Seasonal precipitation over the Southwestern United States (SWUS) has been historically linked to Equatorial Pacific Sea Surface Temperature (SST) anomalies associated with El Niño–Southern Oscillation (ENSO) phases. However, the strength and spatial expression of this teleconnection vary over time, and ENSO does not always produce the expected canonical precipitation response. Precipitation anomalies opposite to those predict...

In spite of forecasts for anomalous dryness based on the canonical La Niña signal, Water Years 2011, 2017, and 2023 brought copious precipitation to California and the Southwestern United States (SWUS). Although El Niño–Southern Oscillation (ENSO) is the main source of seasonal precipitation predictability for the region, outstanding Atmospheric River (AR) activity produced the unexpected regional wetness in each of these here...

The Sierra Nevada and Southern Cascades—California’s snowy mountains—are primary freshwater sources and natural reservoirs for the states of California and Nevada. These mountains receive precipitation overwhelmingly from wintertime storms including atmospheric rivers (ARs), much of it falling as snow at the higher elevations. Using a seven-decade record of daily observed temperature and precipitation as well as a snow reanaly...

The growing season start and duration, along with other temperature‐related measures of importance to premium wine grapes in Napa Valley, California have changed as climate over the western United States has warmed. The growing season start has varied from year to year with a standard deviation of about 3 weeks, but over the 1958–2016 record a linear fit to the time sequence shows it advanced by more than 4 weeks. Over the stu...

Santa Ana winds (SAWs) are associated with anomalous temperatures in coastal Southern California (SoCal). As dry air flows over SoCal’s coastal ranges on its way from the elevated Great Basin down to sea level, all SAWs warm adiabatically. Many but not all SAWs produce coastal heat events. The strongest regionally averaged SAWs tend to be cold. In fact, some of the hottest and coldest observed temperatures in coastal SoCal are...