C-19 Chat Post – May 24 2021

DAYS 1-5 (MAY 23-27)

The feel of summer will be in full force today, but this is not really that unusual for late May, as we tend to get shots of summertime heat and a bit of humidity like this on maybe 2 out of 3 years in May across the region. Regardless, this stretch is about to come to an abrupt end tonight after a sharp cold front moves across the region. While the dynamics are not great, they are enough that the front will likely trigger a broken line or at least a line / zone of scattered showers and thunderstorms as it moves across the region tonight. And then in comes a brief but sharp shot of cool air for Monday, delivered by Canadian high pressure. But this won’t last long as the high ends up south of the region by Tuesday and a warm front moves in from the west, bringing clouds, higher humidity, and a shower chance. The warm front’s passage will introduce a shot of hotter and humid weather for Wednesday, which itself won’t last long as another cold front arrives later in the day or at night with a shower and thunderstorm threat, and a return to cooler and drier weather once again for Thursday, but this time not as strong a push of cool air as the one we will see tonight and Monday.

TODAY: Mostly sunny through midday. Variably cloudy with passing showers and thunderstorms possible from north to south across the region during the afternoon. Highs 86-93 except 78-85 South Coast and 70-77 Cape Cod. Wind W 10-20 MPH. Humid – dew point over 60. Wind SW 10-20 MPH but can be variable with locally strong gusts near any storms.

TONIGHT: Clearing. Lows 48-55. Much drier – dew point falling to 40s. Wind NW to N 10-20 MPH.

MONDAY: Sunshine and passing clouds. Highs 62-69, coolest coast. Wind N to NE 10-20 MPH, diminishing late.

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

TUESDAY: Variably cloudy. Chance of showers. Highs 70-77. Wind W 5-15 MPH.

TUESDAY NIGHT: Partly cloudy. More humid. Lows 60-67. Wind SW 5-15 MPH.

WEDNESDAY: Partly sunny. Chance of late-day showers/thunderstorms. Humid – dew point over 60. Highs 85-92 except cooler South Coast. Wind SW 10-20 MPH.

WEDNESDAY NIGHT: Mostly cloudy with a chance of showers/thunderstorms early, then clearing. Lows 50-57. Wind shifting to NW 5-15 MPH, higher gusts.

THURSDAY: Mostly sunny. Highs 75-82. Wind NW 5-15 MPH.

DAYS 6-10 (MAY 28 – JUNE 1)

There continues to be conflicting guidance regarding the last several days of May, including the May 29-31 Memorial Day Weekend. Continuing with the thought process of increased moisture in the area and a chance of some wet weather May 28, maybe into May 29 before high pressure takes over with drier weather for the balance of the long weekend and possibly through June 1. Still not a very high confidence outlook.

DAYS 11-15 (JUNE 2-6)

Looking for a frontal boundary in the region with more moisture and some wet weather opportunities and a lack of temperature extremes.

C-19 Chat Post – May 23 2021

DAYS 1-5 (MAY 22-26)

This weekend will feature a preview of summer, followed by a reminder on Monday that it is not really summer just yet, followed by a reminder toward the middle of next week that summer is just right around the corner. Fickle. Fitting. Fast-changing. That’s our weather, and it will be on display for you to love, loathe, or just experience, depending on your preference(s). We start today where we have been for a couple days now, on the eastern side of an upper level ridge of high pressure, where the wind above us is blowing from the northwest, but at the surface a general southerly to westerly air flow means higher humidity and very warm to even hot conditions this weekend. With a fair amount of cloud cover much of the time today, the temperature will not reach the levels it would have under a clear sky with full sunshine, but you will notice it becoming rather warm after a modestly mild start, and the most sensitive will notice an uptick in humidity as we go through the day. The northwesterly air flow above us will be transporting yet another disturbance down across New England from Canada, and this, combined with what heating we do get from the sun, will pop a few isolated showers and possibly a thunderstorm this afternoon and early evening. While most areas will likely escape this activity, the few areas that do see it can be visited by a brief downpour but more likely a lighter shower. Bottom line: you probably won’t get wet, but if you do, it won’t last long. Sunday will feature more sunshine but a bit more wind ahead of an approaching cold front which will be heading rapidly southward out of Canada into New England. Before it arrives, many areas will make a run at 90 and some may reach or exceed it for the first time this year. While the dynamics are not there for a widespread thunderstorm outbreak, the front is likely to trigger at least scattered showers and storms, a few of which may be on the strong side. So if you have outdoor plans, pay attention to the sky (and a radar app if you have one), especially during the afternoon. By Sunday night, the front will be exiting via the South Coast and we’ll already be feeling the change to a much cooler air mass, which will be in control of Monday’s weather as high pressure moves in from southeastern Canada. Many areas will be 18 to 25 degrees cooler for high temperature on Monday than they will be on Sunday. But this cool-down will be short-lived, as the same high pressure area that brings the cool air will settle to the south of New England by Tuesday and the return flow around it from the southwest and west will warm us right back up, lasting into Wednesday when we may heat up about as much as we do on Sunday. And another front will approach later Wednesday with a shower and thunderstorm threat, but that being 5 days away I can’t speculate much on that particular event at this point.

TODAY: Variably cloudy. Isolated showers and a slight chance of thunderstorms in the afternoon and early evening. Increasing humidity – dew point approaching 60. Highs 68-75 South Coast, 75-82 southeastern MA not at immediate coast, and 83-90 elsewhere. Wind SE to S up to 10 MPH early, becoming SW 5-15 MPH, but local sea breeze possible.

TONIGHT: Mostly cloudy evening with possible showers. Clearing overnight. Areas of ground fog forming. Lows 58-65. Humid – dew point upper 50s to lower 60s. Wind SW up to 10 MPH.

SUNDAY: Mostly sunny morning-midday. Partly sunny to mostly cloudy with a chance of showers and thunderstorms afternoon. Humid – dew point 60s. Highs 85-92 except 78-85 South Coast and 70-77 Cape Cod. Wind SW 10-20 MPH.

SUNDAY NIGHT: Clearing. Lows 50-57. Much drier – dew point falling to 40s. Wind NW to N 10-20 MPH.

MONDAY: Sunshine and passing clouds. Highs 62-69, coolest coast. Wind N to NE 10-20 MPH, diminishing late.

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

TUESDAY: Variably cloudy. Chance of showers. Highs 70-77. Wind W 5-15 MPH.

TUESDAY NIGHT: Partly cloudy. More humid. Lows 60-67. Wind SW 5-15 MPH.

WEDNESDAY: Partly sunny. Chance of afternoon showers/thunderstorms. Humid – dew point over 60. Highs 85-92 except cooler South Coast. Wind SW 10-20 MPH.

DAYS 6-10 (MAY 27-31)

High pressure from Canada brings cooler/dry weather May 27. Uncertainly on how the last several days of May play out, including the May 29-31 Memorial Day Weekend. For now thinking we may need to watch for a wave of low pressure bringing some wet weather around May 28-29 then high pressure moving in with drier weather, but this is very low confidence and may look rather different to me just 24 hours from now.

DAYS 11-15 (JUNE 1-5)

Air mass boundary in area the first several day of June with variable temperatures and at least a couple opportunities for showers/thunderstorms. No early indications of any extreme temperatures.

C-19 Chat Post – May 22 2021

DAYS 1-5 (MAY 21-25)

Upper level high pressure dominates and will continue to do so through the weekend, but this doesn’t automatically mean clear skies, as you can see this morning as the sky is filled with much cloudiness from a disturbance from Canada. This is because the axis of the upper ridge is to the west and the air above us is blowing from northwest to southeast. We often see moisture and energy from the other side of the ridge, or the trough to its west, ride up and over the ridge and down its eastern side. This will continue to be the case through the weekend, which will certainly be no wash-out, but will carry opportunities to see showers (and even thunderstorms by Sunday) as a series of disturbances and finally a stronger cold front comes through. But before that cold front arrives and despite the northwesterly flow aloft, at the surface the dominant air flow is going to be from the southwest, which will work on warming our air up today and bringing the feel of mid summer along with slightly higher humidity for the weekend. Then the cold front will come through, and this sets us up for a dry and cooler Monday as high pressure drops out of Canada. But that high will keep on moving and by Tuesday it’ll be south of the region with warmer air coming back, along with more cloudiness and even another shower threat.

TODAY: Mostly cloudy to partly sunny. Slight chance of a shower mainly north and west of Boston until mid-morning and again late in the day. Highs 68-75 South Coast, 76-83 elsewhere. Wind S 5-15 MPH.

TONIGHT: Variably cloudy. Possible showers. Lows 53-60. Wind SW 5-15 MPH.

SATURDAY: Partly sunny. Isolated to scattered showers and a slight chance of thunderstorms mainly mid afternoon on. More humid, dew point upper 50s to middle 60s. Highs 68-75 South Coast, 75-82 southeastern MA not at immediate coast, and 83-90 elsewhere. Wind SW 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy evening with possible showers. Clearing overnight. Areas of ground fog forming. Lows 58-65. Humid – dew point upper 50s to lower 60s. Wind SW up to 10 MPH.

SUNDAY: Mostly sunny morning-midday. Partly sunny to mostly cloudy with a chance of showers and thunderstorms afternoon. Humid – dew point 60s. Highs 85-92 except 78-85 South Coast and 70-77 Cape Cod. Wind SW 10-20 MPH.

SUNDAY NIGHT: Clearing. Lows 50-57. Much drier – dew point falling to 40s. Wind NW to N 10-20 MPH.

MONDAY: Sunshine and passing clouds. Highs 62-69, coolest coast. Wind N to NE 10-20 MPH, diminishing late.

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

TUESDAY: Variably cloudy. Chance of showers. Highs 70-77. Wind W 5-15 MPH.

DAYS 6-10 (MAY 26-30)

Early for too many details but a shot of heat possible May 26 with showers/thunderstorms possible, cooler/drier following by May 27 then high pressure may hold over the region with dry weather and a warming trend thereafter.

DAYS 11-15 (MAY 31 – JUNE 4)

Low confidence forecast. High pressure may keep the region dry through May 31 followed by an increase in shower chances sometime in the first several days of June as an air mass boundary may be in the area.

C-19 Chat Post – May 21 2021

DAYS 1-5 (MAY 20-24)

High pressure both at the surface and aloft dominate today with fair weather. The axis of the ridge aloft is far enough west to allow a north to northwest flow of air above us, and this has been carrying some smoke across the region at high altitude as a result of some wild fires in Canada. We’ll continue to see some of this today and possibly through Friday too. A series of disturbances will also come out of Canada Friday through Sunday. Friday’s may bring a shower into areas mostly north and west of Boston by late in the day. Saturday’s brings more clouds and a better shot at showers, but still not even close to a wash-out of a day. Sunday’s will be in the form of a strong cold front, probably timed for late-day or early evening, and this will bring a better chance of showers and possible thunderstorms to the region from north to south, but again much of that day will be rain-free. Another high pressure area comes out of Canada with refreshing air Monday after a weekend that will feature noticeably higher humidity.

TODAY: Smoke-filtered sun and also some actual high clouds dimming it more at times. Highs 69-76 coast, 77-84 inland, but turning cooler at least coastal areas afternoon. Wind variable to SE 5-15 MPH.

TONIGHT: Variably cloudy including smoke aloft. Lows 55-62. Wind SE to S up to 10 MPH.

FRIDAY: Partial hazy sun with continued smoke aloft. Chance of a late-day shower mainly north central MA and southern NH. Highs 68-75 South Coast, 76-83 elsewhere. Wind S 5-15 MPH.

FRIDAY NIGHT: Variably cloudy. Possible showers. Lows 53-60. Wind variable 5-15 MPH.

SATURDAY: Variably cloudy. Possible showers. More humid with dew point approaching 60. Highs 65-72, coolest coast. Wind variable 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Chance of showers. Areas of fog forming. Lows 55-62. Dew point middle to upper 50s. Wind variable up to 10 MPH.

SUNDAY: Partly sunny. Chance of showers and thunderstorms, especially afternoon/evening. Moderately humid with dew point lower 60s. Highs 75-82. Wind SW 5-15 MPH, higher gusts, may shift to NW late.

SUNDAY NIGHT: Clearing. Lows 48-55. Wind NW to N 10-20 MPH.

MONDAY: Sunshine and passing clouds. Highs 62-69, coolest coast. Wind N to NE 10-20 MPH, diminishing late.

DAYS 6-10 (MAY 25-29)

High pressure retreats to the south and southeast with a warm-up May 25-26 along with an increased chance of showers with warm air moving back in May 25 and a chance of shower/thunderstorms as a cold front approaches from the northwest May 26. High pressure brings dry/cooler weather May 27 then settles over the region with fair/warmer weather May 28-29.

DAYS 11-15 (MAY 30 – JUNE 3)

Low confidence forecast. High pressure may keep the region dry through May 31 followed by an increase in humidity and shower chances sometime in the first few days of June.

C-19 Chat Post – May 20 2021

DAYS 1-5 (MAY 19-23)

Is there ever such thing as a “high confidence forecast” beyond a few days? It’s rare, if it exists at all. Yes you can look at a pattern and know with some confidence that there may be a storm threat, or some stretch of heat or cold, or various things like that, but as far as getting specific beyond a few days, it really can’t be done beyond “educated guessing”. I’m not going to cite anyone else’s forecasts but my own here. A few days ago I felt fairly confident that a place like Boston would fail to reach 80 yesterday, but have no problem today. Well, it turns out that they were one of the warm spots at 84 yesterday, but today if they even get close to 80 I’ll be wholly surprised. What I have talked about for days now is not to count out the influence of the ocean, and while it did not show itself to have much influence on Boston’s temperature yesterday, it’s very likely to do so the next 2 days. And this won’t be true for just Boston, but for all coastal areas, and even inland for some distance, as we are going to have a set-up with high pressure at the surface and aloft, but with the highest of the surface pressure to the northeast of New England, that opens the door for easy-developing onshore wind, since it’s already getting a bit of a push from air that naturally wants to flow away from high pressure. This will be another lesson for the reader / listener not to get numbers mentioned a few days in advance too solid in their minds, because there is always the chance that adjustments will be needed. Or at the very least one needs to keep in mind what the seasonal potentials are. Here in New England, especially near the coast, that should be easy to do in the spring. Yesterday, somebody asked me which day would be sunniest this week. My initial answer was Wednesday (today), although now it looks like Thursday ends up sunnier. Yes, even the sky condition can be that difficult to pin down exactly 24 hours in advance. What I did warn them about though was to expect the beach to be significantly cooler than their inland home if they were planning a visit to the coast. And we won’t even talk about the water temperature… 😉 Anyway, the same ridge of high pressure that is giving us this classic spring weather in New England this midweek will contribute to a slightly different kind of classic late spring weather late this week. With the upper level ridge axis to our west, and a northwesterly air flow aloft, this allows disturbances to drop out of Canada and come across the region. We’ll see two of them, one late Friday into Saturday, and another one on Sunday. While it remains fairly dry both dew point wise and in terms of rain threat into Friday (there may be a few showers around later Friday), we will see the humidity uptick itself to a somewhat noticeable 60-ish during the course of the weekend, and a few opportunities for passing showers on Saturday with the first disturbance. The second disturbance on Sunday will feature a fairly strong surface cold front dropping southward out of Canada, and this may trigger some thunderstorm activity along with the shower threat at some point that day or evening. We’ll have to fine-tune the timing and magnitude of that threat as we get closer to it.

TODAY: Partly cloudy. Highs 68-75 coast, 76-83 inland, but turning cooler from east to west midday on. Wind N under 10 MPH shifting to E 5-15 MPH.

TONIGHT: Mostly clear. Lows 50-57. Wind E to variable under 10 MPH.

THURSDAY: Mostly sunny. Highs 69-76 coast, 77-84 inland, but turning cooler at least coastal areas afternoon. Wind variable to SE 5-15 MPH.

THURSDAY NIGHT: Mostly clear. Lows 55-62. Wind SE to S up to 10 MPH.

FRIDAY: Partly sunny. Chance of a shower late in the day. Highs 68-75 South Coast, 76-83 elsewhere. Wind S 5-15 MPH.

FRIDAY NIGHT: Variably cloudy. Possible showers. Lows 53-60. Wind variable 5-15 MPH.

SATURDAY: Variably cloudy. Possible showers. More humid with dew point approaching 60. Highs 65-72, coolest coast. Wind variable 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Chance of showers. Areas of fog forming. Lows 55-62. Dew point middle to upper 50s. Wind variable up to 10 MPH.

SUNDAY: Partly sunny. Chance of showers and thunderstorms, especially afternoon/evening. Moderately humid with dew point lower 60s. Highs 75-82. Wind SW 5-15 MPH, higher gusts, may shift to NW late.

DAYS 6-10 (MAY 24-28)

An area of high pressure from eastern Canada brings dry and cool weather May 24. Milder weather returns after this with a mostly dry pattern into the middle of next week and maybe a shower threat by the end of the period.

DAYS 11-15 (MAY 29 – JUNE 2)

Unsettled weather potential for part of the May 29-31 Memorial Day Weekend and maybe again by the end of the period as our region will likely be near a boundary between air masses.

C-19 Chat Post – May 19 2021

DAYS 1-5 (MAY 18-22)

A disturbance will cross the region from northwest to southeast today bringing some cloudiness especially this morning, and allowing for the development of a few isolated showers with the sun’s heating this afternoon. Upper level high pressure builds over the region with mainly dry weather at midweek. Look for sea breeze development both today and Wednesday. The wind may end up turning onshore more regionally during Thursday (timing uncertain) as a weak back door cold front moves into the region. There’s a little more uncertainty in the forecast for late week (Friday and Saturday) as the axis of the ridge is far enough west to allow a reinforcing back-door front into the region from the northeast and a couple disturbances to come through the region with chances for showers. There will be some fine-tuning needed on that part of the forecast.

TODAY: Variably cloudy. Isolated afternoon showers. Highs 73-80, coolest coast. Wind variable up to 10 MPH with coastal sea breezes developing.

TONIGHT: Clearing. Lows 50-57. Wind variable under 10 MPH.

WEDNESDAY: Mostly sunny. Highs 80-87 except 70s in some coastal locations and 60s on parts of Cape Cod and the Islands. Wind variable up to 10 MPH with coastal sea breezes developing.

WEDNESDAY NIGHT: Partly cloudy. Lows 55-62. Wind variable under 10 MPH.

THURSDAY: Partly sunny. Chance of a shower late in the day. Highs 77-84 but may turn considerably cooler at least in eastern coastal areas by late. Wind SW to variable 5-15 MPH possibly shifting to NE by later in the day especially in southeastern NH and eastern MA.

THURSDAY NIGHT: Variably cloudy. Possible showers. Lows 55-62. Wind variable to NE 5-15 MPH.

FRIDAY: Variably cloudy. Possible showers. Highs 63-70, coolest coast. Wind NE 5-15 MPH.

FRIDAY NIGHT: Variably cloudy. Possible showers. Lows 53-60. Wind variable 5-15 MPH.

SATURDAY: Variably cloudy. Possible showers. Highs 65-72, coolest coast. Wind variable 5-15 MPH.

DAYS 6-10 (MAY 23-27)

Frontal boundary likely in the region with possible showers and thunderstorms as higher humidity May 23. Front pushes to the south with cooler weather and potential rain due to a wave of low pressure May 24. Drier/cooler weather follows from high pressure in eastern Canada mid period then milder with possible unsettled weather again later in the period as the next disturbance approaches / arrives.

DAYS 11-15 (MAY 28 – JUNE 1)

Trends on medium range guidance say we sit in between warm high pressure to the south and cool high pressure in Canada and this leaves us vulnerable to shower activity and variable temperatures. Not a very high confidence forecast with re-evaluation to come.

C-19 Chat Post – May 18 2021

DAYS 1-5 (MAY 17-21)

Deeper into May we go, and as we start this new week off we’ll be talking a little bit of spring and a little bit of summer preview. First, we have the continuation of the active pattern today, this time a weak cold frontal boundary moving down from the north which will help trigger more cloud development and a few showers and possible thunderstorms, somewhat similar to what we saw yesterday. So it will start bright and sunny across most areas (except a few cloud patches) but we’ll see lots more clouds pop as the day goes on. Some areas will get wet, and many will not, but those that do will not see it linger very long. And yes once gain a few locations may see rainbows later in the day if the timing and placement of a departing rain shower or thunderstorm is just right. Things will settle down tonight. On Tuesday, we transition toward a preview of summer, but we won’t be fully there yet. It’s still going to be a little bit chilly aloft, so we’ll see some clouds pop again, and again some of them may build enough to produce a shower or thunderstorm in some locations, so if you do have plans to be outside, keep an eye on the sky (and the radar if you can), especially during the afternoon. Wednesday, high pressure aloft and a surface high centered to the west will combine to produce the sunniest and warmest day of this week. Areas away from the direct influence of the ocean should easily break 80 for a high temp, but with the gradient wind not all that strong, there is always the chance for some sea breeze development near the coast. While the upper level pattern says “warm” for later this week, the high pressure ridge being centered far enough west is an unlocked door for cooler air to slip down from the Canadian Maritimes via the Gulf of Maine, and by Thursday we’ll have to watch for the potential arrival of a back-door cold front. While at least inland locations should warm nicely, that warming may be thwarted closer to the eastern coastal areas, and then depending on how far southwest that expected boundary pushes will determine how cool the remainder of the region trends through Friday. There should also be some cloudiness with this air mass change, but any rainfall should be limited to just a few showers, if that. Back-door fronts don’t often produce much precipitation unless they are combined with tropical moisture, which we won’t have, or a stronger disturbance coming along in the jet stream, which we also won’t have. Keep in mind that there is still the possibility that a back-door front never quite does make it all the way into or across the region, but given past history, I’ll lean toward it doing so for now and adjust the forecast if necessary going forward this week…

TODAY: Lots of sun to start then lots of clouds popping up during the day. Isolated to scattered showers and thunderstorms developing this afternoon. Highs 69-76, coolest near the coast. Wind variable to N up to 10 MPH with some coastal sea breezes.

TONIGHT: Lots of clouds and a lingering shower possible early, then clearing. Lows 47-54. Wind N to variable under 10 MPH.

TUESDAY: Sunny start, then a sun/cloud mix with isolated afternoon showers and thunderstorms possible. Highs 72-79, coolest in coastal areas. Wind variable up to 10 MPH with coastal sea breezes developing.

TUESDAY NIGHT: Clearing. Lows 50-57. Wind variable under 10 MPH.

WEDNESDAY: Mostly sunny. Highs 80-87 except 70s in some coastal locations and 60s on parts of Cape Cod and the Islands. Wind variable up to 10 MPH with coastal sea breezes developing.

WEDNESDAY NIGHT: Partly cloudy. Lows 55-62. Wind variable under 10 MPH.

THURSDAY: Partly sunny. Chance of a shower late in the day. Highs 77-84 but may turn considerably cooler at least in eastern coastal areas by late. Wind SW to variable 5-15 MPH possibly shifting to NE by later in the day especially in southeastern NH and eastern MA.

THURSDAY NIGHT: Variably cloudy. Possible showers. Lows 55-62. Wind variable to NE 5-15 MPH.

FRIDAY: Sun/cloud mix. Highs 63-70, coolest coast. Wind NE 5-15 MPH.

DAYS 6-10 (MAY 22-26)

Frontal boundary hanging in the region May 22 means clouds and possible showers, then this front should push back to the north allowing a warmer May 23 but still with a chance of showers and thunderstorms as a cold front approaches. There’s a chance of some wet weather about May 24 if this front slows down and allows a wave of low pressure to move across the region. Drier weather should be back in place by later in the period.

DAYS 11-15 (MAY 27-31)

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

C-19 Chat Post – May 17 2021