Blogs

When we last wrote two weeks ago, the forecasts suggested that the stratospheric polar vortex would continue to weaken and warm into January. Though there were a few days around the end of December where forecasts moved closer to predicting a full reversal of the west-to-east winds at 60 degrees North* that comprise a major “sudden stratospheric warming”, the ingredients did not fully come together. Instead, in the last few days there was a minor warming of the vortex. Temperatures in the mid-stratosphere (~19 miles above the surface) rose about 30 degC (55 deg F!) during the 6-day period between December 30 and January 5th, and the winds at 60 degrees North slowed considerably but did not r…   Read article

We threw plenty of information at you in our last post introducing the Arctic stratospheric polar vortex. So let’s take a step back and examine that information a little more closely. If the last post was the “meet cute” with the stratosphere, then this post is more like a first date, where we get to know the polar vortex and find out what it’s been up to lately. Tell me more about yourself We’ll start by taking a closer look at the average behavior of the temperature and wind patterns across the polar stratosphere throughout the year. The first thing you might notice is that the winds change direction in the late summer and spring. Or that the temperatures are colder in the winter tha…   Read article

El Niño is zipping along in the tropical Pacific. There’s a 54% chance that this El Niño event will end up “historically strong” (more details below), potentially ranking in the top 5 on record. Looking ahead, it’s likely that El Niño will end and neutral conditions return by April­–June. Sail across the Pacific El Niño is associated with specific changes to weather and climate around the world, and the stronger an El Niño, the more likely we are to see those impacts. Of course, nothing is ever guaranteed when it comes to our complex Earth system, and the unpredictable effect of chaos may interrupt the expected impacts. For an excellent, in-depth explanation of why a strong El Niño…   Read article

We are excited to announce that NOAA Climate.gov, home of the highly popular ENSO Blog, is venturing into a colder, darker, and windier corner of the atmosphere with the new Polar Vortex Blog. We plan to explore various facets of the winds, climate, and chemistry within the fascinating region of the atmosphere known as the polar stratosphere, and explain how this region can sometimes drive big changes in our weather patterns! While ENSO may be the seasoned celebrity in the seasonal forecasting world, in recent years the stratospheric polar vortex has become a rising star: constantly making headlines and being stalked by the paparazzi, but often misunderstood or misrepresented. We hope to …   Read article

After the last three winters of La Niña conditions (weren’t we all ready for a change!), the tropical Pacific is looking much different this year, with a strong El Niño likely this winter (1). Historically, how has El Niño shaped precipitation (rainfall + snowfall) over the U.S.? Let’s dig in and find out! What happened during December-February for previous strong El Niños? For the 7 strongest El Niño events since 1950, wetter-than-normal conditions occurred along the West Coast and southern tier of the U.S., especially in the Southeast. This is expected because El Niño causes the jet stream to shift southward and extend eastward over the souther…   Read article