C-19 Chat Post – December 29 2020

DAYS 1-5 (DECEMBER 28 – JANUARY 1)

The next-to-next-to-next-to-last day of 2020 (today) will be a mild one by late December standards as low pressure tracks east northeastward down the St. Lawrence Valley and a warm front goes by this morning followed by a late-day cold frontal passage. This moisture-starved system will bring only the threat of a rain shower ahead of or along its cold front and despite dominant cloudiness much of the day, we may see some clearing late today. The next-to-next-to-last day of 2020 (Tuesday) will feature a cold wind but dry weather with sun & a few clouds as we’ll be between departing low pressure in eastern Canada and approaching Canadian high pressure. The next-to-last day of 2020 (Wednesday) will be cold but tranquil as high pressure builds over the region, though some high cloudiness will show up. The last day of 2020 (Thursday a.k.a. New Year’s Eve), much like today, will feature lots of clouds and milder air ahead of yet another low pressure area taking a similar track north of our area, and there may be a few rain showers during the day, although these should exit by evening for any limited outdoor festivities taking place that night, just as colder air arrives. The first day of 2021 holds the most complex outlook of this 5-day period, as cold high pressure will have built into eastern Canada while another low pressure area approaches New England from the southwest. Cold air will be stubborn, at least at the surface, as the moisture from this system arrives during the day – a set-up for potential icing conditions and maybe some frozen precipitation, before rain becomes dominant, but all of this will depend on the depth of the cold air and how difficult it is to dislodge. Obviously, fine-tuning will be necessary as this event draws closer.

TODAY: Mostly cloudy through early afternoon then partial sun by late day. Chance of passing rain showers, especially during the afternoon hours. Highs 43-50. Wind S 10-20 MPH.

TONIGHT: Partly cloudy evening. Clearing overnight. Lows 26-31. Wind W 10-20 MPH.

TUESDAY: Sun & passing clouds. Highs 32-39. Wind NW 10-20 MPH.

TUESDAY NIGHT: Clearing. Lows 13-20. Wind NW 5-15 MPH, diminishing.

WEDNESDAY: Sun & high clouds. Highs 33-40. Wind W up to 10 MPH.

WEDNESDAY NIGHT: Partly cloudy. Lows 23-30. Wind S under 10 MPH.

THURSDAY: Mostly cloudy. Chance of rain showers. Highs 45-52. Wind SW 5-15 MPH.

THURSDAY NIGHT (NEW YEAR’S EVE): Mostly cloudy. Lows 28-35. Wind N 5-15 MPH evening, diminishing overnight.

FRIDAY (NEW YEAR’S DAY): Overcast. Rain arriving from southwest to northeast, may begin as freezing rain and/or sleet in some locations. Highs 33-40. Wind N to NE 5-15 MPH.

DAYS 6-10 (JANUARY 2-6)

Low pressure exits during January 2 which starts wet then ends dry & colder. High pressure builds in with dry and cold weather for January 3. Low pressure may pass close to or south of the region with an unsettled weather threat January 4 with the next system likely to be one passing north of the region with milder air and rain showers by January 6, but this being quite a few days away it’s not a high confidence outlook.

DAYS 11-15 (JANUARY 7-11)

Much of this period looks quiet other than a chance of some unsettled weather about January 8. The overall pattern may be shifting to more of a blocking set-up here though which has some potential implications for mid January.

C-19 Chat Post – December 28 2020

DAYS 1-5 (DECEMBER 27-31)

High pressure provides us with bright but cold weather today, and as we come down the home stretch to the finish line of 2020 we’ll be seeing a few more changes in the weather. First, a broad but moisture-starved area of low pressure passes north of our area Monday, dragging its warm front through the region during the morning with lots of cloudiness, then its cold front through in the afternoon with perhaps a rain shower as milder air will have taken over. But quickly behind this comes another shot of cold air between the departing low via eastern Canada and approaching high pressure in the Great Lakes Monday night and Tuesday with a gusty breeze. High pressure will settle over the region then slip to the south with fair and seasonably chilly weather Wednesday. By Thursday, weaker low pressure will travel eastward, passing north of this area but dragging a cold front through. This front may be accompanied by a few rain showers.

TODAY: Mostly sunny. Highs 34-41. Wind W 5-15 MPH becoming variable under 10 MPH.

TONIGHT: Increasing clouds. Lows 25-32. Wind S up to 10 MPH.

MONDAY: Mostly cloudy morning. Partly sunny with a passing rain shower possible afternoon. Highs 43-50. Wind S 10-20 MPH.

MONDAY NIGHT: Partly cloudy evening. Clearing overnight. Lows 26-31. Wind W 10-20 MPH.

TUESDAY: Sun/cloud mix. Highs 34-41. Wind NW 10-20 MPH.

TUESDAY NIGHT: Clearing. Lows 18-25. Wind NW 5-15 MPH.

WEDNESDAY: Sunny. Highs 33-40. Wind W 5-15 MPH, diminishing.

WEDNESDAY NIGHT: Partly cloudy. Lows 23-30. Wind S under 10 MPH.

THURSDAY: Variably cloudy. Chance of rain showers. Highs 45-52. Wind SW 5-15 MPH.

DAYS 6-10 (JANUARY 1-5)

As high pressure builds over eastern Canada and another low travels in our direction from the southwest, what yesterday’s guidance was showing more as a set-up similar to the one we had on Christmas, it now has been leaning toward a little more complex scenario where high pressure to the north is strong enough to force the low’s track a little further south and keep colder air in the region for New Year’s Day. This could be a set-up for a more complex precipitation situation, something we’ll have to keep a close eye on during the next several days. Any precipitation exits by early January 2 followed by dry/colder weather for the January 2-3 weekend. Temperatures moderate with a minor disturbance bringing a chance of mix/rain showers January 4 and/or 5.

DAYS 11-15 (JANUARY 6-10)

Best chances for unsettled weather from passing systems January 8 & 10. Evolution of pattern and storm track is a little uncertain at this time and we’ll be watching for some blocking to potentially set up before the end of this period which could shift the track of future storms more to the south.

C-19 Chat Post – December 27 2020

COMMENTARY

10 years ago today I published the first blog entry here as we were dealing with a significant winter storm. That was fun, and it’s been an interesting and fun ride since. Thank you everybody who has supported this blog during its first decade of existence!

DAYS 1-5 (DECEMBER 25-29)

Back to seasonably cold weather for this weekend. Today we may see some snow showers making their way all the way across New England via the Great Lakes, so while we have a mixed sky, some of those clouds may release some snowflakes and even brief minor accumulations in some areas. While today is rather blustery, Sunday will end up more tranquil with less wind, more sun, and no snow shower threat. Low pressure will track eastward, passing north of New England early in the week, bringing milder air and clouds in during Monday with a few rain showers, but perhaps a few snow showers west and north of Boston in the evening as colder air returns. Regardless, this will be a minor system and serve mostly to bring a new shot of cold air in for Tuesday, with wind and possibly a passing snow shower, followed by cold but more tranquil weather as high pressure builds in by Wednesday.

TODAY: Sun/cloud mix. Passing snow shower possible, a few of which may result in minor accumulation. Highs 32-39. Wind W 10-20 MPH, higher gusts.

TONIGHT: Clear. Lows 17-24. Wind NW 5-15 MPH.

SUNDAY: Mostly sunny. Highs 34-41. Wind W 5-15 MPH.

SUNDAY NIGHT: Partly cloudy. Lows 25-32. Wind SW 5-10 MPH.

MONDAY: Variably cloudy. Chance of rain showers. Highs 42-49. Wind SW 10-20 MPH

MONDAY NIGHT: Variably cloudy evening with a rain or snow shower. Clearing overnight. Lows 26-31. Wind W 10-20 MPH.

TUESDAY: Partly cloudy. Chance of a passing light snow shower. Highs 35-42. Wind NW 10-20 MPH.

TUESDAY NIGHT: Clearing. Lows 18-25. Wind NW 5-15 MPH.

WEDNESDAY: Sunny. Highs 33-40. Wind NW 5-15 MPH, diminishing.

DAYS 6-10 (DECEMBER 31– JANUARY 4)

High pressure shifts offshore December 31 with fair and milder weather. Low pressure tracks across southeastern Canada with its frontal system bringing the chance of some rain shower activity here for January 1. Colder/drier January 2-3 followed by moderation and a risk of unsettled weather returning to the region by the end of the period on January 4.

DAYS 11-15 (JANUARY 5-9)

Best chances for unsettled weather from passing systems January 5 & 8. Evolution of pattern and storm track is a little uncertain at this time and we’ll be watching for some blocking to potentially set up before the end of this period which could shift the track of future storms more to the south.

C-19 Chat Post – December 26 2020

Merry Christmas to all who are celebrating it today!

DAYS 1-5 (DECEMBER 25-29)

A warm wind & rain for Christmas Morning 2020. We have had a variety of weather on Christmas Day over the years & decades – nothing unusual since we live in a part of the world that sees great variety. Hopefully the power outage issue will be as minimal as possible. Look for poor drainage and small stream flooding this morning due to the heavy rainfall, so be aware of that if traveling. As the rain gradually ends later today and wind backs off, we can be thankful that drying should take place for a number of hours before the temperatures drop below freezing, so we will avoid a flash freeze, but not necessarily some icy areas that will form eventually with any standing water and wet, untreated surfaces, so be aware of that later this evening and into Saturday morning. In addition, the advection of cold air from Canada via the Great Lakes will carry with it some remnant snow showers from lake-effect snows, and we may see some flakes flying at times tonight and Saturday, but not to worry – it won’t be an accumulation snow event. A few rivers may get near flood stage on Saturday, but should, for the most part, be able to handle the run off from rain and melting snow. Dry and cold weather is expected for Sunday as high pressure dominates. Early next week, our next unsettled weather threat times out for later Monday, but looks fairly benign, just a period of rain and possible snow showers as low pressure tracks north of the region. Behind it will come a shot of colder air with dry weather for Tuesday.

TODAY (CHRISTMAS DAY): Overcast with widespread rain showers, some heavy, and a chance of thunder, tapering off from west to east by late day. Areas of fog early. Highs 55-62 early, then cooling to the 40s during the day. Wind S 15-30 MPH, gusts as high as 45-60 MPH, strongest in exposed areas, shifting to W and diminishing during the day.

TONIGHT: Variably cloudy with a chance of snow showers. Lows 25-32. Wind W 15-25 MPH and gusty.

SATURDAY: Sun and passing clouds. Highs 32-39. Wind W 10-20 MPH and gusty.

SATURDAY NIGHT: Clear. Lows 15-22. Wind NW 5-10 MPH.

SUNDAY: Mostly sunny. Highs 33-40. Wind W 5-15 MPH.

SUNDAY NIGHT: Partly cloudy. Lows 23-30. Wind SW 5-10 MPH.

MONDAY: Variably cloudy. Chance of rain and/or snow showers late-day. Highs 37-44. Wind SW 10-20 MPH.

MONDAY NIGHT: Mostly cloudy evening with a rain or snow shower. Clearing overnight. Lows 26-31. Wind W 10-20 MPH.

TUESDAY: Partly cloudy. Highs 35-42. Wind NW 10-20 MPH.

DAYS 6-10 (DECEMBER 30 – JANUARY 3)

Dry and seasonably chilly December 30 as high pressure dominates. Similar to this week, high pressure moves offshore for New Year’s Eve with moderating temperatures as low pressure heads for the St. Lawrence Valley, passing northwest of New England, bringing a chance of rain showers for the first day of 2021, followed by drier and colder weather January 2-3.

DAYS 11-15 (JANUARY 4-8)

Milder but unsettled weather expected January 4-5, details dependent on the track of low pressure moving through the Northeast. Drier/colder January 6-7 then the next chance of unsettled weather comes at the end of the period.

C-19 Chat Post – December 25 2020

DAYS 1-5 (DECEMBER 24-28)

Not bad today as high pressure slips offshore, and while there will be a lot of clouds around, it will turn milder with a bit of an increase wind before the end of the day – but decent for any day-before-Christmas errands you may have. The well-advertised “event”, which really is going to be a glorified cold frontal passage, will take place Christmas Day, arriving as increasing southerly wind and warming temperatures first during Santa’s visit, peaking as a band of moderate to heavy rain showers, possible thunder, and additional strong wind gusts well into Christmas morning, before the front passes, rain showers taper off, and wind settles back after shifting to west. Yes, wind damage and flooding are both a concern, wind damage and some resultant power outages most especially. Flooding is going to depend on several factors – how much rain, the state of storm drains, quick-filling streams, and structures vulnerable to basement flooding especially when there is snow on the ground. This will vary from place to place, but if you are prone to seeing flooding, please be aware. As far as rainfall amounts, even under 24 hours before the main rain event, the guidance is still not really in agreement on how much will take place, with some short range guidance having amounts under 1.00 inch near the MA East Coast with a bit more to the west and over Cape Cod to the ECMWF (Euro) having widespread 2-3 inch rainfall amounts. At the moment, I side a little more with the lower numbers. Regardless of how much rain falls, thankfully, because of a decent gap of time between the end of the rain and the arrival of below freezing temperatures, we can rule out a flash freeze. However, standing water and any surfaces that don’t dry off or are untreated will end up icing over later Friday night into Saturday morning. The weekend itself will feature cold and dry weather due to Canadian high pressure. The next low pressure system approaches on Monday, with the current thinking is that this low, fairly moisture starved, will head through the Great Lakes bringing a rain/snow shower risk here by late Monday.

TODAY: Mostly cloudy. Highs 45-52. Wind S 5-15 MPH, gusts above 20 MPH.

TONIGHT (CHRISTMAS EVE): Cloudy. Rain showers arriving west to east overnight. Areas of fog. Temperatures rise to 48-55. Wind S 15-25 MPH, higher gusts, as high as 50-60 MPH especially in coastal areas and higher elevations, strongest toward dawn.

FRIDAY (CHRISTMAS DAY): Cloudy. Areas of fog early. Widespread rain showers, some heavy, and embedded thunderstorms possible morning into midday, tapering off from west to east during the afternoon. Highs 53-60 morning, falling into the 40s by late-day. Wind S 15-30 MPH with gusts as high as 50-60 MPH, especially coastal areas and higher elevations, during the morning, shifting to W and diminishing somewhat during the afternoon.

FRIDAY NIGHT: Variably cloudy with a chance of snow showers. Lows 25-32. Wind W 15-25 MPH and gusty.

SATURDAY: Sun and passing clouds. Highs 32-39. Wind W 10-20 MPH and gusty.

SATURDAY NIGHT: Clear. Lows 15-22. Wind NW 5-10 MPH.

SUNDAY: Mostly sunny. Highs 33-40. Wind W 5-15 MPH.

SUNDAY NIGHT: Partly cloudy. Lows 23-30. Wind SW 5-10 MPH.

MONDAY: Variably cloudy. Chance of rain and/or snow showers late-day. Highs 35-42. Wind SW 10-20 MPH.

DAYS 6-10 (DECEMBER 29 – JANUARY 2)

Drier, shot of colder air December 29-30 then turning milder December 31 as 2020 goes out with fairly quiet weather. Next threat of unsettled weather comes on the first day of 2021 followed by fair weather on January 2.

DAYS 11-15 (JANUARY 3-7)

Dry/chilly January 3, milder/unsettled January 4-5, colder/dry January 6-7.

C-19 Chat Post – December 24 2020

DAYS 1-5 (DECEMBER 23-27)

Don’t look now, but we’ve already gained 10 seconds of daylight back! You won’t really notice it for a week or 2, but the days are indeed getting longer, post-solstice. The rate of increase is very slow at first, but will pick up the pace as we head through the winter. Speaking of winter, it will feel like it today as high pressure brings dry and seasonably cold weather to our region. You’ll notice some high cloudiness starting to increase as the day goes on. This is a signal of the approach of a warmer air mass. The warmer air, being less dense than colder air, rides up and over it at first, creating the high clouds. Eventually that warmer air mass will arrive at the surface in a gradual way on Thursday, which will feature lots of clouds but some intervals of sun. I expect the daylight hours to be rain-free. As we get deeper into Christmas Eve, our rain shower chance will go up, but it looks like most of the rainfall will hold off until the pre-dawn hours of Christmas morning for arrival, and a ribbon of moderate to heavy rain showers will traverse the region during the morning, exiting west to east by midday and afternoon. During the wet weather time will be the strongest winds, from the south, 15-30 MPH with gusts in the 35-55 MPH range. A few gusts above that are possible in higher elevations, such as Blue Hill in Milton MA. After the main rain shower area exits, the wind, while still gusty, will have shifted to the west and dropped off somewhat during the remainder of Christmas Day, and a stray snow shower may wander into the region as a breakaway from a Great Lakes snow squalls. Canadian high pressure builds in for the weekend with cold and dry conditions.

TODAY: Mostly sunny. Highs 33-40. Wind NW 5-15 MPH, diminishing.

TONIGHT: Partly cloudy. Lows 20-27. Wind SW up to 10 MPH.

THURSDAY: Mostly cloudy. Highs 45-52. Wind S 5-15 MPH.

THURSDAY NIGHT (CHRISTMAS EVE): Cloudy. Rain showers likely, mainly overnight. Temperatures rise to 48-55. Wind S 15-25 MPH, higher gusts, as high as 40-50 MPH especially in coastal areas and higher elevations, strongest toward dawn.

FRIDAY (CHRISTMAS DAY): Cloudy morning with rain showers, some heavy. Breaking clouds and rain showers ending early afternoon, then a risk of a snow shower late rin the day. Highs 50-57 early then temperatures fall through the 40s and into the 30s. Wind S 15-25 MPH with higher gusts, shifting to W.

FRIDAY NIGHT: Variably cloudy with a chance of snow showers. Lows 18-25. Wind W 15-25 MPH and gusty.

SATURDAY: Sun and passing clouds. Highs 28-35. Wind W 10-20 MPH and gusty.

SATURDAY NIGHT: Clear. Lows 15-22. Wind NW 5-10 MPH.

SUNDAY: Mostly sunny. Highs 32-39. Wind variable 5-15 MPH.

DAYS 6-10 (DECEMBER 28 – JANUARY 1)

Unsettled weather threat in the December 28-29 period, early indications are low pressure passing north of here with rain and snow showers. Fair and seasonably chilly weather returns to end the year, then the next storm threat looms for New Year’s Day.

DAYS 11-15 (JANUARY 2-6)

Dry/chilly January 2-3, milder/unsettled January 4-5, colder/dry January 6.

C-19 Chat Post – December 23 2020

DAYS 1-5 (DECEMBER 22-26)

Drying air eliminates any patchy fog early today and then we will see a sun/cloud mix as an upper level disturbance crosses the region, but with only a minimal chance of a passing snow flurry. This system will result mainly a shot of chilly air with gusty winds developing. It will remain cold but become more tranquil Wednesday as high pressure crosses the region. This high shifts offshore and allows temperatures to moderate on Christmas Eve as a low pressure area heads northeastward into southeastern Canada via the Great Lakes. The strong cold front trailing from this low will develop a wave of low pressure over the Appalachians which will move through NY in the early hours of Christmas Day and whip the front through the region with a short period of rain showers and very mild air, then a quick temperature drop behind it with drying weather and just a chance of a few snow showers surviving the trip from the Great Lakes region. Look for a chilly and breezy but dry Saturday between low pressure in the Canadian Maritimes and high pressure in the Appalachians.

TODAY: Any early freezing fog patches dissipate but watch for areas of black ice. Sun/cloud mix. Slight chance of a passing light snow shower. Highs 34-41. Wind NW 5-15 MPH, higher gusts.

Mostly cloudy. Snow showers likely, except rain or snow showers South Coast. Highs 35-42. Wind W 5-15 MPH, higher gusts.

TONIGHT: Clearing. Lows 15-22. Wind NW 5-15 MPH, higher gusts.

WEDNESDAY: Mostly sunny. Highs 31-38. Wind NW 5-15 MPH, diminishing.

WEDNESDAY NIGHT: Mostly clear. Lows 18-25. Wind SW up to 10 MPH.

THURSDAY: Partly sunny. Highs 38-45. Wind S 5-15 MPH.

THURSDAY NIGHT (CHRISTMAS EVE): Cloudy. Rain showers likely. Temperatures rise to 48-55. Wind S 15-25 MPH, higher gusts, as high as 40-50 MPH especially in coastal areas and higher elevations,.

FRIDAY (CHRISTMAS DAY): Cloudy start with rain showers possibly ending as snow showers, then a sun/cloud mix with a possible snow shower. Highs 50-57 early then temperatures fall through the 40s and into the 30s. Wind S 15-25 MPH with higher gusts, shifting to W.

FRIDAY NIGHT: Variably cloudy with a chance of snow showers. Lows 18-25. Wind W 15-25 MPH and gusty.

SATURDAY: Sun and passing clouds. Highs 28-35. Wind W 10-20 MPH and gusty.

DAYS 6-10 (DECEMBER 27-31)

Fair and seasonably cold December 27. A storm threat in the December 28-29 period. Fair and seasonably chilly weather returns to end the year.

DAYS 11-15 (JANUARY 1-5)

2021 may begin with a rain/mix/snow threat followed by dry weather, a cold shot, then moderation.

C-19 Chat Post – December 22 2020