ENSO Blog
Our second La Niña year in a row is in full swing now, and is forecast to last through the winter. In November, the average surface water temperature in the Niño3.4 region of the central Pacific Ocean was about 1.0°C cooler than the long-term average. A “double-dip” La Niña is not uncommon—seven La Niña winters in the 1950-present historical record followed La Niña the previous winter: 1955, 1971, 1974, 1984, 1999, 2008, and 2011. In fact, two years, 1975 and 2000, were third-year La Niñas. Only four years, 1964, 1988, 1995, and 2005, were single-year La Niñas.
This graph illustrates something interesting about our current La Niña. During multi-year La Niñas, the surface temperature i…
Read article
This is a guest post by Dr. Stephen Baxter who is a NOAA Climate Prediction Center (CPC) meteorologist and does applied research on subseasonal-to-seasonal climate variability. In particular he specializes in understanding how the middle-to-high latitude circulation is influenced by the tropics versus other processes. He also has a lot of opinions on Siberian snow cover and the role of the western tropical Pacific in forcing seasonal climate over North America.
Recent cold air outbreaks over the north-central and northwestern U.S., along with record cold on Veterans Day in parts of the Northeast and Mid-Atlantic, should have people excited about (or dreading) the upcoming win…
Read article
Well, it’s November, and the CPC/IRI ENSO forecast is declaring the presence of La Niña conditions! I could just link to my November 2016 post and head home for the day… but that would be no fun! There’s about a 65-75% chance that La Niña conditions will continue at least through the winter. As we head into our fifth “double dip” La Niña (an unofficial term for when neutral conditions briefly prevail in between La Niña winters) in the historical record, let’s dig into what we talk about when we talk about La Niña.
A quick flashback
If you recall, last month there were several signs of the presence of La Niña conditions. East-central tropical Pacific sea surface temperatures were co…
Read article
If it’s October, it must be time for my annual blog post detailing NOAA’s forecast for the upcoming winter. And as always seems to be the case (well not in 2015), we’re still trying to figure out what will happen across the tropical Pacific. Here I look ahead to provide some insight as to what is most likely to occur during the upcoming winter with regards to both precipitation and temperature.
Standard reminder: probabilities are not certainties
Before discussing the outlooks, I do want to remind readers again that these forecasts are probabilities (% chance) for below, near, or above-average climate outcomes with the maps showing only the most likely outcome (1). Because the probabil…
Read article
The task of a climate forecaster is to see the forest, and not get hung up on the individual trees. Especially that extra tall one over there, with the gnarl that looks like a face, and the low branches that would be so easy to climb, and… uh, right. My point is that we try to look beyond shorter-term weather to see longer-term monthly and seasonal patterns. After all, a particular winter can have several colder-than-average days and still be warmer than average overall.
Which brings me to the current situation in the tropical Pacific! The October ENSO forecast says La Niña conditions are favored during the fall and winter 2017-18, but at press time the ocean-atmosphere system didn’t…
Read article