Wednesday, February 10, 2016
Earlier this week, a massive ridge of high pressure settled over the West Coast, giving us clear skies, light winds, and extremely warm temperatures, especially if you got above the humongous inversion that was insulating many lowland regions from the extreme warmth. Many places were extraordinarily warm; Quillayute on the coast hit 70 degrees on Monday and 73 on Tuesday (their highest average summertime high is 69), and on Monday at Mt. Rainier, Paradise Ranger Station at 5,400 feet and Camp Muir at 10,110 feet hit 71 and 48 degrees, respectively. North Bend on the Oregon Coast hit 82 degrees, the highest temperature ever recorded on the Oregon Coast in February, and temperatures at the 850 hPa level of the atmosphere (around a mile above sea level) around our area were the highest on record for any January, February, or March day on record. That’s impressive.
All things considered, this was a very short stretch of summer-like weather, but nevertheless, many media outlets, particularly ones in Southern California, immediately published stories seemingly questioning the legitimacy of our current “Godzilla” El Niño. Are these suspicions well-founded, or is it just a bunch of bunkum and balderdash?
Like so many other things in life, it depends who you ask. If you ask somebody from Los Angeles, particularly somebody who lived through the 1997-1998 El Niño, they may say that El Niño never came and that all of the forecasters were completely wrong. October, November, and December were all drier than normal for most regions of SoCal, and January was only slightly wetter than normal for some areas. February 1998 broke all-time monthly precipitation records throughout the region, and that does not look likely this year for anywhere on the West Coast.
Meanwhile, Northern California has gotten plenty of precipitation, and the Sierra and Intermountain West have a healthy snowpack. Some reservoirs are now above average
for this time of the year, which is truly amazing considering all the talk about California being in their most significant drought in the past 1200 years
. On the flipside, seasonal predictions were going for drier and much warmer than normal conditions in the Pacific Northwest, and that simply hasn’t happened.
This is what the Climate Prediction Center was predicting for the December/January/February period for the U.S. Drier and warmer north, and wetter south. Looking at the past three months, this hasn’t necessarily been the case, at least for the Western U.S.
The temperature forecast wasn’t half bad, but the precipitation forecast was way off.
However, temperature and precipitation only tell part of the story. Let’s take a look at what’s going on in the upper atmosphere, as that may be a better indicator of whether this El Niño has significantly influenced our weather this winter. As the graphic below shows, El Niño winters often have a large low pressure anomaly in the Northeastern Pacific from January to March. According to scholars far more learned than I, there is no correlation between the existence of an El Niño and temperature/precipitation on the West Coast before January 1st.
However, if we look at the 500 hPa height anomaly from October-December of 1982 and 1997 (the other super big El Niño winters), you can see a clear area of low pressure in the Northeastern Pacific, suggesting that the typical wintertime El Niño circulation may set up earlier during very strong El Niño years. That same area of low pressure does not appear in 2015. Two years is an awfully small sample size, but it’s still something to consider.
However, since January 1st, the precipitation and temperature distributions across the West have been much more in line with what we would expect during an El Niño year.
The bulk of the precipitation has clearly moved southward into Northern California, so although it didn’t make it all the way to Baja California like the Climate Prediction Center was forecasting, it at least made it into the Sunshine State. The West Coast and northern tier of the country have been warmer than normal, just like the CPC forecast.
Take a look at the 500mb heights over the Eastern Pacific for January 2016. Classic El Niño circulation. The height anomalies this past January look very similar to those from the past mega El Niños of 1982-1983 and 1997-1998.
Bottom line: since January 1st, we have, for the most part, been in a textbook El Niño pattern. There have been some exceptions, such as the incredible warmth we saw earlier this week, but they have been few and far between. Our massive December snowpack is now more-or-less average, while snowpack is still well-above normal in many places in California and Nevada.
Take a look at Folsom Lake in Northern California- it has skyrocketed to above-normal levels!
Why hasn’t Southern California gotten pummeled by rain? Some climate scientists, such as Daniel Swain of Stanford University, say that the warm air above the warm water in the tropical Pacific moved further north than expected, causing the storm track to bypass southern California. Others, like Kevin Trenberth, a scientist for the National Corporation for Atmospheric Research, say that the differences in air temperatures along the equator with this El Niño are much less than previous mega El Niños and that this El Niño is being interfered with by activity in the Indian Ocean. Whatever the reason, it looks highly unlikely that Southern California will get a significant amount of precipitation for the remainder of this winter.
Given the lack of rain in some areas that have been rainy with similarly strong El Niños, we’ll see if a significant Californian population is left with the impression that El Niño “never came.” If so, it shows that there is still a giant disconnect between the scientific community and the average person, and that scientists need to be more effective in communicating the uncertainties and intricacies of the climate system to the public.
Thanks for reading!