With a potentially drenching storm system making its way to the area, San Diego officials said Tuesday the city is preparing for rainfall over the next several days and providing tips for area residents to minimize the effects of flooding.
A major pattern change is set to deliver California’s first atmospheric river of the season next week. Significant rain and snow is in the forecast for the Golden State, while damp, dreary days are ahead for other parts of the West as signs of El Niño’s influence on the upcoming winter season emerge.
Conditions were much warmer than average this summer across the Pacific Northwest, AZ and NM, and across much of far northern California. Elsewhere in CA, summer temperatures were mostly near long-term averages or even somewhat below in some of the SoCal coastal counties.
El Niño is anticipated to continue through the Northern Hemisphere winter (with a greater than 95% chance through January – March 2024). An El Niño Advisory remains in effect.
In August, sea surface temperatures (SSTs) were above average across the equatorial Pacific Ocean [Fig. 1], with strengthening in the central and east-central Pacific. All of the latest weekly Niño indices were in excess of +1.0°C: Niño-4 was +1.1°C, Niño-3.4 was +1.6°C, Niño-3 was +2.2°C, and Niño1+2 was +2.9°C [Fig. 2]. Area-averaged subsurface temperatures anomalies increased compared to July [Fig. 3] in association with anomalous warmth in the central and eastern equatorial Pacific Ocean [Fig. 4]. Tropical atmospheric anomalies were also consistent with El Niño. Over the east-central Pacific, low-level winds were anomalously westerly, while upper-level winds were anomalously easterly. Convection was slightly enhanced around the International Date Line, stretching into the eastern Pacific, just north of the equator. Convection was mostly suppressed around Indonesia [Fig. 5]. The equatorial Southern Oscillation Index (SOI) and the traditional station-based SOI were both significantly negative. Collectively, the coupled ocean-atmosphere system reflected El Niño.
The most recent IRI plume indicates El Niño will persist through the Northern Hemisphere winter 2023-24 [Fig. 6]. Despite nearly the same ensemble mean amplitude as last month, the shorter forecast horizon means that the odds of at least a “strong” El Niño (≥1.5°C for the November-January seasonal average in Niño-3.4) have increased to 71%. However, a strong El Niño does not necessarily equate to strong impacts locally, with the odds of related climate anomalies often lower than the chances of El Niño itself (e.g., CPC’s seasonal outlooks). In summary, El Niño is anticipated to continue through the Northern Hemisphere winter (with greater than 95% chance through January – March 2024; [Fig. 7]).
This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA’s National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Additional perspectives and analysis are also available in an ENSO blog. A probabilistic strength forecast is available here. The next ENSO Diagnostics Discussion is scheduled for 12 October 2023.
El Niño is anticipated to continue through the Northern Hemisphere winter (with a greater than 95% chance through January – March 2024). An El Niño Advisory remains in effect. Graphic: NOAA
Full discussion on the latest El Niño update from the National Weather Service Climate Prediction Center: www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml
The curling of the jet stream — an atmospheric stream of fast-moving air with speeds over 100 mph that travels thousands of miles — over the Pacific Ocean has triggered recent shifts in California’s spring weather patterns. Californians have seen leaps from snowmelt-inducing heat waves in the Sierra Nevada to marine layer clouds that stretch from the Bay Area to Sacramento.
My fellow Californians often remark that the weather in this state feels like it has been reduced to two seasons, both defined by natural disasters: In summer and fall, huge, intense wildfires rip their way across dry land, while winter and early spring bring intense atmospheric rivers with heavy rainfall, floods and landslides along with winds that take down trees.
After a four-year hiatus, El Niño is widely expected to make a grand reentrance this summer, ushering in the possibility of yet another wet, stormy winter.
“It looks like it’s full steam ahead,” UCLA climate scientist Daniel Swain said in a live YouTube interview last week, in which he placed the likelihood of a strong El Niño event at greater than 50% — even as projections still vary widely.
During the El Niño of 1983, Californians counted their blessings. The warm Pacific waters sloshing eastward certainly brought heavy spring rains and record snow. But the state largely escaped the flood risks being frantically managed farther east.
While many areas of California are coping with the destructive impact of relentless rainfall, the news is nothing but good when it comes to the state’s snowpack. As of Monday, California’s snow water equivalent was 199% of normal for the date (January 9), according to the California Department of Water Resources.
California’s major reservoirs have seen significant gains in water level in recent days after two weeks of exceptionally heavy rain across the state. It comes after months of severe drought in the region, leaving water levels in the state’s most important reservoirs well below their historical average.
The Water News Network is San Diego County’s source for water news and information.
