COMMENTARY

On December 1, the 5-day period that I am about to forecast just below in the DAYS 1-5 section was in the DAYS 11-15 section. This is what it said: “Fast-flowing jet stream but more of a southwesterly flow and a milder trend expected with a couple minor precipitation threats during this period.” This vaguely-written medium range outlook will verify, somewhat. It’s not a perfect outlook by any stretch, but this 5-day period will be warmer, on average, than the 5-day period that preceded it, and we do have a fast-flowing jet stream pattern, which starts out from the west southwest then goes more westerly in response to high pressure ridiging centered to the southwest. Our first “minor precipitation threat” is today’s event. Ok, maybe this is not “minor” in the sense that there is some moderate rain pockets around with a warm front passing by as I write this commentary, and we are expecting some gusty wind today and this evening along with another round of rain showers, some of which may be heavy. But it’s also not a major storm in the sense we often think of them at this time of year. So the wording I used, while vague, did cover the chance of something happening in the weather pattern we are in, and the use of the phrase “milder trend” would have hinted that we’d probably have at least a slightly better chance of rain than we would snow. Ok, yes, there has been some icy roads over portions of interior MA and southern NH early this morning, due to surface temperatures having fallen below freezing before the onset of the rain, but do you think that could have been predicted in a day-11 forecast? Not likely, since model guidance didn’t have anything until at least the next day, and was showing it as just rain. Even anticipating error in a model still doesn’t make it a wise idea to try to get too detailed that far out. The reason I bring this up is because if I tried to just go with what the easy access model that goes out that far then there would have been too much day to day detail, more than is possible in this situation, and it would have been wrong, as noted above, since the guidance at that time had dry and cool to mild weather for today (Dec 11), unsettled weather moving in Dec 12-13 with warmer temperatures, and drying weather with a slight cool-down for Dec 14-15. As you often hear myself and other meteorologists say, in one way or another, you can’t really use medium range model guidance for day-to-day detailed weather beyond just a few days out, as the error increases with time, and most especially so as we have noted in a pattern such as this. I just wanted to cite another example of this as a reminder. Oh yes, my self-quote of my vaguely written 11-15 day outlook did mention a “couple” minor precipitation events, so what about the second one? Is there a second “minor threat”? Read on to find out… 😉

DAYS 1-5 (DECEMBER 11-15)

Today we experience a weather system somewhat similar, but not quite as potent, to the one we had go through here on Monday. That system was low pressure coming out of the Midwest, through the Great Lakes, and into southeastern Canada, quite a strong low with a significant pressure gradient. This one tracks similarly, but is not as strong, however after its warm front goes by here and our periodically rainy / showery and foggy patches morning comes to an end, we’ll find ourselves in a breezy warm sector again, with temperatures pushing or exceeding 60 as winds pick up this afternoon. Before that happens we may even see some thunderstorm activity due to some very unstable air moving into the region. But at least we’ll spend a fair amount of the afternoon free of rainfall in the region, so if you don’t mind a lot of clouds and a gusty breeze, it’s going to be quite mild out there, not bad for running errands or taking a walk, etc. It is this evening when we will see rain showers return from west to east ahead of and along a sharp cold front. There is the risk of isolated tree damage and power outages, but to a slightly lesser degree than earlier in the week. We may start with some cloudiness on Sunday, otherwise expect a dry, breezy, and seasonably chilly December day. The breezy weather will continue Monday as high pressure slips off to the south of the region, but this will allow a temperature moderation so it’ll be a little bit milder. But a media-advertised “big warm up” with implied staying power is not really in the cards for us here. The center of high pressure ridging is too far west to allow that to take place here. We’ll have a cold front quietly slip through the area Monday night and a bubble of high pressure move across southeastern Canada Tuesday and Wednesday, and this will keep us from continuing a warm up here. It won’t be all that cold, but don’t expect to be breaking out your Bermuda shorts either. After fair weather Tuesday along with a gusty breeze, we should be seeing an increase in clouds and the chance of some light precipitation before Wednesday is over as a warm front approaches the region ahead of the next low pressure area the jet stream is carrying.

TODAY: Cloudy with areas of fog and periodic rain, along with embedded heavier showers and possible thunder, ending from west to east midday. Mostly cloudy afternoon. Highs 57-64. Wind S to SW increasing to 10-20 MPH with gusts above 25 MPH likely and gusts to around 40 MPH possible, especially South Coast and higher elevations.

TONIGHT: Mostly cloudy. A shower, possibly heavy, including the slight chance of thunder and small hail, from west to east late evening to early overnight hours. Lows 38-45. Wind SW 10-20 MPH frequently gusting to 30 MPH and occasionally gusting stronger, shifting to W from west to east.

SUNDAY: Mostly cloudy start, then increasing sunshine. Temperatures steady 38-45. Wind W 10-20 MPH, higher gusts.

SUNDAY NIGHT: Mostly clear. Lows 22-29. Wind W 5-15 MPH, higher gusts.

MONDAY: Sun/cloud mix. Highs 45-52. Wind W 5-15 MPH, higher gusts.

MONDAY NIGHT: Partly cloudy. Lows 23-30. Wind NW 5-15 MPH.

TUESDAY: Mostly sunny. Highs 43-50. Wind N 5-15 MPH.

TUESDAY NIGHT: Mostly clear. Lows 24-31. Wind NE up to 10 MPH.

WEDNESDAY: Increasing clouds. Chance of light snow/mix/rain at night. Highs 42-49. Wind E up to 10 MPH.

DAYS 6-10 (DECEMBER 16-20)

While we continue to see a pattern of fast-moving systems, there will be a transition starting to take place during this period as it appears right now. Two more systems should pass by to the north with brief warm-ups, more confident in the first one December 16, maybe one more around the middle of the period, and by the end of the period a shot of much colder air is possible. Again with iffy guidance at best, this doesn’t help confidence in a medium range forecast, but the signs are for pieces of colder air to make it further south and east in Canada and some other atmospheric readjustment to make our air flow a little more northwesterly by the end of the period. Obviously lots of fine-tuning to come.

DAYS 11-15 (DECEMBER 21-25)

As we approach Christmas we’ll eye the possibility of a colder pattern and while initially it looks fairly dry, we’ll have to keep an eye on jet stream disturbances which are not well-seen by guidance this far in advance. I cannot offer any detail this far in advance with too many forecast unknowns.

C-19 Chat Post – December 11 2021

DAYS 1-5 (DECEMBER 10-14)

Not a lot of change needs to be made to the previously-posted outlook. Overnight, a little very light snow occurred in some areas, mostly north of I-90, but it was so light that you’d probably never know if you didn’t see it. Today’s abundant cloud cover is the result of the air warming above us. We’ll feel a tiny bit of that warming at the surface too in that the maximum temperatures today will be a few to several degrees higher than yesterday. Low pressure tracks from the Upper Midwest through the Great Lakes tonight through Saturday then onward across southeastern Canada Sunday. This track will put us in line for a warm frontal passage early Saturday with some rainfall, then a cold frontal passage with a line of convective showers (maybe some thunder) Saturday evening / night from west to east. Between the two fronts we will find ourselves in the warm sector with a gusty breeze. This system is similar to but a little less potent than the one we experienced back on Monday. Behind this will come cooler weather for Sunday along with a gusty wind but dry conditions. The large scale pattern will set-up with a ridge of high pressure building in the east central US as we head into early next week, but with the axis of this ridge far enough west and the core of it far enough south, this will leave our region in a more west northwesterly air flow and with dry weather, the warm-up we see will be modest.

TODAY: Mostly cloudy. Highs 38-45. Wind E to SE under 10 MPH.

TONIGHT: Cloudy. Periods of rain overnight, with pockets of freezing rain possible over some locations away from the coast for a short time. Lows 30-37 evening, followed by a slow temperature rise overnight. Wind SE to S up to 10 MPH.

SATURDAY: Cloudy with periods of rain early to mid morning. Mostly cloudy to partly sunny late morning on. Highs 57-64. Wind S to SW increasing to 10-20 MPH with gusts above 25 MPH likely and gusts to around 40 MPH possible, especially South Coast and higher elevations.

SATURDAY NIGHT: Mostly cloudy. A shower, possibly heavy, including the slight chance of thunder and small hail, from west to east late evening to early overnight hours. Lows 38-45. Wind SW 10-20 MPH frequently gusting to 30 MPH and occasionally gusting stronger, shifting to W from west to east.

SUNDAY: Mostly cloudy to partly sunny. Temperatures steady 38-45. Wind W 10-20 MPH, higher gusts.

SUNDAY NIGHT: Mostly clear. Lows 22-29. Wind W 5-15 MPH, higher gusts.

MONDAY: Sun/cloud mix. Highs 42-49. Wind WNW 5-15 MPH, higher gusts.

MONDAY NIGHT: Partly cloudy. Lows 23-30. Wind WNW 5-15 MPH.

TUESDAY: Partly sunny. Highs 44-51. Wind WNW 5-15 MPH.

DAYS 6-10 (DECEMBER 15-19)

Low pressure passes north of the region during the middle of next week while the upper ridge stays in place to the southwest of New England but extending across much of the region before slightly retrograding westward later next week. The resultant weather here based on the best-guess I can make after applying the uncertainty factor is that we see some clouds from a warm front passing by December 15, the “warmest” day December 16 ahead of a cold front that then cools us down for the end of next week, but with mostly fair weather expected. Although, we must be on the look-out for at least a weak disturbance somewhere around the December 18-19 weekend that the model guidance doesn’t “see” this far in advance.

DAYS 11-15 (DECEMBER 20-24)

Fast flowing west-to-east pattern expected. While day-to-day details can’t be determined this far in advance, the trend is to be seasonably cool with at least one disturbance bringing a precipitation opportunity.

C-19 Chat Post – December 10 2021

DAYS 1-5 (DECEMBER 9-13)

The first kind-of-widespread snowfall of the season is in the books, and it was quite a minor event as it was expected to be – a coating to 2 inches. While only some minor snow removal in some areas this morning, of more concern will be some icy patches where there was a snow-melt / re-freeze. Watch for that if you are out during the early to mid morning hours before the combination of the temperature rising above freezing, an increasing breeze, and dry air will eliminate the icy patches. We’ll have a nice day today as high pressure builds in, but it will be chilly with a breeze. A disturbance will move toward the region today and through the area Friday bringing some clouds and perhaps a brief period of snow/mix/rain, favoring the morning hours. The next formidable low pressure area is destined to take a track similar to the one we were impacted by on Monday, through the Great Lakes and into eastern Canada, sending a warm front through here with an early rain threat Saturday, a mostly rain-free day in the warm sector with a gusty breeze, and a cold front swinging through at night with a rain shower or downpour (something we will have to fine-tune timing and details on during the next couple of days). Behind this system comes a shot of windy, colder weather for Sunday and lasting into Monday as well with a slight temperature moderation.

TODAY: Sunny morning. Sun/cloud mix afternoon. Highs 35-42. Wind NW 5-15 MPH, gusting up to 20 MPH, diminishing during the afternoon.

TONIGHT: Variably cloudy evening. Cloudy overnight. Lows 25-32. Wind variable under 10 MPH.

FRIDAY: Cloudy with a brief period of snow/mix north and mix/rain south in the morning. Mostly cloudy to partly sunny afternoon. Highs 37-44. Wind E under 10 MPH early, then S 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy. Chance of rain overnight, may start as a brief mix with sleet and snow interior higher elevations. Lows 30-37 evening, rising temperature overnight. Wind SE up to 10 MPH shifting to S 5-15 MPH.

SATURDAY: Cloudy with a chance of rain early, then variably cloudy. Highs 52-59. Wind SW 10-20 MPH, higher gusts possible.

SATURDAY NIGHT: Cloudy through late evening with rain showers likely including a chance of a thunderstorm with small hail. Mostly cloudy overnight. Lows 42-49. Wind SW 10-20 MPH with higher gusts, shifting to W.

SUNDAY: Mostly cloudy to partly sunny. Temperatures steady 39-46. Wind W to NW 10-20 MPH, higher gusts.

SUNDAY NIGHT: Mostly clear. Lows 22-29. Wind W 5-15 MPH, higher gusts.

MONDAY: Sun/cloud mix. Highs 42-49. Wind W 5-15 MPH, higher gusts.

DAYS 6-10 (DECEMBER 14-18)

While the upper atmosphere says “let’s warm up!” and we will see it here to some degree (no pun intended), there are things going on elsewhere that say we may not see anything that lasts too long without being interrupted by a shot of colder air from Canada as a series of high pressure areas will be moving across that area and into a position that can push cold into the northeastern US. For now will go with a warming trend for the middle of next week, followed by a late-week colder shot. There will probably be some briefly unsettled weather at transition time but timing and details will have to be worked out as we get closer to that.

DAYS 11-15 (DECEMBER 19-23)

The trends continue to be for colder air to win out over any sustained warm ups, and we also see precipitation (including snow) chances go up in this time frame as we add a little bit more moisture to the mix. Obviously far too soon to try to pinpoint anything specific for any of these days.

C-19 Chat Post – December 9 2021

COMMENTARY

Well, very few lessons get learned these days when it comes to communication and interpretation of weather information. I’ve already seen people wake up early this morning, as I predicted would happen, and ask “so, where’s the snow?” Ask that question if it’s supposed to be snowing in your area this evening and it isn’t. That’s when most of this event occurs. I’m sure there are people out there who saw a model run with many inches of snow for today several days ago and will still expect that to verify. Yes, we still have a problem with information / communication when it should be much easier. Apparently there’s still a lot to work on. Those snow maps that were posted on the TV weathercasts last Saturday night for today certainly are not going to verify. There’s a reason why it’s not wise to do such a thing. How many more “events” are going to be incorrectly presented and/or misinterpreted before these people learn? Good question…

DAYS 1-5 (DECEMBER 8-12)

We sit in the midst of the active December pattern we were anticipating. Today’s event will be a minor one, a result of a weak area of low pressure passes south of New England later today and this evening. It will start to gather some strength as it interacts with an upper level disturbance as it begins to pull away this evening, and that combination along with cold enough air in place will result in some accumulating snow, most of which will occur near and after sunset until late evening. The best combination of steadiest precipitation and coldest air to result in “the most snow” (which will still not be a lot – let’s keep this in perspective) will occur mostly over the region from north central to northeastern MA and into southern NH. Although areas that get little or no accumulation or are rain for a portion of the event will have to watch for some black ice formation overnight into early Thursday morning as the temperature drops below freezing. Keep that in mind if you have to be outside at those times. High pressure brings fair and chilly weather Thursday. On Friday, dissipating low pressure will make a run at the region, bringing clouds and maybe some light and insignificant precipitation. The next stronger low pressure area that will impact the region this weekend will take a track similar to Monday’s system, north of New England. You may have already heard this event touted as a significant rain-producer by some media (I know I have), but it’s not really going to be the case. We’ll have a warm front move through, expected timing early Saturday, with some rainfall as it will have warmed up enough by then, and we’ll spend some time in a breezy warm sector on Saturday which the majority of ends up rain-free. After that we’ll watch for a cold front to move across the region between late Saturday and early Sunday with rain showers and gusty winds. That precipitation ending as a mix or snow is a potential but would likely be insignificant if it happened. Colder air does return to the region on Sunday, but modified, not arctic air.

TODAY: Cloudy. Scattered areas of snow except rain in some coastal areas especially south of Boston. Spotty coatings of snow possible interior higher elevations. Highs 31-38. Wind NE up to 10 MPH.

TONIGHT: Cloudy evening with snow of a coating to 2 inches, with isolated amounts up to 3 inches possible favoring northern MA and southern NH, and rain/mix changing to mix/snow with a coating possible closer to the South Coast. Breaking clouds overnight. Watch for black ice formation. Lows 24-31. Wind N 5-15 MPH gusting up to 20 MPH.

THURSDAY: Sun/cloud mix. Highs 35-42. Wind NW 10-20 MPH, diminishing.

THURSDAY NIGHT: Variably cloudy. Lows 25-32. Wind SW 5-15 MPH.

FRIDAY: Mostly cloudy. Chance of light rain and snow. Highs 35-42. Wind variable 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy. Chance of rain overnight, may start as a brief mix with sleet and snow interior higher elevations. Lows 28-35 evening, rising temperature overnight. Wind W up to 10 MPH.

SATURDAY: Cloudy with a chance of rain early, then variably cloudy. Highs 52-59. Wind SW 10-20 MPH.

SATURDAY NIGHT: Cloudy with rain showers likely. Lows 42-49. Wind SW 10-20 MPH and gusty shifting to W.

SUNDAY: Mostly cloudy to partly sunny. Temperatures steady 42-49. Wind W to NW 10-20 MPH, higher gusts.

DAYS 6-10 (DECEMBER 13-17)

While the upper atmosphere supports above normal temperatures with mainly fair weather, we’ll have to watch the surface pattern for a bubble of high pressure in eastern Canada that may send a cold front southward at some point, putting a lid on what could otherwise be a warmer stretch. Low confidence forecast.

DAYS 11-15 (DECEMBER 18-22)

Hints of a colder trend that may eventually lead to a winter precipitation chance or two. This is still a very low confidence outlook. Any medium range guidance remains very unreliable.

C-19 Chat Post – December 8 2021

DAYS 1-5 (DECEMBER 7-11)

Active pattern continues. We had a strong cold front go through last night with showers and downpours of rain, along with gusty winds, enough to take down some trees resulting in isolated power outages and a few instances of property damage. Today will be a quieter weather day but with a gusty breeze, and considerably colder than yesterday. Next we look at the over-advertised midweek storm threat. Yes, low pressure is going to pass southeast of New England, close enough for a swath of snow and rain, but this is not going to be a very strong system, and it will be moving quickly, as most systems tend to in this pattern. So we are looking at a rather minor snow event with the best chance of accumulation away from the immediate coast, and most of it will take place Wednesday afternoon and evening. That one is outta here quickly by Thursday morning and that day will turn out fair and chilly. The next low pressure area moves in from the west on Friday as a weakening clipper system, with some light rain and snow expected from it – again not a significant system. This one doesn’t have a push of cold air behind it, and in fact is kind of a predecessor for another low that will track northwest of our region by later Saturday when we experience some unsettled weather, but also a warm-up.

TODAY: Partly cloudy. Highs 35-42. Wind WNW 5-15 MPH, gusts 20-25 MPH.

TONIGHT: Increasing clouds. Lows 23-30. Wind variable up to 10 MPH.

WEDNESDAY: Cloudy. Periods of snow except rain or snow eastern shores and rain South Coast. Highs 31-38. Wind NE 5-15 MPH.

WEDNESDAY NIGHT: Cloudy evening with periods of snow except rain to mix/snow coastal areas, accumulations of a coating to up to 2 inches possible. Breaking clouds overnight. Lows 22-29. Wind N 5-15 MPH.

THURSDAY: Sun/cloud mix. Highs 35-42. Wind NW 10-20 MPH.

THURSDAY NIGHT: Variably cloudy. Lows 25-32. Wind SW 5-15 MPH.

FRIDAY: Mostly cloudy. Chance of light rain and snow. Highs 35-42. Wind variable 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy. Lows 25-32. Wind W up to 10 MPH.

SATURDAY: Variably cloudy. Chance of rain showers. Highs 50-57. Wind SW 5-15 MPH.

DAYS 6-10 (DECEMBER 12-16)

Expecting a cold front to push through on December 12 with rain showers that may end as snow showers for some areas. A weak disturbance may impact the region around mid period but overall a fair and mild pattern is expected.

DAYS 11-15 (DECEMBER 17-21)

Hints of a colder trend that may eventually lead to a winter precipitation chance or two. This is still a very low confidence outlook. Any medium range guidance remains very unreliable.

C-19 Chat Post – December 7 2021

DAYS 1-5 (DECEMBER 6-10)

The first of 3 systems in the next 5 days will impact our region today. This one is low pressure passing north of us, with a warm front moving through early today with a batch of rain showers and even a few downpours. In the warm sector for a good part of the day today we see the clouds break enough to allow some areas to see sunshine and with a gusty southwest wind temperatures will climb well above normal. We still have to watch for a couple isolated showers or thunderstorms near the South Coast through midday that can produce locally damaging winds. A cold front will move across the region this evening with a band of rain showers and possible thunder, along with additional gusty and shifting winds. Cold air arrives without delay tonight and sets up a breezy and much colder day Tuesday but with dry weather. The next storm system will impact the region Wednesday, and today we’re bringing the impacts into a little better focus. The low will be passing south of New England, in the right spot with cold air in place to bring snow to much of the region, but probably rain to the South Coast which may end as snow. Right now this fast-moving system should produce a minor snow accumulation (probably under 3 inches), but being the first potential widespread accumulation of the season, it always seems to have more impact than it should – so be ready for that. It’s out of here Wednesday night and we have another fair and chilly day on Thursday before the third system arrives from the west Friday with more clouds and what looks like a minor rain and snow event at this time.

TODAY: Cloudy through mid morning with rain showers likely. Variably cloudy late morning on with a slight chance of an isolated shower or thunderstorm near the South Coast through midday. Highs 63-70. Wind SE-S 5-15 MPH becoming SW 10-20 MPH with gusts as high as 35-45 MPH..

MONDAY NIGHT: Mostly cloudy evening with a passing rain shower and potential downpour with possible thunder and/or small hail west to east. Partly cloudy overnight. Lows 33-40. Wind SW 10-20 MPH gusting 30-40 MPH and potentially higher in any convective activity, shifting to NW from west to east.

TUESDAY: Partly cloudy. Temperatures steady 33-40. Wind NW 10-20 MPH with higher gusts, diminishing later in the day.

TUESDAY NIGHT: Increasing clouds. Lows 23-30. Wind variable up to 10 MPH.

WEDNESDAY: Cloudy. Snow likely with accumulation of up to a few inches possible, except rain/mix along the South Coast. Highs 31-38. Wind NE 5-15 MPH, a few higher gusts especially in coastal areas.

WEDNESDAY NIGHT: Clearing. Lows 22-29. Wind N 5-15 MPH.

THURSDAY: Sun/cloud mix. Highs 35-42. Wind NW 10-20 MPH.

THURSDAY NIGHT: Variably cloudy. Lows 25-32. Wind SW 5-15 MPH.

FRIDAY: Mostly cloudy. Chance of light rain and snow. Highs 35-42. Wind variable 5-15 MPH.

DAYS 6-10 (DECEMBER 11-15)

Active pattern continues. Odds favor a low pressure system passing northwest of our area over the weekend of December 11-12 with some rain showers that may end as snow showers as colder air returns to the region after a mild shot of air initially. Another unsettled weather system should arrive before the end of the period but timing and details are not possible.

DAYS 11-15 (DECEMBER 16-20)

Hints of a colder trend that may eventually lead to a winter precipitation chance or two. This is a very low confidence outlook.

C-19 Chat Post – December 6 2021

COMMENTARY

It’s not often you get two of these in a row out of me, but I feel compelled to comment again here in the blog post (and not the comments section only) about what I said yesterday, and a couple other things. As we often see, many people (including some media members) nearly skip over a weather situation in the short term (in this case Monday), because it doesn’t have snow involved in it, and jump right to something beyond day 3 (in this case Wednesday, which is currently day 4) because they can use the “s” word. Fine if you want to talk about it, but if you are in media you better have your focus on the event sooner-to-come, especially since it may result in localized damage due to strong wind gusts. I’ve been disappointed by media that should know better already this weekend. I’ve seen an on-air snow map for a system that was 4 days away, with detail, and spoken about as if it was absolute. I’ve seen discussions putting emphasis on tools that just 24 hours before were declared unreliable. No, they don’t have to answer to me. I’m not their authority. I may be a meteorologist myself, but I am also a viewer, and they owe their viewers something a little better in my opinion. There’s a logical method to all of this. But we still have to jump to the exciting thing because it gets people listening, right?! I don’t agree with it, at least the way it’s done in today’s media world. I never have and I ever will. So on I go, my way as usual…

DAYS 1-5 (DECEMBER 5-9)

If you were out and about last evening you may have seen a few flakes of snow or drops of rain. I drove through some of each between Milford and Woburn MA. This was the last gasp of a dissipating clipper system that prompted me to put the insignificant precipitation in last night’s forecast. With that out of the way, we enjoy a dry but somewhat chilly day today, but with a lack of wind out there it won’t really feel all that bad. But we have some changes on the way, so get ready to ride the weather roller coaster once again. The rest of this discussion will be very similar to yesterday’s. Today’s high pressure area will shift offshore tonight and we’ll come under the influence of a strong low pressure system passing to our north Monday. First, its warm front will produce some rain Monday morning (which may start as a brief mix of rain and frozen precipitation over the interior higher elevations in the pre-dawn hours of Monday). Right after that we’ll be in the warm sector of the system with a gusty southwesterly wind and lots of clouds, but a lack of rainfall, with the exception of the South Coast region which may experience some isolated but potentially strong showers and even thunderstorms, a few of which may produce locally damaging winds. The cold front trailing the low passing by to our north will charge across the region from west to east Monday evening, accompanied by rain showers and possibly a thunderstorm, along with gusty and shifting winds, followed by a sharp temperature drop after an unseasonably warm day. Tuesday’s weather will be dry but blustery and up to 25 or 30 degrees colder than Monday – a bit of a shock to the system. We then can turn our attention to the next low pressure system approaching, clearly set to take a track much further south than its predecessor, and with cold enough air in place here we’ll be talking about at least some frozen precipitation (yes, snow) for at least a portion of the region. With the track and strength of the low center still in question, it’s still too early to determine precipitation type and intensity for any specific location, but with it being day 4 at this point, I can say that odds continue to favor a mostly snow event for interior areas such as southwestern NH and central MA, with odds favoring more of a rain event for the South Coast, and some combination of liquid and frozen precipitation in between. I’ll bring this into better focus for tomorrow’s blog post, but for now just be ready for our first fairly widespread winter weather threat. Following that system, expect fair, chilly weather Thursday as low pressure moves away and high pressure moves in.

TODAY: Partly cloudy. Highs 37-44. Wind N up to 10 MPH.

TONIGHT: Increasing clouds. Chance of light rain overnight that may begin briefly as snow and/or sleet interior higher elevations. Lows 30-37 evening, rising into the 40s overnight. Wind variable under 10 MPH evening, SE 5-15 MPH overnight.

MONDAY: Cloudy with a chance of rain early, then mostly cloudy to partly sunny. Slight chance of an isolated rain shower or thunderstorm near the South Coast mid morning to early afternoon. Highs 61-68. Wind SW 10-20 MPH, frequent gusts 30-40 MPH and occasional gusts above 40 MPH.

MONDAY NIGHT: Mostly cloudy evening with a passing rain shower and potential downpour with possible thunder and/or small hail west to east. Partly cloudy overnight. Lows 33-40. Wind SW 10-20 MPH gusting 30-40 MPH and potentially higher in any convective activity, shifting to NW from west to east.

TUESDAY: Partly cloudy. Temperatures steady 33-40. Wind NW 10-20 MPH with higher gusts, diminishing later in the day.

TUESDAY NIGHT: Increasing clouds. Lows 23-30. Wind variable up to 10 MPH.

WEDNESDAY: Cloudy. Snow/mix likely southern NH and interior MA, snow/mix/rain elsewhere with rain favoring the South Coast region. Highs 33-40. Wind NE 5-15 MPH, higher gusts.

WEDNESDAY NIGHT: Cloudy with precipitation tapering off. Lows 26-33. Wind N 5-15 MPH, higher gusts.

THURSDAY: Sun/cloud mix. Highs 35-42. Wind NW 10-20 MPH.

DAYS 6-10 (DECEMBER 10-14)

The active weather pattern continues but model guidance remains unreliable. Watching for a weak low pressure area to bring a minor precipitation threat December 10. Another period of unsettled weather may occur in the December 12-14 window, with odds favoring a milder system.

DAYS 11-15 (DECEMBER 15-19)

Hints of a colder trend that may eventually lead to another winter precipitation chance or two. This is a very low confidence outlook.

C-19 Chat Post – December 5 2021

COMMENTARY

Reminder for model watchers: Do NOT get hung up on anything you see beyond 3-days in advance. A perfect example, the day 5 forecast between the 00z run for the Canadian, US, and European models all differ enough that a forecast made verbatim from each of them would look like a forecast for 3 different low pressure systems impacting the region. And this applies to everybody regarding their weather app forecasts beyond a couple days. Some of this guidance is already 24 hours off on day-of-impact with things under a week away, and when they have the right day other things are wrong. Do yourself a favor and listen to meteorological discussions that have taken into account glaring model issues in this weather pattern…

DAYS 1-5 (DECEMBER 4-8)

A chilly weekend is in store for us but nothing outrageously cold. The remains of a dissipating clipper low will be moving in today and you’ll notice it in the form of clouds. These clouds have the potential to release a few snowflakes but the air is dry enough that they may never reach ground where they fall. A sliver of high pressure brings fair weather for Sunday. Timing worked out for a generally nice weekend, but we’re still in an active pattern and there will be two low pressure systems to contend with before this 5-day period ends. The first one will be a strong low that I’m confident will be heading east northeastward from the Great Lakes across southeastern Canada on Monday. Its warm front will come through during the early to mid morning when we have our best chance of rain. After that, it’s time for a warm wind from the southwest behind the warm front and ahead of an approaching strong cold front. The wind will be quite gusty so if you have outdoor decorations vulnerable to wind you’ll want to secure them before this weekend is over, if you have not done so already. While the region is in the warm sector, the atmosphere will be unstable enough so that we may see a couple of isolated showers and even thunderstorms Monday afternoon favoring the South Coast region. It would be these that would have the best potential to produce damaging wind gusts, even show some rotation. The timing of Monday’s cold front appears to be evening, after sunset, from west to east, and it should produce a band of rain showers, a few of which may be heavy and contain small hail, with even the possibility of a thunderstorm. Gusty, shifting winds will occur with the passage of this front. Following the frontal passage will come a sharp temperature drop and Tuesday, while dry, is going to be up to 30 degrees colder than what we have Monday. Classic La Nina temperature roller coaster pattern. This cold air sets up the potential for frozen precipitation for at least portions of the region for the next low pressure threat, which is Wednesday. Keeping in mind this is day 5, the only thing I can say at this point is this low track will be much further south than Monday’s, passing over or just south of New England, with highest probability of snow/sleet being over interior locations and a higher chance of mix/rain closer to the coast. Fine-tuning of both the low’s track and resultant precipitation type and intensity/accumulation will take place as this event gets closer, and after we improve the focus a little bit for tomorrow’s blog post, it will be Monday’s discussion will contain much more detail on the system. I will tell you that I’ve already seen snow amounts mentioned somewhere in media for this system. I will not say where, but I will say that I highly disagree with such a practice for any system that far in advance and most especially for something occurring in the situation I discussed in my commentary…

TODAY: Sun/cloud mix. Highs 36-43. Wind W up to 10 MPH.

TONIGHT: Variably cloudy. Slight chance of a very light snow shower. Lows 21-28. Wind NW up to 10 MPH.

SUNDAY: Mostly sunny. Highs 37-44. Wind N up to 10 MPH.

SUNDAY NIGHT: Increasing clouds. Chance of light rain overnight. Lows 30-37 evening, rising into the 40s overnight. Wind variable under 10 MPH evening, S 5-15 MPH overnight.

MONDAY: Cloudy with a chance of rain early, then mostly cloudy to partly sunny. Slight chance of an isolated rain shower or thunderstorm near the South Coast in the afternoon. Highs 61-68. Wind SW 10-20 MPH, gusts 30-40 MPH and slight chance of gusts above 40 MPH.

MONDAY NIGHT: Mostly cloudy evening with a passing rain shower and potential downpour with possible thunder and/or small hail west to east. Partly cloudy overnight. Lows 33-40. Wind SW 10-20 MPH gusting 30-40 MPH and potentially higher in any convective activity, shifting to NW from west to east.

TUESDAY: Partly cloudy. Temperatures steady 33-40. Wind NW 10-20 MPH with higher gusts, diminishing later in the day.

TUESDAY NIGHT: Increasing clouds. Lows 23-30. Wind variable up to 10 MPH.

WEDNESDAY: Cloudy. Rain and snow likely. Highs 33-40. Wind NE 5-15 MPH.

DAYS 6-10 (DECEMBER 9-13)

The active weather pattern continues but model guidance is not reliable. Best guess is that a weak low pressure area brings a minor precipitation threat December 10 and a stronger one tracks north of the region later in the period with a milder surge and a rain chance of some kind.

DAYS 11-15 (DECEMBER 14-18)

Mild and active pattern to start with a chance or two of unsettled weather from passing systems through the middle of this period and then the chances of a return to some cold for later in the period.