Partly cloudy. Isolated to scattered afternoon showers. Highs 67-74 except cooler some coastal areas. Wind variable up to 10 MPH with sea breezes.

SATURDAY NIGHT: Partly cloudy. Areas of ground fog forming. Lows 48-55. Wind variable up to 10 MPH.

SUNDAY: Partly sunny. Scattered afternoon showers. Highs 60-67 coast, 68-75 inland. Wind variable up to 10 MPH becoming SE to S.

SUNDAY NIGHT: Partly cloudy with a chance of showers during the evening. Clearing overnight. Lows 46-53. Wind N up to 10 MPH.

MONDAY: Increasing clouds. Highs 60-67, coolest coast. Wind N up to 10 MPH shifting to E.

MONDAY NIGHT: Mostly cloudy. Lows 48-55. Wind E under 10 MPH.

TUESDAY: Mostly cloudy to partly sunny. Highs 62-69, coolest coast. Wind variable to SE up to 10 MPH.

DAYS 6-10 (MAY 19-23)

Trends indicate a mainly dry stretch with high pressure in control with temperatures not too far from seasonal normal.

DAYS 11-15 (MAY 24-28)

A shot of some rainfall early in the period then back to mainly dry weather again. Temperatures variable, but no significant lasting departures from normal expected.

C-19 Chat Post – May 14 2021

DAYS 1-5 (MAY 13-17)

As we head through mid May we are further away from the days of early spring which are often dominated by lingering Canadian cold, chilly ocean water, and a still fairly dynamic jet stream, and we are inching close to the days of summer which are characterized by a jet stream that is much weaker and often lifts itself at least over or many times north of our region. We’re in that transition time now. And the weather pattern will reflect it. There are no particularly strong surface features to impact the weather here during the next 5 days. What we will see through the weekend is daily diurnal cloud development, today from the lingering atmospheric conditions that triggered yesterday’s clouds and scattered showers, only today the clouds will not build enough to produce showers, as it is a tiny bit more stable with high pressure to our west edging a little bit closer. That high will never really “get here” as it sinks more to the south and allows an upper level disturbance to get a bit closer Friday then drift across the region during the weekend. These 3 days will feature an afternoon shower chance which runs at about 10% Friday, 30% Saturday, and 50% Sunday, but even with that 50/50 shot of passing showers Sunday afternoon, it’s not worth cancelling any outdoor plans for. Just keep an eye on the weather each of those days if you plan to be outside. By Monday, that disturbance will be beyond the region and we will see a slightly cooler, dry northerly air flow to start, which probably goes to an east or southeast wind during the day to the north of a frontal boundary which will have stretched out to our south. So while Monday will likely be free of any risk of rainfall, we may see an abundance of high and/or mid level cloudiness fanning into our area north of that boundary.

TODAY: Sunny start, then sun and passing clouds. Highs 65-72. Wind W up to 10 MPH.

TONIGHT: Partly cloudy evening, mostly clear overnight. Lows 43-50. Wind W under 10 MPH.

FRIDAY: Mostly sunny start, then partly sunny midday and afternoon with isolated afternoon showers possible. Highs 67-74 but cooler in some coastal areas. Wind NW up to 10 MPH but with some coastal sea breezes.

FRIDAY NIGHT: Partly to mostly cloudy. Lows 48-55. Wind variable up to 10 MPH.

SATURDAY: Partly cloudy. Isolated to scattered afternoon showers. Highs 67-74 except cooler some coastal areas. Wind variable up to 10 MPH with sea breezes.

SATURDAY NIGHT: Partly cloudy. Areas of ground fog forming. Lows 48-55. Wind variable up to 10 MPH.

SUNDAY: Partly sunny,. Scattered afternoon showers and possibly a thunderstorm. Highs 60-67 coast, 68-75 inland. Wind variable up to 10 MPH becoming SE to S.

SUNDAY NIGHT: Partly cloudy with a chance of showers during the evening. Clearing overnight. Lows 46-53. Wind N up to 10 MPH.

MONDAY: Increasing clouds. Highs 60-67, coolest coast. Wind N up to 10 MPH shifting to E.

DAYS 6-10 (MAY 18-22)

Current idea is one low pressure area passes well to the south early May 18 and a disturbance from the west may bring a shower or thunderstorm later. High pressure should dominate thereafter with fair and mild to warmer weather at least to start, but then have to watch for the possibility of cooler air arriving from the north or from the ocean, and possibly a shower threat again by the end of the period.

DAYS 11-15 (MAY 23-27)

Best chance of wet weather around May 24-25 otherwise mostly dry with variable temperatures, not likely any significant departures from normal.

C-19 Chat Post – May 13 2021

DAYS 1-5 (MAY 12-16)

A lobe of energy associated with upper level low pressure will cross the region from northwest to southeast today, bringing a shower threat mainly this afternoon then moves off to the southeast tonight setting the region up for a couple very nice days as high pressure builds into the region. Another disturbance will drift eastward across the Northeast this weekend, bringing pop up afternoon and early evening showers each day.

TODAY: Lots of sun to start, then lots of clouds with passing showers and a slight chance of thunderstorms this afternoon. Highs 57-64. Wind NW 10-20 MPH.

TONIGHT: Clearing. Lows 40-47. Wind NW 5-15 MPH.

THURSDAY: Mostly sunny. Highs 60-67. Wind W 5-15 MPH.

THURSDAY NIGHT: Mostly clear. Lows 42-49. Wind WSW up to 10 MPH.

FRIDAY: Mostly sunny to partly cloudy. Highs 63-70. Wind SW 5-15 MPH.

FRIDAY NIGHT: Partly to mostly cloudy. Lows 47-54. Wind SW 5-15 MPH.

SATURDAY: Partly cloudy. Isolated to scattered afternoon showers. Highs 58-65 coast, 65-72 inland. Wind variable up to 10 MPH with sea breezes.

SATURDAY NIGHT: Partly cloudy. Areas of ground fog forming. Lows 48-55. Wind variable up to 10 MPH.

SUNDAY: Partly sunny,. Scattered to numerous afternoon showers and possibly a thunderstorm. Highs 58-65 coast, 65-72 inland. Wind variable up to 10 MPH with sea breezes.

DAYS 6-10 (MAY 17-21)

Continued lower than average confidence on the outlook beyond a few days. Current thinking though is that low pressure passes south of the region May 17-18 with some clouds for a time but generally dry weather, then high pressure dominates with fair and seasonably mild weather thereafter.

DAYS 11-15 (MAY 22-26)

Best chance of wet weather mid period. Not convinced we are all that warm and may end up near to below normal in temperature once again.

C-19 Chat Post – May 12 2021

DAYS 1-5 (MAY 11-15)

Upper level low pressure and it’s associated cold pool of air aloft will move across the region through Wednesday resulting in variable cloud patches and diurnal cloud development both days. The best chance of any shower activity will come in the form of a few sprinkles favoring the hills well north and west of Boston this afternoon, near the South Coast from a disturbance passing quickly through the region tonight, and one more lobe of energy with a trough swinging through during Wednesday afternoon. I’d previously thought Wednesday would have less of a chance than today, but that’s going to turn out to be the opposite. Anyway, by Thursday and Friday, a weak area of high pressure will provide fair weather, though by later Friday more cloudiness will be appearing in advance of the next disturbance, an upper level low pressure area which will bring cooler air in aloft and set the stage for pop up showers when we get to Saturday.

TODAY: Partly sunny. A passing very light rain shower possible mainly well north and west of Boston this afternoon. Highs 56-63. Wind NW 10-20 MPH, higher gusts.

TONIGHT: Partly cloudy. Chance of a shower during the evening mainly near the South Coast. Lows 38-45. Wind NW 5-15 MPH, higher gusts.

WEDNESDAY: Variably cloudy. Isolated to scattered afternoon showers. Highs 57-64. Wind NW 10-20 MPH, higher gusts.

WEDNESDAY NIGHT: Decreasing clouds. Lows 40-47. Wind W 5-15 MPH.

THURSDAY: Mostly sunny. Highs 60-67. Wind W 5-15 MPH.

THURSDAY NIGHT: Mostly clear. Lows 42-49. Wind WSW up to 10 MPH.

FRIDAY: Mostly sunny to partly cloudy. Highs 63-70. Wind SW 5-15 MPH.

FRIDAY NIGHT: Partly to mostly cloudy. Lows 47-54. Wind SW 5-15 MPH.

SATURDAY: Partly cloudy. Isolated to scattered afternoon showers. Highs 58-65 coast, 65-72 inland. Wind variable up to 10 MPH with sea breezes.

DAYS 6-10 (MAY 16-20)

Upper level low pressure hanging around May 16 will help trigger some diurnal cloud and scattered shower development. A warm front approaching May 17 brings clouds and eventually some risk of light rain. Brief warm sector potential with a chance of showers/thunderstorms May 18. High pressure moves in to bring fair and slightly cooler weather later in the period. Not a high confidence forecast with quite a bit of uncertainty.

DAYS 11-15 (MAY 21-25)

Leaning dry/seasonable to start and wetter/milder later in the period.

C-19 Chat Post – May 11 2021

DAYS 1-5 (MAY 10-14)

A wave of low pressure brought 90% of its rain to the region from around midnight to sunrise this morning, and the other 10% will be exiting via the eastern coastal areas by mid morning. And that’s it. The rest of the day, clouds will start to break with the arrival of drier air, although complete regional clearing is not expected. Another disturbance has to move through from west to east tonight and may trigger a quick passing rain shower or two. An upper level low pressure area with lots of cold air aloft has to cross the region Tuesday into Wednesday, and will be responsible for the development of diurnal cloudiness each day (clouds that form from the sun’s heating of the ground and the heated moisture in the air rising into colder air above). Some of these clouds may grow enough to produce a few showers Tuesday afternoon, but they should not quite reach that capability on Wednesday. High pressure builds into the region Thursday and Friday with nice weather, though by later Friday a disturbance will be approaching from the west and may already be sending at least some cloud patches into our sky.

TODAY: Cloudy start with rain exiting eastern areas early. Clouds breaking for partial sun by midday and afternoon. Highs 56-63. Wind N to W 5-15 MPH.

TONIGHT: Variably cloudy. A passing rain shower possible. Lows 41-48. Wind SW 5-15 MPH shifting to NW.

TUESDAY: Sunny start, then lots of clouds with a passing rain shower possible. Highs 56-63. Wind NW 10-20 MPH, higher gusts.

TUESDAY NIGHT: Clouds decrease. Lows 38-45. Wind NW 5-15 MPH, higher gusts.

WEDNESDAY: Sunny start, then a cloud/sun mix. Highs 57-64. Wind NW 5-15 MPH, higher gusts.

WEDNESDAY NIGHT: Clearing. Lows 40-47. Wind W 5-15 MPH.

THURSDAY: Mostly sunny. Highs 60-67. Wind W 5-15 MPH.

THURSDAY NIGHT: Mostly clear. Lows 42-49. Wind WSW up to 10 MPH.

FRIDAY: Mostly sunny to partly cloudy. Highs 63-70. Wind SW 5-15 MPH.

DAYS 6-10 (MAY 15-19)

A slow-moving but fairly weak upper level low pressure area will drift across the region from west to east during the May 15-16 weekend, with both days having the risk of isolated to scattered showers, but mostly rain-free and seasonably mild. The early part of next week holds uncertainty. There are still signs of a warm-up, but how extensive it is and how long it lasts is a question any time there is chilly air still nearby, which there will be, in eastern Canada. More to come on that…

DAYS 11-15 (MAY 20-24)

Leaning cooler to start, then moderation, mostly dry, and maybe finally a chance of some rainfall later in the period.

C-19 Chat Post – May 10 2021

DAYS 1-5 (MAY 9-13)

High pressure brings nice weather to southeastern New England for Mother’s Day, and I would like to wish all moms reading the blog today a very happy one! The rain, which has made an appearance many times on this day over the years, will be holding off until later tonight as low pressure makes a run at the region, passing through on Monday morning when the rain will come to an end. We will have a pool of chilly air aloft that has to come across the region between late Monday and sometime Wednesday, so we’ll see some cloudiness at times but minimal chance of any additional rainfall, just maybe a passing shower sometime Tuesday. By Thursday, high pressure is expected to provide pleasant spring weather.

TODAY: Sunshine followed by increasing cloudiness. Highs 58-65. Wind W up to 10 MPH morning, variable up to 10 MPH with coastal sea breezes afternoon.

TONIGHT: Cloudy. Rain arriving west to east. Lows 46-53. Wind SE up to 10 MPH.

MONDAY: Cloudy with rain ending from west to east during the morning. Clouds break for partial sun afternoon. Highs 57-64. Wind variable 5-15 MPH, becoming W during the afternoon.

MONDAY NIGHT: Partly cloudy evening. Clearing overnight. Lows 38-45. Wind W 5-15 MPH shifting to NW.

TUESDAY: Sunny start, then lots of clouds with a passing rain shower possible. Highs 55-62. Wind NW 10-20 MPH, higher gusts.

TUESDAY NIGHT: Clouds decrease. Lows 38-45. Wind NW 5-15 MPH, higher gusts.

WEDNESDAY: Sunny start, then a cloud/sun mix. Highs 57-64. Wind NW 5-15 MPH, higher gusts.

WEDNESDAY NIGHT: Clearing. Lows 40-47. Wind W 5-15 MPH.

THURSDAY: Mostly sunny. Highs 60-67. Wind W 5-15 MPH.

DAYS 6-10 (MAY 14-18)

A fair and mild May 14 before a disturbance from the west brings the chance of a few showers May 15. Generally dry weather, starting seasonable then a warming trend the remainder of the period, though by the end of the period way may see the approach of a cold front with a shower/thunderstorm risk.

DAYS 11-15 (MAY 19-23)

Going with the warm-up scenario later in the 6-10 day period and a cool-down with mostly dry weather May 19-20 followed by a gradual moderation. Still fairly low confidence on the pattern this far in advance.