Are Reservoirs are Now Full, Months Ahead of Time

The recent rain has done something amazing:  filled many of our reservoirs to full, months ahead of time    

Levels of fill that normally require snowpack melt during spring.

Consider the all-important Yakima Reservoirs (below), which are now at levels normally only reached in mid-June.  Amazing.

In Seattle, the reservoir levels exceeded normal maximum levels in June, and they released some water to ensure sufficient capacity to handle flooding:

What about Spada Lake, the massive storage reservoir for Everett?  It is now full! (blue line is this year, brown line is full)

The Northwest River Forecast Center's predictions for local streamflow are getting more favorable for regional rivers, as illustrated by the 120-day prediction of streamflow for mid-summer (below),   Most are around 100% of normal

To provide a specific example, there is the extended forecast for the Yakima River.  Black is the predicted for this year.  Much above normal (green line) into May and near normal during mid-summer.

Bottom line:   I am cautiously optimistic about our Washington State water resources this summer and that there will be no drought.

How Unusual Has This Winter Been?

It is now officially spring, and a good time to check on how unusual this winter has been. 

Meteorologists often do so by reviewing conditions over the water year (October-now), and I will do the same.

 First, consider Seattle's accumulated precipitation during the present water year (green line, observed; red line, climatological average).  

We have been a bit above normal overall!   Wet periods in December and March.

Yakima, on the east,  is similar, with a water year total near normal.  There is a reason I have been discouraging the drought talk.

Temperature?  See below, with blue being observed, tan showing the normal range, and red/light below showing the record highs and lows.

At Seattle, temperatures have been unremarkable, with periods of above and below normal warmth.  No records broken.

At Yakima, there is a clear warm bias this year, particularly in December and recently.  

These two warm periods are the reason the snowpack is now below normal for the Yakima Basin, but why the reservoirs are well above normal in water stored.    

I know some folks are interested in climate change, so what do the long-term trends for water year temperatures and precipitation look like? (October through February shown below)

Consider the situation for Western Washington from 1896 to the present.

For temperature, this year was warmer than normal but not a record. Over the past 130 years, there has been a slow warming of roughly 1.5 F.  

A modest global warming signal.

In contrast, a slight increase in precipitation....too small to be noticeable or significant.

Because of the two warm spells, the snowpack over the region is about 60% of normal (see below).   

Let me stress, this is mainly about the warm/wet periods associated with atmospheric rivers and Kona Storms, NOT global warming, as being claimed by some media and amateur YouTube channels.