Weekend Outlook: April 16-19, 2021

It’s not April 1, and this isn’t a joke – there’s snow in forecast for parts of our area.

Low pressure is moving off the Mid-Atlantic coast this afternoon while an upper-level low pressure area moves in from the west. The upper-level low will draw the surface low northward towards southeastern New England while it intensifies. Rain is spreading across the region this afternoon, and it will become steadier and heavier tonight as the low moves up the coast. With the upper-level low moving in, we’ll have some very cold air aloft. As the rain becomes heavier, it will pull the cold air down from above, a process called “dynamic cooling”. As this occurs Friday morning, we’ll see the rain change over to snow across the hills from northwestern Rhode Island and central Massachusetts into southwestern New Hampshire. Some wet snow may mix in across the lower elevations of southern New Hampshire and northern Massachusetts as well but we’re not expecting much, if any, accumulation, and what does accumulate will be mainly on grassy surfaces because the pavement is too warm, and air temperatures won’t drop below freezing. It’ll be a different story across the hills from Worcester County into the Monadnocks of southwestern New Hampshire, where several inches may accumulate. Even heavier snow is possible for the Berkshires and the Green Mountains of Vermont. We should note that there are some models that are forecasting accumulating snow, and in some cases quite a bit of it, across most of eastern Massachusetts and Rhode Island. While we can’t completely rule out this scenario, we’re not expecting it to occur.

Most of us won’t see much, if any, snow from this system. Image provided by WeatherBell.

The surface low will pass near or over Cape Cod or southeastern Massachusetts Friday afternoon, allowing any mixed precipitation to change back to all rain and milder air moves in. The rain will taper off to showers in the afternoon, but the showers may not completely end until early Saturday as the system slowly starts to move away. Given the recent lack of rainfall, we’re starting to see drought conditions develop. With 1-2 inches of rain expected from this storm, we’ll help put a nice dent in that developing drought.

Much-needed rain is expected over the next 48 hours. Image provided by Weathermodels.com

Saturday won’t be quite as chilly as Friday, but we probably won’t see much sunshine either as the system only slowly moves away. High pressure starts to build in on Sunday with more clearing and milder temperatures. However, an upper-level disturbance will be moving through, so a couple of pop-up showers can’t be ruled out. Patriots Day on Monday is shaping up to be a nice Spring day with partly sunny skies and mild temperatures, but again, a pop-up shower can’t be ruled out as another weak upper-level disturbance crosses the region.

Monday looks to be a mild day. Image provided by WeatherBell.

Thursday night: Periods of rain, possibly heavy at times, changing to snow across the hills from northwestern Rhode Island and central Massachusetts into southwestern New Hampshire, breezy. Low 33-40.

Friday: Windy with rain mixed with snow at times in the morning, tapering off to showers during the afternoon. High 37-44, possibly a little warmer south of Boston.

Friday night: Cloudy and breezy with showers ending. Low 33-40.

Saturday: Plenty of clouds, possibly a few showers near the coast, some sunny breaks may develop in the afternoon. High 44-51.

Saturday night: Partly to mostly cloudy. Low 32-39.

Sunday: Intervals of clouds and sunshine, slight chance for a shower. High 49-56.

Sunday night: Clear to partly cloudy. Low 33-40.

Monday: Partly sunny, slight chance for a shower. High 56-63.

More Snow on the Way

This shouldn’t be a surprise, since it’s February, but there’s snow in the forecast.

Today’s sunshine and cool temperatures are a product of high pressure building in across the eastern Great Lakes. However, as that high slides off to the east, low pressure, currently in the western Gulf of Mexico, will slowly make its way toward the region. However, it’s not as simple as a storm system passing off to the south and bringing in some snow. This will actually be a three-part system that lasts quite a while.

Aside from a few high clouds, most of the Northeast is enjoying sunshine this afternoon. Loop provided by NOAA.

The initial low pressure system will move off the Southeast coast and head northeastward, passing south of the area late Thursday and Thursday night. This will spread some light snow in Thursday afternoon and evening, mainly south of the Mass Pike. As that system pulls away, another weak system will emerge from the Carolina coast, spreading more snow in. This will overspread most of the area. Along the South Coast, we’ll see some milder air move in, especially aloft, which will likely result in some sleet or rain mixing in. That system pulls away early Friday, but yet another weak system follows in its wake, passing south of the area during the day on Friday, with even more snow expected, even down to the South Coast, as some cooler air filters in behind the previous system. That system finally pulls away Friday night, but with an upper-level low pressure system moving across the Northeast, some more snow showers are possible on Saturday.

It’s important to note that this isn’t your classic Nor’easter with a powerful system off the coast, strong winds, and bursts of heavy snow. Instead, we’re just left with a series of weak systems that will produce off-and-on light snow for a period of 24-to-36 hours across the region. Of course, even light snow will add up if it persists for that long, but this isn’t the “blockbuster” 1-to-2 feet that we sometimes receive at this time of year.

So, how much are we expecting?

Central NH (Concord): 2-4″
Southern NH (Manchester/Nashua): 2-5″
NH Seacoast/Merrimack Valley: 3-6″
MetroWest/MetroBoston: 4-7″
Southeastern Massachusetts/RI: 5-9″
South Coast: 4-7″
Cape Cod: 3-6″ (heaviest near the Canal)

The NWS Blend of Models is probably closest to our thinking right now. Image provided by Weathermodels.com

Another system may bring in some light snow or rain on Monday. We’ll have a little more detail on that in our Weekend Outlook tomorrow.

Weekly Outlook: February 15-21, 2021

This week is going to be messy with not one but two different storms that will produce a variety of precipitation across the region.

We start off the week with plenty of clouds and some light snow and/or freezing drizzle this afternoon as a weak system passes well south of the region. However, another storm system will be moving out of the Tennessee Valley and heading our way. This is the same storm that wreaked havoc on Texas and the Southern Plains over the weekend. At one point over the weekend, all 254 counties in Texas were under a Winter Storm Warning. We’re not sure if that has ever happened before, but it’s certainly a rare event. That storm will head northeastward today, moving up the Appalachians. It will then redevelop south of Long Island tonight, and pass near or across southeastern Massachusetts Tuesday morning.

A variety of watches, warnings, and advisories are in effect across the Northeast ahead of the next storm system. Image provided by Pivotal Weather.

With the low passing to our south, cold air will remain in place for much of the region, mainly north and west of Boston. As milder air moves in aloft, we’ll see snow change over to sleet and then freezing rain this evening and tonight. Before it changes over, we’re looking at an inch or less of snow for much of Massachusetts and Rhode Island, with an inch, possibly 2 inches across southern New Hampshire. Once you get north of Concord, NH, several inches are possible before the flip to sleet/freezing rain. An extended period of freezing rain is possible in parts of the area, especially from the Merrimack Valley into Southern New Hampshire. This will obviously result in hazardous driving conditions, but also will increase the threat of power outages due to downed trees and wires from the weight of the ice. From Boston southward, we’re looking at mostly rain, with temperatures above freezing. How far inland that above-freezing air gets is still a question mark, but right now, we’re thinking that areas north and west of Interstate-95 will likely stay below freezing the entire time. Most of the models try to bring the warmer air all the way into the Merrimack Valley or even Southern New Hampshire. However, the models also tend to overestimate how quickly the cold air will erode, especially when there is snow on the ground. Plus, they have significantly underestimated the magnitude of the cold air that moved in across Texas and the Southern Plains over the last few days. For these reasons, we’re going to stay a little colder than the models. Across Cape Cod and parts of southeastern Massachusetts, cold air won’t be an issue, and in fact, temperatures could get to 50 or even warmer for a while Tuesday morning if the storm passes across southeastern Massachusetts instead of just to the south.

Everything winds down by early afternoon, then skies clear out, with colder air returning for Tuesday night and Wednesday as high pressure builds in. From Boston southward, this means that everything will quickly ice back over Tuesday evening as temperatures drop below freezing. Keep this in mind if you’ll be out an about, as many untreated surfaces will become slick. Although Wednesday will feature sunshine, it will be quite chilly, with temperatures likely staying in the 20s to lower 30s, which is as much as 10 degrees below normal.

Temperatures will be 5-10 degrees below normal on Wednesday. Image provided by Weathermodels.com

By Thursday, another system will approach the region, and this one also looks messy, but a little colder. This system will likely stay south of the region, but some milder air will move in aloft. So, once again, we’re looking at snow, changing to sleet and freezing rain, and possibly plain rain in some areas. The airmass ahead of this system will be a little colder than the one we have in place today, so we could be looking at more snow before the changeover, especially from the Merrimack Valley northward. However, this one could also feature a period of freezing rain across the interior. Details like this are nearly impossible to pin down 4-5 days in advance, so we’ll get into more detail towards midweek as things become clearer.

Thursday night and Friday are looking messy once again. Images provided by Pivotal Weather.

High pressure returns next weekend with drier and colder conditions once again. There are some signs that the colder weather we’ve been dealing with for much of the month could start to retreat in Canada next week, but that’s a long ways away, and things can still change.

Above normal temperatures next week? It’s possible, at least according to one model. Image provided by WeatherBell.

Monday: Cloudy with some light snow or snow showers, possibly mixed with a little sleet or drizzle, especially along the coast. High 27-34.

Monday night: Light snow during the evening, mainly from the Merrimack Valley into Southern New Hampshire, eventually changing to sleet and freezing rain, except precipitation falls mainly as rain south and east of Interstate 95. Low 25-32 during the evening, then temperatures may rise a few degrees overnight.

Tuesday: Freezing rain across the interior and rain in the coastal plain ending by early afternoon. High 30-37 north and west of Interstate 95, 38-45 south and east of I-95, potentially as warm as 45-55 across parts of southern Rhode Island, southeastern Massachusetts, and Cape Cod during the morning.

Tuesday night: Clearing, breezy. Low 14-21.

Wednesday: Sunshine and some late-day clouds. High 25-32.

Thursday: Cloudy, light snow is possible late in the day, possibly changing to sleet and freezing rain at night. High 26-33.

Friday: Snow, sleet, freezing rain, and rain ending in the morning, breezy. High 33-40.

Saturday: Intervals of clouds and sun, breezy, a few flurries are possible. High 25-32.

Sunday: Partly to mostly sunny. High 27-34.

Super Snow Sunday?

It seems as though we are getting a snowstorm after all tomorrow. It won’t be a big one, or a long-duration one, but it will impact your Sunday.

At the end of our Weekend Outlook, we mentioned the chance for snow on Sunday, but closed with this:

“Overall, not a big deal for most of us. Parts of the South Coast could see a few inches of snow depending on how far north the ocean storm actually gets, but otherwise, we’re not anticipating much accumulation across the region, unless things change in the next day or two.”

Well, things have changed. Low pressure will move off the Mid-Atlantic coastline tonight, and pass south and east of Nantucket on Sunday, farther north than we were thinking on Thursday. This will result in accumulating snow for most of the region, with this ending up as a moderate snowstorm far parts of southeastern Massachusetts.

Low pressure will pass south and east of the region on Sunday. Loop provided by WeatherBell.

Snow will develop from southwest to northeast during the morning, and from late morning into mid-afternoon, snow may be moderate to heavy at times, with snowfall rates of 1 inch per hour or more. The snow will start to wind down by late afternoon or early evening, just in time for the Super Bowl to begin. For most of us, this will be just a snow storm. However, for parts of Cape Cod and the Islands, there is a chance that some sleet or rain could mix in, which would keep accumulations down slightly.

So, how much are we expecting?

Central NH (Manchester/Concord): 2-4″
Southern NH/North-Central MA: 3-5″
NH Seacoast/Merrimack Valley: 4-7″
The Rest of Eastern MA/RI: 5-9″, except 3-6″ across the Outer Cape and Islands and the immediate east coast of MA

The NWS Blend of models is probably closest to our thinking right now. Image provided by Weathermodels.com

As was pointed out to us by a colleague for parts of Southeastern Massachusetts, this will be one of the biggest storms this area has seen in a few years. Using Middleboro as an example. they have only received 6 or more inches from a single storm twice in the last 3 years – 6.5″ December 2-3, 2019, and 8.5″ on March 4, 2019.

Beyond this, our next chance for some snow will be with another weak system on Tuesday. That storm will produce a little light snow, possibly rain south of Boston. However, given the performance of the models more than a day or two out, would you really be surprised if it becomes something bigger? We’ll have more on that in our Weekly Outlook Monday morning.

Weekly Outlook: February 1-7, 2021

March is supposed to come in like a lion, and it still may, but for now, February is going to as well.

As you may have heard, it’s going to snow today. We’re not going to rehash that too much, since we just wrote a very detailed post about the storm Sunday evening, and our thinking really hasn’t changed much. Suffice to say, snow will become heavy at times this afternoon and tonight, changing to rain for the immediate coast and Cape Cod. It’ll start to wind down early Tuesday, but occasional snow showers and periods of light snow continue on Tuesday with rain eventually going back to snow near the coast. Strong winds this afternoon and tonight slowly diminish on Tuesday as well.

The NWS Blend of Models is still closest to our thinking with snowfall for the current storm. Image provided by Weathermodels.com

So, let’s get to what comes next. On Wednesday, the storm pulls away, heading towards Nova Scotia, but we may still have a few snow showers around, especially during the morning. Skies may start to clear out late in the day. The airmass behind the storm isn’t that cold, so unlike past storms, we don’t have to worry about another arctic blast freezing everything up. High pressure then builds in for Thursday and the sun should return, with temperatures right around where they should be in early February.

Average high temperatures in early February are in the middle to upper 30s across the region. Image provided by Weathermodels.com

Friday and the weekend are when things get interesting again. You may recall a few days ago when some of the tv meteorologists were talking about a big warmup and rainstorm around here for this coming Friday, which would help get rid of a lot of the snow we’re getting today. Well, that’s not quite what’s going to happen now. Yes, low pressure will still travel into the Great Lakes and then Ontario, passing well north and west of us, and temperatures will moderate a bit on Friday. However, temperatures will likely only get into the upper 30s to lower 40s, which is still a little above normal, but not the 50s some of the models were showing a few days ago. We’re also not looking at a lot of rain either. There will likely be some precipitation ahead of a strong cold front, and much of it will be rain, but it might not start as rain across the interior.

The cold front moves through Friday night and high pressure starts to build in with colder air once again. It won’t be as cold as what we had this past weekend, but temperatures will be near to perhaps a little below normal. That’s not the end of the story though. That cold front likely stalls out across the Southeast and then a wave of low pressure will move out of the Gulf of Mexico and start to ride up along the front. Some of the models are showing the potential for that system to bring in some more snow next weekend. It’s still 6-7 days away, and most of the models have not performed that well beyond 2-3 days for quite some time, so we’re not completely convinced of this yet, but it’s something we’ll start to focus on once we get our current storm out of the way. If it starts looking more likely, we’ll have more details in our Weekend Outlook Thursday afternoon.

The models have lots of differences in timing and track of a potential system next weekend. Images provided by Pivotal Weather.

Monday: Becoming windy with snow, heavy at times by late afternoon, changing to rain along the coast. High 28-35.

Monday night: Windy with snow, heavy at times inland, and rain from Cape Cod and parts of southeastern and coastal Massachusetts. Precipitation tapers off toward daybreak. Temperatures hold steady or rise a few degrees overnight.

Tuesday: Cloudy and breezy with periods of light snow and snow showers, except rain showers for southeastern Massachusetts. High 30-37, a little warmer across Cape Cod and possibly southeastern Massachusetts.

Tuesday night: Cloudy and breezy with additional snow showers possible. Low 21-28.

Wednesday: Cloudy with a few more snow showers possible early, some glimpses of sunshine are possible in the afternoon. High 29-36.

Thursday: Partly to mostly sunny. High 32-39.

Friday: Cloudy and breezy with showers developing, possibly starting as snow or a wintry mix north and west of Boston. High 38-45.

Saturday: Some early sun is possible otherwise mostly cloudy with a chance of snow or rain. High 33-40.

Sunday: Mostly cloudy with snow or rain possible. High 32-39.

Here Comes the Snow

We really haven’t had a decent-sized snowstorm around here since mid-December. That will change in a hurry on Monday. As a result, the Extreme Hype Watch we issued on Thursday has been upgraded to an Extreme Hype Warning.

Low pressure moving across the Ohio Valley this afternoon is just one ingredient in the mix for the upcoming storm. Image provided by the Weather Prediction Center.

High pressure remains in place across Quebec, keeping plenty of cold air in place across the Northeast this afternoon. Meanwhile, low pressure is moving across the Ohio Valley, producing a swath of snow from the Great Lakes into the Mid-Atlantic states. As that low moves eastward, it will weaken tonight, but a new area of low pressure will develop off the Mid-Atlantic coastline. At the same time, and upper-level low pressure area will also move toward the East Coast. As the new surface low gets caught underneath the upper-air low pressure area later Monday and Monday night, it will stall out or meander around south of Long Island. Eventually, it will resume an east to northeast motion on Tuesday, passing south and east of Nantucket before moving into the Gulf of Maine.

Snow is falling from Chicago to New York City late this afternoon. Loop provided by Weathertap.

As we mentioned, an Extreme Hype Warning has been issued, which means you’ll see blanket coverage from the network stations around here, hourly updates even when they go to regular programming, and of course, obligatory live shots from (take your pick):

  • The side of an Interstate
  • Logan Airport
  • A local DPW salt pile
  • A beach showing the rough surf and coastal flooding
  • A Dunkin Donuts where they are talking to a plow operator
  • All of the above

You’ll also get network reports about how the snow is creating chaos in New York City, how it put Washington at a standstill, and possibly how it dumped heavy snow on the Midwest. The latter is debatable, because anything west of the Appalachians is considered “flyover country” to the media around here.

OK, we’ve explained what’s going on in the big picture, now let’s focus on some of the details for our area (Southern New Hampshire, Eastern Massachusetts, Rhode Island):

Winter Storm Warnings are in effect from Maine to Virginia.

As you can see on the radar above, snow is already moving into the Tri-State area, and will continue to make slow progress northward tonight. By morning, east to northeast winds will start to increase around here, and we’ll see some ocean-effect snow showers develop in parts of southern New Hampshire and eastern Massachusetts. These aren’t directly related to the storm, but may drop 1/4-1/2″ of snow. This is also a common occurrence before some storms around here. The snowfall from the storm will move in during the late-morning and early afternoon hours and should become moderate to heavy by late afternoon or early evening. Snow may fall at the rate of an inch or two per hour at times. This will continue overnight with precipitation starting to taper off before daybreak. For much of the region, that precipitation will fall as all snow, but a change to rain is likely along the coast and across parts of southeastern Massachusetts and southern Rhode Island. How far inland that rain-snow line penetrates will obviously have a large impact on accumulations. Right now, we don’t expect it to get past Interstate-95, and it might not even get that far.

By Tuesday morning, the steady precipitation will taper off, but the storm will still be south of Long Island. So, what we’re looking at is occasional snow showers and periods of light snow throughout the day, with rain or mixed precipitation in southeastern Massachusetts and southern Rhode Island, This likely won’t add too much accumulation, but in some places, we could see another inch or two. As the low finally gets moving, colder air will work its way back in, changing everywhere back to all snow before it ends late Tuesday night or Wednesday morning.

There are several factors that could cause problems around here. First and foremost is the wind. Northeast winds will increase to 15-25 mph inland, and 20-30 mph along the coast, with gusts of 30-50 mph. This will create near-blizzard conditions at times Monday night, with reduced visibility and blowing and drifting snow. If you don’t have to go out Monday night, stay home. Driving will be extremely hazardous. Across Cape Cod and the Islands, a High Wind Warning is in effect. Sustained winds of 25-35 mph with gusts to 60 mph are possible here. Winds will only slowly diminish across the region on Tuesday.

Peak wind gusts of 40-50 mph are expected across the region. Image provided by WeatherBell.

Along with the wind, we have coastal flooding to worry about. A Coastal Flood Watch is in effect for eastern Massachusetts, mainly for the high tide cycles Monday night and Tuesday morning. Those strong northeast winds, combined with tides that are still astronomically high, will likely produce some coastal flooding, especially in some of the normally prone areas (like Morrissey Boulevard in Boston). By Tuesday afternoon, winds will become more northerly, reducing the coastal flood threat.

Finally, we get to the part you’re all interested in – how much snow? The good news is that they heaviest snow from this storm will likely be south and west of us, from southeastern New York and northern New Jersey into parts of Pennsylvania. Many locations in this area could see 20 or more inches of snow before everything winds down. Even New York City could see a foot to perhaps a foot and a half of snow. Around here, there will likely be many reports in excess of a foot, especially north and west of Boston. As for specifics, here’s what we’re thinking:

Cape Cod: 1-3″, heaviest near the Canal
South Coast/Immediate East Coast: 3-6″
Interior Southeastern Massachusetts/I95 Corridor from RI into Eastern MA: 6-10″
Areas North and West of Interstate-95 (including southern/Central NH): 10-15″ with some heavier amounts possible.

Our thinking is closest to what the NWS Blend of Models is showing. Image provided by Weathermodels.com

Obviously, some of these amounts are dependent on when/if rain starts to mix on or a complete change to rain occurs. Most of the accumulating snow will occur between late Monday afternoon and daybreak Tuesday, but there will still be some snow falling during the day on Tuesday.

Another storm will move in late this week, but this one looks to be milder, with rain for a bigger chunk of the region, though snow is a possibility across the interior. We’ll have more on that in our Weekly Outlook tomorrow morning.

Weekend Outlook: January 29-February 1, 2021

Bond villian Elliot Carver said it in “Tomorrow Never Dies”, but it’s appropriate for the forecast for the next several days – “Let the mayhem begin”

We start off with a developing low pressure system well offshore tonight. The system will continue to strengthen, but also continue to pull away, so it won’t directly impact us. However, it will produce northerly winds around here that will serve two purposes. First, they’ll continue to produce some ocean-effect snow across parts of eastern Massachusetts and the New Hampshire Seacoast, and second, they’ll usher in some of the coldest air thus far this winter.

Low pressure well south of New England shows up nicely on satellite imagery this afternoon. Loop provided by NOAA.

First, we’ll look at the ocean-effect snow. It’s been ongoing since early this morning, and will continue off and on into this evening. While it won’t amount to much for a good chunk of the region, right along the coast, especially Cape Ann, coastal Plymouth County, and Cape Cod, could see an inch or two in spots. On Friday, a disturbance rotating around the ocean storm will bring some more ocean-effect snowfall back into Cape Cod. This could result in additional accumulations, especially across the Outer Cape, where a few inches is possible.

A few inches of snow may accumulate across the Outer Cape over the next day or two. Image provided by Weathermodels.com

Back to the cold air. This past week has been rather chilly compared to the rest of January, but temperatures have only been near to a little below normal. That’s going to change tonight and this weekend. Skies will start to clear out tonight (except for Cape Cod), and it’s going to get cold. Temperatures will likely drop into the single numbers for much of the region tonight, but it will remain quite breezy, so we’re looking at wind chills of 10 to 20 below zero Friday morning. Wind Chill Advisories have been posted from Worcester County westward, but even without the advisory, you should know enough to dress warmly if you have to go outside.

Bundle up before you head outside Friday morning because it’s going to be chilly. Image provided by WeatherBell.

Friday looks rather chilly as well. Some clouds may move in from the ocean, but even in places where the sun is out, it’ll still be breezy and cold, with daytime highs only in the teens to lower 20s. Skies clear out again Friday night and winds will start to diminish, so we’re looking at another cold night, with some places possibly dropping below zero. Saturday should feature a lot of sunshine, but it will still be cold, with highs only in the upper teens to lower 20s. After another bitterly cold night Saturday night, temperatures should start to moderate a bit on Sunday, but we’ll also see clouds starting to move back in ahead of another storm system heading this way. This brings us to Monday.

For several days now, most of the forecast models have been showing the potential for a storm system to impact the Northeast early next week. They’ve bounced around with the details on strength, timing, and track, but in general, there’s been a fairly strong signal that something is going to happen around here after we flip the calendar to February. Well, that signal hasn’t gone away, and the Universal Hub website has upgraded to a Level 2 on the French Toast Alert System. In other words, don’t worry just yet. However, knowing how the media can be around here, and knowing what the models are showing, we’re issuing our own Extreme Hype Watch. An Extreme Hype Watch is issued when conditions are favorable for media hype of an event to reach extreme levels within the next 48-72 hours. If conditions warrant, a Hype Advisory or Extreme Hype Warning will be issued as the event draws nearer.

As for the system itself, there are still plenty of questions that need to be answered. We’ll have a large high pressure area in eastern Canada keeping some cold air in place. It’s not quite in the ideal position for a big storm here, but it is there. We’ll have a low pressure system moving through the Midwest that will redevelop over the Mid-Atlantic states, then head northeastward, likely passing south and east of New England, close to the “benchmark”. The benchmark is at 40 degrees North latitude and 70 degrees West longitude, about 90 miles south of Nantucket. Storms that pass over that spot are usually (but not always) in a prime position to deliver heavy snow to much of the region. Storms that pass north and west of there usually end up with a rain/snow line farther inland, and storms that pass south and east of there don’t always deliver snow far inland. This is more of a general rule than an absolute, but it’s something we look for. The other issue we have is that an upper-level low pressure area will be moving in, and the storm may get stuck underneath it, which could stall it out or have it meander around south of us for a day or so, which would result in an extended period of precipitation.

In addition to the models, another tool we use is analogs. You will most often hear about these in relation to a seasonal pattern or a hurricane season, but we can also use them for individual storms. Basically, we compare the pattern to previous setups, and see how it compares, and see what those previous setups produced to give us an idea of what is possible. Now, these analogs are run compared to the forecast of one model, so if that model isn’t the one your using, then the analogs might not be of much help. Based on the midday run of that model, the best analog for the pattern early next week is the storm of January 26-28, 2015. You may recall that storm received an extreme amount of media hype, and did produce very heavy snow around here, but was considered a “bust” in New York City, where the actual amounts fell well short of the forecast. It also was the storm that essentially kick-started our 6-week snow blitz (and also was responsible for the formation of the original StormHQ Facebook page). Using the Top 15 analogs for the forecast pattern, here’s the average of snowfall from those 15 systems:

Analog snowfall forecast for Monday-Tuesday. Image provided by the Cooperative Institute for Precipitation Systems (CIPS).

As you can see, there is a signal for a significant snowstorm, which is why we’re going to be monitoring this closely for the next several days. We’re not going to post any model snow forecasts yet because there’s still too much uncertainty. We’ll let the media and Facebook Forecasters take care of that. If conditions warrant, we’ll issue another blog post either Saturday or Sunday as the details become more clear.

Thursday night: Mostly cloudy along the coast with a few snow showers across the Cape, clearing inland, breezy. Low 1-8.

Friday: Intervals of clouds and sun, more snow showers across Cape Cod, windy. High 13-20.

Friday night: Lingering clouds across Cape Cod, clear elsewhere, still breezy during the evening. Low 2-9.

Saturday: Plenty of sunshine, except for some clouds across the Outer Cape. High 16-23.

Saturday night: Clear skies. Low 0-7.

Sunday: High clouds stream in. High 22-29.

Sunday night: Thickening clouds. Low 12-19.

Monday: Cloudy and breezy with a chance of snow (or possibly rain south of Boston) High 30-37.

Weekly Outlook: January 25-31, 2021

This is shaping up to be one of those weeks that ages a meteorologist rapidly, since there are not only multiple systems to track, but the bust potential is much higher than normal.

The week starts off rather quietly, with high pressure moving offshore. We’ll still be on the chilly side, but close to normal for late January, and not as cold as the past few days were. Clouds will start streaming in as well, ahead of a storm system moving into the Midwest. This is the first headache of the week.

On average, high temperatures should be in the lower to middle 30s around here in late January. Image provided by Weathermodels.com

As that low pressure area moves into the Midwest, a secondary area of low pressure will develop near the Mid-Atlantic states, and will pass offshore to our south later Tuesday. However, some energy from the original system will still move towards us late Tuesday into Wednesday. The bulk of the precipitation from the secondary storm will stay to the south, with some snow showers or flurries possible along the South Coast, possibly as far north as the Mass Pike. What complicates things is the energy from the original storm. Some of the models have that move across the region with another area of snow, and possibly a decent amount. This has been a recent development in the models over the last 24 hours, which makes us skeptical, but many of the models show something similar, so we can’t completely ignore it. Right now, we’re thinking that a period of light snow is likely Tuesday night into early Wednesday, with some accumulations expected. There are some models that show significant accumulations in parts of the region. While that is possible, we don’t think it’s likely at the moment. If that were to change, we’d update the blog later Monday or Tuesday.

There is plenty of disagreement among the models about how much snow to expected between now and Wednesday afternoon. Images provided by Pivotal Weather.

That system pulls away on Wednesday and high pressure builds in. However, with the high building in north of us, we’ll stay chilly, but we’ll also have northeast winds. This may result in some ocean-effect snow in eastern parts of the area, especially Cape Cod, coastal Plymouth County, and Cape Ann. Some persistent snow showers could result in accumulations, possibly several inches, but this far in advance it’s too tough to predict if or where those bands may setup.

Ocean-effect snow is essentially the same as lake-effect snow. Image provided by NOAA.

Another storm system will head towards the Mid-Atlantic by Thursday, and again, this storm should also pass far enough south to have little direct impact on us. However, unlike the system on Tuesday that will be weakening as it moves this way, this storm will strengthen. In fact, once it moves offshore, it should become a powerful storm over the North Atlantic. It may produce some gusty winds along the coast, especially Cape Cod, and possibly some additional ocean-effect snowfall, but the precipitation shield associated with the storm itself should remain offshore.

Behind that storm, much colder air will settle in for Friday and Saturday. We should finally start to clear out as high pressure builds in, though a few more ocean-effect snow showers are possible, especially across Cape Cod. The more noticeable impact is that it will be very chilly, likely colder than we just experienced this weekend. Daytime highs in the 20s (even some upper teens), and overnight lows in the teens and single-digits seem reasonable right now, with sub-zero wind chills, especially Friday into early Saturday.

Wind chills may be well below zero around here Saturday morning. Image provided by WeatherBell.

This brings us to Sunday, and our next headache. Yet another storm system will be heading for the Mid-Atlantic states, sending clouds our way. With high pressure over southern Quebec, we’ll still be on the cold side. The exact track this storm takes is still a big question mark, but this one doesn’t look like it’ll pass offshore to our south. In fact, several models bring the storm right across southern New England on Monday. We’re not going to get into too many details because it’s a week away, and technically outside the usual range of this forecast, but we’ll just let you know that there is the potential for a decent amount of snow early next week for parts of the region. It’s just potential for now and far from a lock, but the models have been showing this potential for several days now. We’ll get into more details on this one in our Weekend Outlook on Thursday.

Monday: Sunny in the morning, clouds start to move in during the afternoon. High 30-37.

Monday night: Becoming partly to mostly cloudy. Low 17-24.

Tuesday: Cloudy, light snow may develop late in the day. High 29-36.

Tuesday night: Cloudy with light snow likely, possibly mixed with some rain along the south coast. Low 22-29.

Wednesday: Cloudy with light snow likely, mainly north and west of Boston, with snow or rain showers likely from Boston southward. High 32-39.

Thursday: Cloudy and breezy with a chance of snow showers, especially near the east coast. High 31-38.

Friday: Becoming partly to mostly sunny, breezy, and cold, though clouds may linger along the east coast with a few more snow showers possible. High 18-25.

Saturday: Mostly sunny and cold. High 19-26.

Sunday: Becoming mostly cloudy with a chance for snow at night. High 28-35.

New Year’s Weekend Outlook: December 31, 2020 – January 4, 2021

As we get into the final days of the year and start of a new year, we’ve got a fairly complex weather pattern shaping up across the region.

A warm front will move across the region tonight, but little precipitation will accompany it. What you will notice is that temperatures will bottom out this evening, then rise as we head through the overnight hours. Low pressure will move into the St. Lawrence Valley early on Thursday, dragging a cold front across the region during the morning. Some showers will accompany that front, but they’ll be gone by midday. High pressure then builds in, allowing skies to clear out in the evening. So, if you have any New Year’s Eve plans, weather won’t be an issue, though it will be on the cold side, as you’d expect at the end of December.

Temperatures should be in the middle to upper 20s under clear to partly cloudy skies at midnight Thursday night. Image provided by WeatherBell.

New Year’s Day starts off sunny and chilly, but clouds stream back in during the afternoon ahead of low pressure moving into the Great Lakes. We’ll see precipitation moving in towards midnight, but with cold air in place, things will be tricky. Along the coast, we’re looking at just a chilly rain, but across interior sections, it’ll be a different story. We’ll likely see it start off as snow, with some minor accumulations (an inch or two), especially from the Merrimack Valley and central Massachusetts into southern New Hampshire.

A little snow may accumulate early Saturday morning across the region, Image provided by WeatherBell.

Eventually, a change to sleet and freezing rain is expected across the interior as milder air moves in aloft. Milder air will also move in at the surface, so precipitation should change over to plain rain everywhere by Saturday morning, but before that happens, a period of freezing rain could result in some slippery travel across the interior before daybreak Saturday. The rain ends by midday, then we’ll see some clearing by late afternoon. This will also be short-lived.

The GFS model shows the progression of the Friday night storm. Loop provided by the College of DuPage.

Clouds come back in on Sunday as a storm system starts to move up the East Coast. There is still plenty of uncertainty with the track of this system, but a period snow or rain is looking likely for late Sunday into early Monday, especially across southeastern Massachusetts. We should have more clarity on this system once the Friday night system moves past the region.

There are discrepancies among the models in regards to our Sunday night storm. Images provided by Pivotal Weather.

Wednesday night: Cloudy and breezy with showers developing after midnight. Low 31-38 during the evening, temperatures rise overnight.

Thursday: Showers ending in the morning, some clearing develops late in the day. High 41-48.

New Year’s Eve: Becoming clear to partly cloudy. Low 19-26.

New Year’s Day: Sunny in the morning, clouds return in the afternoon. High 34-41.

Friday night: Cloudy with rain developing after midnight across the South Coast. Inland, snow will develop, changing to sleet, freezing rain, and eventually plain rain from south to north. Low 28-35 during the evening, temperatures rise overnight.

Saturday: Any remaining wintry mix across the interior changes to plain rain early, ending by midday. Some sunny breaks develop in the afternoon. High 35-42 north and west of I-495, 43-50 elsewhere.

Sunday night: Partly cloudy. Low 25-32.

Sunday: Cloudy with rain or snow possible late in the day. High 36-43.

Sunday night: Cloudy with a chance of rain or snow. Low 27-34.

Monday: Rain or snow ending in the morning, some clearing late in the day. High 35-42.

Snow is On the Way

After several days of media hype, and people posting model forecasts for extreme amounts of snow on social media, it looks like we do actually have a snowstorm on the way, and it could be a decent-sized one for parts of the region.

High pressure over Ontario and low pressure over Texas are two things we need to pay attention to for the next day or two. Image provided by NOAA.

Low pressure over Texas this afternoon will combine with a second area near the Texas coast to become a single storm system later today, which will then head northeastward into the Tennessee Valley tonight, bringing plenty of moisture with it from the Gulf of Mexico. Meanwhile, a strong high pressure system is moving across southeastern Canada, bringing plenty of cold air into the Northeast. When you get copious amounts of moisture running into cold air, you end up with snow, potentially a lot of it,. That’s what’s going to happen here late Wednesday into Thursday.

Winter Storm Watches are in effect for all of Southern New England. Image provided by Pivotal Weather.

That low pressure area will move from the Tennessee Valley to the Mid-Atlantic coastline on Wednesday before moving offshore and passing south of New England. While there are still some questions as to the exact track it will take, which has implications for the forecast itself, the models have come into better agreement today on a more northerly track than they were showing last night. This has several implications for the forecast around here:

1. Snow will likely penetrate even farther inland, with heavier snow farther inland as well.
2. Rain/snow ratios will be lower across southeastern New England, resulting in a wetter snow.
3. A change to sleet or rain is now possible across Cape Cod, and possibly parts of southeastern Massachusetts and southern Rhode Island.

We mentioned in our Weekly Outlook that there would likely be a sharp cutoff in the northern extent of the snow, going from heavy snow to little snow in a short span, but we weren’t sure where that cutoff would set up. At this point, it’s looking more and more likely that it will set up somewhere in central or southern New Hampshire, meaning that most of us will be shoveling by Thursday morning. This detail is still not definite, so obviously things can change in the next 24 hours or so.

Plenty of cold air will be in place before the storm moves in. Image provided by Weathermodels.com

That high pressure area in southeastern Canada will provide us with plenty of cold air, which will be evident tonight when temperatures drop into the teens or even single numbers. As the snow moves in Wednesday night, we’ll see a coastal front setup across eastern Massachusetts and Rhode Island. This is a common occurrence in winter storms. Basically, the northeast to east winds off the water send temperatures up to the lower to middle 30s along the coast and a short distance inland (anywhere from 20-40 miles). On the other side of that front, northeast to north winds keep the colder air locked in, with temperatures in the teens and lower 20s. Obviously, in the “milder” air on one side, you’ll get a wetter snow, with the possibility of some mixed precipitation, while the colder area gets mostly snow that is more powdery. We said “mostly snow”, as you can get some milder air aloft which could allow for some sleet to mix in, which obviously would have a significant impact on snow accumulations. That coastal front will eventually collapse southeastward toward the coast as the low pressure area moves by, allowing the colder air to eventually move back in everywhere, and any mixing that does take place eventually goes back over to all snow.

The snow to rain ratio varies by temperature, as this chart shows. Image provided by Weathertrends360.com

As for the timing, most of Wednesday should be fine, so you can do any errands that need to be completed before the storm moves in. Snow should move into the South Coast towards the evening rush, quickly spreading northward, reaching the MA/NH border by midnight. Snow may fall moderate to heavy at times overnight, with some mixing possible across Cape Cod and the Islands (and possibly southeastern Massachusetts) late at night and early Thursday morning. Most of the steady precipitation should wind down by midday, but some lingering snow showers are possible, especially along the coast, through the afternoon.

Snow isn’t the only threat with this system, as gusty winds are also expected, especially along the coastline. While this storm won’t be that strong, at least compared to many winter storms in the past, the gradient between it and the large high pressure area to the north will create some gusty winds. Sustained winds of 15-25 mph, with gusts to 40 mph or more, are likely. These gusty winds may enhance the snow across parts of eastern Massachusetts. However, with high astronomical tides, the winds may also result in some coastal flooding around high tide, especially at northeast and east facing coastal areas.

Wind gusts to 40 mph or more are possible, especially along the coast. Image provided by WeatherBell.

So, how much snow are we looking at? Obviously, there’s still some things that complicate this part of the forecast (snow ratios/mixing/northern extent of the snow), so this is preliminary for now, and we may adjust it tomorrow if needed, but here’s our thinking:

Central New Hampshire: 2-4″
Southern New Hampshire/Seacoast: 4-8″
Merrimack Valley/Central Massachusetts: 5-10″
North Shore/MetroWest/Metro Boston: 6-12″
Interior Southeastern Massachusetts/Rhode Island: 8-14″
Cape Cod and the Islands: 4-8″

This model is probably closest to our thinking on snow accumulations at the moment. Image provided by Pivotal Weather.

Colder air will settle back into the region behind the storm for Thursday night and Friday, so you’ll want to clear out the driveways and walkways before everything freezes solid.