As the train of storms from the Pacific continues, a dose of heavy rain will greatly assist in California and regional drought relief during the second half of this week.
While the storm will bring major problems, including flooding, mudslides and damaging winds, it will bring much needed rain to the region.
From 1-3 inches of rain will fall on coastal Southern California with an average of 3-6 inches of rain forecast over central and northern parts of the state. This translates to between 17 and 100 million gallons per square mile from this storm alone.
Locally higher amounts of rain, up to a foot, are possible on some of the west- and southwest-facing slopes of the coastal ranges, Sierra Nevada and southern Cascades.
While more rain than what this storm will deliver will be needed to end the drought completely, this will be a major step in the right direction. The ground will be thoroughly soaked.
Significant rainfall will spread southward and inland, reaching into the heavy agricultural areas of the Sacramento and San Joaquin valleys.
Runoff from the storm will cause water levels to surge rapidly in streams and will eventually begin to empty into lakes and reservoirs. The storm from early in the month sent water flowing through Yosemite Falls.
A couple of additional soaking storms are possible during next week, before the pattern shifts later in the month.
Much of California and portions of neighboring states have been in the throes of extreme to exceptional drought from this summer into this fall. The drought has its roots to a couple of years ago, when storm systems with rain and mountain snow became scarce.
During the last part of November 2014, storms with soaking rain began to return to the region.
From Dec. 1, 2012, to Nov. 29, 2014, San Francisco racked up a deficit of 20.9 inches, which was about 50 percent of its normal average rainfall. Since Nov. 29, the city has received nearly 5 inches of rain, which is more than four times that of average. This has reduced the approximate two-year deficit by about 20 percent.
Los Angeles incurred a rainfall deficit of 14.9 inches, which was about 44 percent of its normal average rainfall. Since the end of November, the city has received about 1.5 inches of rain, which is nearly three times that of average. The recent rainfall has reduced the deficit for the same period by nearly 10 percent.
A further reduction in the rainfall deficit will occur this week and next week.
According to Western Weather Expert Ken Clark, "This will be the second storm in a week with more rain in a week than most places had for the entire winter year."
Up to several feet of snow has fallen prior to this week's storms in the high country of the northern Sierra Nevada and southern Cascades. Yards of snow will fall over the higher terrain of these mountain ranges, which will be water in the bank for this coming spring and summer as it melts and flows into area streams and viaducts.