perhaps colder and wetter than previously thought?

From the National Weather Service:

A SERIES OF WEATHER SYSTEMS WILL TAKE AIM AT NORTHERN CALIFORNIA
OVER THE NEXT FEW DAYS...WHICH WILL BRING SIGNIFICANTLY COLDER
TEMPERATURES TO THE REGION AS WELL AS VALLEY RAIN AND HIGHER
ELEVATION SNOW. THE FIRST SYSTEM WILL JUST BRUSH THE FAR
NORTHERN PORTIONS OF THE STATE TODAY...BRINGING ISOLATED SHOWERS
AS WELL AS A CHANCE FOR LATE AFTERNOON AND EVENING THUNDERSTORMS.
TEMPERATURES WILL ALSO COOL A FEW DEGREES OVER THE WARM SPRING-
LIKE TEMPERATURES OF THE PAST FEW DAYS.

TWO COLDER SYSTEMS WILL THEN MOVE ACROSS NORTHERN CALIFORNIA ON
MOTHERS DAY AND MONDAY. THE MOTHERS DAY SYSTEM WILL BRING SOME
LIGHT VALLEY RAIN AND SOME HIGHER ELEVATION SNOW TO THE REGION...
WITH TEMPERATURES TAKING ANOTHER 10 TO 15 DEGREE HIT OVER TODAY.
SNOW LEVELS WILL ALSO START TO LOWER FROM ABOVE 6000 FEET TO
BETWEEN 4500 AND 5500 FEET BY SUNDAY AFTERNOON...POSSIBLY
BRINGING SOME LIGHT SNOWFALL ACCUMULATIONS TO THE HIGHER PASS
LEVELS. ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL ALSO BE
POSSIBLE WITH BRIEF HEAVY RAIN...SMALL HAIL...OR MOUNTAIN SNOW
AS WELL AS SOME GUSTY WINDS ACCOMPANYING THE HEAVIER SHOWERS. THE
THREAT OF SHOWERS WILL DECREASE SUNDAY NIGHT.

HOWEVER...THE MONDAY SYSTEM WILL QUICKLY SPREAD PRECIPITATION BACK
ACROSS THE REGION DURING THE DAY. TEMPERATURES WILL ALSO FALL
ANOTHER FEW DEGREES WITH THIS SYSTEM...BRINGING AVERAGE
TEMPERATURES DOWN TO BETWEEN 15 AND 20 DEGREES BELOW NORMAL FOR
THIS TIME OF THE YEAR. THIS SYSTEM ALSO APPEARS TO BE WETTER WHICH
MAY BRING A BETTER CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TO THE
REGION. SNOW LEVELS WILL CONTINUE TO FALL TO BETWEEN 4000 FEET
OVER THE NORTHERN MOUNTAINS AND 5000 FEET OVER THE SIERRA...WITH
MODERATE SNOWFALL ACCUMULATIONS POSSIBLE OVER THE HIGHER
ELEVATIONS.

IF TRAVELING OVER THE HIGHER MOUNTAIN PASSES EARLY NEXT WEEK...
CARRY CHAINS AND BE PREPARED FOR SOME WINTER-LIKE DRIVING
CONDITIONS.