El Niño, what it means for the sierra
The National weather service Reno office has produced a El Niño forecast 2015, Sierra Edition. The forecast addresses myths and conspiracy theories while also predicting what the system could mean for the western US.
From the National Weather Service, Reno:
Common Myths and Conspiracy Theories
Let’s just get the myths and conspiracy theories out of the way first!
El Niño will bring us a big snow winter. Not guaranteed. We’ve had dry and/or warm El Niño winters too.
El Niño will end the drought. No, it will take more than one wet winter to end our four-year drought.
We’re in a drought, so no worries about flooding. No, droughts in Cal/Nev have ended with (big) floods.
An 8-Ball or dice are used for these seasonal forecasts, right? No, while seasonal weather prediction lags behind the skill of a 7-day weather forecast, sophisticated science and computer simulations are used
What Does El Niño Mean for Us?
Warm waters of El Niño drive changes in the wintertime storm track into North America, favoring Southern California and southern Nevada with above normal precipitation.
Overall, El Niño has very little relationship with wintertime precipitation in the Sierra and western Nevada. Since the 1930s, we’ve had 6 strong El Niño winters – some have been dry and some have been wet. The two strongest were quite wet.
The official forecast for this coming winter slightly favors above normal precipitation for the Sierra, with more precipitation in mid/late winter. With the strong El Niño in place, the risk of another dry winter is less, but not zero.
Warm waters off the west coast coupled with the long term atmospheric warming trends could result in an increased frequency of warm storms with high snow levels. Although some past El Niño winters have been cold as well.
“Overall based on all the simulations of El Niño and the atmosphere – the scales are tipped toward favoring an above normal precipitation winter for the central/northern Sierra and western Nevada. However it’s not guaranteed and much of the impacts could wait until mid/late winter. The risks of seeing another dry winter are lower with this strong El Niño, so that’s certainly good news.” Chris Smallcomb, National Weather Service, Reno.Warning Coordination Meteorologist