A number of you have asked about this coming winter and the status of La Niña.
Will the snowpack continue to increase? Will those worried about flooding and drought get the answers they are looking for?
The only useful meteorological tool for predicting more than a few weeks ahead is the correlation of our weather with El Nino and La Niña.
La Niña occurs when the central tropical Pacific sea surface temperatures are cooler than normal. El Nino conditions occur when the water is warmer than normal (the area considered---called the Nino 3.4 area--is shown below)
We are now in a weak to moderate La Niña, as shown by the sea surface temperature differences from normal (called anomalies) below:
The Nino 3.4 temperatures over time are shown below. Since August, they have been below normal, ranging from 0.5 to 0.9 °C below normal. This is a weak to moderate La Niña.
Interestingly, such cold water periods have an impact on the weather in our region.
During weak to moderate La Niña winters, we tend to be a bit cooler than normal, modestly wetter than normal, and the snowpack is modestly enhanced.
The European Center seasonal precipitation prediction for January through March is for wetter than normal conditions.
At this point, there is little reason to expect to have low snowpack going into the summer.
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Forecast for Dec was similar, turned out well above average precipitation but also above average temps consistently and higher freezing levels, other than a few days after Boxing Day. 7 day forecast is looking mild with another warmer atmospheric approaching Sunday. I have lost hope for any prolonged cold this winter.
ReplyDeleteThanks for this post, Cliff. I understand that you expect at least a near-normal Washington snowpack by April, based on past effects of La Nina on our region, and on the NOAA season forecast as of December 18. However, the NOAA one-month outlook (updated December 31) leans toward above-average temperatures in January, which is bad for snowpack, and this is consistent with today's ten-day forecasts. The January forecasts seem relevant because presumably they have higher confidence than a 90-day outlook that was generated earlier in the season, and because La Nina is predicted to weaken after February, as you note in your post.
ReplyDeleteGiven that we are beginning the season in a snowpack deficit (ask any skier), and that forecasts call for normal snowfall at best, might it be too early to predict a normal snowpack by the end of the season? Given the reality of global warming, perhaps we shouldn't hang our hats too much on historical La Nina snowpacks.
It really is nice when the mountains completely disappear from view for a few days, only to reappear with a much more strikingly white hue. As far as lowland snow goes, both Weather and AccuWeather have been indicating a nice (and most importantly - not freezing cold) dry stretch for next week. Perhaps we'll get weather that stamps out the last of the most resilient dandelions, but it won't be anytime soon.
ReplyDeleteI like the sound of an above normal snowpack! As long as it doesn't melt too quickly so that we can store as much of it as possible in our reservoirs and the farmers get every drop they need for their operations.
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