Sneakerwave in California, November 11, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
402 AM PST TUE NOV 11 2014

.SYNOPSIS...ONSHORE FLOW WILL HELP TO USHER IN COOLER TEMPERATURES
TODAY. DRY CONDITIONS WILL CONTINUE THROUGH WEDNESDAY EXCEPT FOR
LOCAL DRIZZLE NEAR THE COAST. A PACIFIC WEATHER SYSTEM WILL SPREAD
RAIN ACROSS MUCH OF THE REGION ON WEDNESDAY NIGHT AND THURSDAY
MORNING. DRY WEATHER WILL RETURN BY FRIDAY FOLLOWED BY ANOTHER
POSSIBLE SHOT OF RAIN LATE ON SATURDAY INTO SUNDAY.

&&

.DISCUSSION... AS OF 3:00 AM TUESDAY...MARINE LAYER CONTINUED TO
INCREASE OVERNIGHT AND IS NOW OVER 3000 FEET. AT THE SAME TIME THE
SURFACE FLOW IS NOW MORE ONSHORE THIS MORNING COMPARED TO PREVIOUS
DAYS. THESE TWO FACTORS WILL HELP TO LOWER HIGHS TODAY ESPECIALLY
FOR INLAND LOCATIONS. HIGHS WILL GENERALLY BE IN THE 60S TODAY.
MAY ALSO SEE SOME PATCHY FOG DEVELOPMENT OVER THE NEXT FEW HOURS,
SO WILL LEAVE THAT IN THE FORECAST FOR THE TIME BEING.

AFTER ANOTHER DRY START ON WEDNESDAY, RAIN WILL RETURN TO THE
PICTURE FOR WEDNESDAY NIGHT INTO THURSDAY AS A PACIFIC STORM
SYSTEM ADVANCES TO THE COAST WITH THE SOUTHERN EXTENT OF MOISTURE
FORECAST TO BE DOWN TO AROUND THE MONTEREY BAY REGION. RAINFALL
WILL LIKELY START OVER NW PORTIONS OF THE NORTH BAY LATE IN THE
EVENING AND DOWN TO SF/MONTEREY BAY REGION BY THURSDAY MORNING.
AMOUNTS ARE EXPECTED TO RANGE FROM 1/2"-3/4" OVER THE NORTH BAY,
AROUND 1/4" AROUND SF BAY, AND LESSER AMOUNTS TO THE SOUTH. RAIN
WILL GENERALLY END BY THURSDAY AFTERNOON.

A RIDGE OF HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING SYSTEM
AND BRING DRY WEATHER BACK AT LEAST TO SATURDAY AFTERNOON.
PREVIOUS RUNS FROM MOST OF THE MODELS HAD BEEN INDICATING ANOTHER
GOOD SHOT OF MOISTURE BY SATURDAY NIGHT, ALTHOUGH NOW THE
OPERATIONAL RUNS INDICATE THAT THE RIDGE WILL REMAIN STRONG ENOUGH
TO KEEP THE RAIN TO OUR NORTH. FOR NOW WENT WITH LOWER POPS BUT
KEPT A MENTION OF RAIN GOING IN CASE THE MODELS SWING BACK TO
A WETTER SOLUTION. EVEN IF IT DOES END UP RAINING, AMOUNTS SHOULD
BE ON THE LIGHT SIDE -- GENERALLY LESS THAN 2/10".

AN EVEN BIGGER AND MORE FRUSTRATING QUESTION REMAINS FOR NEXT WORK
WEEK WITH THE THREE MAIN OPERATIONAL MODELS ALL BRINGING
SUBSTANTIAL AMOUNTS OF RAIN TO OUR CWA WITH THE FOCUS BEING ON
THREE DIFFERENT DAYS. 0Z ECMWF CONTINUES TO BE THE FASTEST, WITH
THE CANADIAN SECOND, AND THE GFS LAST. EVERYTHING WILL HINGE ON
THE STRENGTH OF THE RIDGE NEAR THE COAST AND HOW FAST THE STORM
WILL BE ABLE TO PROGRESS TO THE CONUS. COMPLICATING THINGS MORE,
NEW 06Z GFS JUST IN HAS NOW PUSHED UP THE START TO MONDAY NIGHT
COMPARED TO THURSDAY WHICH THE PREVIOUS RUN SUGGESTED. ON THE PLUS
SIDE, CONFIDENCE IS HIGH THAT WE WILL HAVE A GOOD CHANCE AT
PICKING UP SOME MUCH NEEDED RAINFALL DURING SOME POINT NEXT WEEK. WE
WILL CONTINUE TO WORK ON THE TIMING AND HOPEFULLY BE ABLE TO COME
UP WITH BETTER AGREEMENT FOR THE START TIME IN THE NEXT DAY OR
TWO. WOULD NOT BE SURPRISED OVER THE NEXT 10 DAYS, IF SOME SPOTS
IN OUR CWA PICK UP MORE THAN 3".

&&

.AVIATION...AS OF 4:00 AM PST TUESDAY...LOW CLOUDS SURGED INLAND
MONDAY EVENING AND ARE CURRENTLY OVER ALL TAF SITES THIS MORNING.
NOT YET OBSERVING REDUCED VISBYS FROM BR OR FG AND CLOUD BASES ARE
GRADUALLY RISING. DO NOT EXPECT AS MUCH FOG THIS MORNING AS A
RESULT OF WARMER TEMPERATURES... SLIGHTLY HIGHER WINDS... AND
INSULATING MID TO HIGH CLOUDS THAT SHOULD ARRIVE BEFORE SUNRISE.
CONFIDENCE IS LOW FOR THE TIMING OF LOW CLOUD DISSIPATION AND
COVERAGE OF ANY FOG.

VICINITY OF KSFO...PRESENTLY MVFR. LOW CONFIDENCE FORECAST EARLY
TUESDAY MORNING REGARDING LOW CLOUDS LOWERING TO THE IFR CATEGORY.
FOG IS POSSIBLE BUT NOT EXPECTED. 10-12 KNOT WEST WINDS BY NOON
TUESDAY.

KSFO BRIDGE APPROACH...SIMILAR TO KSFO.

MONTEREY BAY AREA TERMINALS...SIMILAR TO THE BAY AREA...MVFR
CIGS HAVE POTENTIAL TO LOWER TO IFR CIGS EARLY TUE MORNING. FOG
IS POSSIBLE BUT NOT EXPECTED.

&&

.MARINE...AS OF 03:40 AM PST TUESDAY...SOUTHERLY WINDS WILL
PREVAIL AHEAD OF AN APPROACHING STORM SYSTEM THROUGH LATE
WEDNESDAY. WINDS SHIFT TO THE NORTH-NORTHWEST THURSDAY AND BEYOND
IN THE WAKE OF THE STORM SYSTEM. MODERATE PERIOD NORTHWEST SWELL
PERSISTS THROUGH TODAY. FURTHERMORE... A LONG PERIOD NORTHWESTERLY
SWELL TRAIN WILL IMPACT THE COASTAL WATERS LATE TUESDAY AFTERNOON
AND CONTINUE THROUGH THE END OF THE WEEK.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .TDAY...NONE.

&&

PUBLIC FORECAST: BELL
AVIATION/MARINE: DRP

VISIT US AT WEATHER.GOV/SANFRANCISCO

FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
WWW.TWITTER.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA