Light rain began yesterday, and Weather West put the current storm in perspective:
The big picture: much-needed precipitation still likely this week; extreme drought continues
...What’s the overall message here? Well, it still looks pretty likely that most of California will see some rain this week, that the Sierra Nevadas <sic> will see some snow, and that said precipitation may be heavy at times in at least some regions.
There will probably be some very short-term relief from the ongoing exceptional drought conditions, as fresh snow falls in the mountains, streams in some watersheds begin to flow, and California’s annual wet-season “green-up” begins in earnest in many areas. On balance, though, this is not really the pattern we need to see for sustained, long-term drought relief–especially if the flow pattern over the Eastern Pacific transitions back toward amplified ridging during early December as is currently being suggested by the GFS. Long-term seasonal forecasts by global modeling centers do suggest that the potential exists for an enhanced subtropical jet during the heart of winter, with the coincident increase in the potential for beneficial rainfall in California. Until we actually start seeing such a zonal flow pattern develop in the real atmosphere, however, any drought relief that does occur will probably be in the form of transient (but potentially quite moist) storm systems in a much higher-amplitude flow regime.
In the meantime, enjoy the (probable) rain and snow this weekend and early next week!
http://www.weatherwest.com/archives/2020" onclick="window.open(this.href);return false;
California's complex water storage and delivery system is highly climate-dependent.
We need precipitation at the
right place, the
right time, and at the
right temperatures, to allow snowpack and reservoir storage to carry over the dry season.
That did not happen last year, and we utilized record draw-downs of non-renewable groundwater resources to carry us over.
And we aren't doing very well (yet, ~a quarter through) this
rain year, either.
While rainfall has been ~normal
where it matters most, in the North:
California Climate Station Precipitation Summary
http://www.cnrfc.noaa.gov/awipsProducts/RNOWRKCLI.php" onclick="window.open(this.href);return false;
Much of the precipitation occurred at the
wrong time, too early in the (record-warm fall) season to add snowpack, or even halt the drawdown of the reservoirs.
Most of the rain stayed where it fell, saturating the soil, and then evaporated without producing much runoff.
So the reservoirs are still at or near their annual lows (most lower than they have been since the 1977 drought) ~ a month later than when they typically increase their storage
The graphic below gives a good picture of the situation:
http://cdec.water.ca.gov/cgi-progs/products/rescond.pdf" onclick="window.open(this.href);return false;
Shasta reservoir finally increased (0.01 inch!) its level today, and that should mean yesterday was the low level of 2014.
Edit: 889.49 low recorded on 11/30/14.
http://www.usbr.gov/mp/cvo/vungvari/daily.pdf" onclick="window.open(this.href);return false;
However, snow levels today are quite high, looks like over 6,000 ft. at Mt Shasta Ski park:
http://skipark.com/the-mountain/cams/" onclick="window.open(this.href);return false;
Hopefully, we will see snow at the base, ~5,500 ft, by tomorrow.
