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I’m definitely starting to sound like a broken record here! La Niña is favored to continue through the summer and into the winter. That said, chances of La Niña through summer have a fairly small edge over chances of a transition to neutral—52% for La Niña vs. 46% for neutral in July–September. There’s about a 59% chance of La Niña by early winter. Dig deep Speaking of broken records, let’s start with the sea surface temperature in the tropical Pacific. The three-month-average sea surface temperature anomaly in the Niño-3.4 region, specifically, according to the ERSSTv5 dataset. (The anomaly is the difference from the long-term average; long-term is currently 1991–2020.) This index…   Read article

Christopher W. Landsea is the Chief of the Tropical Analysis and Forecast Branch at the National Weather Service's National Hurricane Center in Miami, FL. Tom Knutson is a Senior Scientist at NOAA’s Geophysical Fluid Dynamics Laboratory in Princeton, NJ. It should be noted that the following discussion represents the authors’ opinions only and does not represent any official position of NHC, NWS, GFDL, or NOAA in general. A NOAA State of the Science Fact Sheet on “Atlantic Hurricanes and Climate”, which has been reviewed by NOAA, is also available. Last month, in a Beyond the Data blog post, we examined whether scientists can detect any significant change in Atlantic hurricane activity to…   Read article

With so much focus here and elsewhere on how ENSO (El Niño-Southern Oscillation) impacts the conterminous United States, our friends in the 49th and 50th states might feel a little neglected. As a former resident of Hawai’i, I am happy to throw the spotlight onto a state that is still near and dear to my heart. Here I attempt to channel the Aloha Spirit and explain how ENSO impacts the weather of our most remote state. (Alaska, don’t worry, you’re up next month!). Recipe for rainbows Before I discuss any ENSO impacts, I would like to say a few words on the unique climate of Hawai’i. When I moved there in 2009, I was immediately struck by how much the rainfall can vary over such sho…   Read article

La Niña continued through April, and forecasters estimate a 61% chance of a La Niña three-peat for next fall and early winter. Current El Niño/Southern Oscillation (ENSO, the entire El Niño and La Niña system) conditions, the forecast for the rest of the year, and some potential impacts are all on the dessert menu today. Mix the butter and sugar together We’ll start by measuring out the tropical Pacific ocean-atmosphere system. The first ingredient in any ENSO recipe is the sea surface temperature anomaly in the Niño-3.4 region of the Pacific. An anomaly is the difference from the long-term average; in this case, the average is 1991–2020. When the sea surface temperature anomaly in…   Read article

Christopher W. Landsea is the Chief of the Tropical Analysis and Forecast Branch at the National Weather Service's (NWS) National Hurricane Center (NHC) in Miami, FL. Tom Knutson is a Senior Scientist at NOAA’s Geophysical Fluid Dynamics Laboratory (GDFL) in Princeton, NJ.  The following discussion represents the authors’ opinions only and does not represent any official position of NHC, NWS, GFDL, or NOAA in general. A NOAA State of the Science Fact Sheet on “Atlantic Hurricanes and Climate”, which has been reviewed by NOAA, is also available. Last summer, one of us (Chris) co-wrote a National Hurricane Center Inside the Eye blog post about the 2020 hurricane season and whether it…   Read article