Last year at about this time, the Climate Prediction Center (CPC) predicted a 70 percent chance of a weak to moderate El Niño onset by last August, and an 80 percent chance that it would occur by last November.
In fact some media outlets advertised that a Super El Nino would create drought-ending rains.
Unfortunately, we didn’t go into an El Niño condition until late February; It was too little too late.
However, the latest guidance from the CPC and other long-range forecast centers indicate the current weak El Niño condition could strengthen to a moderate or even a strong event by late fall or winter.
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A weak El Niño is classified as sea surface temperatures warmer than normal within a 0.5 to 1 degree Celsius range. A moderate El Niño is classified as a 1 to 1.5 degree Celsius anomaly and a strong El Niño is above 1.5 degrees Celsius in waters in the central and eastern tropical Pacific Ocean for three consecutive months.
Well, the CPC ensemble forecasts — we’ll explain that term in a minute — indicate that warmer than normal sea surface temperature will continue through January 2016. Some of the model solutions indicate as much as 2.5 degrees warmer than normal while the consensus line indicates around 2 degrees.
Jan Null is recognized as an expert on El Niños and their relationship to California’s weather. According to Null’s studies, weak and moderate El Niños give near average rainfall along the Central Coast.
However, strong El Niño events can produce about 140 percent of above-normal rainfall for our area and even greater amounts in other parts of the state.
So what is ensemble forecasting?
Well, the atmosphere is a fluid; sure, it’s not as dense as water but it does behave like a liquid. Mathematical equations that express the laws of physics for thermodynamics and fluid dynamics can be written for computer programs to estimate or predict the state of the sky in the future.
These computer programs are called numerical weather models and collect weather information from weather balloons, marine buoys, ship and surface observations, aircraft, satellites and other oceanographic resources.
Unfortunately, since the atmosphere is chaotic, the smallest of errors are multiplied as you look further into the future.
To overcome this problem, multiple forecasts are created with slightly different physical measurements of the atmosphere and ocean at the start or initialization of each model run. As each model run is initialized with different parameters, dissimilar forecast solutions emerge.
The output from this collection of runs is called an ensemble forecast. The yield from these models is frequently displayed as spaghetti diagrams.
For example, a hurricane track map may show diverse courses the storm may take. Meteorologists can compare the different courses and take a consensus and hopefully provide a more accurate forecast.
With that being said, the predictions of El Niño conditions are often wrong, like last year for example. However, if the current models verify we could see higher than normal amounts for rainfall in California this winter, but there are no guarantees, only time will tell the story. …
Our mothers deserve to be showered with love for all they do. This Mother’s Day, PG&E urges everyone to keep the sparkle and flash to family photography, and to avoid unweighted metallic balloons, which can potentially cause electric service disruptions, significant property damage or serious injuries, if they come in contact with overhead power lines.
In 2014, more than 300 power outages were caused by metallic balloons that drifted into PG&E power lines, affecting electric service to more than 155,000 homes and businesses throughout Northern and Central California.
So if you’re celebrating Mother’s Day with metallic helium balloons, make sure they are secured with a weight to prevent them from floating away.