Some much-needed rain is on the way, but unfortunately much of it will fall on a holiday.
We start the week off with a cold front stalling out across the region. North of the front we’ll have some showers today with temperatures likely staying in the 60s. Closer to the South Coast, temperatures may be in the 70s with less rain at first, but still plenty of clouds. A wave of low pressure will ride along the front, bringing some additional showers or a period of steady rain in late today and tonight. By Tuesday, the front starts to push off to the south, and the shower activity winds down during the afternoon. How much rain we’ll see is still a bit of question, even as it has already started across parts of the area. Some models are still showing the potential for 3-6 inches of rain (or more) across the region, while others show less. Either way, we need all the rain we can get to help put a dent into the ongoing drought and to help refill the rivers, lakes, ponds, and reservoirs across the region. With most places likely to see at least a period of heavy rain, Flood Watches have been issued for much of the region through later Tuesday.
Skies start to clear out Tuesday night, then high pressure builds in for Wednesday right into the weekend, with a return to dry weather. After a couple of chilly day Monday and Tuesday, temperatures will return to near to above normal levels for the rest of the week and the weekend, with many days featuring highs getting back into the 80s across parts of the area once again.
Monday: Occasional showers. High 64-71 north of the Mass Pike, 71-78 south of the Pike.
Monday night: Periods of rain and showers, some of the rain could be heavy. Low 57-64.
Tuesday: Cloudy and cool with showers gradually ending during the afternoon. High 62-69.
Tuesday night: Overcast with a few lingering showers during the evening, then some late night clearing may develop. Low 53-60.
While the clocks “spring ahead” with Daylight Saving Time beginning this weekend, we’ll still be dealing with winter at times.
High pressure remains in control into Friday with generally dry weather. We’ll be on the chilly side tonight, but temperatures should rebound nicely on Friday, though we’ll see clouds streaming in and thickening up late in the day. This is in advance of a developing low pressure system that will impact us on Saturday. Earlier in the week, it looked like this system would pass west of us, with strong southerly winds bringing in very mild air and rainfall. Well, the latest indications are that the storm will pass right across southern New England, or possibly even south of it. This means that it won’t be as windy or warm as we were thinking earlier, but we’re not looking at a major snowstorm, it’ll still be too mild. We’ll have rain developing by daybreak Saturday, and it could be heavy at times during the day. It may still be quite breezy along the South Coast and across Cape Cod if the system does move across southern New England. Once it passes by during the afternoon it will continue to intensify, with strong northwest winds behind it ushering much colder air back in by late in the day. This will likely result in the rain changing to snow before it ends in the evening. How quickly it changes over and how quickly it moves out will determine whether the snow will accumulate. Right now, the best odds for any accumulation will be from central Massachusetts into southwestern and central New Hampshire. Farther north and west, this will be quite a storm for ski country, which is good news for them.
Behind the storm, we’ll clear out for Saturday night and Sunday with high pressure building in. It will be breezy and quite chilly, but this won’t last long. Winds will subside Sunday afternoon, and as the high moves off to the east, temperatures will moderate nicely on Monday.
Thursday night: Clear to partly cloudy. Low 24-31.
Friday: Some morning sun, then increasing and thickening clouds. High 46-53.
Friday night: Mostly cloudy, rain develops before daybreak. Low 31-38.
Saturday: Rain, heavy at times, possibly changing to snow late in the day, becoming windy. High 45-52, possibly a little warmer across southeastern Massachusetts and Rhode Island. Temperatures will quickly drop during the afternoon
Saturday night: Windy with rain or snow showers ending in the evening, clearing late at night. Low 16-23.
Sunday: Sunshine and some afternoon clouds. High 30-37.
Sunday night: Clear to partly cloudy. Low 23-30.
Monday: Mostly sunny, some clouds may pop up in the afternoon. High 46-53.
As we head into the final days of February, yesterday’s record highs are just a memory and a snowstorm now gets all of our attention.
Low pressure will head toward the Ohio Valley tonight, then redevelop off the Mid-Atlantic coast, passing south of New England on Friday. We’ll see snow developing before daybreak on Friday, and it will quickly become heavy. Warmer air will start to move in Friday morning, first aloft, then at the surface. This will allow for a change to sleet, and along the South Coast and Cape Cod, eventually rain. The big question mark remains how far north does that sleet progress, since it will have a significant impact on snow accumulations? At this point, we’re thinking it gets to at least the Mass Pike, possibly Route 2. Is there a chance it makes it into southern New Hampshire? Yes, there is. By early afternoon, precipitation will lighten up, and as the storm starts to pull away, everything will go back to snow from northwest to southeast, with the snow ending during the evening.
How much snow do we expect? We really haven’t changed our thinking too much from yesterday:
Cape Cod: 2-5″ South Coast: 3-6″ Southeastern MA/RI: 5-9″ Metro Boston/MetroWest/Merrimack Valley/North Shore: 7-11″ Central and Southern New Hampshire/NH Seacoast: 6-10″
If the sleet doesn’t mix in, accumulations will be toward the higher end of the ranges, especially locations north of the Mass Pike. The longer that sleet occurs, the more likely accumulations will be toward the lower end of the ranges.
Skies clear out late Friday night and Saturday as the storm pulls away and high pressure builds in. Another weak system moves through on Sunday with some clouds and possibly a snow shower or two. High pressure builds back in for Monday with some rather chilly weather for the final day of February.
Thursday night: Mostly cloudy with snow developing 3-5am. Low 19-26.
Friday: Breezy with snow, heavy at times in the morning, mixing with or changing to sleet south of Route 2, and changing to rain across the South Coast. Precipitation lightens up during the afternoon before changing back to snow showers. High 27-34.
Friday night: Snow showers end in the evening, skies start to clear out after midnight. Low 7-14.
Saturday: Sunshine and a few clouds. High 27-34.
Saturday night: Clear to partly cloudy. Low 13-20.
Sunday: A mix of sun and clouds, chance for a snow shower. High 33-40.
While today is turning out to be a fantastic day across the region, significant changes are coming, and it won’t take long for them to happen.
A cold front is crossing the region this afternoon, which will bring an end to our record warmth. A few spots even managed to reach 70 today, but you can kiss the mild weather goodbye, as it won’t be back for a while. Temperatures quickly drop this evening and tonight as high pressure builds in, but clouds will start to stream back in on Thursday as low pressure heads toward the Ohio Valley. The system will then redevelop off the Mid-Atlantic coastline, and pass south of New England on Friday. As you’d expect with a system passing south of us in late February, this will produce snow for most of the area. The exact track of the system will determine how much snow we get (more on that in a bit).
We’ll see snow develop before daybreak on Friday, and it may fall heavy at times during the morning and afternoon. At the same time, warmer air will be trying to move in aloft, which would allow the snow to change to sleet and/or freezing rain from south to north during the late morning and early afternoon. At this point, the only places that are likely to get above freezing and change to plain rain will be along the South Coast and across the Cape and the Islands. The question now is, how far north does that change to sleet occur, since it will have a significant impact on the accumulation totals? Most of the models only bring the change as far north as the Mass Pike. However, there is at least one model that brings the changeover all the way northward into southern New Hampshire. This concerns us a little, and we’re going to hedge our bets against this in the snowfall forecast, as you’ll see below.
No matter how far north the changeover gets, as the system starts to pull away later on Friday, everything should change back to snow before winding down and ending in the evening. While this will likely impact the evening commute, the impact will be considerably less than what the morning commute experiences.
As for amounts, this is where things get tricky, since any mixing will cut down amounts significantly. There has been a trend in the models over the past 12 hours or so to shift the axis of heaviest snow into northern and central Massachusetts, with a bit less as you head into southern New Hampshire. Having said that, here’s our thinking as of now:
Cape Cod: 2-4″ South Coast: 3-6″ Southeastern MA/RI: 5-9″ Metro Boston/MetroWest/Merrimack Valley/North Shore: 6-12″ Central and Southern New Hampshire/NH Seacoast: 5-10″
The ranges are a bit wider than we normally like, but this reflects the uncertainty. The less sleet that mixes in, the more likely you are to be near the higher end of the range. Conversely, the more sleet that mixes in, the more likely you are to be toward the lower end of the range. We’ll update this forecast in our Weekend Outlook tomorrow afternoon.
We’ve got quite the week coming up with everything from some snow and bitterly cold temperatures to heavy rain and possibly more record highs by the end of the week.
Snow showers will come to an end this morning, then skies will start to clear out this afternoon as high pressure starts to build in. Despite the developing sunshine, temperatures will only be in the 20s, which is 10-15 degrees below normal for mid-February. As skies become clear tonight and winds diminish, combined with the fresh snowcover, we’ll have some radiational cooling. Temperatures will likely drop into the single numbers, with some sub-zero readings possible. Tuesday remains chilly, but not quite as cold as today as the high pressure area continues to build in. By Wednesday, that high shifts offshore, and a significant temperature moderation develops. The milder air will be accompanied by clouds though as a storm system begins to move toward the region.
By Thursday, that system draws nearer, with gusty southwest winds sending temperatures well into the 50s and possibly 60s, with more record highs possible. While temperatures will be mild during the day, it looks like the warmest temperatures will be at night. We could be near or above 60 degrees at midnight Thursday night across the region. We’ll also have some heavy rain as the system gets closer, which combined with the mild weather, will help melt much of the snow that remains on the ground. A widespread soaking rainfall is likely, with rainfall totals of more than an inch possible. We wouldn’t even be surprised if there’s a rumble of thunder. This storm will likely produce some severe weather across the South, and while that’s not likely here, a few thunderstorms are possible. Friday likely starts off warm and wet with temperatures still in the 50s at daybreak, but as a strong cold front comes through during the morning, the rain will end, and temperatures will drop during the day. High pressure builds back in for the weekend with dry and seasonably cool conditions for Saturday, but we may start to turn milder again on Sunday.
Monday: Snow showers ending in the morning, skies start to clear out by late in the day, breezy. High 18-25.
Monday night: Becoming mostly clear. Low -2 to +5.
Tuesday: Sunshine and some afternoon clouds. High 23-30.
Tuesday night: Clear to partly cloudy. Low 6-13.
Wednesday: Sunny in the morning, clouds start to stream in during the afternoon, becoming breezy and milder. High 38-45.
Thursday: Plenty of clouds with some sunny breaks, especially in the morning, showers developing in the afternoon, becoming windy. Wind-swept rain likely at night, possibly some thunder as well. High 56-63. The warmest temperatures are likely at night.
Friday: Windy with rain ending in the morning, clearing during the afternoon. High 47-54 at daybreak, temperatures drop during the day.
Hope you enjoyed the record warmth today, because Mother Nature is going to quickly remind you that it is still February.
Unseasonably mild temperatures continued across the region on Saturday, with a few records set, but a cold front moved through around midday, and a stronger one will move through this evening, bringing an abrupt end to the mild weather. Temperatures will quickly drop tonight as the front pushes offshore, and on Sunday, most places will likely be in the 30s or even upper 20s during the daytime. That’s not the big story though.
A wave of low pressure will ride along the front on Sunday, passing south and east of the region. It will be close enough to produce some light snow and snow showers across parts of eastern Massachusetts and Rhode Island, possibly even into southern New Hampshire, during Sunday morning and early afternoon. Most of the snow will remain light, with accumulations of an inch or two possible, mainly from Boston southward. The story doesn’t end there. As the low passes by, winds will shift into the northeast, which will result in some ocean-effect snow across parts of Cape Cod and coastal Plymouth County, and possibly Cape Ann as well. The areas that receive snow will be highly dependent on the wind direction. Northeast winds will spread the snow inland across southeastern Massachusetts, but as winds shift into the north Sunday night, the bands of ocean-effect snow will retreat closer to the coast of Plymouth County and across Cape Cod. By Monday morning, winds will shift into the northwest, bringing an end to the snow for most of us.
How much snow may fall? North and West of I-495, just a dusting to perhaps a half an inch. From 495 to I-95, some spots could see an inch, possibly 2 inches. It’s areas south of Boston (and Cape Ann), that may need shovels (and possibly plows). Across interior portions of southeastern Massachusetts as well as Cape Ann, we could see 2-4 inches of snow. The “jackpot” is likely to be across coastal Plymouth County as well as parts of Cape Cod, where as much as 4-7 inches could accumulate.
High pressure builds in behind this system on Monday with much colder weather. Despite sunshine developing in the afternoon, temperatures will only rise into the lower to middle 20s for highs, with single numbers and lower teens likely Monday night as skies clear out and winds die down. Tuesday also looks chilly, though likely a few degrees milder, but a big warmup is likely for the middle to latter half of the week. In fact, we could make a run at 60 again on Thursday, before another system brings in some rain.
There are some indications that this arctic blast for Monday and Tuesday could be the last really cold blast of the winter. Oh, it’ll still be cold, it’s only mid-February after all, but days with highs in the 20s and lows in the single numbers or below zero may be done for the year, though this is far from a guarantee. We’ve been known to have arctic blasts into March and even early April, though with the increasing sun angle, they tend to lose their staying power. This does not mean that winter is over, not by a longshot. We still can get snow around here well into April and even May if things set up properly. The longer range models are indicating that a milder pattern should start to take hold soon, and last into March. However, these same models also still show the threat for snow well into March, so don’t go putting away the winter gear just yet.
It’s mild today, but a messy Friday is on the way.
A strong cold is making its way toward the region this afternoon. We’ll have some rain ahead of it tonight, and the rain may be quite heavy. The combination of rain and mild temperatures will help to melt a lot of the snow that remains from last weekend’s blizzard. The front moves through this evening, and colder air will slowly make its way into the region early on Friday, first at the surface, then aloft. As temperatures drop, the rain will change to freezing rain and then sleet from north to south. With the roads already wet from the rain and temperatures dropping, a flash freeze is likely, and it will unfortunately be timed for the morning commute. If you’re going to be out in the morning, use plenty of caution, as untreated surfaces will become very icy quickly.
Temperatures will continue to drop during the day, with the freezing rain and sleet likely ending as some wet snow, mainly north of the Mass Pike. Everything winds down in the evening, then skies gradually clear out at night as high pressure builds in. This sets up a sunny but cold Saturday across the region. The high slides off to the east for Sunday and Monday, keeping us dry, but allowing temperatures to begin to moderate once again.
Thursday night: Rain, possibly heavy at times, changing to freezing rain and sleet late at night, mainly across southern New Hampshire and northern Massachusetts. Low 26-33 north of the Mass Pike, 34-44 south of the Pike.
Friday: Rain and freezing rain changing to sleet, and eventually some wet snow north of the Mass Pike. Temperatures dropping during the day.
Friday night: Wintry mix ending, some clearing late at night. Low 12-19.
Saturday: Becoming mostly sunny, breezy, and cold. High 19-26.
Saturday night: Clear and cold. Low -7 to 0 north and west of Boston, 1-8 south of Boston.
Sunday: Sunshine and some afternoon clouds. High 24-31.
Saturday is not going to be a pretty day around here, but most of you already knew that. There are some changes to our forecast though. Once again, we’ll start with the basics (which really haven’t changed), then work our way into the details (which have changed a bit).
Low pressure will develop off the Southeast coast this afternoon and will head up the Eastern Seaboard tonight and Saturday, rapidly intensifying as it does so. The system will likely pass just south and east of Nantucket Saturday night, and pull away from the region on Sunday. A few snow showers are possible today as a cold front moves through, completely unrelated to the storm. What that front will do is bring colder air back in, so that we’ll be dealing with all snow across nearly all of the region, except possibly Nantucket and Outer Cape Cod.
OK, let’s get to the details. We’ll start with temperatures. North and west of Boston, temperatures will likely be in the teens for much of the storm, resulting in a fluffy snow. This will make cleanup easier, but also make it easier for accumulations to pile up quicker. South of Boston, temperatures will be in the 20s to start, but will drop during the day, so we’re also looking at a fluffier snow here as well. Across Cape Cod, temperatures will be closer to freezing, so it’ll be a wetter snow, with the possibility of rain mixing in, depending on how close the storm actually tracks. The general rule is that 1 inch of liquid equals about 10 inches of snow, which works fine with temperatures close to freezing. The colder you get, the higher the ratio gets. When temperatures drop into the teens, the ratio can get to 20:1, which means 1 inch of liquid results in 20 inches of snow. We’re not sure it’ll get that high, as there are other factors involved beyond the temperature at the ground, but it is certainly possible. The other thing to keep in mind is that the temperatures, combined with strong winds (see next paragraph), will result in very cold wind chills, so keep this in mind if you’re heading outside to do some shoveling during the storm.
Next, we’ll get to the winds and coastal flooding. As the storm gets cranked up south of the region, winds will pick up on Saturday. Sustained winds of 15-25 mph are likely inland, with sustained winds of 20-40 mph along the coast. Wind gusts of 40-50 mph are likely inland, but along the coast, wind gusts of 50-70 mph seem likely, with higher gusts possible, especially across Cape Cod. Some trees and power lines could come down, so be prepared for power outages, but with a fluffier snow, there might be less widespread than you’d normally expect. The winds, combined with astronomical high tides, will result in some coastal flooding, especially at northeast and north-facing coastal areas during both the morning and evening high tides on Saturday.
With strong winds and heavy snow (more on that in a moment), blizzard conditions are expected on Saturday. If you don’t have to go out, then don’t. Whiteout conditions will make travel nearly impossible during the afternoon and evening. The National Weather Service has issued a Blizzard Warning for most of eastern Massachusetts and Rhode Island, as well as the New Hampshire Seacoast and coastal Maine.
Sustained winds or frequent gusts ≥ 35 mph AND considerable falling and/or blowing snow frequently reducing visibility < ¼ for ≥ 3 hours.
Blizzard conditions need to be the predominant condition over a 3 hour period.
Official definition of a Blizzard Warning from the National Weather Service
Now to the part that you’ve all been waiting for – how much snow is going to fall? If you read our Weekend Outlook yesterday, or are a regular reader of the blog, then you know that we are normally very conservative in our snowfall forecasts – no hype here. Well, many of the forecast models continue to forecast insane snowfall totals, and most of the guys on TV are buying in. With that in mind, we are issuing an Extreme Hype Warning.
When an Extreme Hype Warning has been issued, it 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
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 (due to the 1-3 inches they’ll get), and possibly how it dumped heavy snow (a.k.a. 1 inch) on parts of the Southeast.
As for our forecast? We’re going to raise forecast amounts from what we had yesterday, but not to the levels that most of the media is forecasting. Light snow may develop by midnight along the South Coast, spreading northward over the ensuing few hours, reaching southern and central New Hampshire and southern Maine by 3-5am. Between about 10am and 7pm, it’s going to snow rather heavily. Snowfall rates of 1-2 inches per hour will be likely in many areas. However, there will be some embedded bands of intense snowfall, with snowfall rates of 2-4 inches per hour. If you’re under one of these bands for any length of time, your totals may end up higher than our forecast, while areas outside the band a few miles away have significantly less snowfall.
OK, we’ve rambled on enough, let’s go to the actual forecast totals:
Central NH (Lebanon/Laconia): 4-8″ Southern NH/Central MA (Concord/Manchester/Nashua/Fitchburg): 10-15″ Merrimack Valley/495 Belt/NH Seacoast (Portsmouth/Haverhill/Lowell/Framingham): 15-20″ I-95 corridor (Beverly/Boston/Providence): 18-24″ Southeastern MA/Cape Cod (Brockton/Weymouth/Plymouth/Taunton/Fall River): 20-26″ with some totals in excess of 30″ possible.
Once the storm pulls away, dry and colder conditions settle in for Sunday and Monday, before temperatures start to moderate. There are some indications for a big warmup late-week and a storm that will bring in rain, but it’s still several days away, so we wouldn’t put too much stock into that just yet,
We’ve certainly got an eventful weekend coming up across the region.
Another chilly night is expected as high pressure slides offshore, but clouds will start to move in, and temperatures may actually start to rise after midnight as winds shift into the south and southwest. Friday will feature plenty of clouds and somewhat milder temperatures, but an approaching cold front may produce a few snow showers during the afternoon. This brings us to the main event.
We’ll give you the general idea first, then get into specifics in the next paragraph or four. Low pressure will move up the East Coast Friday night and Saturday. There are still some questions as to exact track and strength, but we are narrowing the possibilities. At this point, it looks like the storm will track just south and east of Nantucket, which means that this will be all snow for everyone, except possibly Nantucket and the Outer Cape. The storm should pull away before daybreak Sunday, with clearing Sunday afternoon, then high pressure builds in with sunshine and colder weather on Monday.
Now, let’s get to the details of the storm. As winds shift into the northeast Friday evening, the onshore flow may produce some flurries or snow showers across the region, but these won’t do much more than whiten the ground. The steady snow will spread across the region between 2 and 5am. Between about 10am and 10pm, we’ll have snow falling moderate to heavy at times, especially near the coast and south of Boston. There will be some embedded bands of intense snowfall, falling at the rate of 1-3 inches an hour, but picking out where those will develop is a fool’s errand at this point. The snow should taper off in the evening, and end from west to east between 3 and 6am Sunday. We’ll detail the amounts in a bit, as snow is not the only concern with this system.
As the storm rapidly intensifies, winds will ramp up, with sustained winds of 15-25 mph inland, and 20-40 mph along the coast and south of Boston. Wind gusts in excess of 50-60 mph are possible, especially across Cape Cod and the Islands. This will result in significant blowing and drifting snow, with blizzard conditions possible. It also will increase the threat for power outages, with trees and power lines coming down. The winds, combined with astronomical high tides (Tuesday is the New Moon), will result in coastal flooding, possibly moderate to major coastal flooding, especially at east and northeast-facing coastlines.
Another factor will be temperatures. We mentioned that this will be all snow for nearly all of the region, but it’s looking like it’ll be a fluffy snow for many of us. This is both good and bad. It’s good, because it makes it a lot easier to clean up, but bad, because it allows the snow to pile up even faster. The reason it will be a fluffy snow is because it’s going to be quite chilly. Areas north and west of Boston may stay in the teens all day Saturday, with 20s from Boston southward. Add in the strong winds, and you’re looking at wind chills in the single numbers and below zero. Keep that in mind if you’re going to try and clean up the driveway a few times during the storm.
OK, we’ve gone over the timing, the winds, the coastal flooding, the temperatures, did we miss anything? Oh yeah, how much to expect. You’ve probably seen or heard that there are many models forecasting some outrageous amounts of snow. Well, as is usually the case, you won’t find that here. Oh, we’re still expecting a rather potent storm, but if you really expect widespread 2-3 feet, then we’re going to disappoint you. Since we’re still 36 hours from the start of the storm, this could still change, and we’ll likely issue another blog post tomorrow, but here’s our current thinking:
Central NH (Lebanon/Concord): 2-6″ Southern NH/Central MA (Manchester/Nashua/Fitchburg): 5-10″ Merrimack Valley/495 Belt/NH Seacoast (Portsmouth/Haverhill/Lowell/Framingham): 8-12″ I-95 corridor (Beverly/Boston/Providence): 10-15″ Southeastern MA/Cape Cod (Brockton/Plymouth/Taunton/Fall River): 12-18″ with some totals in excess of 20″ possible.
Thursday night: Becoming partly to mostly cloudy. Low 15-22, but temperatures may start to rise after midnight.
Friday: Cloudy with a chance of snow showers. High 30-37.
Friday night: Snow showers becoming a steady light snow, becoming breezy. Low 18-25 north and west of Boston, 26-33 south.
Saturday: Windy with snow, heavy at times. Temperatures will hold steady or drop during the day.
Yes, the rumors are true, a storm system is on the way for the weekend, and there is the potential for some significant snowfall. Nothing is definite yet though, so let’s separate the truth from the exaggeration. First, we’ll set the table for what’s going to happen.
Low pressure will move out of the Gulf of Mexico and up the East coast Friday into Saturday while rapidly intensifying. (You’ll hear the word bombogenesis used for sure.) Before that happens, a cold front will move across the Northeast on Friday, producing some snow showers. These are unrelated to the storm system, and could drop an inch or less on the region. That front will likely dissipate south of New England as the approaching coastal storm overwhelms it. Meanwhile, behind that front, a large high pressure system will build into southeastern Canada, locking cold air into place.
OK, now that we have the basic setup, let’s delve into a few things that we’ve heard or read today and how truthful they are.
Statement: An historic blizzard could set records across the Northeast this weekend. Truth: Yes, some models are showing a rather extreme storm system with the potential for extraordinary snowfall totals. But, it’s still 4 days away, and a lot can change. This is far from a given. We’ll explain below.
Statement: This will be all snow for the entire region. Truth: Again, given that there is still some uncertainty in the track, a mix or change to rain can’t be ruled out, especially for Cape Cod, and possibly eastern Massachusetts of Rhode Island. Again, read on for more details.
Statement: Significant coastal flooding is likely. Truth: This one rings true. With a New Moon on Tuesday (we were that close to a Duran Duran song), tides will be running astronomically high. Add in strong east to northeast winds pounding the shoreline for 2 and potentially 3 high tide cycles, yes, coastal flooding is likely, especially the normally vulnerable locations.
OK, now let’s get into what could happen on Saturday. A rapidly intensifying storm system will head up the East Coast, producing strong winds and heavy snow ahead of it. While most of the models are fairly similar to each other with a track close to the “benchmark” (40N/70W), this is far from definite. The storm could end up farther offshore, which would limit the how far inland the heavy snow extends. The storm could also track closer to the coast, which would allow milder air to move in and change the snow to rain, how far inland the change could occur would be determined by the track obviously. This is the type of the detail that won’t become clearer for another day or two at best.
One factor in determining that track? The upper-level energy responsible for the storm is just moving into from the Pacific tonight. Why is that important? Let us explain. Every day around the world, we send up weather balloons twice a day to sample the upper atmosphere. This is done at 00UTC and 12UTC everywhere (7am/7pm in EST). This data is then fed into the models. The upper-level energy that will create our storm has been over the Pacific for the past several days, where there is little data. In the past, we would get observations from planes as well to supplement the balloons, especially over the water, where there are no balloon launches obviously. Well, since the pandemic, air traffic is less than half what it used to be, so there are a lot less of those aircraft observations. So, we are basically at the mercy of the balloon data. Once that upper-level energy moves over land, as it is doing now, it will be into the balloon network. The models should now start to have a better idea of its structure and converge on a solution.
Complicating things is the fact that some models show the system being captured by the upper-level trough of low pressure, or even getting stuck underneath a “cutoff” upper-level low pressure system. (It’s called that because it becomes cut off from the jet stream.) This would potentially allow the low to stall out south of New England for a while, prolonging the impacts to the region. How strong the storm gets (also up for debate) could determine whether or not this scenario occurs, but will also impact how strong the winds will be and in turn the amount of coastal flooding that may occur. Right now, the timing of the system looks to be generally between midnight Saturday morning and midnight Sunday morning, but obviously, this is far from definite.
As for how much snow will fall? Well, we’re not even going to attempt to put any numbers down yet. There is still FAR too much uncertainty. In addition to all the factors we talked about above, another one is temperature. Some models keep the cold air locked into place, with temperatures in the teens and 20s for much of the region during the storm. This would result in a much fluffier snow, making it a little easier to clean up, but also allowing it to pile up a lot quicker. If the warmer air does move in, especially near the coast, then temperatures could be near or even above freezing in spots. The general rule is that 1 inch of liquid precipitation equals 10 inches of snow. This holds true at temperatures close to freezing. With temperatures in the lower 20s, that 1 inch of liquid could result in 20 inches of snow. Most of the snow maps you may see online are ones that use the 10:1 ratio only, so in colder scenarios, like this one could be, they will underestimate the amount of snow.
If you really want, there are plenty of people all over Facebook, Twitter, and the web, who are more than happy to share all of those various model forecast maps, no matter how far-fetched they may seem. We’re not going to do that. We’ll just say that the potential is there for this to be a significant snowstorm.
Given all of this, we are issuing an Extreme Hype Watch for the StormHQ viewing area. 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. We’ll hazard an initial attempt at amounts when we publish our Weekend Outlook Thursday afternoon. In addition, well do another full blog post on Friday.