C-19 Chat Post – February 21 2021

DAYS 1-5 (FEBRUARY 20-24)

Like little sprinkles of powdered sugar upon the wintry cake Mother Nature slow baked for us over the last couple days, light snow showers are adding some flakes to the top as they roam across the region this morning from south central and southeastern NH across parts of eastern MA. Actually, the atmosphere being somewhat unstable today, we may see a few more of these pop up through the afternoon, but with no accumulation, and most of the day generally dry and cold in a northwest flow behind the storm and in advance of high pressure, which today will be centered over the eastern Ohio Valley. This high center will slide eastward just to the south of New England Sunday, which will feature lots of sun and less wind, but still chilly air. The jet stream express train will bring the next low pressure system into and across New England Monday, center passing north of our area Monday evening. Its trailing warm front / cold front combo will bring a period or two of precipitation, probably starting as snow for most (maybe mix/rain South Coast) but a warmer air invasion above will probably flip this to a rain situation for most areas in the I-95 belt southeastward, with snow most likely holding on well to the northwest in north central MA and southwestern NH, with a mix zone between. This will not be a big precipitation producer. I’ll just have to detail the precip-type distribution as it gets closer. This system is out of here and fair weather returns for Tuesday and Wednesday, first with a bit cooler air Tuesday, then a quick moderation for Wednesday. If it were not for snow cover that will still be on the ground, we’d probably reach or exceed 50 that day, but my early call is to hold the temperatures in the 40s due to the refrigeration-effect. Still, looks like a nice day Wednesday – one that may kick-start your spring dreams. 🙂 Just remember where we live and don’t get too used to the milder air. 😉

TODAY: Clouds dominant this morning with a few snow showers likely. Variably cloudy, bit more sun, but also isolated snow showers afternoon. Highs 28-35. Wind NW increasing to 10-20 MPH, a few higher gusts possible.

TONIGHT: Clearing. Lows 12-19. Wind NW 5-15 MPH, diminishing.

SUNDAY: Mostly sunny. Highs 28-35. Wind NW up to 10 MPH morning, becoming variable.

SUNDAY NIGHT: Increasing clouds. Lows 18-25. Wind variable under 10 MPH.

MONDAY: Cloudy. Snow/mix arriving midday-afternoon, becoming mix interior and northwest and rain coastal and southeastern areas. Highs 35-42. Wind variable 5-15 MPH.

MONDAY NIGHT: Clearing. Lows 25-32. Wind W 5-15 MPH.

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

TUESDAY NIGHT: Clear. Lows 15-22. Wind W under 10 MPH.

WEDNESDAY: Partly cloudy. Evening rain showers possible. Highs 41-48. Wind SW 10-20 MPH.

DAYS 6-10 (FEBRUARY 25 – MARCH 1)

Quick turn to colder but dry weather February 25-26 – small storm system may pass south of the region February 26. Next threat of unsettled weather comes over the February 27-28 weekend with fair weather returning to end the period. This represents a more zonal flow pattern.

DAYS 11-15 (MARCH 2-6)

West to northwest flow pattern expected. Low confidence on timing, but early call is unsettled weather with passing low pressure March 2, variable temperatures, one more disturbance around mid period and a shot of colder air following.

C-19 Chat Post – February 20 2021

DAYS 1-5 (FEBRUARY 19-23)

Elongated low pressure passing just south of New England will continue to cause episodes of snow with additional slow-building accumulation through this evening before gradually ending as snow showers overnight tonight. Additional snowfall accumulations from this system will be 2 to 5 inches, most areas seeing 4 or less additional, but spot 5 inch amounts possible with some ocean-enhancement potential from Seacoast NH into eastern MA. This will bring the snowfall totals for the entire event mostly into the lower halves of the 2-4/4-8 inch ranges previously mentioned, with only spot locations getting to around 6+ total. But again one more reminder that the long-duration of this event and the lack of pavement accumulation of snow make it a less impactful system than if we were getting all of the snowfall accumulation from a heavier burst over a shorter period of time. Saturday, some instability will mean additional passing clouds and possible snow showers, along with a gusty breeze, before high pressure builds in for a dry and cold but more tranquil Sunday with less wind. Low pressure crosses the region Monday with unsettled weather – a precipitation shield that will have a rain/snow line to fine-tune. High pressure builds in with fair weather returning Tuesday.

THROUGH THIS EVENING: Overcast with periodic to frequent snow, except mixed with sleet at times South Coast and islands and possibly rain for a time Nantucket. Additional snowfall accumulation (not including what has already fallen), 2 to 5 inches, most areas under 4 inches. Total snowfall accumulation for event 4 to8 inches with any greater-than-6 inch amounts isolated and favoring eastern MA. Temperatures generally steady 27-34. Wind N to NE 5-15 MPH.

TONIGHT: Mostly cloudy with a chance of snow showers. Lows 20-27. Wind N to NW 10-20 MPH.

SATURDAY: Sun/cloud mix. Risk of passing snow showers. Highs 28-35. Wind NW 10-20 MPH, higher gusts.

SATURDAY NIGHT: Clearing. Lows 12-19. Wind NW 5-15 MPH, diminishing.

SUNDAY: Mostly sunny. Highs 28-35. Wind NW up to 10 MPH morning, becoming variable.

SUNDAY NIGHT: Increasing clouds. Lows 18-25. Wind variable under 10 MPH.

MONDAY: Cloudy. Snow/mix/rain likely. Highs 35-42. Wind variable 5-15 MPH.

MONDAY NIGHT: Clearing. Lows 25-32. Wind W 5-15 MPH.

TUESDAY: Mostly sunny. Highs 35-42. Wind W 5-15 MPH.

DAYS 6-10 (FEBRUARY 24-28)

Medium range guidance is struggling trying to identify how things play out as we head through the final days of February. My current feel is that we get back into another boundary zone and have a couple opportunities for unsettled weather, but timing and precipitation type for these would be impossible to really elaborate on this far in advance. Re-evaluation to come.

DAYS 11-15 (MARCH 1-5)

West to northwest flow pattern expected. At least one Pacific low pressure area should make its way across the country to visit us in the early days of March, once again timing uncertain this far into the future. We’ll have to keep an eye on additional cold air building in Canada in early March.

C-19 Chat Post – February 19 2021

DAYS 1-5 (FEBRUARY 18-22)

Around the net the last day or so I’ve experienced a lot of folks expecting a high impact storm. No. It’s NOT going to be a high impact storm. It’s going to be a long-duration event, as result of elongated low pressure broken up into a few centers, like an elongated soap bubble wobbling along, instead it will be stretched out low pressure passing just south of New England between today and Friday night. Several inches of snow falling over a 30+ hour period is not going to have a major impact, and it may be that the total accumulation in any given spot will never be how much new snow is actually on the ground, since some of this will melt as or not long after it falls during the daylight hours of Friday. So keep that in mind when viewing the forecast accumulations. A forecast of 4 to 8 inches does NOT mean you will have an instantaneous 8 inches of new snow sitting on every available surface. It may only be 4 inches, it may be 5, 6, 7, 8. The storm probably won’t over-achieve anywhere but it could very well under-achieve in places that happen to miss out on some of the steadier batches of snow. That’s the nature of this kind of system. I cannot stress that enough and it seems like collectively the lesson is never fully learned. Not every storm is a hard-hitting thump of heavy snow that drops all its accumulation in a handful of hours. The weather pattern we are in is conducive to just the kind of system we’re about to experience. At least this time it won’t be an ice storm for anybody. As far as the synoptics of the situation and the next few days go, there are no real changes. The long-lasting passage of the low pressure system takes place, and yes I still expect it to drop as much as 4-8 inches of snow (leaning toward the lower side of the range) in a large portion of the region with under 4 inches in southern NH and north central MA and possibly the islands south of Cape Cod, and then we see it exit by early Saturday, although some instability will mean additional passing clouds and maybe a snow flurry during Saturday, otherwise expect a dry weekend, on the cold side, with a gusty wind Saturday and a much calmer Sunday as high pressure arrives. But we’re not done with the active pattern just yet, and quickly comes another round of unsettled weather on Monday, but this time it will be from a fast-moving but more compact low pressure area, with a little milder air around, so we’ll probably be dealing with a snow/mix/rain situation, not too heavy, and we’ll have to wait until we’re a bit closer to the event for precipitation-type details. After all, that is day 5 of this forecast.

THROUGH FRIDAY EVENING: Overcast with periodic to frequent snow, except mixed with sleet at times South Coast and islands and possibly rain for a time Nantucket. Temperatures generally steady 27-34. Snowfall accumulation 4 to 8 inches except 2 to 4 inches islands and north central MA to southwestern NH. Wind N to NE 5-15 MPH.

FRIDAY NIGHT: Mostly cloudy with a chance of snow showers. Lows 20-27. Wind N to NW 10-20 MPH.

SATURDAY: Sun/cloud mix. Risk of a few passing light snow showers. Highs 27-34. Wind NW 10-20 MPH, higher gusts.

SATURDAY NIGHT: Clearing. Lows 12-19. Wind NW 5-15 MPH, diminishing.

SUNDAY: Mostly sunny. Highs 28-35. Wind NW up to 10 MPH morning, becoming variable.

SUNDAY NIGHT: Increasing clouds. Lows 18-25. Wind variable under 10 MPH.

MONDAY: Cloudy. Snow/mix/rain likely. Highs 35-42. Wind variable 5-15 MPH.

DAYS 6-10 (FEBRUARY 23-27)

High pressure moves in with fair and slightly milder weather middle of next week before low pressure brings the next unsettled weather threat later in the week.

DAYS 11-15 (FEBRUARY 28 – MARCH 4)

Fairly zomal pattern but may tilt more to a northwesterly flow after a quiet ending to February. The early days of March may feature a vigorous disturbance followed by a shot of cold air, but this is low confidence at this time.

C-19 Chat Post – February 18 2021

DAYS 1-5 (FEBRUARY 17-21)

An area of high pressure brings us dry and cold weather today. Elongated low pressure will take a couple of days to pass by our region (center passing just south of New England sometime Friday), bringing our next bout of wintry weather, which will be a fairly long-duration event, starting out slowly during Thursday afternoon and evening as periods of snow along the South Coast eventually expanding northward at night through Friday, when enough warm air may get in aloft to flip the precipitation to sleet or at least a mix of snow and sleet in the South Coast region, and maybe to rain over the islands, before it winds down as snow showers Friday night. Expect generally moderate snowfall accumulations from this event (4 to 8 inches), but some areas to the northwest may be lighter (2 to 4 inches) simply for not having enough moisture, and the South Coast may be a touch lower if mixing is involved. It’s also important to note that the accumulation will be taking place over a nearly 24 hour period and without bands of heavy snowfall with rapid rates of accumulation, so this will make the impact lower as far as travel and cleanup goes. We’re now at the time of winter where a higher sun angle makes it more difficult for snow that is not falling heavily to accumulate on roads during the daylight hours. Low pressure pulls away Saturday and the air flow between it and high pressure over the Great Lakes will cause it to be a blustery and cold but dry day. High pressure builds in with dry and cold but more tranquil weather for Sunday.

TODAY: Bright sun morning. Sun & high clouds afternoon. Highs 25-32. Wind NW 5-15 MPH, diminishing during the afternoon.

TONIGHT: Increasing high clouds. Lows 12-19. Wind N under 10 MPH.

THURSDAY: Thickening overcast. Periods of snow South Coast afternoon. Highs 24-31. Wind N to NE 5-15 MPH.

THURSDAY NIGHT: Overcast. Snow likely. Temperatures steady 24-31 evening may rise slightly overnight. Wind NE 5-15 MPH.

FRIDAY: Overcast. Periods of snow except sleet possible South Coast region and rain possible islands region. Highs 27-34. Wind NE 5-15 MPH, gusts over 20 MPH South Coast region.

FRIDAY NIGHT: Cloudy with periods of snow evening. Variably cloudy with scattered snow showers overnight. Lows 20-27. Wind N to NW 10-20 MPH.

SATURDAY: Sun/cloud mix. Highs 27-34. Wind NW 10-20 MPH, higher gusts.

SATURDAY NIGHT: Clearing. Lows 12-19. Wind NW 5-15 MPH, diminishing.

SUNDAY: Mostly sunny. Highs 28-35. Wind NW up to 10 MPH morning, becoming variable.

DAYS 6-10 (FEBRUARY 22-26)

Low pressure moves through the region with a rain/mix/snow threat February 22 then exits followed by dry weather few a few days before the next unsettled weather threat arrives for the end of the period. The long-standing blocking pattern eases and in response, temperatures moderate to near to above normal for much of the period.

DAYS 11-15 (FEBRUARY 27 – MARCH 3)

A somewhat more zonal pattern expected, bringing a couple disturbances and precipitation threats with up and down temperatures, likely mildest relative to normal to end February with a colder trend for the start of March. Low confidence based on timing uncertainties.

C-19 Chat Post – February 17 2021

DAYS 1-5 (FEBRUARY 16-20)

Low pressure cuts across the South Coast region this morning before exiting and taking its rainfall with it. After some icing conditions from freezing drizzle & freezing rain in a good portion of the region we thankfully saw the temperature climb to above freezing from southeast to northwest during the overnight, avoiding what could have been a more serious icing situation, but as drier and colder air moves in tonight behind this system, we will indeed have to watch for the formation of black ice on any untreated surfaces that are still wet – and there will likely be quite a few. High pressure brings bright and cold weather to our region Wednesday before the next in a series of low pressure areas makes a run at us later Thursday, passing just south of the region early Friday. This system will have colder air to work with and start as snow, with a few to several inches likely before a flip to sleet / freezing rain / rain, the details of which will be worked out for the next two blog updates. This storm system exits later Friday and sets us up for a cold and dry start to the weekend.

TODAY: Overcast with areas of rain (a few pockets of icing still possible interior valleys of north central MA and southwestern NH) this morning. Mainly cloudy with areas of fog this afternoon. Highs 33-40 except 40-47 far southeastern MA. Wind E to N 5-15 MPH except may be briefly SE to SW 10-20 MPH and gusty Nantucket area.

TOIGHT: Clearing. Lows 16-23. Wind N to NW 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 25-32. Wind NW 5-15 MPH.

WEDNESDAY NIGHT: Increasing high clouds. Lows 13-20. Wind N up to 10 MPH.

THURSDAY: Thickening overcast. Snow arriving southwest to northeast late day. Highs 25-32. Wind NE 5-15 MPH.

THURSDAY NIGHT: Overcast. Snow/sleet/freezing rain/rain likely, with greatest chance for frozen precipitation interior and north, greatest chance for freezing and/or liquid precipitation coast and south. Temperatures rise to 28-35. Wind NE to E 5-15 MPH.

FRIDAY: Overcast with snow/sleet/ice/rain morning. Breaking clouds afternoon. Highs 33-40. Wind E to N 5-15 MPH morning, NW 10-20 MPH afternoon.

FRIDAY NIGHT: Clearing. Lows 18-25. Wind NW 10-20 MPH.

SATURDAY: Partly cloudy. Highs 27-34. Wind NW 10-20 MPH.

DAYS 6-10 (FEBRUARY 21-25)

High pressure from Canada delivers dry but cold weather for the February 21. Disturbance from the west brings precipitation threat February 22-23 followed by fair and seasonably cold weather to end the period.

DAYS 11-15 (FEBRUARY 26 – MARCH 2)

We may see a transition out of blocking into more of a west zonal pattern with a storm track bringing weaker systems over or north of the region with a couple precipitation chances and some temperatures swings.

C-19 Chat Post – February 16 2021

DAYS 1-5 (FEBRUARY 15-19)

One wave of low pressure is passing south of us today, but a more important low pressure area will come at the region tonight into Tuesday. While the track of this low will be across the South Coast region or even just south of the region, with the strength of a ridge of high pressure over the southeastern US and a slight retreat of the arctic air that had leaked into the Northeast we now see the ability for it to warm up a little more above us as this system passes by. But, as we know, cold air is still in place here at the surface and is very often tough to dislodge, especially with a storm tracking as it is, instead of west of the area. So while it is cold enough for spotty and fairly insignificant mostly frozen precipitation today, once the main shield of moisture arrives tonight into Tuesday and it warms aloft for rain to be falling across the area, that rain will be freezing upon contact with the surface in a fair amount of the region due to below-freezing temperatures at ground level. The precise location of that freezing line during the event will determine who ends up with icing conditions and who escapes them. It’s a fairly safe bet that most if not all areas outside the I-95 belt will experience at least some icing, and areas that stay freezing rain for the duration will experience the most significant icing, with between 1/4 and 1/2 inch of ice accretion likely. The I-95 belt including Metro Boston and even Metro Providence initially will be more “on the line” and more vulnerable to areas that are icy and areas that are not because of marginal temperatures, while the coastal plain and especially the South Shore of MA and South Coast region will be least likely to experience any icing conditions. Please use utmost caution if you have to travel during this event. After this first messy bout of precipitation tapers off as the low pulls away later Tuesday, a clearing sky and quick temperature drop that night will lead to black ice formation on any untreated wet surfaces, including areas that had been above freezing and ice-free during the precipitation, so continued extreme caution walking or driving is a must from Tuesday night right into Wednesday, which will be a dry but cold day between storm systems. Yup, systems, because another one is heading in for Thursday into Friday, and this one, having more cold to work with at least initially, is bound to bring a little more snow with it to start out, arriving during Thursday afternoon and evening from southwest to northeast. But while the primary low pressure area responsible for this bout of unsettled weather has its eyes on a path northwest of here, high pressure in Canada will hold up a stop sign and the low will kind of “Jello” its way just south of New England, basically transferring its energy along a trough line where the border of the cold and warm air is, and re-emerge as a new low offshore which will then move away during Friday and Friday night. During this process once again we should see some warming aloft so that at least a portion of the region will experience sleet and freezing rain and/or rain (depending on temperature profile). For this system I’ll keep the forecast more generalized and then try to detail the precipitation set-up during the next couple of blog posts leading up to the event.

TODAY (PRESIDENTS DAY): Cloudy. Occasional light snow/sleet likely, with freezing rain/rain possible. Minor snow/sleet accumulation possible. Light glazing of ice possible. Highs 27-34. Wind N up to 10 MPH.

TONIGHT: Cloudy. Increasing coverage of snow/sleet/freezing rain/rain evening, with additional minor snow/sleet accumulation mostly northwest of Boston, changing to freezing rain & rain overnight with significant glazing likely where temperatures are below freezing. Temperatures steady 27-34 evening, rising slightly overnight. Wind N to NE 5-15 MPH.

TUESDAY: Overcast. Rain coastal areas and freezing rain interior especially west and north of Boston morning, tapering off afternoon. Additional icing likely over interior locations. Highs 30-37 interior locations, coldest in valleys of north central MA and southern NH, 38-45 in coastal locations, mildest over Cape Cod, except briefly near 50 possible Nantucket. Wind E to N 5-15 MPH except may be briefly SE to SW 10-20 MPH and gusty Nantucket area.

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

WEDNESDAY: Mostly sunny. Highs 25-32. Wind NW 5-15 MPH.

WEDNESDAY NIGHT: Increasing high clouds. Lows 13-20. Wind N up to 10 MPH.

THURSDAY: Thickening overcast. Snow arriving southwest to northeast late day. Highs 25-32. Wind NE 5-15 MPH.

THURSDAY NIGHT: Overcast. Snow/sleet/freezing rain/rain likely, with greatest chance for frozen precipitation interior and north, greatest chance for freezing and/or liquid precipitation coast and south. Temperatures rise to 28-35. Wind NE to E 5-15 MPH.

FRIDAY: Overcast with snow/sleet/ice/rain morning. Breaking clouds afternoon. Highs 33-40. Wind E to N 5-15 MPH morning, NW 10-20 MPH afternoon.

DAYS 6-10 (FEBRUARY 20-24)

High pressure from Canada delivers dry but cold weather for the February 20-21 weekend. Disturbance from the west brings precipitation threat February 22-23 followed by fair and seasonably cold weather to end the period.

DAYS 11-15 (FEBRUARY 25 – MARCH 1)

We may see a transition out of blocking into more of a west zonal pattern with a storm track bringing weaker systems over or north of the region. This would produce a couple risk of precipitation and some swings in temperature. This is a fairly low confidence forecast at this time.

C-19 Chat Post – February 15 2021

DAYS 1-5 (FEBRUARY 14-18)

The pattern is the same – we remain in the moisture conveyor belt between cold air to the north and west and warm air over the southeastern US. Adjustments to the outlook have been made to indicate more warming aloft due to a stronger ridge of high pressure – yes the ridge we’ve waited for to appear, nearly declared a total failure, then decides to show up in this La Nina pattern. Anyway here we go with a continued series of low pressure areas moving along. We’ve had one go by last night and early today, causing some slippery roads from freezing rain/drizzle near the South Coast, and the next one Monday will really just contain a spotty light precipitation variety. There are two more coming along that have more moisture to work with, Tuesday, and Thursday night into Friday, with a dry/cold interlude Wednesday. Each of these final two systems can produce a complex precipitation pattern with snow, sleet, freezing rain, and rain, depending on the temperature profile of the atmosphere and temperatures at the surface. That’ll be fun to figure out over the coming days…

TODAY: Cloudy. Highs 27-34. Wind N up to 10 MPH.

TONIGHT: Cloudy. Lows 22-29. Wind N up to 10 MPH.

MONDAY (PRESIDENTS DAY): Cloudy. Occasional light snow/sleet likely, with freezing rain/drizzle possible. Highs 27-34. Wind N 5-15 MPH.

MONDAY NIGHT: Cloudy. Spotty light snow or snow/sleet mix evening. Steady snow/sleet/freezing rain/rain arriving overnight. Temperatures steady 27-34. Wind N to NE 5-15 MPH.

TUESDAY: Overcast. Snow/sleet/freezing rain/rain likely, tapering off from west to east later in the day. Highs 29-36. Wind NE to N 5-15 MPH.

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

WEDNESDAY: Mostly sunny. Highs 25-32. Wind NW 5-15 MPH.

WEDNESDAY NIGHT: Increasing high clouds. Lows 13-20. Wind N up to 10 MPH.

THURSDAY: Thickening overcast. Snow arriving by late-day, may turn to sleet/freezing rain/rain at night. Highs 25-32, but temperatures may rise at night. Wind NE 5-15 MPH.

DAYS 6-10 (FEBRUARY 19-23)

Mix/rain most likely February 19 as low pressure passes by the region probably just to the south. Dry, seasonably cold February 20-21 weekend. Another disturbance may bring some snow/mix to the region in the February 22-23 window.

DAYS 11-15 (FEBRUARY 24-28)

We may see a transition out of blocking into more of a west zonal pattern with a storm track bringing weaker systems over or north of the region. This would produce a couple risk of precipitation and some swings in temperature.

C-19 Chat Post – February 14 2021