From KUNC (Jackie Fortier):
The United States is currently experiencing the third strongest summertime El Niño since 1950, and it could strengthen.
“Basically since mid-May things have coalesced into a very strong El Niño and I would say we are on the verge of calling it a super El Niño. That may take a few months to be certain, but that’s where it’s drifting,” said University of Colorado, Boulder researcher Klaus Wolter.
“Certainly this is the biggest event since 1997/1998 which was the last super El Niño.”
What Makes An El Niño ‘Super’?
Researchers use complex modeling including data from buoys in the tropical Pacific to predict large climate events like El Niño – all while keeping an eye on the past. According to Wolter, a big indicator is temperature. If sea surface temperatures keep going up in the tropical Pacific, so does the likelihood of a super El Niño…
What Does A Super El Niño Mean For Colorado?
Between the typical monsoon season, from July to September, along with the strong El Niño, Colorado will see a wet fall. That might test some rain-weary Coloradans, but in drier parts of the West it will be welcome.
“It makes a much bigger difference for California,” Wolter said. “They have a much better shot at recovering from the drought this winter with a super El Niño situation than with a weak to moderate one.”
According to past events, Wolter said the hallmark of an El Niño and a monsoon is the landfalling hurricanes in the eastern Pacific, most commonly in September, which equates to heavy downpours on the western slope…
How Will A Super El Niño Affect Colorado’s Snowpack?
If the El Niño continues into the winter, it will affect the frequency of storms, said Wolter.
“You actually might get some fairly big snowstorms pretty early in the season, which can set the base. If you don’t get that, if you don’t have a string of storms in Oct. or even Nov. going into the winter, then the chance of recovering [the snowpack] during the winter is minimal.”
But if the El Niño holds together into spring 2016, the snowpack could recover.
“The super El Niño in 1983 went right into the summer. That’s really the best case scenario. If you get a reasonably wet fall, put some good snow down early in the season, make it through the winter on a shoestring if you will, then get that wet spring, that can more than make up for a dry winter,” Wolter said.
That situation would benefit both the ski industry and the parched southwest, including Lake Mead, which relies on the Colorado River basin for water.
Colorado has seen false starts in El Niño-related weather before. During the spring of 2014, weather patterns and conditions seemed to point to a strong event, but the El Niño did not progress over the summer.
But this 2015 El Niño is different.
“There’s no way it’s going to disappear any time soon,” Wolter said. “The question is will it last well into the spring, or is it going to die early next year. But it will be around for the next 6 months, there’s no question about that.”
By October, Wolter will know for sure.
“Right now I’m thinking it’s a 70 to 80 percent chance of a super El Niño.”
From TheDenververChannel.com (Matt Makens):
…El Nino is part of a complex global weather pattern and cannot be singled out as the cause for a specific type of weather feature. For Colorado, and the US, we have many dominate weather patterns tied to other events similar to the El Nino Southern Oscillation (ENSO).
I speak often of the Pacific Decadal Oscillation (PDO) and the Atlantic Multi-Decadal Oscillation (AMO) as they control our drought frequencies over periods of decades. These are ocean areas that control weather patterns depending on how warm, or cold, the water is. Like ENSO, if warm they bring one type of weather, and if cold can bring another type. I point out these other features now as a possible explanation at a later date – you are about to see why when I show you just how little affect El Nino actually brings to the state.
Simply looking at only ENSO’s impact on Colorado, I’ve found some very interesting things that will defy many of your “beliefs” and memories of El Nino years in the past…
We currently have a strong El Nino signal coming from a very warm Pacific Ocean in the ENSO region. This will likely persist through the end of 2015 and into the first half of 2016 based on current climate modeling.
So, what does this mean for Denver? This is where you may be surprised. Denver, and Colorado, is mostly impacted by El Nino in the fall and spring, not the winter.
Since El Nino is commonly misconstrued as causing bad winters, let’s talk about the snowfall seasons with El Nino versus a neutral pattern or a La Nina.
I looked at Denver’s snowfall data back to 1882. El Nino snowfall seasons are just a bit snowier than average (2-inches snowier) and La Nina’s have a bit less snow (4-inches below average). The difference is likely much less than you were thinking. We are talking the difference of a single snow, or a couple smaller snow storms… not all that oppressive. Note: Boulder, Castle Rock, and other higher suburbs do have a more significant increase in the odds of bigger snow storms during El Nino…
There is some accuracy to say that yes El Nino years can bring bigger snowstorms than La Nina years. However, the season itself may not necessarily be snowier by much more than a few inches. That list alone shows that most of our biggest snows occurred in a neutral phase. Surprised yet?
At this point I’m not saying your memories of 1997 are invalid. There was a singular big snowstorm that pushed the season to 72-inches, 15-inches snowier than normal. However, that was due to one storm. Overall 1997-98 wasn’t known for its winter, it was known for a very active monsoon in the summer and fall.
The summer of 1997 was incredibly wet. The Front Range was 3.33 inches wetter than average. The fall was nearly 1.5-inches wetter than average, but then it stopped. The winter of 1997/98 was a quarter of an inch dry and the following spring was nearly an inch drier than average.
That’s using 1997 as an example, but that pattern is repeated in history. Other similar years had wetter summers and falls before drying out a lot in winter. Yes, that’s in an El Nino period…
If you are interested in how El Nino has impacted our mountains I’m going through all that data right now. It appears to be a similar connection to the Denver area. The strong El Nino of 1997 didn’t bring the mountains much snow. In fact, much of that winter into 1998 had only 50-90% of average mountain snowpack.