"Here is a plot of the difference of precipitation from normal for the past month. Precipitation has been ABOVE NORMAL over more than half of the State, with some portions (north Cascades and Olympics) being hugely above normal. This is not a drought pattern." - Cliff Mass, Professor of Atmospheric Sciences
Cliff Mass is Professor of Atmospheric Sciences at the University of Washington. His Cliff Mass Weather Blog is looked to as a recognized authority on weather patterns in the northwest.
Friday, Cliff’s blog posting
said the media and government agencies are exaggerating drought conditions, and says, “The drought is not going to get worse and we should be in a much better place next spring than this year. And California will get substantial relief.
I really worry that some of the media and in political circles are going too far in painting an end of the world picture for next year. Crying wolf undercuts credibility.”
Cliff’s observations that this strong El Nino forecast should bring a season of snowpack to the cascades much more like a normal year (80% of snowpack) as opposed to last winter (20% of snowpack). That’s consistent with the data we have on strong El Nino months
and we anticipate a season that will bring close to 400 inches or more. Our average season accumulation from our opening storm through the end of operations is 430 inches.
Here's the link to the Cliff Mass Weather Blog and we encourage you to read it and draw your own conclusions.
Below are selected observations from Cliff’s weather blog that indicate this winter’s weather should provide a great season for us.
Let's examine what we really know. And as I will show, the odds are that next year will bring substantial IMPROVEMENT over this year regarding snowpack and drought. The first thing to keep in mind is that the key weather feature that has kept us warm and dry, the large high pressure area over the West Coast and eastern Pacific, is no longer there.
I can prove it to you. Here are the anomalies (difference from normal) of the heights of a mid-tropospheric level (500 hPa) first for last spring (left) and for the last three weeks (right). Red indicates higher pressure than normal (ridging) and blue below normal (troughing)
Can you see the profound difference? The ridge is gone and there is no hint it is coming back. In fact, the current strong El Nino will make sure of that.
We made change to a more normal pattern during the latter part of August, resulting in the return of precipitation to our region. In fact, here is a plot of the difference of precipitation from normal for the past month. Precipitation has been ABOVE NORMAL over more than half of the State, with some portions (north Cascades and Olympics) being hugely above normal. This is not a drought pattern.
So the main reason that we were so dry and warm (the eastern Pacific High pressure) is now gone. And furthermore, its direct offspring, the BLOB (the area of warm water off our coast), is rapidly weakening. To demonstrate this, here is the change of sea surface temperatures over the past month.
Blue is cooling. The BLOB is in its death throes. Sad, but true.
All good news, right? But then there is the scary El Nino threat. A very strong El Nino (warm sea surface temperatures in the eastern tropical Pacific) is developing-- in fact, the strongest since the late 1990s.
Based on past experience, strong El Nino's have their main impact after the new year, mainly making it warmer than normal, resulting in less snow pack than normal (about a 20% reduction on average). But this is HUGELY MORE than the snowpack we had last year (80% reduction).
NOAA and others run seasonal climate prediction models out to roughly 9 months. What do they say? The largest ensemble (average) of many models (IMME, International Multi Model Ensemble), shown below, prediction wetter than normal conditions on our NW coast and near normal for most of the rest of our area for October, November, and December. In stark contrast, to the the drier than normal fall suggested in the Seattle Times headline story today.
For January, February, and March IMME is going for drier than normal over the NW and much wetter across CA. Classic strong El Nino pattern. Big relief for California.
So temperatures and precipitation are running near normal now and I expect the same will be true for precipitation overall until the first of the year. There will be rain and storms and we will have an opportunity to fill our reservoirs. After the new year it will be warmer and drier than normal, but not as warm as last year. So there should be a far healthier snowpack on April 1, but less than normal.
Armed with this knowledge, the folks than manage our reservoirs should store as much water as possible as early as possible. We tend not to have major floods in strong El Nino years, so they can fill the reservoirs higher than normal with less fear of dangerous overtopping.
The drought is not going to get worse and we should be in a much better place next spring than this year. And California will get substantial relief.
I really worry that some of the media and in political circles are going too far in painting an end of the world picture for next year. Crying wolf undercuts credibility.