Soggy Slog? Uncertainty Reigns

The new Sacto discussion is posted. Various scenarios are described, ranging from rain on Saturday into Sunday to rain holding off until Sunday afternoon to rain not arriving until Monday. Net result is a forecast for below normal temps and above-normal rain chances with "uncertainty in the timing, coverage and amount of precipitation."

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
330 PM PST MON NOV 30 2009

...EXTENDED DISCUSSION (FRIDAY NIGHT THROUGH MONDAY)...THE MODELS HAVE VARIOUS SOLUTIONS FOR THE WEEKEND AND INTO NEXT MONDAY BUT EITHER WAY IT WILL MOST LIKELY BECOME COOLER AND WETTER FOR AT LEAST A PORTION OF INTERIOR NORTHERN CALIFORNIA. THE 18Z GFS HAS A LOW COMING DOWN INTO MONTANA FRIDAY NIGHT INTO SATURDAY. THE LOW THEN RETROGRADES TO NEAR THE ORCA BORDER ON SUNDAY NIGHT AND OVER NORTHERN CALIFORNIA ON MONDAY. THIS WOULD BRING COOLER TEMPERATURES AND A CHANCE OF PRECIPITATION TO THE AREA BY SUNDAY AFTERNOON AND INTO MONDAY. THE ECMWF HAS A LOW FROM THE GULF OF ALASKA OFF THE PACIFIC NORTHWEST COAST ON FRIDAY NIGHT AND THEN IT MOVES SOUTH AND COMBINES WITH ANOTHER LOW THAT MOVES EAST FROM 140 WEST SUNDAY NIGHT AND THEN THE SYSTEM MOVES INLAND THROUGH CALIFORNIA ON MONDAY. A MOISTURE PLUME IS EXPECTED WITH THIS SYSTEM WHICH WOULD BRING WETTER WEATHER THAN THE GFS. THE ECMWF SHOWS 500 MB HEIGHTS OF 5300M WITH THIS SYSTEM WHICH IS THREE STANDARD DEVIATIONS BELOW CLIMATOLOGY SO THIS SYSTEM COULD BRING A SIGNIFICANT PRECIPITATION EVENT TO THE AREA. THE GEM MODEL IS BETWEEN THE GFS AND ECMWF AND JUST BRING THE LOW OVER THE PACIFIC NORTHWEST AND THROUGH CALIFORNIA ON SUNDAY. THIS WOULD BRING A CHANCE OF PRECIPITATION SATURDAY INTO SUNDAY. AFTER LOOKING AT THE VARIOUS SOLUTIONS THE FORECAST CURRENTLY LEANS TO BELOW NORMAL TEMPERATURES AND ABOVE CLIMATOLOGY FOR THE POPS BUT THERE IS STILL UNCERTAINTY IN THE TIMING...COVERAGE AND AMOUNT OF PRECIPITATION.