Rain

storm151101.jpeg

Above: From NASA’s Worldview site, an image of California’s first real storm of the wet season (click for a larger version, or check it out on Worldvew). Here’s (a slightly edited version of) how the National Weather Service’s San Francisco Bay Area forecast office described the weather system as it was shaping up early Sunday:

AS OF 09:59 AM PST SUNDAY...NORTH AND CENTRAL
CALIFORNIA ARE CURRENTLY POSITIONED IN THE BOUNDARY
BETWEEN TWO LARGE FEATURES. TO THE SOUTH...THE
HIGH PRESSURE THAT HELPED TO BRING CLEAR SKIES AND UNSEASONABLY
WARM TEMPERATURES OVER THE PREVIOUS FEW DAYS. TO THE NORTH...AN
APPROACHING STORM SYSTEM WITH A POTENT MOISTURE TAP. A COLD
FRONTAL BOUNDARY IS SEPARATING THESE TWO AIR MASSES AND IS EVIDENT
ON BOTH RADAR AND SATELLITE FROM THE THICK BAND OF CLOUDS AND
CONTINUOUS RAINFALL REFLECTIVITIES ASSOCIATED WITH IT. THIS
FRONTAL BOUNDARY IS CURRENTLY DRAPED FROM NORTHWESTERN CALIFORNIA
THROUGH SOUTHEASTERN OREGON AND HAS BROUGHT UP TO 2.5" OF RAIN
ALONG THE HIGHER TERRAIN OF THE OREGON COAST AND UP TO 2" OVER THE
HIGHER TERRAIN OF THE NORTHWESTERN CALIFORNIA COAST. THESE HIGHER
VALUES ARE SUPPORTED BY A TROPICAL pMOISTURE PLUME WITH PRECIPITABLE WATER VALUES
RANGING FROM 1.2"-1.6" WHICH ARE 150-200 PERCENT WETTER THAN NORMAL.
LOWER ELEVATION LOCATIONS IN THESE AREAS HAVE NOT PICKED UP NEARLY
AS MUCH... RANGING FROM SEVERAL HUNDREDTHS TO A FEW TENTHS. WE
WILL LIKELY SEE SIMILAR ELEVATION BASED PRECIP SCALING FROM THE
FRONT AS IT MOVES THROUGH OUR AREA THIS AFTERNOON AND INTO EARLY
MONDAY.

The rain started here in Berkeley about 9 p.m. or so. It’s been more than a drizzle: .29 of an inch in the last couple of hours, on the off chance that the backyard rain gauge (which I got just after the last rain of the spring) is correct. That seems to line up with other rain gauges around town that report on Weather Underground. We’ll see how accurate it looks tomorrow.