A potential nor'easter may bring snow to the East Coast just after spring officially arrives, despite a winter that had been relatively lacking in snow, with one big exception. 
 
 (MORE: The Science Behind the First Day of Spring) 
 
 If you needed any more reminders of how changeable the weather can be this time of year, this is your exhibit A. 
 
 Consider what we've seen recently in the East: 
 
 If it wasn't for the near record-setting snowfall from Winter Storm Jonas, New York's Central Park would be on pace for its least snowy season in 14 years. Only 4.8 inches of snow has fallen outside of that late January snowstorm. 
 
 It only stands to reason, then, that a chance of snow moves into the East after all that. 
 
 Let's break down what we know, and what we still don't know at this time. 
 
 Big Question Marks 
 
 As is fairly typical for most East Coast snow events, there remains a degree of uncertainty this far out. 
 
 First, colder air will gradually work its way into the East Friday, a pattern change led by a gyre of low pressure is slowly spinning down over the Great Lakes. 
 
 (MORE: Midwest Winds, Snow From a Pattern Change) 
 
 One of the reasons for the uncertainty is a complicated upper-level pattern. Exactly how the interaction of (A) a digging shortwave trough from the Rockies, (B) a remnant circulation from the aforementioned Midwest gyre and (C) a sharp southward dip in the jet stream nosediving southeastward from Canada will help determine how this potential East Coast system evolves. 
 
 Fascinating interplay of upr systems for pot'l #noreaster. Could argue remnant of Midwest gyre ("B") plays role. pic.twitter.com/a34cBTaK4g — Jonathan Erdman (@wxjerdman) March 17, 2016 
 
 In response to all this, low pressure should develop and intensify somewhere near or off the East Coast Sunday and Monday. 
 
 The $64,000 question then is, "Where will the center of low pressure track?" 
 
 A closer track to the East Coast would bring a better chance of significant snow, or perhaps even a period of rain closer to the coast, from parts of Virginia and North Carolina to New England. At this time, the majority of our guidance suggests this potential Sunday and Monday, to some degree. 
 
 However, it's too early to rule out a track farther offshore, which would only brush coastal New England with light snow, leaving other areas except in the Appalachians dry. This scenario is now looking less likely based on the computer model forecast guidance that came out on Thursday afternoon. 
 
 (FORECAST: Boston | New York | Philadelphia | Washington D.C. | Bangor, Maine) 
 
 Our latest forecast Sunday and Monday is shown below. 
 
 If the snowier East Coast scenario would come to pass, this could pose travel headaches including flight delays/cancellations out of some major Northeast hubs and a challenging Monday morning commute in parts of New England. 
 
 (MAPS: 10-Day Forecast Highs/Lows | Weekly Planner) 
 
 Fortunately, this system should move rather quickly, either out to sea or into Atlantic Canada by Monday night. 
 
 Check back with us at weather.com for the latest on this potential storm and any likely forecast changes ahead. 
 
 MORE ON WEATHER.COM: Winter Storm Jonas (PHOTOS) ||||| Everyone is eager to get back to warm weather, so find out when spring starts! This year marks spring’s earliest arrival since 1896. 
 
 March Equinox 2016 Show 
 
 The video (below) is a replay of the live broadcast from Saturday, March 19. It will replay all day Sunday, March 20, the first full day of spring! (We apologize for a couple of drops in the live stream Saturday and hope you enjoy this replay.) 
 
 Courtesy of our astronomy partners, SLOOH, watch telescope views of our majestic Sun from the Prescott Observatory in Arizona, as well as the spectacle of the aurora borealis. Bob Berman, SLOOH and Almanac astronomer, will discuss the significance of the equinox; Mare-Anne Jarvela, senior Almanac editor, will share wisdom on gardening and spring folklore. 
 
 Whether you’re a sky gazer, gardener, or seek a deeper connection to the ebb and flow of nature, join the global community as we all celebrate this weekend’s vernal equinox—as humans have done since antiquity. 
 
 Video: 
 
 March Equinox 2016 Dates and Times 
 
 This year, the vernal equinox arrives on Saturday, March 19 or Sunday, March 20, 2016, depending on your time zone: 
 
 Saturday, March 19, 2016 at 9:30 PM PDT 
 
 Saturday, March 19, 2016 at 10:30 PM MDT 
 
 Saturday, March 19, 2016 at 11:30 PM CDT 
 
 Sunday, March 20, 2016 at 12:30 AM EDT 
 
 Sunday, March 20, 2016 at 04:30 UTC (Universal Time) 
 
 When Does Spring Begin? 
 
 Astronomically speaking, the equinox (March 19 or 20 this year) marks spring’s beginning in the Northern Hemisphere (whereas it announces fall’s arrival in the Southern Hemisphere). The equinox happens at the same moment worldwide, even if our clock times reflect a different time zone. 
 
 Did You Know: 2016 will bring the earliest arrival of spring of our lifetime (thus far!) in the Northern Hemisphere. Find out why in Bob Berman’s article, The Earliest Spring of our Lives. 
 
 Meteorologically speaking, in the Northern Hemisphere, the official spring season always begins on March 1 and continues through May 31. Summer begins on June 1; autumn, September 1; and winter, December 1. 
 
 Weather scientists divide the year into quarters this way to make it easier to compare seasonal and monthly statistics from one year to the next. The meteorological seasons are based on annual temperature cycles rather than on the position of Earth in relation to the Sun, and they more closely follow the Gregorian calendar. Using the dates of the astronomical equinoxes and solstices for the seasons would present a statistical problem because these dates can vary slightly each year. 
 
 What is an Equinox? 
 
 At the Vernal Equinox, the Sun crosses the celestial equator on its way north along the ecliptic. 
 
 All over the world, days and nights are approximately equal. The name equinox comes from Latin words which mean “equal night”—aequus (equal) and nox (night). 
 
 Enjoy the increasing sunlight hours, with earlier dawns and later sunsets. See your personalized Sun rise and set calculator. 
 
 On the equinox, Earth’s two hemispheres are receiving the Sun’s rays about equally because the tilt of the Earth is zero relative to the Sun, which means that Earth’s axis neither points toward nor away from the Sun. (Note, however, that the Earth never orbits upright, but is always tilted on its axis by about 23.5 degrees.) 
 
 Enjoy our page on the reason for the seasons. 
 
 Scientific explanation aside, our ancestors were more connected to the Sun than we are today. They observed its pathway across the sky; they tracked how the sunrise, sunset, and daylength changed, using the Sun (and Moon) as a clock and calendar. If you have ever been to Stonehenge or Machu Picchu, you’ll see examples of ancient seasonal markers. 
 
 Equinox Facts 
 
 Question: Are Day and Night Truly Equal on the Equinox? 
 
 Answer: Nope, day and night are not exactly equal at the equinox for two reasons. First, daytime begins the moment any part of the Sun is over the horizon, and it is not over until the last part of the Sun has set. If the Sun were to shrink to a starlike point and we lived in a world without air, the spring and fall equinoxes would truly have ‘equal nights.’ 
 
 Read more about why day and night are NOT quite equal. 
 
 Signs of the Equinox in Nature 
 
 The vernal equinox signals the beginning of nature’s renewal in the Northern Hemisphere! 
 
 Worms begin to emerge from the earth. Even the March Moon is called “The Full Worm Moon” for this reason. 
 
 Notice the arc of the Sun across the sky as it shifts toward the north. Birds are migrating northward, along with the path of the Sun. 
 
 Speaking of birds, did you know that the increasing sunlight triggers bird song? Cool, eh? Enjoy our Bird Songs page. 
 
 Trees, shrubs and flowers are sensitive to temperature and daylength, too! Since ancient days, people have used them as indicators of when the weather is right for planting. For example: Blooming crocus are your cue to plant radishes, parsnips and spinach. See more of nature’s signs 
 
 Of course, the longer days bring warmer weather! Both we and the animals around us strip off our clothes and heavy coats! 
 
 Ready, set, plant! March is time to start gardens and sow seeds in many regions. See your personalized Best Planting Dates. 
 
 Question: According to folklore, you can stand a raw egg on its end on the equinox. Is this true? 
 
 Answer: Folklore or not, this egg trick sounded like a bit of fun to us. One spring, a few minutes before the vernal equinox, several Almanac editors tried this trick. For a full workday, 17 out of 24 eggs stood standing. Three days later, we tried this trick again and found similar results. Perhaps 3 days after the equinox was still too near. Perhaps the equinox has nothing to do with it. Perhaps we just don’t like to take ourselves too seriously! Try this yourself and let us know what happens. 
 
 Spring Verse 
 
 One swallow does not make a spring. 
 
 Bluebirds are a sign of spring; warm weather and gentle south breezes they bring. 
 
 In spring, no one thinks of the snow that fell last year. 
 
 Don’t say that spring has come until you can put your foot on nine daisies. 
 
 Spring-time sweet! 
 
 The whole Earth smiles, thy coming to greet. 
 
 Look around! Observe! What are the signs of spring in your region? Please share below! 
 
 More seasonal pages: 
 
 When is the next summer solstice? 
 
 When is the autumnal equinox? 
 
 When is the winter solstice? ||||| Although there’s nothing official about it, it’s traditional to say the March or vernal equinox signals the beginning of spring in the Northern Hemisphere and autumn in the Southern Hemisphere. This equinox does provide a hallmark for the sun’s motion in our sky, marking the passage of the sun across the celestial equator, going from south to north. The March 2019 equinox happens on March 20 at 21:58 UTC, which is 4:58 p.m. Central Daylight Time for us in the central U.S.; translate to your time zone. 
 
 In the Northern Hemisphere now, we’re enjoying earlier sunrises, later sunsets, softer winds, sprouting plants. Meanwhile, you’ll find the opposite season – later sunrises, earlier sunset, chillier winds, dry and falling leaves – south of the equator. 
 
 For all of us on this March 2019 equinox, the full moon will come less than 4 hours after the equinox: on March 21 at 1:43 UTC. What’s more, this will be the final in a series a 3 full moon supermoons. 
 
 The equinoxes and solstices are caused by Earth’s tilt on its axis and ceaseless motion in orbit. You can think of an equinox as happening on the imaginary dome of our sky. 
 
 The Earth-centered view is that the celestial equator is a great circle dividing Earth’s sky into northern and southern hemispheres. The celestial equator wraps the sky directly above Earth’s equator. At the equinox, the sun crosses the celestial equator, to enter the sky’s Northern Hemisphere. 
 
 The Earth-in-space view is that, because Earth doesn’t orbit upright, but is instead tilted on its axis by 23 1/2 degrees, Earth’s northern and southern hemispheres trade places in receiving the sun’s light and warmth most directly, as Earth orbits the sun. We have an equinox twice a year – spring and fall – when the tilt of the Earth’s axis and Earth’s orbit around the sun combine in such a way that the axis is inclined neither away from nor toward the sun. 
 
 At the equinox, Earth’s two hemispheres are receiving the sun’s rays equally. Night and day are often said to be equal in length. In fact, the word equinox comes from the Latin aequus (equal) and nox (night). For our ancestors, whose timekeeping was less precise than ours, they likely did seem equal. But we today know it’s not exactly so. 
 
 Read more: Are day and night equal at the equinox? 
 
 Here’s another equinox truism. You might hear that the sun rises due east and sets due west at the equinox. True? In fact, this is true. And that’s true no matter where you live on Earth. At the equinoxes, the sun appears overhead at noon as seen from Earth’s equator, as the illustration above shows. This illustration shows the sun’s location on the celestial equator, every hour, on the day of the equinox. 
 
 No matter where you are on Earth, you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator – the imaginary line above the true equator of the Earth. 
 
 That’s why the sun rises due east and sets due west for all of us. The sun is on the celestial equator, and the celestial equator intersects all of our horizons at points due east and due west. 
 
 Read more: Sun rises due east and sets due west 
 
 Since Earth never stops moving around the sun, the position of the sunrise and sunset – and the days of approximately equal sunlight and night – will change quickly. 
 
 The video below was the Astronomy Picture of the Day for March 19, 2014. APOD explained: 
 
 At an equinox, the Earth’s terminator – the dividing line between day and night – becomes vertical and connects the north and south poles. The time-lapse video [below] demonstrates this by displaying an entire year on planet Earth in 12 seconds. From geosynchronous orbit, the Meteosat satellite recorded these infrared images of the Earth every day at the same local time. The video started at the September 2010 equinox with the terminator line being vertical. As the Earth revolved around the sun, the terminator was seen to tilt in a way that provides less daily sunlight to the northern hemisphere, causing winter in the north. As the year progressed, the March 2011 equinox arrived halfway through the video, followed by the terminator tilting the other way, causing winter in the southern hemisphere — and summer in the north. The captured year ends again with the September equinox, concluding another of billions of trips the Earth has taken — and will take — around the sun. 
 
 Where can you look to see signs of the equinox in nature? Everywhere! Forget about the weather for a moment, and think only about the daylight. In terms of daylight, the knowledge that spring is here – and summer is coming – permeates the northern half of Earth’s globe. 
 
 Notice the arc of the sun across the sky each day. You’ll find it’s shifting toward the north. Responding to the change in daylight, birds and butterflies are migrating back northward, too, along with the path of the sun. 
 
 The longer days do bring with them warmer weather. People are leaving their winter coats at home. Trees are budding, and plants are beginning a new cycle of growth. In many places, spring flowers are beginning to bloom. 
 
 Meanwhile, in the Southern Hemisphere, the days are getting shorter and nights longer. A chill is in the air. Fall is here, and winter is coming! 
 
 Bottom line: The 2019 equinox comes March 20 at 21:58 UTC; translate to your time zone. It’s an event that happens on our sky’s dome – and a seasonal marker in Earth’s orbit around the sun! 
 
 A Chinese perspective on the spring equinox
– Residents of the Northeast are expecting a snowstorm this weekend, but they can warm themselves with one thought: It's spring. The new season officially arrives at 12:30am EDT on Sunday, March 20, notes the Old Farmer's Almanac. And as EarthSky points out, this happens to be the earliest arrival of spring since 1896—the result of a fluke in the calendar. "In a nutshell, this earliest spring is happening because the tropical year, as measured between successive March equinoxes, doesn't have an even number of days (365.242 days)," explains the post. And so leap years (366 days) vs. non-leap years (365 days) adjust its timing. And Pope Gregory XIII threw a wrench into things: In 1582 he decreed that leap year not fall on centennial years, unless that year was divisible by four—so 2000 was considered a leap year, but not 1900. That "causes the March equinox to arrive roughly three-quarters of a day earlier in the 21st century than at corresponding years in the 20th century," explains the post. Every four years, the March equinox will shift earlier, ultimately bringing us to the earliest one of the 21st century: 10:03am March 19, 2096. Come 2100, where there is also no leap year, the March equinox times will be pushed forward, and will once again occur on March 21 in 2102. As for that potential nor'easter, it looks like Sunday will be the day for snow, but much remains iffy about the forecast, reports Weather.com.