Blogs

The United States has experienced some intense weather patterns lately, including flooding in California and a Nor’easter in New England. We can’t trace these back to a butterfly flapping its wings on the other side of the world, but we can connect them to tropical rainfall patterns that seem just as far away. The tropical Pacific and Indian Oceans have some of the warmest oceans temperatures in the world. They provide plenty of heat and humidity for heavy rain and thunderstorms — storms that are so strong they can change global wind patterns and affect weather around the globe. El Niño and La Niña are the best-known examples of how shifts in those rainfall patterns can have global effect…   Read article

This is a guest post by Dr. Aaron Levine who is a National Research Council postdoctoral associate at the NOAA Pacific Marine Environmental Laboratory. His research is on ENSO dynamics and predictability, and focuses on how changes in weather (or what is often referred to as “noise” in climate studies) influence the evolution of ENSO. While you can’t set your watch to El Niño or La Niña because it occurs irregularly and sometimes with little warning, when one does emerge it is strongly linked to the calendar month. Typically, events peak during the Northern Hemisphere winter and then weaken or disappear during the spring or summer (1). In part because ENSO is transitioning, the spring is …   Read article

Well, that was quick! The ocean surface in the tropical Pacific is close to average for this time of year, putting an end to La Niña, and forecasters expect that it will hover around average for a few months. Let’s dig in to what happened during January, and what the forecast looks like. Not with a bang This La Niña wasn’t exactly one for the record books. Our primary index, the three-month-average sea surface temperatures in the central Pacific Niño3.4 region, only dipped to about 0.8°C cooler than the long-term average during the fall of 2016. However, these cooler-than-average temperatures persisted for several months, and the atmosphere over the tropical Pacific responded as expect…   Read article

Just a few days ago, on January 26th, 2017, we saw something in the U.S. climate that we hadn’t seen since March 2011. Well, technically, we didn’t see something, I guess. For the first time since March 2011, there was no D4, “exceptional drought,” anywhere in the United States, as analyzed by the U.S. Drought Monitor. The last vestige of D4—the most severe category in the monitoring system—disappeared from its southern California holdout, part of a larger pattern of substantial mid-January drought improvements in California. (note: it is always difficult to describe drought improvements as “improvements” knowing they came, as they often do, with the price tag of major flooding and…   Read article

This is a guest post by Dr. Ángel G. Muñoz who works at the Atmospheric and Oceanic Sciences Program at Princeton University and NOAA Geophysical Fluid Dynamics Laboratory. He focuses on the study of climate extremes and regional climate variability, predictability and model diagnostics, with an emphasis on Latin America and the Caribbean.  Imagine an orchestra playing your favorite concerto or film score, each instrument contributing its share to the entire piece. Sometimes one of them seems to lead the others, to become soon after just another thread in the musical tapestry, no more important than any other instrument. Like in concertos, sometimes ENSO (El Niño-Southern Oscilla…   Read article