Weather Watch blog: Another boost for the snowpack
By: Robert Krier

The storm expected to hit the state this weekend should bring two to five feet of snow to the Sierra. It's exactly what the state's water managers ordered.

Storms last month lifted California's snow-water equivalent to 113 percent of normal, as of yesterday. But the storms need to keep coming if we're going to get help with the state's water supply. If the Sierra gets another five feet, that would probably lift the state's snow-water equivalent above 125 percent of normal.

Of course, we'll still have problems getting the water around the Sacramento-San Joaquin Delta later in the year, but conditions are improving south of the delta, too, where pumping restrictions won't be an issue. In Central California, the San Luis reservoir, one of the largest in the state's system, has been steadily creeping toward average levels after being very low for the last few years. The San Luis has added 275,000 acre feet of water in the last month. It's now at 72 percent of average; it was below 50 percent last year. ...

Locally, we might manage a few hundredths of an inch of rain this afternoon through tomorrow afternoon. But we should do much better over the weekend.

The morning forecast discussion says a warm front should arrive Friday afternoon. We can expect light to moderate rain, less than a quarter inch, with high snow levels. Then it starts to get interesting.

Friday night through Saturday, rain bands ahead of a cold front should bring moderate to heavy precipitation. The rainfall estimates are about an inch at the coast and three inches in the mountains.

The rain could arrive just in time for San Diego to avoid falling below average rainfall for the date. As of today, the season total is 5.78 inches at Lindbergh Field. That's 0.27 of an inch above normal. But if no rain is measured before Saturday, the total will be back below normal. ...