C-19 Chat Post – May 6 2021

DAYS 1-5 (MAY 5-9)

Another low pressure system moving across the Northeast will give us another day of unsettled weather today. A couple more waves of showers are to come through the region before drier air finally works in tonight. High pressure builds in for a nice day Thursday. We’re still watching the evolution of a low pressure system for Friday and Saturday, but as has been the trend on guidance as we’ve gotten closer, this system is going to develop to the south and stay mostly offshore, not merging with another piece of energy to its northwest. We’ll experience more fringe effects from that storm than anything direct, getting into an easterly air flow north of it on Friday, which will then shift to northerly on Saturday. At most, its rainfall area may get into coastal southeastern New England sometime Friday night or Saturday morning. It does look like we’ll get that nice day under an area of high pressure on Sunday, but will keep an eye on that as well as sometimes when one low ends up further offshore the next one sneaks in more quickly. So, optimistic for Sunday, but no guarantees at this point.

TODAY: Mainly cloudy with periodic rain showers and a slight chance of thunderstorms. Areas of drizzle and fog mostly NH Seacoast, eastern MA, and RI this morning. Highs 53-60. Wind NE to variable up to 10 MPH.

TONIGHT: Mostly cloudy with a chance of rain showers during the evening. Clearing overnight. Lows 43-50. Wind W 5-15 MPH.

THURSDAY: Sunny to partly cloudy. Highs 61-68. Wind NW 5-15 MPH becoming variable.

THURSDAY NIGHT: Increasing clouds. Lows 43-50. Wind NE up to 10 MPH.

FRIDAY: Mostly cloudy. Highs 55-62, coolest coast. Wind E 5-15 MPH.

FRIDAY NIGHT: Cloudy. Chance of rain showers, favoring coastal areas. Lows 44-51. Wind NE 5-15 MPH.

SATURDAY: Partly sunny. Chance of rain showers, favoring eastern areas during the morning. Highs 55-62. Wind N 10-20 MPH.

SATURDAY NIGHT: Clearing. Lows 45-52. Wind NW 5-15 MPH.

SUNDAY: Sunny to partly cloudy. Highs 58-65, coolest coast. Wind variable up to 10 MPH with coastal sea breezes.

DAYS 6-10 (MAY 10-14)

An area of low pressure may clip the region but may largely miss to the south on May 10. Another system may bring some wet weather later in the period but the overall trend is for drier and slightly cooler than average conditions.

DAYS 11-15 (MAY 15-19)

Weak to moderate zonal flow with mean trough in the northeastern US seems the most likely pattern with a couple episodes of showers otherwise mostly dry weather and temperatures near to below normal.

C-19 Chat Post – May 5 2021

DAYS 1-5 (MAY 4-8)

Low pressure moving along a frontal boundary just to the south of New England brought in another round of rainfall overnight, which will exit today. We may see slight improvement in the weather later today in the form of breaks in the clouds as a bit of dry air tries to move in from the north, but the next low pressure is not far behind and will thicken the clouds back up tonight. This low is destined to take a track further north, passing north of the region during Wednesday while a secondary low tries to form near or just south of the region before the entire system pushes offshore at night. This will allow high pressure to build in with nice weather on Thursday after additional unsettled weather during Wednesday. I’ve been eyeing the situation for late week with the potential for impact from yet another storm system. The guidance has been fairly consistent over several runs in trending this system weaker and further southeast – something we have seen a lot of over the last couple months with guidance forecasts of a system as we get closer to it. Most of the time this has worked out and I see no reason to turn my back on it this time. So while I do think we will be somewhat unsettled again Friday, I don’t expect a significant storm system. This low will start to intensify as it pulls away Saturday, which should be a mostly dry but rather blustery and cool spring day as it stands now…

TODAY: Overcast with periods of rain and areas of fog in the morning. Cloudy with areas of drizzle and fog early-mid afternoon. Breaking clouds late afternoon. Highs 48-55. Wind NE 5-15 MPH.

TONIGHT: Mostly cloudy evening. Cloudy with numerous to widespread rain showers and a chance of thunderstorms overnight. Areas of fog overnight. Temperatures steady 48-55. Wind N 5-15 MPH early evening, variable up to 10 MPH late evening, SE 5-15 MPH overnight.

WEDNESDAY: Mainly cloudy with periodic rain showers and a slight chance of thunderstorms through early afternoon. Variably cloudy with an additional passing rain shower possible mid to late afternoon. Highs 58-65, coolest South Coast / Cape Cod. Wind S 10-20 MPH shifting to SW.

WEDNESDAY NIGHT: Clearing. Lows 41-48. Wind SW 5-15 MPH shifting to NW.

THURSDAY: Sunny to partly cloudy. Highs 61-68. Wind NW 5-15 MPH becoming variable.

THURSDAY NIGHT: Increasing clouds. Lows 43-50. Wind NE up to 10 MPH.

FRIDAY: Mostly cloudy. Light rain and areas of drizzle possible, favoring southern areas in the afternoon. Highs 51-58. Wind E 5-15 MPH.

FRIDAY NIGHT: Cloudy. Chance of rain showers. Lows 42-49. Wind NE 5-15 MPH.

SATURDAY: Partly sunny. chance of rain showers. Highs 55-62. Wind N 10-20 MPH.

DAYS 6-10 (MAY 9-13)

A small area of high pressure is expected to bring fair weather during the day May 9 before the next disturbance arrives from the west with additional rounds of unsettled weather May 10-12, before improvement later in the period. Temperatures near to below normal.

DAYS 11-15 (MAY 14-18)

Weak to moderate zonal flow with mean trough in the northeastern US seems the most likely pattern with a couple episodes of showers otherwise mostly dry weather and temperatures near to below normal.

C-19 Chat Post – May 4 2021

DAYS 1-5 (MAY 3-7)

A beneficially wetter pattern has taken over and has the potential to reduce the longer-term dry issue during the next 5 days. Our frontal friend hangs about still, having moved back to the south as a cold front yesterday, but not before allowing temperatures into the 60s and 70s across the region. Today will be a cooler day with a general onshore (east to northeast) air flow, though most rainfall is going to hold off until we get to tonight as a low pressure wave moves eastward along the frontal boundary as it sits just south of New England. This low will move away Tuesday, with the wettest part of the day in the morning. Some drier air will make an attempt to push into the region from the north during the afternoon as the departing low strengthens, but we probably only see breaks in the clouds at best later Tuesday before the next low approaching from the west thickens the clouds back up later at night. This low is likely to track north of here, and even though the surface frontal boundary may not push all the way northward through the region, it will warm up aloft and a more showery rainfall is likely to occur Tuesday night and Wednesday morning with the passage of this system. Can’t rule out some thunder in this set-up as well. I still believe this system will be moving quickly enough that we have a shot to salvage the second half or at least late day and evening of Wednesday with drier weather and at least some partial clearing. Finally by Thursday, we’ll get a break as high pressure moves in with a nice spring day. But that won’t last. The next low pressure system will already be evolving to our southwest and will be moving into the water just south of New England by later on Friday. This brings are next shot at wet and this time fairly chilly weather as we end up with a slightly stronger onshore air flow to the north of the system. The questions with this are timing and just how far north its precipitation shield comes, so some fine-tuning will be done during the week on this…

TODAY: Thickest clouds north of I-90 and thinning clouds with partial sun to the south this morning. Thinning of clouds further north may allow for some sunshine midday through mid afternoon before cloudiness thickens up from southwest to northeast again by late afternoon or early evening. Highs 55-62 coast, 62-69 inland. Wind E 5-15 MPH.

TONIGHT: Cloudy. Periods of rain. Areas of fog. Lows 45-52. Wind E 5-15 MPH.

TUESDAY: Cloudy with periods of rain and areas of fog in the morning. Clouds breaking at times but still a possible rain shower in the afternoon. Highs 55-62. Wind E up to 10 MPH morning, shifting to N 10-20 MPH afternoon.

TUESDAY NIGHT: Mostly cloudy evening. Cloudy with numerous to widespread rain showers and a chance of thunderstorms overnight. Areas of fog forming. Lows 48-55. Wind N 5-15 MPH early evening, variable up to 10 MPH late evening, SE 5-15 MPH overnight.

WEDNESDAY: Cloudy with numerous rain showers and a chance of thunderstorms morning. Lots of clouds and intervals of sunshine afternoon with a slight chance of an additional passing rain shower. Highs 58-65, coolest South Coast / Cape Cod. Wind S 10-20 MPH shifting to SW.

WEDNESDAY NIGHT: Clearing. Lows 41-48. Wind SW 5-15 MPH shifting to NW.

THURSDAY: Sunny to partly cloudy. Highs 61-68. Wind NW 5-15 MPH becoming variable.

THURSDAY NIGHT: Increasing clouds. Lows 43-50. Wind NE up to 10 MPH.

FRIDAY: Cloudy. Chance of rain/drizzle with areas of fog in the afternoon. Highs 50-57. Wind E 10-20 MPH.

DAYS 6-10 (MAY 8-12)

Low pressure may impact the region with rain or even some higher elevation rain/snow mix early May 8 followed by drying but breezy/cool conditions. May squeeze in a nice day May 9 before the next system from the west brings additional unsettled weather potential in the May 10-12 window as the active pattern continues. Temperatures near to below normal.

DAYS 11-15 (MAY 13-17)

Weak to moderate zonal flow pattern expected with low amplitude trough tendency in the northeastern US. This would lead passing episodes of showery weather with dry weather between but near to below normal temperatures overall.

C-19 Chat Post – May 3 2021

DAYS 1-5 (MAY 2-6)

Over the next several days we’ll see a battle between air masses play out over us while we see a battle between model guidance to resolve the details. Today, instead of going into specific model differences in this discussion, I’m just going to outline the outcome I see most likely and forecast that and its impact. There is not a whole lot of change to the discussion I wrote yesterday, so paraphrasing myself, this is how I see it all playing out now: Frontal boundary sits over us today but a bit to the north, allowing a warm-up, with less wind than we had yesterday. The boundary will start to slip to the south with time, and as it does so more moisture will be coming in from the west above us, so while some areas are still under a canopy of cloudiness and will still be when I post this blog shortly after 8:00 a.m., it is the middle part of the morning that may be the sunniest for the region overall, with variable to considerable amounts of cloudiness both moving into and forming over the region as we go through the day. Some of this cloudiness may be thicken enough to generate patches of light rainfall which may dot or wet the ground in a few locations later in the day or this evening, but this day is not going to turn into a washout by any stretch. Still, a nice Sunday overall given the warmer temperatures and lack of wind in comparison to the 2 days preceding it. Now, this frontal boundary will still be hanging about the region, mainly just to the south Monday and trying to push back to the north Monday night and Tuesday, with more unsettled weather, and one final low pressure wave will move through sometime on Wednesday, leaning toward slightly quicker timing right now, so that we may dry out before that day is over. This leads us to what will likely be the pick of the upcoming week – Thursday, as high pressure moves in.

TODAY: Variably cloudy – most sunshine morning, least sunshine afternoon. Slight chance of brief light rain in some locations during the afternoon. Highs 66-73, except 58-65 in some coastal areas. Wind SW 5-15 MPH, gusting 20-25 MPH.

TONIGHT: Variably cloudy. Lows 47-54. Wind shifting to N 5-15 MPH.

MONDAY: Partly sunny to mostly cloudy. Chance of light rain by late-day favoring areas south and west of Boston. Highs 55-62 southern NH and northeastern MA, 63-70 elsewhere. Wind shifting to E 5-15 MPH.

MONDAY NIGHT: Mostly cloudy. Periods of rain. Patches of fog. Lows 48-55. Wind E 5-15 MPH.

TUESDAY: Cloudy with periods of rain and areas of fog in the morning. Mostly cloudy with a chance of rain showers during the aftenroon hours. Highs 55-62. Wind E to variable 5-15 MPH.

TUESDAY NIGHT: Mostly cloudy. Rain showers likely. Lows 48-55. Wind variable to S 5-15 MPH.

WEDNESDAY: Mostly cloudy with rain showers likely during the morning. Partly sunny afternoon. Highs 57-64. Wind S 10-20 MPH shifting to W.

WEDNESDAY NIGHT: Clearing. Lows 39-44. Wind NW 5-15 MPH.

THURSDAY: Sunny to partly cloudy. Highs 58-65. Wind NW to variable 5-15 MPH.

DAYS 6-10 (MAY 7-11)

Watching for potential impact from low pressure near or south of New England May 7-8 with slow improvement to follow as that system moves away and high pressure builds in. Still somewhat low confidence on this forecast and will detail these days better as they get closer.

DAYS 11-15 (MAY 12-16)

Weak to moderate zonal flow pattern expected with low amplitude trough tendency in the northeastern US. This would lead to a couple non-lingering bouts of unsettled weather with variable temperatures, tending to be close to or even slightly below normal if the pattern verifies as expected.

C-19 Chat Post – May 2 2021

DAYS 1-5 (MAY 1-5)

On this first day of May we find ourselves still under some influence of low pressure which continues to move away from the region via the Maritime Provinces of Canada. One more lobe of energy had to come around the back side of it last night, producing rainfall for a few hours, and maybe even some snow mixed in at higher elevations (though I have not seen any reports of this as of yet). Some cloudiness and even a few sprinkles have been around eastern areas early this morning but that is all on its way out now. There may be a few pop up cumulus due to land heating and chilly air above, but as the day goes on any of these that should pop up will dissipate as it warms aloft. But this warming aloft will bring in patches of higher cloudiness from the west, and they may dominate the sky by tonight. This will be that frontal boundary that we’ve all become well-acquainted with (and some of us rather annoyed with) coming back as a warm front. But you may feel a little better about what that boundary does for your Sunday weather. While there may still be a fair amount of cloudiness around at times, it turns into a much milder day for a good portion of the region as a southwesterly air flow gets established, however briefly. As always, a few coastal areas where a southwest wind comes across ocean water first will be cooler. Don’t get used to that warm-up because “the boundary” slips back to the south again by Monday, and a day that had “80” on it in forecast icons too far in advance to be that accurately specific, it’s going to be up to and more than 20 degrees cooler than that in some locations, and certainly significantly cooler than Sunday will be. Also, cloudiness will re-thicken and probably lead to some rainfall at least by Monday evening. And as low pressure comes along the boundary, right now Tuesday looks like a fairly overcast, showery, and somewhat cool day, as the actual front will probably stay mostly to the south (though some uncertainty on that at this point). Are you tired of this pattern yet? Well, we’re far from done with it. Next round of unsettled weather doesn’t wait as the front stays in the region and another disturbance comes along on Wednesday.

TODAY: Early clouds eastern MA/NH/RI, sunshine & passing fair weather clouds for a while, a sunnier interlude, then partly cloudy again later day. Highs 57-64. Wind NW 10-20 MPH gusting up to 30 MPH in the morning, shifting to W diminishing to 5-15 MPH gusting up to 20 MPH afternoon.

TONIGHT: Variably cloudy. Lows 45-52. Wind W to SW 5-15 MPH

SUNDAY: Variably cloudy. Highs 66-73, except 58-65 in some coastal areas. Wind SW 5-15 MPH, gusting 20-25 MPH

SUNDAY NIGHT: Variably cloudy. Lows 47-54. Wind shifting to N 5-15 MPH.

MONDAY: Mostly cloudy. Chance of light rain by late-day favoring areas south and west of Boston. Highs 55-62 southern NH and northeastern MA, 63-70 elsewhere. Wind shifting to E 5-15 MPH.

MONDAY NIGHT: Mostly cloudy. Periods of rain. Patches of fog. Lows 48-55. Wind E 5-15 MPH.

TUESDAY: Mostly cloudy. Periods of rain. Areas of fog. Highs 55-62. Wind E to variable 5-15 MPH.

TUESDAY NIGHT: Mostly cloudy. Chance of rain. Areas of fog. Lows 48-55. Wind variable 5-15 MPH.

WEDNESDAY: Mostly cloudy. Chance of rain or showers. Highs 57-64. Wind variable 5-15 MPH.

DAYS 6-10 (MAY 6-10)

No big changes to the pattern. Greatest chance of direct impact from low pressure with resultant rainfall looks like it will be around mid period, but this is very low confidence.

DAYS 11-15 (MAY 11-15)

May finally transition out of this into a more distinctive high pressure / low pressure cycle with a west-to-east flow, but again very low confidence on anything out this far.

C-19 Chat Post – May 1 2021

DAYS 1-5 (APRIL 30 – MAY 4)

The story’s the same. We’ll be dealing with a frontal boundary in the area for days to some. But today as the third in a series of disturbances in this stretch moves away from the region, it’s going to be intensifying significantly, and resulting in quite a bit of wind. This air coming from the west will dry us out after yesterday’s wet weather. Yesterday’s rainfall amounts were heaviest north of I-90, but this was an area that needed it more than areas along the South Coast, so in general this was quite good. After a milder day today due to the air flow coming from land, a cold front will pass through the region this evening, shifting the wind to northwest, and a secondary trough will follow that, with a band of rain and even some snow showers as it will be getting marginally cold enough at the surface and definitely cold enough aloft to support this. No snow accumulation will occur, but technically there may be some areas that see very early May flakes with this happening after midnight. During the day Saturday it will start out quite windy and chilly with a sun/cloud but the wind will relax. But already by afternoon we’ll be seeing high and mid level clouds racing back in from the west ahead of that frontal boundary which will already be heading back in this direction as a warm front ahead of another low pressure disturbance. This races by Saturday night and pulls the front back south again, maybe with a few showers around, but not cold enough air for any mix/snow this time, and then the front sits right in the area Sunday into early next week, with the last few days of this forecast carrying a fair amount of uncertainty, dependent on the position of the boundary and the timing of disturbances moving along it…

TODAY: Variably cloudy. A passing rain shower possible. Highs 58-65. Wind W increasing to 10-20 MPH but gusting 30-40 MPH at times by afternoon.

TONIGHT: Variably cloudy. A passing rain or snow shower possible overnight. Lows 35-42. Wind NW 15-25 MPH, gusts 35-55 MPH, strongest in highest elevations.

SATURDAY: Partly sunny. Highs 55-62. Wind NW 10-20 MPH, diminishing and shifting to W.

SATURDAY NIGHT: Mostly cloudy. Light rain possible overnight. Lows 44-51. Wind variable 5-15 MPH.

SUNDAY: Mostly cloudy. Slight chance of rain. Highs 57-64. Wind variable 5-15 MPH.

SUNDAY NIGHT: Variably cloudy. Slight chance of rain. Lows 47-54. Wind variable to W 5-15 MPH.

MONDAY: Variably cloudy. Highs 55-62 southern NH and northeastern MA, 63-70 elsewhere. Wind variable 5-15 MPH.

MONDAY NIGHT: Variably cloudy. Chance of rain showers. Lows 48-55. Wind variable 5-15 MPH.

TUESDAY: Mostly cloudy. Chance of rain. Highs 55-62. Wind variable 5-15 MPH.

DAYS 6-10 (MAY 5-9)

For now it looks like a similar pattern with a boundary hanging in the New England area, variable temperatures and episodes of unsettled weather but not possible to time individual rain threats and specific milder or cooler days.

DAYS 11-15 (MAY 10-14)

Overall pattern similar to start then may break down into a more conventional west-to-east moving weather pattern with time.

C-19 Chat Post – April 30 2021

DAYS 1-5 (APRIL 29 – MAY 3)

A frontal boundary will be spending most of its time in or at least close enough to have significant impact on the weather in the southeastern New England region (aka the WHW forecast area) during this entire 5-day period. It’s already played havoc with my own forecast made just yesterday morning, within hours of me posting it, when it became sunnier and warmer than I thought just a few hours in advance. I don’t think too many people will complain about a nicer spring day than had been expected, so there is that! My idea had been that today would turn out like yesterday did, and yesterday would have been more like today is likely to be. I don’t think I’m going to get surprised with nice weather today though, as the overcast will be hanging around and there will be an increasing chance of rain showers as we go through the day, so that by later this afternoon wet weather is pretty widespread across the region. This in response to the third in a series of disturbances / low pressure waves riding along the frontal boundary, which separates Canadian coolness from springtime warmth to the south. Model indications have been that if we’re going to bust into the warmer air on the other side, that we may have to wait until Monday, but yesterday that was a day 6 forecast, and do I need to repeat how those can go? Today’s guidance is not so sure about the Monday warmth, with some models “deciding” that the frontal boundary is going to stay down to the south. From a pure temperature forecasting standpoint, this could make a difference of at least 20 degrees in the temperature at some locations. Just for an example, a warm push on Monday with a west or southwest wind could drive Boston’s temperature toward 80, while being on the other side of the boundary with an east or northeast wind could hold them closer to 55 or even lower, depending on cloud cover. So not only does the forecast challenge include timing and coverage of any precipitation, but also taking into account temperature and wind direction based on the forecast position of that front. Rewind a bit to Friday. After today’s general onshore flow keeps it cool, we get “milder” for a while as the wind flow shifts to a strong land breeze during Friday, with many areas breaking 60 for high temperatures. But did you notice I said “precipitation” and not just “rain” earlier? Yes, there is a reason. On Friday, when the third disturbance pulls away from the region, it will be intensifying and there will also be a lot of cold air aloft with an upper level disturbance that still has to make its way through the region. A lobe or two of energy rotating around the back side of the departing low will create some showers, and these can fall as rain, mix, or snow during the late night hours of Friday and early morning of Saturday. This will likely be dependent on elevation and/or intensity of precipitation. So while it’s highly unlikely anybody will see accumulating snow, it is distinctly possible that parts of the region may see very early May flakes. During the day Saturday we’ll see nothing more than a passing additional rain shower in a few locations, otherwise it should be dry but breezy and rather chilly for the start of May. Many times when we have a day like that, the next day is likely to be tranquil and somewhat milder as high pressure builds in. Nope. Not this time. This is such a fast-moving pattern right now and the frontal boundary is not getting that far south of us Saturday that it’s ready to be pulled back northward Sunday by another approaching disturbance. It’s going to be tough to time this one for a couple days, until we get closer. Some guidance has it moving more rapidly than other guidance. But the idea is that Sunday will likely feature a fair amount of cloudiness and possibly the threat of some light rainfall at some point. And this leads us to the day 5 dilemma for Monday. A faster-moving disturbance would drag the boundary back to the south during Sunday and yet another approaching disturbance from the west could push it back to the north Monday, at least giving us a shot at getting into the warm air. A slower-moving disturbance would drag the front back to the south as it departed Sunday night into Monday, making it more likely we’d be on the cooler side for Monday. This is one of those times when I am just going to say I have no idea how this is really going to play out yet, so I’ll write the forecast below to cover this uncertainty as best I can and then re-evaluate for the next update. That’s about all I can do from a forecasting standpoint right now…

TODAY: Cloudy. Isolated to scattered rain showers through early afternoon. Scattered to numerous rain showers becoming widespread by late day including a slight chance of thunderstorms. Areas of fog. Highs 48-55 eastern coastal areas and Cape Cod, 56-63 elsewhere. Wind E up to 10 MPH.

TONIGHT: Cloudy, areas of fog, widespread rain showers with a chance of thunderstorms evening. Mostly cloudy with scattered rain showers overnight. Lows 45-52. Wind E up to 10 MPH evening, N 5-15 MPH overnight.

FRIDAY: Variably cloudy. A passing rain shower possible. Highs 58-65. Wind NW 10-20 MPH but gusting 30-40 MPH at times.

FRIDAY NIGHT: Variably cloudy. A passing rain or snow shower possible overnight. Lows 35-42. Wind NW 15-25 MPH, higher gusts.

SATURDAY: Sun/cloud mix. A brief rain shower possible. Highs 52-59. Wind NW 10-20 MPH with higher gusts.

SATURDAY NIGHT: Mostly cloudy. Light rain possible overnight. Lows 40-47. Wind variable 5-15 MPH.

SUNDAY: Mostly cloudy. Slight chance of rain. Highs 52-59. Wind variable 5-15 MPH.

SUNDAY NIGHT: Variably cloudy. Slight chance of rain. Lows 43-50. Wind variable to W 5-15 MPH.

MONDAY: Partly sunny. Highs 60-67 southern NH and northern MA, 68-75 to the south except cooler parts of South Coast. Wind variable to SW 5-15 MPH.

DAYS 6-10 (MAY 4-8)

Oh goodie! More uncertainty as it appears we’ll have a frontal boundary in our vicinity much of the time. Best chance of “warm” is very early in the period, otherwise leaning cooler with episodes of unsettled weather.

DAYS 11-15 (MAY 9-13)

Overall pattern similar, frontal boundary tends to hang nearby with episodes of unsettled weather and variable temperatures averaging not that far from normal.

C-19 Chat Post – April 29 2021