Weak La Nina expected to bring more snow than normal
Randy Mann | Hagadone News Network | UPDATED 8 years, 1 month AGO
Sea-surface temperatures are very different today than they were a year ago. Scientists say that we have a weak cooler than normal sea-surface temperature event, La Nina, in the south-central Pacific Ocean.
Over the past year, there has been a rapid cooling and warming of ocean waters. I’ve been studying sea-surface temperatures for over 30 years and it’s one of the craziest ocean temperature fluctuations I’ve seen. What used to take years for ocean waters to warm and cool is now happening within months.
For example, late last year, we were starting to come out of the warm El Nino sea-surface temperature pattern. In October of 2016, ocean temperatures cooled to below average levels across the Equator, indicating we were on track have a new “La Nina.” Later in the month, sea-surface readings warmed to “above” normal levels near the West Coast of South America and westward about a few hundred miles along the Equator. This was starting to point to the continuation of a “La Nada,” or in-between the El Nino and La Nina event. Recently, ocean temperature did cool once again and now we have a weak La Nina.
The recent cooling of ocean waters seemed to have an influence on weather patterns, especially in the Far West. October precipitation totals were at much above normal levels in the Pacific Northwest and were also higher than average in Northern California which helped ease the drought situation. Record rains were reported across much of the Inland Northwest in October with many stations receiving over a third of their normal precipitation in only a month.
Despite the recent and welcomed rainfall in Southern California, the region’s 6-year dry spell is one of the worst droughts in about 1,000 years. Researchers point out that trillions of gallons of groundwater have been depleted with no signs of easing anytime soon. With the new La Nina, we could see a winter season with very good moisture totals for Northern and Central California, but near to below normal in the southern portions. The Golden State usually needs a flow from Hawaii to bring the drought-breaking rains to Southern California.
With cooler ocean waters along the Equator, there are still plenty of warmer than normal sea-surface temperatures in the eastern Pacific Ocean, the Caribbean and along the East Coast of the U.S. But, there is a stretch of cooler waters that seem to be expanding from the Sea of Japan toward the Gulf of Alaska. This area needs to be watched more closely as it could influence our winter pattern, perhaps to the colder side.
Another area of warming is from the Gulf of Alaska into the Arctic regions and eastward toward Greenland. Earlier this summer, ocean waters in the Arctic were over 5 degrees above normal. Readings did cool in the last few weeks, but have warmed up once again. A recent report from the Danish Meteorological Society states that some parts of the Arctic have air temperatures that are an incredible 36 degrees above normal.
With ocean temperatures cooling down near the Equator, areas north of Interstate 80 east of the Rockies should see snowfall totals a little above average for the upcoming winter season. South of I-80, snowfall totals may be a little less than average. Dry conditions may persist in the Southeast with increasing moisture in the Northeast.
In our part of the country, Cliff and I are predicting that most stations will see snowfall totals around 30 percent higher than average. We did see our first snowflakes on Wednesday, Nov. 16. No measurable snowfall was observed in Coeur d’Alene, but one could see some accumulated snow on Canfield Mountain.
Over the Thanksgiving holiday weekend, we will probably have instances of rain and snow shower activity. The chances for measurable snowfall increase during the “new moon” cycle of Nov. 29 through Dec. 6 as we see a series of storms move through the region. Cliff and I also agree that December and the early portion of 2017 looks snowier than normal across the Inland Empire. Assuming La Nina starts to fade by the spring of 2017, then we should see precipitation totals start to decrease by March or April. Stay tuned.
Contact Randy Mann at randy@longrangeweather.com
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