Messy Tuesday, Frigid Thursday

The Winter Solstice is Saturday, but winter will certainly make it’s presence felt over the next few days.

The low pressure system that produced severe weather across the South on Monday will head northeastward, impacting our area on Tuesday. The storm will be moving fairly quickly, and it doesn’t have a lot of cold air to work with, so we’re not expecting a big snowstorm. That doesn’t mean it won’t cause any problems.

Winter Weather Advisories are in effect for most of the region. Image provided by Pivotal Weather.

Snow will develop around midnight across parts of Connecticut and Southern Rhode Island, gradually spreading northward across the rest of the region before daybreak. The snow should quickly change to rain after daybreak across the South Coast and Cape Cod. As warmer air moves in aloft, a change to sleet and freezing rain will start to take place across the interior, with plain rain along the coast as milder air moves in off the still relatively mild ocean. Right now, it looks like the mixing may get as far north as the Merrimack Valley during the afternoon. North of there, precipitation should stay all snow. The precipitation will lighten up during the afternoon, but won’t completely end until the evening or first part of the overnight.

The morning and evening commute will both be impacted by this storm, but the greater impacts will certainly be during the morning commute. Not only could icing be a problem, especially in parts of Connecticut and Rhode Island, we could be looking at a band of moderate to heavy snow along and south of the Mass Pike. With temperatures expected to drop below freezing at night, many roads could ice back up, so untreated surfaces could become slick, especially in areas that changed over to rain during the afternoon.

Icing could become a significant problem across parts of Connecticut and Rhode Island on Tuesday. Image provided by Pivotal Weather.

As for how much snow to expect, we haven’t changed our thinking much from our earlier forecast.

South Coast/Cape Cod: Less than 1″
Southeastern Massachusetts (including the I-95 corridor): 1-2″
MetroWest/North Shore: 1-3″
Merrimack Valley: 2-4″
Central + Southern New Hampshire/NH Seacoast: 3-6″

The High Resolution NAM model is probably closest to our expectations for snowfall. Image provided by WeatherBell.

Behind this system, we’ve got to pay attention to an arctic cold front that will move across the region late Wednesday. It could produce some snow showers or squalls as it moves through. These won’t impact everyone, but in places they do, visibility could rapidly drop, and a quick half an inch to an inch of snow could fall.

Wind chills will likely drop below zero across most of the area Wednesday night into Thursday morning. Image provided by Weathermodels,com

Behind that front, some of the coldest air so far this season will settle in for Thursday. Wind chills will be below zero during the morning hours, and actual temperatures may not make it out of the teens during the afternoon. Friday will see temperatures start to moderate a bit, but it will still remain quite chilly, even by December standards.

Weekly Outlook: December 16-22, 2019

We’ve got another week coming up with just about everything Mother Nature has to offer. Well, not quite everything, since we won’t have a warm day this week. To make up for it, we’ll have at least one day that is extremely cold. How’s that for a trade off?

The week starts off with high pressure in control. That means we’ll have some sunshine, less wind, and chilly temperatures today. The sunshine will not last long though, as clouds quickly move in ahead of our next system. That storm will move from the Tennessee Valley into the Mid-Atlantic states, passing south of New England on Tuesday. That’s about the only part of the storm that isn’t complicated.

Snow will develop across much of the region before daybreak on Tuesday. Yes, that means your morning commute on Tuesday will be even worse than normal. The snow should quickly change to rain along the South Coast. Away from the coast is where the problems start. Warmer air will move in aloft, with a change to sleet, freezing rain, and eventually plain rain expected to work its way northward on Tuesday. How quickly it moves northward, and how far north that changeover gets are still up in the air. Obviously, this has a major impact on how much snow accumulation we can expect. The other problem is, how long do some areas stay sleet or freezing rain, as this will have a significant impact on road conditions.

The High-Resolution NAM model shows the progression of the the precipitation and changeover line with the next storm system. Loop provided by WeatherBell.

So, how much snow can we expect before the changeover? Obviously, this is still a low-confidence forecast, despite the fact that it’s only a little more than a day away. Here’s what we’re thinking for now:

South Coast/Cape Cod: Little to no accumulation
Southeastern Massachusetts/Rhode Island (South and East of I-95): A coating to 2 inches.
Northern Rhode Island/MetroWest/North Shore/Merrimack Valley/NH Seacoast: 1-3″
Southern NH (Nashua-Manchester): 2-4″
Central NH (Concord-Lebanon): 4-7″

We’ll try to do an updated blog post late Monday, once we get a little more clarity on some of the details.

The GFS model is probably the closest to our thinking for snowfall amounts right now. Image provided by Weathermodels.com

So, everything winds down Tuesday evening, and then things improve on Wednesday, right? Not so much. A strong cold front will move across the region during the afternoon. This front may produce some snow showers or possibly snow squalls as it moves through during the afternoon and evening. Behind the front, some much colder air settles in for Wednesday night and Thursday. Now, it won’t be as cold as it was in the Dakotas and Minnesota, where it stayed below zero all day Saturday and Sunday (Can someone please explain why people choose to live in North Dakota?), but many parts of our area could stay below 20 all day on Thursday. When you fact in the wind, it will feel like it’s below zero, especially during the morning.

Heading out before daybreak Thursday? Bundle up, because wind chills will likely be below zero across the region, Image provided by WeatherBell.

High pressure builds in for Friday with dry weather, but it shouldn’t be as cold as Thursday. This brings us to the weekend. This is where things get questionable again. You may have heard some chatter online about a big snowstorm this weekend. Well, it’s a possibility, but then again, it’s also possible that the Patriots defense won’t give up a single point for the rest of the season. Most of the models have been signalling that there will be a potent storm system developing off the East Coast this weekend. Every now and then, one of the runs puts that storm right off of Cape Cod and shows the potential for a blizzard, sending all of the Facebook Forecasters into a frenzy. Of course, these same models have also shown the same storm moving off of Florida and then eastward across the Bahamas instead. Will there be a strong storm? Probably. Will it impact us? Probably not. However, one thing that may happen, is a weak system moving eastward bringing in a period of light snow sometime either late Saturday or Sunday. Given where the storm forms, it’s not really an Alberta Clipper, calling it a Dakota Dasher would probably be more accurate.

Nearly every run of the GFS over the past 5 days has had a strong storm near the East Coast this weekend. However, the placement and strength of the storm has varied on every run. Loop provided by Pivotal Weather.

If you’re really looking ahead, right now Christmas Eve and Christmas Day look dry and seasonably chilly.

Monday: Some sunshine early, then clouds thicken up. High 30-37.

Monday night: Cloudy with snow developing after midnight. Low 23-30.

Tuesday: Snow, changing to sleet, freezing rain, and plain rain from south to north. Areas north of the Mass Pike may never go to plain rain. High 27-34 north and west of Interstate 95, 34-41 south and east of Interstate 95.

Tuesday night: Precipitation ends in the evening, then skies clear out late at night. Low 21-28.

Wednesday: Morning sunshine, clouds return in the afternoon with some snow showers or squalls possible late in the day, becoming windy at night. High 30-37.

Thursday: Sunshine and a few clouds, breezy, and cold. High 17-24.

Friday: Partly to mostly sunny. High 22-29.

Saturday: Mostly cloudy, chance for some light snow or snow showers late in the day and at night. High 29-36.

Sunday: Partly to mostly cloudy with a chance of snow showers, especially in the morning. High 34-41.

Weekly Outlook: December 9-15, 2019

Given a choice, would you prefer cold weather or warm weather? What about a choice between rain, snow, or dry weather? Well, you’re going to get ALL of these this week!

Temperatures could reach 60 across parts of the area on Tuesday. Image provided by WeatherBell.

We start the week with low pressure moving into the Great Lakes and then eventually up the St. Lawrence Valley. With low pressure passing to our north and west, we’ll be on the warm side, with rain expected, mainly in two waves. The first one will come in today, with rain developing this morning, and continuing into tonight, when it cold be locally heavy. The warm air should move in south of Boston fairly quickly, but it may take until tonight to get into the Merrimack Valley and southern New Hampshire.

Warm air comes in today, and is quickly pushed out by cold air late Tuesday into Wednesday. Loop provided by Weathermodels.com

We’ll have a bit of a lull tomorrow morning, but a cold front will approach later in the day, with rain coming back ahead of that front. We’ll still be on the mild side, that is until the front comes through. Temperatures will quickly drop behind the front late Tuesday and Tuesday night but the precipitation may linger, so we will likely see rain changing to snow Tuesday night.

The NAM model shows the progression of the storm with 2 waves of rain followed by some snow. Loop provided by Tropical Tidbits.

On Wednesday, a little disturbance will move across the region, bringing us some additional light snow, mainly in the morning. There’s still a bit of uncertainty with this, but plan on the morning commute being impacted. We’re probably only looking at a few inches, but all it really takes to screw up the morning commute is a few flakes at all. High pressure builds in late in the day and into Thursday with drier and much colder weather.

A few inches of snow could really mess up the Wednesday morning rush hour. Image provided by Pivotal Weather.

By Friday, temperatures start to moderate again as the high slides offshore. It’ll still be chilly (it is December after all), but not quite as cold as Thursday. The weekend looks even milder once again, but that’s because we’ll have another storm system passing to our north and west, so we’re looking at another round of rain, possibly heavy once again.

Saturday could end up quite mild once again, but wet as well. Image provided by WeatherBell.

Monday: Cloudy and becoming breezy with periods of rain and showers. High 49-56.

Monday night: Cloudy and breezy with rain likely, possibly heavy at times, tapering off late at night. Temperatures hold steady or possibly rise a few degrees.

Tuesday: Cloudy and breezy with showers redeveloping late in the day. High 53-60, but temperatures start to quickly drop from northwest to southeast during the afternoon.

Tuesday night: Cloudy with rain changing to snow during the evening. Low 26-33.

Wednesday: Cloudy with light snow ending around midday. Skies clear out at night. Temperatures hold steady or drop a few degrees during the day.

Thursday: Plenty of sunshine, but cold. High 24-31.

Friday: Becoming mostly cloudy. High 32-39.

Saturday: Cloudy, breezy, and milder with rain likely. High 46-53.

Sunday: Partly to mostly cloudy and breezy, chance for a few showers. High 42-49.

Weekly Outlook: December 2-8, 2019

Winter’s back, and it’s not going anywhere for a while. We’ve got more snow on the way in the next 24 hours, so we’ll get right to it.

Some moderate to heavy snowfall totals were observed on Sunday, especially north and west of Boston. More will be coming today into Tuesday. Image provided by the National Weather Service in Norton, MA.

We went into great detail yesterday, so we won’t spend too much time on today. Basically, the daylight will be fairly quiet as the low move towards the Gulf of Maine. We’ll have some occasional showers and/or drizzle across eastern Massachusetts, with freezing drizzle or a few flurries farther inland and up into southern New Hampshire. Late in the day, temperatures will start to drop, so things could get icy across eastern Massachusetts as well.

The High-Resolution NAM model depicts the progress of our storm system today into Tuesday. Loop provided by Tropical Tidbits.

Tonight is when things get interesting again. As the low pressure area moves into the Gulf of Maine it will intensify and become a pretty potent system. With gusty north to northwest winds keeping most of the area quite chilly, we’ll snow moving in from the ocean, on the backside of the storm. It is still uncertain how far inland that snow will get and how much will fall. We’re fairly confident that there’s going to be a band of heavy snow that sets up, but we’re still thinking that the heaviest stays just offshore. Still, with light to occasionally moderate snow going through Tuesday afternoon, we’ll still see some decent amounts, especially close to the coast. How much more? We think that much of the region could see 3-6″ between Monday night and Tuesday afternoon, with lesser amounts into southern New Hampshire. From the North Shore up into the New Hampshire Seacoast , another 4-7″ may fall.

The High Resolution NAM model is closest to our thinking for snowfall tonight into Tuesday. Image provided by WeatherBell.

Everything winds down Tuesday night, then high pressure builds in for Wednesday and Thursday with dry and chilly conditions. An Arctic front will move across the region late Friday, with a few snow showers or squalls ahead of it. After that, high pressure returns next weekend with even colder weather on Saturday. By Sunday, the high will slide offshore and temperatures will start to moderate, but will likely still be below normal for early December.

Temperatures may stay below freezing all day on Saturday. Image provided by WeatherBell.

Monday: Cloudy and breezy with showers and drizzle across eastern Massachusetts, flurries and freezing drizzle elsewhere. High 29-36 north and west of I-95, 37-44 south and east of I-95, though temperatures in this area will start to drop in the afternoon.

Monday night: Cloudy and breezy with precipitation becoming steady light to occasionally moderate snow. Low 24-31.

Tuesday: Cloudy and breezy at times with snow ending by early afternoon, some sunshine may develop in the afternoon the farther west you go. Additional accumulation 1-3″ in southern NH, 3-6″ most elsewhere, except 4-7″ from the North Shore to the NH Seacoast. High 30-37.

Tuesday night: Partly to mostly cloudy. Low 18-25.

Wednesday: More clouds than sunshine. High 34-41.

Thursday: A mix of sun and clouds. High 32-39.

Friday: Partly to mostly cloudy with some late-day snow showers or squalls possible. High 34-41.

Saturday: Sunshine and a few clouds, breezy. High 26-33.

Sunday: A mix of sun and clouds. High 36-43.

Better Find Those Shovels

We warned you yesterday, and now it’s just about here. The first winter storm of the season, coincidentally falling on the first day of meteorological winter.

Low pressure is moving into the Great Lakes this afternoon while a secondary area of low pressure is starting to develop across the Delmarva Peninsula This secondary low will move northeastward tonight, then meander around south of Long Island, before drifting eastward on Monday. This will spread snow into the region later this afternoon and evening. Snow may fall moderate to heavy at times during the evening and into the first part of the overnight. As warmer air moves in aloft and at the surface, a change to sleet and then rain is expected along the coast, pushing inland as the night moves on. There’s still a bit of a question as to how far inland that changeover occurs. Right now, our best estimate is somewhere around the Massachusetts/New Hampshire border, give or take 10 miles.

Winter Storm Warnings and Winter Weather Advisories are in effect for much of the Northeast. Image provided by Pivotal Weather.

Precipitation should lighten up considerably toward daybreak as the low moves southeast of New England. We’ll still have occasional snow showers with some drizzle or freezing drizzle as the intensity lightens up, with only light accumulations during the day , mainly north and west of I-95. If you’re south and east of I-95, these will be mostly rain showers, as temperatures will likely be in the upper 30s or 40s, thanks to a coastal front.

The ECMWF model is fairly similar to our thinking for how the storm progresses. Loop provided by Pivotal Weather.

As the low moves east of Cape Cod on Monday, an upper-level low pressure system will move overhead, pulling the system northward into the Gulf of Maine, where it will start to intensify and also slow down. This will result in another period of steady snow Monday night into midday Tuesday. There will likely be a band of heavier snow that sets up on the backside of this storm. Exactly where that band sets up is still a question. Several models want to keep moderate snow going to much of the day Tuesday across most of eastern Massachusetts and into the New Hampshire Seacoast and most of Maine. We’re still not convinced that will happen. Right now, we think it’s more likely that band stays just offshore, clipping the Seacoast and the Eastern Massachusetts coastline. If we need to make changes to this part of the forecast, we’ll do so in our Weekly Outlook early Monday morning.

Again, the big question – how much snow can we expect? Our thinking isn’t very different than yesterday:

Cape Cod: 1-2″ (mainly on Tuesday)
Southeastern MA: 2-5″ (1-2″ Sunday night, another 1-3″ Tuesday)
I-95 corridor (Boston/Providence): 3-6″ (1-2″ Sunday evening, 2-4″ Monday night/Tuesday) The farther away from the coast, the higher the amounts.
North Shore/MetroWest: 4-8″ (3-5″ Sunday night, 1-3″ Monday night/Tuesday) The farther away from the coast, the higher the amounts.
Merrimack Valley: 6-12″ (4-8″ Sunday night, 2-4″ Monday night/Tuesday)
Central and Southern NH: 8-12″ (6-10″ Sunday night, 1-2″ Monday night/Tuesday)
NH Seacoast: 10-15″ (6-9″ Sunday night, 3-6″ Monday night/Tuesday)

Once again, the GFS Ensemble Mean is closest to our thinking with respect to snowfall totals. Image provided by WeatherBell.

The good news is that the rest of the week looks storm-free. It’ll be chilly (it is December after all), but no more snowstorms for now. Don’t expect that to continue for the rest of the month.

Time’s Up, Winter is Arriving

We made it through November with just a few flakes, but your luck has run out. Mother Nature has decided to start December with a bang. We’ve got a very complicated storm coming, and for most of us, it’ll include snow, potentially a lot of it.

Winter Storm Watches and Warnings have already been posted for parts of the Northeast. Image provided by Pivotal Weather.

Today is a sunny albeit chilly day thanks to high pressure moving into southeastern Canada. As that high slides into Quebec, our sunny, chilly day will become a clear and cold night. Meanwhile the storm that’s been slamming the Rockies and Plains states for the past few days will head towards the Midwest. Normally, that would be good, as storms heading in that direction will move up the St. Lawrence Valley, keeping us mild with some rain. That’s not the case this time.

A secondary area of low pressure will develop off the Mid-Atlantic coastline on Sunday, and slowly drift south of Long Island. This will spread snow into the region during the mid/late afternoon hours on Sunday. Snow may fall moderate to heavy at times during the evening and into the first part of the overnight. As warmer air moves in aloft and at the surface, a change to sleet and then rain is expected along the coast, pushing inland as the night moves on. Precipitation should lighten up considerably toward daybreak as the low moves southeast of New England. So, that’s it, right? A quick 12-hour burst of snow and/or slop and we’re all done, right? Nope.

The GFS model shows the progression of the storm over the next few days. Loop provided by Tropical Tidbits.

We’ll have some occasional flurries, drizzle, and freezing drizzle during the day on Monday as the system slowly moves out. At the same time, an upper-level low will move into the Northeast, spawning another system south of Long Island. This will bring colder air back into the region, with another period of steady snow Monday night into Tuesday morning, with everything winding towards daybreak Tuesday.

Now, there are several things that are still in doubt, that could have a significant impact on the forecast. First and foremost – the change to sleet and/or rain Sunday night. How quickly does the changeover happen and how far inland does it get? There’s at least one model that shows the change to sleet happening quickly and as far inland as southern New Hampshire, with a prolonged period of sleet for much of the evening and overnight. This is a detail that we’ll hopefully have a better handle on in the next 12-24 hours. Second problem – the second batch of snow Monday night. This is not set in stone either, and if it does occur, we’re still not sure exactly where that band sets up or how heavy it will be.

So, having said that, how much do we expect? Keep in mind, this is preliminary, and we will almost certainly update it again before the snow starts Sunday afternoon:

Cape Cod: 1″ or less, mainly with the batch Monday night:
Southeastern MA: 2-4″ (1-2″ Sunday afternoon, another 1-2″ Monday night)
I-95 corridor (Boston/Providence): 3-5″ (1-3″ Sunday afternoon/evening, 1-2″ Monday night)
North Shore/MetroWest: 4-7″ (3-5″ Sunday afternoon/night, 1-2″ Monday night)
Merrimack Valley: 6-10″ (4-8″ Sunday afternoon/night, 1-2″ Monday night)
Southern NH/NH Seacoast: 8-12″ (6-10″ Sunday afternoon/night, 1-2″ Monday night)
Central NH: 10-15″ (Mostly Sunday night into midday Monday)

The GFS Ensemble Mean is probably closest to our thinking at the moment. Image provided by WeatherBell.

Obviously, we’re staying very conservative with that 2nd batch, and we’re hoping to have better clarity on that with the next few model runs. We’ll update again tomorrow.

Boston May Need an Ark, Bismarck Needs a Plow

Two developing storm systems – one off the East Coast and one in Plains, will both wreak havoc in the next few days, but for very different reasons.

Two low pressure areas are developing off the East Coast early this morning. The northern system is the stronger of the two, but the southern one is being monitored by the National Hurricane Center. It has the potential to develop into a tropical depression or subtropical storm later today. Whether it does or not, these two low pressure areas will eventually merge and become a rather strong non-tropical system over the next 24 hours. There is very little in the way of steering currents right now, so the system will just meander around off the coast until Saturday.

Low pressure won’t be in a hurry to go anywhere off the East Coast for the next few days. Loop provided by Tropical Tidbits.

As the system drifts northward, it will produce gusty winds along the coast, especially in New England. Tides are astronomically low at the moment, but will be rising later this week, so coastal flooding, while not a major concern, will still be possible in some locations. A coastal flood watch has been issued for parts of Plymouth County, Cape Cod, and Martha’s Vineyard. Rough seas will also be a large concern for marine interests, with Storm Warnings now in effect offshore. However, the biggest concern and also the biggest question mark right now is heavy rainfall.

Wind gusts in excess of 50 mph are possible across much of Southern New England. Yeah, that blows. Image provided by WeatherBell.

While the storm will likely spread some heavy rainfall into New England, there is still plenty of uncertainty as to how far north the heavy rain gets, as well as how much rain actually falls. Some of the models are producing extremely heavy rainfall, with totals in excess of 10″ in southeastern Massachusetts! While we aren’t buying the extreme totals, the fact that most of the models are showing this potential means that some very heavy rain is likely, especially south of Boston, where a Flood Watch has been issued.

That’s a lot of water coming out of the sky over the next 3 days. Some models have even more than this! Image provided by WeatherBell.

Thanks to some dry weather over the past couple of months, we shouldn’t have to worry about any flash flooding, though downpours will result in ponding of water on roadways, and some locations normally prone to flooding in heavy rain will also have problems. However, since we’re expecting a prolonged period of heavy rain, flooding is still a possibility in some locations, other than the ones we just mentioned, especially some of the smaller streams and rivers. Strong winds will also start to take some of the leaves off of trees, which may clog up storm drains, resulting in some flooding as well.

Recent dryness means that flash flooding is not likely in New England with this storm. Image provided the the Northeast River Forecast Center.

While all this is taking place off the East Coast, some very cold air will settle into the Rockies and Plains states as low pressure starts to develop across the Central Plains. Record lows are likely to be set in numerous locations over the next few mornings across the region. This system will head north-northeastward while strengthening. The system isn’t expected to become that strong, but with a large high pressure area building in behind it, it will produce some strong winds. It will also draw warm and moist air northward from the Gulf of Mexico. As this air runs into the much colder air on the backside of the storm, the first significant snowstorm of the season is expected to develop across the Northern Plains.

Winter Storm Watches and warnings have been posted from parts of Idaho Montana, and Wyoming into parts of northern Nebraska and the Dakotas as well as northwestern Minnesota. across Idaho, Montana, and Wyoming, snowfall totals of 6-12 inches are possible, with some heavier amounts in the higher elevations. The biggest issues are expected across the Dakotas and northwestern Minnesota.

Wind gusts of 40-50 mph or more are expected across the Northern Plains. Image provided by WeatherBell.

The precipitation will start as rain across this area later today, but strong northerly winds will usher much colder weather in, changing the rain to snow from west to east on Thursday. Like its East Coast counterpart, this storm won’t move at a rapid pace, so snow, possibly heavy at times will continue across this area into early Saturday, with snow showers lingering into Sunday.

This storm also has some questions with it’s precipitation shield. While heavy snow is likely across a large area, how much falls and where the heaviest snow will fall is still a question. Right now, it looks like the heaviest snow will fall from central South Dakota into central and eastern North Dakota, but that still could change. As for amounts, many areas could see more than a foot, with totals in excess of 2 feet possible in some areas. The snow will be accompanied by winds gusting to 40-50 mph, resulting in blizzard conditions, especially late Thursday into Friday.

Welcome to winter! Snowfall totals of 1-2 feet or more are possible across the Dakotas. Image provided by Pivotal Weather.

While snow in October is not unusual across this region, snowfall amounts of this magnitude this early in the year are extraordinarily rare. In Grand Forks, ND, the largest October snowstorm on record occurred October 24-26, 2001, and it dropped 10.9″ on the city. In Fargo, ND, the largest October snowstorm on record is only 8.1″ on October 30-31, 1951. For Pierre, SD, the October snowstorm of record occurred October 30-31, 1943, and it only produce 7.2″ of snow. Current model forecasts are forecasting amounts that are 3-4 times the records. These model forecasts are likely too high, but it seems likely that many of these October records are going to be obliterated in the next few days. Hopefully, this is not a sign of what’s to come this winter.

Trouble Brewing in the Gulf

It’s been a fairly slow start to hurricane season in the Atlantic, which is fairly normal, but things are starting to heat up in the Gulf of Mexico.

A disturbance dropped southward from the Tennessee Valley over the weekend, moving into the Gulf of Mexico on Tuesday. With plenty of warm water and only a little wind shear, the system is starting to get organized this afternoon, and could become a tropical depression later today or on Thursday.

Thunderstorm activity is getting more organized in the northern Gulf of Mexico this afternoon. Loop provided by NOAA.

As of 2pm Wednesday, the system was centered about 155 miles east-southeast of the mouth of the Mississippi River, moving toward the west-southwest at 8 mph. It is producing sustained winds of 30 mph, with some higher gusts. Steady strengthening is expected for the next few days. A Tropical Storm Watch has been posted from the Mouth of the Mississippi River to Morgan City, Louisiana. A Storm Surge Watch has also been posted from Pearl River to Morgan City.

Forecast tracks for Potential Tropical Cyclone Two from various forecast models. Image provided by WeatherBell.

The forecast models are fairly unanimous that the system will continue westward for the next 36-48 hours, but after that point things become unclear. A turn toward the northwest and eventually north is expected as an upper-level trough moves into the Great Plains, but when that turn occurs has a very significant impact on the system. A quicker turn means that the storm spends less time over the warm waters of the Gulf, and thus has less time to strengthen. A later turn means the opposite, more time over water, more time to strengthen, and the greater likelihood of it becoming a hurricane. Intensity forecasts are notoriously poor to begin with, and this system is no different. Very few models are predicting the system to reach hurricane strength, but the National Hurricane Center’s official forecast does call for the system to become a hurricane before landfall. As we mentioned already, the eventual track of the system will play a large part in determining this.

Intensity forecasts from various models for Potential Tropical Cyclone Two. Image provided by the University of Wisconsin.

Storm surge is a danger with any storm system, and this one is no different. Storm surge of 2-4 feet is likely near where the center makes landfall. Since much of southern Louisiana is already low-lying, this could result in flooding for much of the region. Wind damage will also be a concern across the region, which again will be dependent on the strength of the system. Winds will pick up Friday night across portions of Louisiana and possibly eastern Texas, with landfall most likely on Saturday right now, but this is obviously subject to change.

Rainfall forecast for the Gulf Coast for the next 6 days. Image provided by Weathermodels.com

By far, the biggest threat with this system will be rainfall. Tropical systems produce copious amounts of rainfall, and this one will be no different. Rainfall totals of 6 to 12 inches are expected across parts of the Gulf Coast, with some amounts to 20 inches possible. This would produce widespread flooding across the region, but in this case, it will just exacerbate existing flooding problems. The Mississippi River remains above flood stage across the region, and this will only worsen the flooding. On top of that, thunderstorms dropped up to 10 inches of rain on parts of New Orleans Wednesday morning, and that’s before the precipitation from the system even reaches the area. The Mississippi River is expected to crest in New Orleans at a level of 20 feet, which is also the same height that the levee system protects the city to. Obviously this will bear watching. Upstream, the River has been above “Major Flood” stage in Baton Rouge since February 26. It’s not likely to drop below flood stage until at least some time in August, if then.

River forecast for the Mississippi River at New Orleans. Record flooding is not expected, but the levee system will likely be tested once again. Image provided by NOAA.

Elsewhere, the Atlantic remains quiet, with no other systems expected to develop in the next week or so.

Weekly Outlook: April 22-28, 2019

Did you enjoy the sunshine and warm temperatures at the end of the past week? Good, because you probably won’t get much of that this week. This week looks rather wet at times. The whole week won’t be wet, but there will be a few days that are quite damp.

We start the week off with some fog this morning, especially along the south coast, since we have plenty of moisture in the air. A weak system will pass offshore today, and it will bring in a period of rain and showers, mainly across eastern New England. Some of this rain will be locally heavy, and thanks to northeast winds off the still-cool Atlantic, temperatures will be cooler than the past few days. The rain may linger into Tuesday morning before the system pulls away. Some sunny breaks may develop in the afternoon, but they won’t last long. Another cold front quickly approaches for Tuesday night into Wednesday morning with more showers.

Some of the rain today into early Tuesday could be heavy across eastern New England. Keep that umbrella handy. Image provided by WeatherBell.

High pressure builds in for later Wednesday into Thursday with sunshine and seasonable temperatures, but this too will only be temporary. The next system approaches on Friday, with, you guessed it, more rain, but it’ll be generally light. High pressure returns for Saturday with some sunshine, but again, not for long. Yet another system will move in for Sunday with another round of rain, and there’s a chance that this could be heavy too. We’ll keep an eye on that as the week goes along, but don;t go cancelling any plans for next weekend just yet.

Rainfall has actually well below normal over the last couple of months across much of the Northeast, so we really need this week’s rain. Image provided by the Northeast Regional Climate Center

Monday: Fog burns off early, then a few sunny breaks are possible before clouds return, with rain likely during the afternoon. Becoming breezy during the afternoon, especially along the coast. High 57-64, but turning cooler in the afternoon along the coast.

Monday night: Periods of rain and showers, possible heavy at times. Low 45-52.

Tuesday: A few lingering showers in the morning, otherwise cloudy with some sunny breaks in the afternoon. High 51-58, except 59-66 north and west of I-495.

Tuesday night: Cloudy with scattered showers. Low 41-48.

Wednesday: Showers ending early, then skies become partly to mostly sunny and breezy in the afternoon. High 60-67.

Thursday: Mostly sunny for much of the day, clouds start to filter back in during the afternoon. High 59-66.

Friday: Mostly cloudy with showers likely. High 54-61.

Saturday: Sunshine to start, clouds come back in the afternoon, breezy. High 54-61.

Sunday: Mostly cloudy with a chance of rain. High 55-62.

Sunday Night Special or Monday Morning Madness?

As promised, the second storm in our one-two punch is heading this way. While most of the snow is expected while you’re asleep Sunday night, it could have a big impact on your Monday morning commute.

Winter Storm Warnings and Winter Weather Advisories are in effect for most of the Northeast as of Sunday morning. Image provided by Pivotal Weather.

High pressure is hanging on this morning, providing us with sunshine, but clouds will quickly move in this afternoon as low pressure starts to move towards the Mid-Atlantic coastline, passing south of New England Monday morning. This storm will be a bit stronger than the one we had yesterday, and also have a little more moisture to work with, but will be moving fairly quickly, limiting the amount of time it spends in the region. One thing working in its favor is that most of the snow will fall at night. We’re at the time of year where the sun angle is high enough that snowfall during the daytime has a hard time sticking on pavement. At night, that’s not an issue.

The high-resolution NAM model shows the snow moving in this evening, becoming heavy overnight, and ending in the morning, with any rain confined to the south coast. Loop provided by Tropical Tidbits.

Snow will move in this evening, likely in the 7-10pm time frame, and will continue through the overnight hours. It may be heavy at times, especially between about 1 and 5am. A change to rain is expected for Cape Cod and the South Coast, but likely won’t advance past Route 44. Everything should wind down and end around 6-8am. That’s also the time of the morning commute. Road crews should have plenty of time to work on getting the roads cleared, but given past experience, and that people will likely leave early since it’ll still be snowing, we expect many roads to still be in awful shape. Give your self a lot of extra time in the morning. We also expect many school districts to cancel classes for Monday.

Snowfall is running about 10-20 inches below normal across the area this winter. Image provided by the Northeast Regional Climate Center.

It’s been a down year for snowfall, running 10-20 inches below normal across the area, but this storm will put a dent in those departure numbers. How much are we looking at?

Cape Cod/South Coast/Southern RI: 2-5″
The rest of the region: 4-8″ with isolated 10″ totals possible, especially from northern RI into the South Shore.

The high-resolution NAM has had a great winter for snowfall predictions, and we’re not straying from it again. Image provided by WeatherBell.

Things look to quiet down and get colder behind this storm, but a pattern change to milder weather could be coming as we head towards mid-March. We’ll have more details on at least the next week in our Weekly Outlook early Monday morning.