Guest view: Cold, snowy winter forecast
Now that the calendar officially declares that fall has arrived, many people around town are beginning to wonder what the upcoming winter will hold for the Eastern Sierra. Will there be an abundance of snow and rain or will our region experience a dry winter? I hope that the following will answer those questions.
The official forecast for our region issued by the Climate Prediction Center calls for above-average temperatures from November through April with equal chances of above average, average or below average precipitation during the same period. In other words, they are not sure what to expect. The Farmer’s Almanac is calling for a cold and snowy winter for our area. In the research that I have recently completed to determine more specifically the outlook for our region, I would cautiously lean toward the forecast of the Farmer’s Almanac and here is why.
While it is true that there has been much discussion about the developing weak to moderate El Niño condition in the tropical Pacific, we must remember that El Niño by itself means very little to our region, as El Niños by themselves produce equal incidents of above average winters, below average winters or average winters historically speaking. The current numbers reveal that during the past spring and summer months, the tropical Pacific transitioned from a weak La Niña or neutral conditions to a weak El Niño. The forecast is for the current El Niño to strengthen slightly, possibly becoming moderate in strength. In addition, we experienced another dry summer with just over one-tenth of an inch of precipitation during July, August and September. The trend so far this autumn has been for colder storms to drop down out of the Gulf of Alaska or Western Canada and then rotate out across the center of the country. The systems are riding over a large area of upper-level high pressure situated around 18,000 feet above sea level around 140 west longitude and then circulating around a large cold upper level low-pressure area, often referred to as the Hudson Bay low because of its proximity to Hudson Bay in Canada.
This upper level low, also at around 18,000 feet above sea level, has been anchored slightly farther west than normal so far, closer to Manitoba in Canada than Hudson Bay. Ultimately, our winter weather pattern will highly depend on where these two upper level features take up winter residence. The final player in the upcoming winter season will be the effects of tropical activity in the western Pacific and its influence on the southern branch of the jet stream. It is possible that we may see some warm, wet storms if the southern branch of the jet stream becomes active and breaks underneath the eastern Pacific high and in turn dislodges the Hudson Bay low.
In summary then, I would cautiously expect our region to experience the following. Expect a colder-than-average winter with above-average snowfall but below average precipitation. Since the storm’s origins will likely be from a colder location, the Sierra cement that we have become accustomed to may not be as prevalent this year and we may experience more powder days instead. There still remains much uncertainty with the upcoming winter season and the outlook is by no means a definitive forecast.
In the end, Mother Nature will ultimately have the final say as to how this winter will turn out.
– Simon Smith is the
co-op observer for South
Lake Tahoe as part of the National
Weather Service in Reno.