Monday marks the first day of meteorological spring. Here's what that means.

[elleng]

'The days get longer and warmer, but the potential for severe thunderstorms grows.

Winter is over — sort of, anyway. The atmosphere doesn’t own a calendar, and is always prone to some humbling surprises. But Monday marked the first day of meteorological spring, the initial step to longer, brighter and warmer days.

Growing daylight and warming temperatures are expected across the nation in the coming months, signaling a habitual, but at times symphonic atmospheric transition from the doldrums of winter to the promise of summer.

Of course, every season comes with a price tag, and we can expect an uptick in tornadoes, severe thunderstorms and flooding.

It’s all thanks to the large-scale dynamics of the atmosphere as several key weather systems realign themselves into a springlike pattern.

What is meteorological spring?

Conventional springtime doesn’t start until March 20 and ends June 20, the day of the summer solstice. March 20 is the equinox, or the point at which the sun’s most direct rays cross north of the equator, and day and night are in balance across the globe. The summer solstice marks the start of astronomical summer and is the longest day of the year.

From a weather standpoint, however, those bounds don’t accurately capture when springtime really falls. Brian Brettschneider, an Alaska-based climatologist, ran the calculations to see when spring actually occurs in most American cities. He defined winter as being the coldest three-month period of the year and summer as the warmest, with spring and fall occupying the times in between.'>>>

https://www.washingtonpost.com/weather/2021/03/01/meteorological-spring-2021/?

[empedocles]

1. TY

[FirstLight]

2. interesting.... woke up to hearing sounds of spring today!

The mountain chickadee only uses this certain call during spring/summer...we call it the "cheeseburger bird" cuz it sounds like that... today I distinctly heard more than one making that sound...I was like "wtf?"

Im at 6200' elevation and the snow has been melting rapidly... false spring? i dont know, but Im welcoming the warmer weather!

[Jeebo]

3. You can also mark the seasons by cumulative day/night duration.

I worked for a newspaper for 45 years. One of my duties was assembling the weather information on page 2A of every morning's paper. That information included sunrise and sunset times. I could see the year-round patterns there, and noticed that the relative daytime/nighttime durations were at the shortest on the winter solstice and started growing longer after that date. Similarly, the durations reached their longest on the date of the summer solstice and started growing shorter after that date. What that means is that the total number of daytime hours is at its greatest for any three-month period (season) not during the season we recognize as the summer, but for about six weeks before and after the summer solstice. What I'm saying is that the solstices and equinoxes mark not the beginning of the seasons but their mid-points, if you go by relative cumulative daytime/nighttime durations. The "season" (three-month period) that begins about six weeks before the summer solstice and ends about six weeks after the summer solstice then becomes the actual summer, because the cumulative daytime hours is at its annual greatest for that three-month period. Likewise, the three-month period that has the winter solstice as its mid-point then becomes the actual winter, because that period's cumulative daylight hours is at the lowest.

A few years ago I posted this as a question over at the Astronomy Picture of the Day site. I asked them, why don't we use the solstices and equinoxes as the mid-points of the seasons instead of as their starting dates? They explained that it's because of the lag time between the equinoxes/solstices and the time when the climate warms up or cools down.

-- Ron