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Heavy Rain and Snow Heading for California, Snowstorm Likely for the Southeast, New England

A developing storm system will bring heavy snow to parts of the Southeast and New England this weekend, while the West Coast braces for a lot of much-needed rainfall.

GFS Model forecast for rainfall through next Friday evening. Image provided by WeatherBell.

We’ll start on the West Coast, where a series of storm systems will bring plenty of rain to drought-stricken California. While this will not alleviate the drought that has been ongoing for years, it will help to put a big dent into it. The first of the storm systems will move in tonight, and by the time the last one moves through next Friday, rainfall totals of 5-10 inches will be widespread across much of central and Northern California, with many locations, especially along the coast and western slopes of mountains receiving 10-20 inches or more.

GFS Model forecast for snowfall through next Friday evening. Image provided by WeatherBell.

At the higher elevations, especially in the Sierra Nevada, incredible amounts of snow are expected. The snowpack, which much of the region depends on for water in the summer as it melts, is already above normal, and over the next week, some locations might see 6-12 FEET of new snow from these storm systems.

A variety of precipitation is falling across the Southeast this evening. Loop provided by Weathertap

Back in the East, a storm system is riding along a stalled out front across the Southeast, producing some snow across parts of the Tennessee Valley and the Southeast. As this system draws in moisture from the Gulf of Mexico and the Atlantic, and runs into an arctic airmass already settling into the region, it will produce heavy snow in places that normally don’t see a lot of snow, such as Georgia, the Carolinas, and the Virginia Tidewater area. In these places, even a dusting of snow can cause traffic nightmares, so heavy snow can bring these areas to a standstill.

GFS model forecast for snow across parts of the Southeast and Mid-Atlantic states through Sunday morning. Image provided by Pivotal Weather.

The heaviest snow from this system is expected across the Appalachians and also across the Virginia Tidewater area, as the storm gathers strength while moving into the Atlantic. Of course, the 6-12 inches expected across much of North Carolina will cause its own problems, but luckily, the bulk of the snow will fall tonight and Saturday, minimizing the travel problems. The heaviest snow should remain just south and east of the big cities of Washington, Philadelphia, and New York, but a few inches may fall in each location.

Once this storm moves off the Mid-Atlantic coast it will head northeastward, passing a couple of hundred miles south and east of Cape Cod. Normally, this would mean just a little bit of light snow for parts of Southern New England, and for the most part, that’s what we’re expecting. However, for southeastern New England, mainly south and east of I-95, it’ll be a different story from Saturday afternoon into Sunday morning.

There are a couple of factors that will enhance snowfall totals across this region. First, with northeasterly winds blowing off the Atlantic, we’ll get some ocean-effect snowfall. This is similar to the lake-effect snow that you often see near the Great Lakes. Second, temperatures will only be in the upper teens to middle 20s. This means that it will be more of a fluffy snow, which will pile up quicker than a much wetter snow.

NAM Model forecast for snowfall through Sunday evening. Image provided by Earl Barker’s Weather Models. — NAM Model forecast for snowfall through Sunday morning. Image provided by Earl Barker’s Weather Models.

The snow should start to develop across Cape Cod and southeastern Massachusetts Saturday morning, and will quickly spread inland. The snow should spread as far inland as central Massachusetts and southern New Hampshire, but it will quickly retreat eastward again, ending in most places during the evening. The exception is Cape Cod and coastal Massachusetts, where northerly winds behind the storm may keep the ocean-effect snow going into the early hours of Sunday morning.

For snowfall totals, we’re not expecting more than an inch or two from southern New Hampshire into Central Massachusetts. Points north and west of Boston and Providence, including the Merrimack Valley, will likely see 2-4 inches, with some heavier amounts across Cape Ann. Along and south of Interstate 95, including the southern and eastern suburbs of Providence and Boston, totals of 6-12 inches seem likely, with the best chance for more than a foot of snow across parts of Plymouth County and Cape Cod, where the ocean enhancement will play a big role.

Behind the system, with fresh snow cover, temperatures will turn colder. Monday morning, temperatures will be in the single numbers across much of the region, with some sub-zero readings likely. The next storm moves in later on Tuesday, and although it will start as some snow or a wintry mix, milder air will move in, with the bulk of the precipitation falling in the form of rain Tuesday night into Wednesday.

Big Changes Coming to the Nation’s Heartland

Even though we’re into the middle of November, it hasn’t felt like late autumn across much of the nation. That’s about to change, especially across the Plains states and the Midwest.

Temperatures have been as much as 10-15 degrees above normal this month across the Northern Plains. Image provided by WeatherBell.

A storm system will move out of the Rockies and across the Plains states over the next few days. Ahead of the system, warm, moist air will be drawn northward from the Gulf of Mexico. High temperatures on Thursday will be in the 70s as far north as Iowa and Illinois, with record high temperatures expected across much of the Mississippi Valley. The warmth won’t last too much longer though, as a strong cold front will be marching eastward across the Great Plains.

Numerous record high temperatures are expected on Thursday across the Mississippi Valley. Image provided by WeatherBell.

Behind the front, much cooler air will settle southward from Canada. With plenty of moisture being drawn northward, it will fall as snow on the backside of the low from the Central Rockies and Central Plains northeastward into the Upper Midwest. Some of the snow could be heavy, especially in parts of South Dakota and Minnesota, where snowfall totals of 10-15 inches are possible by Saturday evening. Winter Storm Watches have been posted from eastern Wyoming and northern Nebraska northeastward to Minnesota.

Snowfall forecast through Saturday evening from the GFS model. Image provided by Pivotal Weather.

Snow isn’t the only hazard with this system. As it strengthens, it will create strong winds across much of the Plains states. Sustained winds of 20-30 mph with gusts to 50 mph or more are expected, especially from the Dakotas into Nebraska. The combination of high winds and snow may result in blizzard conditions at times. A blizzard watch has been issued for southwestern Minnesota, northeastern South Dakota, and extreme southeastern North Dakota.

Current watches and warnings across parts of the Plains States. Image provided by NOAA.

Once the system moves into southern Canada this weekend, some of the coldest air so far this season will settle into the region. While these temperatures aren’t that unusual for late November, they will be quite a change from the recent warmth that has enveloped the area. Low temperatures will likely drop into the teens and 20s across the region this weekend, with single digits possible. In some of the locations with fresh snowcover some sub-zero readings are possible. The cool air will be short-lived, as temperatures will likely warm back up to above normal readings by early next week. Current indications are that the unseasonably mild weather will persist for the most part well into December across the region.

October in the Northeast Means a Little Bit of Everything

October can be a time of change in the Northeast. While the first thing that comes to mind is the changing colors of the foliage across the region, the weather also changes, sometimes quite frequently. That’s what we’re going to be dealing with for the next few days.

Unseasonably warm weather was observed across much of the Northeast for the past few days, with high temperatures soaring well into the 70s and 80s across much of the region. This resulted in dozens of record high temperatures. However, some changes are coming, and the warm weather will be a distant memory within the next 24-48 hours.

Record high temperatures broken across the Northeast on Monday October 17 and Tuesday October 18. Image provided by NOAA.

Record high temperatures broken across the Northeast on Wednesday October 19. Image provided by NOAA.

A cold front moved across the region on Wednesday with little fanfare. That front will stall out to the south of New England overnight. On Thursday, a wave of low pressure will start to approach from the west. This will spread rain and showers into the area. Some of the rain will be heavy, especially from New York into Pennsylvania late Thursday into Friday. With rainfall totals of 1-3 inches and locally up to 5 inches expected, some flooding is likely. Across New England, where a serious drought is ongoing, rainfall will be much lighter, with most locations likely receiving under half an inch of rain.

Expected rainfall through Friday evening across the Northeast. Image provided by Pivotal Weather.

As that wave of low pressure moves into Upstate New York on Friday, it will lift that cold front northward across the region as a warm front once again. While Friday won’t be as warm as the past few days, high temperatures will still get into the 60s and lower 70s. With dewpoints also in the 60s, it will be a rather muggy day for mid-October.

Computer model forecasts for the track of a tropical disturbance in the Bahamas. Image provided by Tropical Tidbits.

Meanwhile, there is a tropical disturbance brewing near the Bahamas. Upper-level conditions are somewhat favorable for development, and the system could become a tropical depression or subtropical storm on Thursday. The system will likely head northward, moving towards the Gulf of Maine and merging with the cold front approaching from the west as we head into the weekend. This will bring another round of heavy rainfall into Maine and Atlantic Canada, areas that were hit hard by heavy rain from Hurricane Nicole just a week ago.

Expected rainfall between Friday evening and Sunday evening across the Northeast. Image provided by Pivotal Weather.

Once the system moves into southeastern Canada, it is expected to stall out under an upper-level low pressure area and become a strong extratropical system. It will drag a cold front across the Northeast, bringing much colder air into the region. With strong low pressure nearby and much colder air filtering in, rain will change over to snow across portions of Upstate New York and Northern New England. While the snow will be confined mainly to the higher elevations, this is the first accumulating snow of the season across the area. Several inches may accumulate across parts of the Adirondacks and the Green Mountains.

Expected snowfall through Monday evening across the Northeast. Image provided by WeatherBell.

While there could be a few wet flakes mixed in with some of the rain across lower elevations of Central New England, accumulating snow is not expected.Sunday will be a chilly day, with highs only in the 40s and 50s across much of the Northeast. These readings are 10-20 degrees below normal. Of course, any mention of snow in October across the Northeast will make residents think back just a few years to the pre-Halloween snowstorm that dropped 1-2 feet of snow across parts of the region, setting numerous records. While this system won’t come anywhere close to that, it should make for some spectacular photos of snow-capped mountains and valleys filled with colorful foliage early next week.

Snowfall from the Halloween snowstorm of 2011. Image provided by NOAA.

The other thing the storm will do and bring gusty winds to much of the Northeast through the weekend. Northwest winds of 15-25 mph may gust to 40 mph at times, especially across New England. This may result in some spotty wind damage across parts of the area. The other effect it will have is to create rather chilly conditions. Just a few days as experiencing temperatures in the 60s, 70s, and 80s, highs will only be in the 40s and 50s across much of the area, with wind chills in the 30s and 40s. This is the type of change that October is known for across the Northeast.

The Rainy Season Is About to Start in the West

Across much of the West, the bulk of the rainfall that falls during the year usually falls between October and April. This year is starting off right on schedule as a storm system is poised to bring heavy rain to parts of the region over the next few days.

Surface analysis across the Pacific Ocean from Monday afternoon October 10. Image provided by NOAA.

A strong low-pressure system passing south of the Aleutians on Monday will move into the Gulf of Alaska over the next 24-48 hours, before heading towards British Columbia and the Pacific Northwest. The storm will bring heavy rainfall and strong winds to the Aleutians and portions of southern Alaska through midweek. Along the coast, wind gusts may reach hurricane force. With the slow movement of the storm, and the strong onshore winds, heavy rain is likely across much of the Aleutians, with totals in excess of five inches possible.

Expected rainfall across the Pacific Northwest through Friday evening. Image provided by WeatherBell.

By midweek, as the storm moves towards the coast of British Columbia and Washington, rain will move into the Northwest. The heaviest rain is expected during Thursday and Friday, with several inches likely west of the Cascades, especially along the west slopes of the coastal mountains. This will likely lead to flooding in some areas. In addition to the rain, strong winds will blast the coastline. Wind gusts of 60-80 mph are possible, especially along the coast of Oregon.

GFS model forecast for peak wind gusts along the coast of Oregon Thursday afternoon. Image provided by WeatherBell.

As the system pushes inland, rain will spread southward into northern California by late Thursday, likely reaching as far south as central California. This will bring beneficial rain into portions of the region, including the Bay Area, where several wildfires continue to burn. After a dry summer, this rain will be very helpful to firefighting efforts across the area. Rainfall totals of 1-3 inches are possible, with heavier amounts along the northwestern coast of the Golden State.

Active wildfires across California as of Monday afternoon October 10. Image provided by California Department of Forestry and Fire Protection.

As the rainfall moves inland, it will change to snow across the higher elevations of the Sierra Nevada. Snow levels will remain fairly high with this system, likely around 7000 feet. Above that, especially above 9000 feet, snowfall totals of 8 to 16 inches are possible. While this is not the first snow of the season in the Sierras, it is the first significant storm of the season.

Once this system pushes inland, another strong storm looks to follow on its heels. Another round of strong winds and heavy rain is expected to move into the Northwest and Northern California for the weekend. That storm may be the remnants of Typhoon Songda, currently passing out to sea and weakening south and east of Japan.

The Feel of Fall is Arriving

Astronomical fall begins on September 22 at 10:21am EDT, but meteorological fall is defined as the period between September 1 through November 30. While it can and does still feel like summer across parts of the nation, there are more and more signs that summer is winding down.

As the nights start to grow a little longer the farther north you go, the cooler air starts to build up a little more, especially as you head into Canada and Alaska. The cold fronts that drop down from Canada and into the Northern US start to pack a little more punch. One of those fronts is moving across portions of the Upper Midwest and the Great Plains today. The airmass moving into the Rockies and Northern Plains behind the front is sending temperatures as much as 15 to 25 degrees below normal this afternoon.

Temperatures will be 15 to 25 degrees below normal across the Northern Rockies and Northern Plains today behind a cold front. Image provided by Pivotal Weather.

As that airmass settles in, low temperatures will drop into the 30s and 40s across the Northern Plains and Rockies tonight. Frost advisories and freeze warnings have been posted for western portions of North Dakota for Tuesday morning. By Wednesday morning, the coldest air will move over Minnesota, where low temperatures could drop into the upper 20s and 30s. Additional frost and freeze advisories will likely be issued for this region.

GFS model forecast for low temperatures across Minnesota Wednesday morning. Image provided by WeatherBell.

Cold temperatures aren’t the only noteworthy item with this cold front. As the cold air surges into the Rockies, precipitation will accompany it. That precipitation will likely fall as snow in many areas, mainly at elevations above 5000 feet. Across some of the higher peaks, more than a foot of snow could accumulate over the next day or two. Winter Weather Advisories have been issued for portions of northern Wyoming as a result.

GFS model forecast for snowfall through Wednesday morning. Image provided by WeatherBell.

Some snow is also possible across the higher elevations of the Sierra Nevada as the cooler air spreads into the West. While accumulations will be minor, this will likely be the first snowfall of the year for this region. Across the rest of the Golden State, temperatures will likely be 6 to 12 degrees below normal on Tuesday, with highs only in the 70s to lower 80s, a welcome change from the 90s and 100s they’ve had for most of the summer.

While this front will bring cooler air into the Northeast later this week, one thing it won’t do unfortunately, is bring beneficial rainfall to the region. It will produce showers and some thunderstorms, and while a few of the storms may contain heavy downpours, they’ll be very localized. Across much of the region, rainfall totals will be generally under half an inch. This will do little to put a dent in the severe drought that much of the region is currently experiencing. Rainfall deficits of 5 to 10 inches below normal since the beginning of March are common across the region.

Rainfall deficits across the Northeast from March 1 through August 31. Image provided by the Northeast Regional Climate Center.

While this early taste of fall moving into much of the Northern US this week is not uncommon for mid-September, it might not be repeated much this fall. Long-range forecasts are showing the likelihood of a warmer than normal fall across much of the United States.

Change is in the Air

As we head into the end of August, some familiar things start to happen. Children will start to head back to school. Baseball’s pennant races heat up while football at all levels gets ready for the start of the season. Halloween candy starts to appear in stores and it will be followed shortly by pumpkin-flavored everything. In terms of the weather, familiar things happen there too. The tropics start getting more active and the cold fronts dropping southward from Canada pack a little more punch than they usually do during the summer.

One of those cold fronts will be moving across the Plains states and into the Midwest over the next few days. Ahead of the front, summertime heat and humidity remains in place, with temperatures well into the 80s and 90s common. Behind the front is much cooler and drier air. By Friday morning, temperatures will be 10-20 degrees below normal across much of the Plains states and Rocky Mountains as a large area of high pressure builds in from Canada. Low temperatures will drop into the 40s and 50s across the Northern Plains, with 30s and even some upper 20s from the Rocky Mountains into interior portions of the Pacific Northwest.

Temperature anomaly map based on the GFS model for Thursday morning. Image provided by Pivotal Weather, — Temperature anomaly map based on the GFS model for Thursday morning. Image provided by Pivotal Weather.

As that cooler air settles into the region, some snow is possible across the higher elevations of the Northern and Central Rockies. Snow levels will remain fairly high, but a few inches of snow may accumulate on top of some of the higher peaks in Wyoming and Colorado.

Snowfall forecast based on the GFS model through Friday morning. Image provided by WeatherBell.

Ahead of the front, a warm and humid airmass will remain in place, with high temperatures well into the 80s and 90s for the next few days. As the front approaches, it will trigger showers and thunderstorms. Some of the storms could be strong to severe, with hail and gusty winds possible, along with a few tornadoes. The biggest threat looks to be heavy rain and flash flooding. Because the front will be moving fairly slowly, some of the heavier storms will linger over the same areas. Rainfall totals of 1-3 inches will be common across parts of the Eastern Plains and Mississippi Valley, with some heavier amounts possible. This will likely lead to flooding in some areas.

Expected rainfall totals across the Midwest through Friday morning. Image provided by WeatherBell.

Meanwhile, in the Atlantic, we’re keeping an eye on a disturbance east of the Lesser Antilles and Tropical Storm Gaston out in the Central Atlantic. There was a third system, Tropical Depression Fiona, but it fizzled southeast of Bermuda earlier today.

Satellite loop showing Tropical Storm Gaston (far right) and a disturbance approaching the Eastern Caribbean. Loop provided by NOAA. — Satellite photo showing Tropical Storm Gaston (far right) and a disturbance approaching the Eastern Caribbean. (Click for loop) Provided by NOAA.

Tropical Storm Gaston is centered about 700 miles west of the Cape Verde Islands this afternoon, heading towards the west-northwest at 21 mph. Maximum sustained winds are near 65 mph, and additional strengthening is expected. Gaston should become a hurricane by Wednesday afternoon. The forecast for Gaston is to turn more towards the northwest, heading out in the Central Atlantic Ocean before starting to weaken in a few days. Gaston will likely bot be a threat to any land areas.

Meanwhile, a disturbance located a few hundred miles east of the Lesser Antilles is being carefully monitored for signs of development. United States Air Force Reserve Hurricane Hunter aircraft investigated the system earlier today and found it to be a weak system with an ill-defined center. Conditions are still somewhat favorable for further development, and anyone with interests in the northeastern Caribbean should continue to monitor the progress of this system. The future of this system is still a big question mark. Most of the forecast models bring the system towards the Bahamas over the next several days, though a few have the system dissipate completely before then. Once it gets to the Bahamas, there is considerable spread among the models as to where it will go, assuming it even survives that long. Some have it turn northward and head towards the Carolinas or Georgia. Some bring it into Florida, then up into the Southeast, and others bring it across Florida and into the Gulf of Mexico. As for how strong it could be, that’s an even bigger question mark. As mentioned previously, some of the models have it dissipate completely. There are other models that keep the system as a tropical depression or weak tropical storm into the Bahamas. There are others that have it as strong as a Category 2 hurricane. Once the storm actually forms (assuming it actually does), the computer models should start to get a better handle on its future.

Computer model forecasts for the track of a disturbance approaching the Eastern Caribbean. Image provided by Tropical Tidbits.

Computer model forecasts for the intensity of a disturbance approaching the Eastern Caribbean. Image provided by Tropical Tidbits.

Strong Storm to Impact the Midwest and Southeast Early Next Week

Two pieces of energy will be phasing or combining this weekend off the West Coast. This will allow for a low pressure system to develop and intensify as the energy digs across southwestern United States. The storm is developing early enough that the storm should take a general northeast track after the storm ejects off the Rocky Mountains.

The two pieces of energy offshore before phasing over the weekend.

After the pieces of energy have phased and storm begins intensifying and turning northeast. — After the pieces of energy have phased and storm begins intensifying and turning northeast early Monday.

It will have all of the precipitation types that winter normally features with snow north of the low pressure system’s track as well as a mixed bag of snow/sleet/freezing rain near the warm front as the warm and moist air runs into the cold air aloft. This cold air begins settling south from Canada early Tuesday, which is when the snow should fall north of the track. It’s way too early to looking at snowfall accumulation maps so outlooks are best at this point for the system. Strong winds are often associated with developing low pressure systems. This system is no different with forecast analogs based on the GFS forecast (America long range forecast model) showing a possibility of blizzard conditions over Iowa. Remember, blizzard conditions are more about wind and visibility than snowfall so that even just light blowing snow could still be designation as a blizzard as long as visibility is reduced.

Appreciable snowfall/sleet highlighted on day 4. Via the Weather Prediction Center.

In addition to the wintry precipitation types, this system will also produce some severe weather. Severe weather is forecast to begin occurring Monday Night across the Southern Plains and continue moving eastward as the cold front and warm sector (area where warm air resides) move east. The limiting factor in this case will be the instability, but there may be enough shear (turning of the wind with height or change in speed with height) to overcome any shortcomings that instability might have. With that in mind, a look at forecast analogs based on the GFS show the potential for severe weather to occur Tuesday in the Lower Mississippi Valley. The winds are strong aloft so wind damage and a few tornadoes are possible from this event as well as some hail. Flash flooding may also be possible under any thunderstorm.

Snapshot of the cold air(north and west of the low) and warm sector (south and east of the low). Notice the stronger winds (barbs with triangles indicating 50+ knot winds) in the area within the packed contours. — Snapshot of the cold air(north and west of the low) and warm sector (south and east of the low). Notice the stronger winds (barbs with triangles indicating 50+ knot winds) in the area within the packed contours just southeast of the pressure system indicating stronger shear. This is at a level where air is at a pressure of 700mb. Via the College of DuPage.

Analog guidance based on the GFS models highlighting severe weather in the Lower Mississippi Valley for Tuesday. — Analog guidance based on the GFS models highlighting the placement of severe weather in the Lower Mississippi Valley for Tuesday. Via the Cooperative Institute for Precipitation Systems.

Tuesday's probability of severe weather over the Lower Mississippi Valley. This seems to correlate well with the CIPS analog guidance's placement of severe weather. Via the Storm Prediction Center. — Tuesday’s probability of severe weather over the Lower Mississippi Valley. This seems to correlate well with the CIPS analog guidance’s placement of severe weather. Via the Storm Prediction Center.

Blizzard of 2016 Recap

This post will go back over some of the highlights of the Blizzard of 2016 with a brief summary of why it happened, some of the reasons why plenty of snow fell where it did and some of the cool visuals that came out of the storm.

The storm had many interesting features that helped it become what it was. It started out over the Pacific Ocean and came onto the United States. As the energy energy ejected out of the Rockies, another low pressure system was entering the West Coast and causing a wave break. This would cause the high pressure ridge to develop behind the storm allowing plenty of cold air to wrap in behind the storm and rapidly develop the storm into a cutoff low even before it exited the East Coast.

Energy (reds and oranges) over the Eastern Pacific before entering the Western US.

The ridge building as a result of a wave break from the storm entering the Western US. The eventual Blizzard of 2016 was in the Eastern US at this point. — The ridge building (green arrow) as a result of a wave break from the storm entering the Western US. The eventual Blizzard of 2016 was in the Eastern US at this point.

Storm position as it affected the Northeast. The blue colors indicate the bent back warm front and frontogensis signature. — Storm position as it affected the Northeast. The blue colors indicate the instability within the bent back warm front and frontogensis signature.

Well forecasted position of the coastal front. The front would have heavier snow along it as a result of air colliding along it.

In fact, there was plenty of “wait for the energy to come on shore” phrases being dropped in the meteorological community because the models had the storm on the map for such a long time. However, the snow maps being generated by the models didn’t really give meteorologists much confidence along the way because there were plenty of differences in how far north the snow would come into the Northeast. It was a given that the storm would drop plenty of snow in the Mid-Atlantic since one of the most similar analogs or similar storms to this storm was the January 1996 Blizzard. This storm had areas of 20+ inches in the Mid-Atlantic, but had way too much snowfall in the Northeast. Meteorologists needed to pin point where the banding would set up. This occurred in a coastal front and another band system called a bent back warm front or TROWAL signature. It had plenty of moisture within it and as the storm was cycling and the moisture was wrapping into the storm, the bent back warm front would slowly pivot from a west to east signature to a northeast to southwest signature and then pivot out to sea as the storm passed by New England to the southeast. One wrinkle leading up to the storm had the model that is easy to disregard, the NAM, adjusted moisture way up for the New York region and many final snow maps didn’t include it because it was such an outlier. In fact, many areas over performed as a result of the bent back warm front band along the South Coast of Southern New England and the Coastal front over Southeastern Southern New England. So taking the NAM into consideration in some way may have actually helped.

Blizzard of 1996 is similar for the DC area in snowfall output, but not so similar to the Northeast.

Coastal flooding would be a huge problem along the East Coast:

This is happening right now in Ocean City, New Jersey #blizzard2016 pic.twitter.com/7gISbgonYe

— Cecily Tynan (@CecilyTynan) January 23, 2016

Some pictures and interesting photos:

Winterized radar image showing snow in the Mid-Atlantic and portions of the Northeast. Image courtesy of Intellicast.com

Rare #thundersnow visible from @Space_Station in #blizzard2016! #Snowzilla #snowmaggedon2016 #YearInSpace pic.twitter.com/l3p6hjnJOq

— Scott Kelly (@StationCDRKelly) January 23, 2016

Astronaut Scott Kelly’s photograph from space of thundersnow.

AMAZING snowfall differences over just 50 miles! Hazleton, PA big winner in our area. #Blizzard2016. pic.twitter.com/OhJS9ldA9r

— NWS Binghamton (@NWSBinghamton) January 24, 2016

It was a case of the haves and have-nots as relatively small distances separated high and low snowfall totals.

PHOTOS: People who should wear more clothes during #blizzard2016: https://t.co/eQuKrd8JsO (Pic: @broshan11) pic.twitter.com/kW47vyeVcS

— Eyewitness News (@ABC7NY) January 23, 2016

After a while, you’ve gotta have fun with it.

Snow and no snow – pretty easy to pick out on this morning's visible satellite image. pic.twitter.com/BVGYElXNMk

— Ryan Hanrahan (@ryanhanrahan) January 24, 2016

The morning after’s visible satellite imagery distinctly showing the snowline.

Alberta Clipper Approaches the Northeast Later this Week

After the weekend, the next storm that the Northeast will be watching comes in the form of an Alberta Clipper late Tuesday into Wednesday. These storms are called Alberta Clippers because they come southeast from Alberta, Canada to the Northeastern United States. This means they have quite the cold punch with them. They also have a strong high pressure system closely trailing the low pressure system so that the cold air usually comes rushing in with strong winds. However, the other part of the name, clipper, gives reference to how the system generally doesn’t drop much precipitation as a result of the area of low pressure being quite dry and moving quite fast through an area.

wx image 4

GFS forecast model showing the clipper and trailing high pressure (added by author). Notice the strong jet stream from north to south, which could help to push the clipper farther south and bring cooler air into the United States. — GFS forecast model showing the clipper and trailing high pressure (added by author). Notice the strong jet stream from north to south in Western Canada, which could help to push the clipper farther south and should bring cooler air into the United States.

In many cases however, the Alberta Clipper can drop plenty of snow in a given region. The Alberta Clipper is known for containing plenty of cold air and an appreciable amount of energy, but a lack of precipitation. So if moisture from a low pressure system to the south is able to phase, or combine into the system, which usually occurs in the Eastern United States, the clipper can redevelop off the East Coast into a strong nor’easter. This occurred January 25-28, 2015 and resulted in snowfall over 30 inches in portions of eastern and central Massachusetts. The other way Alberta Clippers can pack a punch, which is usually weaker than when clippers phase to strengthen the system, is to have the trough that the low pressure system resides in turn negative. This means that the direction from the northern part of the trough to southern part of the trough goes from northwest to southeast. This causes a strong draw of moisture into the storm on favorable winds and can also cause a redevelopment low into a strong low pressure system in the Northeast, usually east of Massachusetts. The proximity of the redevelopment low pressure system to land can determine if the resultant storm skirts by the region with minimal snowfall or a closer track leading to higher snowfall. One other part of forecasting an Alberta Clipper is to forecast its track from Northwestern Canada to Northeastern United States. There have been plenty of times where the models have the system way to far north and end up trending it farther south over time. This can trend any negatively tilted troughs further west and have a new, stronger low pressure system develop closer to land than out to sea.

The storm total snowfall via the NESIS scale from January 25 -28, 2015.

GEFS forecast showing the negative trough (red line), possible evolution of the trough farther south with the blue colors south of the red line. Also the blue colors north of the line indicate a possible strong storm north of the red line already at this hour. This indicates the uncertainty with this forecast. — GEFS forecast showing the negative trough (red line added by author) and possible evolution of the trough farther south with the blue colors south of the red line. Also the blue colors north of the line indicate a possible strong storm north of the red line already at this hour. This indicates the uncertainty with this forecast.

The Alberta Clipper system taking aim at the Northeast does have a negatively tilted trough and also has quite a bit of instability in the low levels of the atmosphere. Snow squalls could occur as a result of the low level instability and a stronger low pressure system does look to develop somewhere east of Massachusetts. Temperatures may be just borderline enough that precipitation could start as rain instead of snow as well. While, it is NOT anticipated that this system will become one like January 25-28, 2015 and produce high amounts of snow, it is possible that current models aren’t depicting the whole picture of what this system could become especially with possible trends south with the system and possible adjustments with the model solutions after the weekend rainstorm moves through. Currently, snow totals are expected to be light.

How does Lake/Ocean-effect Snowfall Happen?

Have you ever wondered how lake effect snow develops? It works as a result of buoyancy and wind direction and is easier for it to take place in the earlier part of winter. One of the biggest pieces of the puzzle, aside from a totally below freezing atmospheric column, is the fact that lakes need to be warmer than the cooler air coming in across the lakes. In fact, it needs to be 13 degrees colder at the surface than at around 1.5 kilometers into the atmosphere. This is because there needs to be enough lift to generate the storm itself.

Visual depiction of how lake effect snow forms. Via The Vane and Dennis Mersereau.

It is easier for this setup to take place in the transition from fall to winter because the area’s average air temperatures are falling while the lake’s average sea surface temperatures are falling slower, or if not, remaining the same. This is as a result of a few of water’s properties (heat capacity and thermal conductivity) which allow it to change from warm to cold or cold to warm temperatures slower than the air. Also later in the winter, the lake has a tendency to have a frozen surface, which shuts off the possibility of lake effect snow. One of the most common ways this setup works is to have a cold front come in from Canada with a vigorous piece of energy associated with it and move right over the lake. This often happens as a strong low pressure system is leaving the Northeast and cold air streams into the Northeast behind it.

Snowfall totals from the November 17-19, 2014 lake effect even. Notice the large gradient near Buffalo, New York. — Snowfall totals from the November 17-19, 2014 lake effect event. Notice the large gradient near Buffalo, New York. Via NWS Buffalo.

So, in our setup, the lake is warm, the air is cold, now buoyancy comes into play because the cooler air aloft is more dense and falls while the warmer air rises, condenses and creates our snow storm. The other piece that is necessary with lake effect snowfall is to have a favorable wind. This is very important because often, if the wind direction stays constant for a long period of time, the snowfall amounts can pile up within the favorable area for snowfall while the area just outside the favorable area can have minimal amounts. For example, from November 17-19 of 2014, around 5 feet of snow fell in Cheektowaga, New York off of Lake Erie while just a few miles away only received a few inches. So wind direction is important because, in some cases it can mean the difference between a few inches and many feet.

GFS Forecast depiction. Note the pink and yellow colorations along the temperature (red) line indicates the dendritic growth layer. It is also close to the moisture (green) line indicating some moisture. Note the 1.5 m temperature at 850 millibars. — GFS Forecast depiction for Hyannis, MA. Note the pink and yellow colorations along the temperature (red) line indicates the dendritic growth layer. It is also close to the moisture (green) line indicating some moisture. Note the 1.5 km temperature at 850 millibars.

This can also work with the ocean in the same way that it does with the lake. A warm ocean compared to very cold temperatures 1.5 kilometers into the atmosphere can lead to snowfall along the eastern side of the Northeast and especially Cape Cod. Such an event is forecast to take place on Monday as a strong arctic cold front approaches from the northwest. Some of the coldest air forecast to come into the region with around -10 to -12 Celsius temperatures at 1.5 km while the sea surface temperatures just east of Massachusetts are still around 9 Celsius. That’s a temperature difference of around 20 degrees Celsius around 1PM on Monday! Of course, enough lift has to be in place and moisture within the area where growth of dendrites, the type of snowflake that allows for the highest accumulations, occurs in the atmosphere. Some dendritic growth zone moisture is available at the time of ocean effect snowfall, but lift is really lacking. So snowfall accumulations should be minimal. Sometimes Boston gets into the snowfall as well, but the wind needs to have a slight easterly component. If it does, then some snowfall could occur.