The highest King Tides of the winter season impacted the Bay Area on December 13 and 14. Minor coastal flooding during the times of high tide was observed at many areas with some minor damage reported.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MTR wrote it up.
The highest King Tides of the winter season impacted the Bay Area on December 13 and 14. Minor coastal flooding during the times of high tide was observed at many areas with some minor damage reported.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Francisco Bay Area, CA wrote its last area forecast discussion before the first event at Dec 13, 10:04 AM PST, 56 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA 1004 AM PST THU DEC 13 2012 .DISCUSSION...AS OF 9:05 AM PST THURSDAY...IT WAS A CHILLY NIGHT IN MANY AREAS IN THE CWA LAST NIGHT. MONTEREY NWS REACHED 40 DEGREES...DOWNTOWN SAN FRANCISCO FELL TO 44 AND SEVERAL LOCATIONS IN THE NORTH BAY VALLEYS HIT THE LOW 30S. TWO NWS EMPLOYEES ALSO REPORTED FROST AT THEIR HOMES THIS MORNING. CURRENTLY THE SATELLITE WATER VAPOUR IMAGE SHOWS A TROUGH OF LOW PRESSURE CENTERED OVER THE CWA. THE VISIBLE SATELLITE IMAGE IS SHOWING MOSTLY CLEAR SKIES BENEATH THE LOW WITH COOL AIR CUMULUS OVER THE COASTAL WATERS. SEA SURFACE TEMPERATURES ARE RUNNING 55 TO 59 DEGREES F ALONG THE COAST WITH 1200Z KOAK SOUNDING INDICATING 850MB TEMPERATURE OF 20 DEGREES F AND 500 MB TEMPERATURE OF -55 DEGREES F. THIS TEMPERATURE STRUCTURE IS RESULTING IN SOME INSTABILITY OVER THE COASTAL WATERS SUPPORTING THE COOL AIR CU. OVERNIGHT TEMPERATURES TONIGHT SHOULD BE A FEW DEGREES WARMER ALONG THE COAST AS WINDS TURN ONSHORE ADVECTING WARMER OCEAN AIR TO THE COASTAL COMMUNITIES. NEAR FREEZING TEMPERATURES WILL ONCE AGAIN BE POSSIBLE IN THE NORTH BAY VALLEYS BUT MAYBE NOT AS WIDE SPREAD WITH 700MB TEMPERATURES EXPECTED TO BE A FEW DEGREES WARMER THAN THIS MORNING. STILL LOOKS LIKE A GOOD POSSIBILITY OF FROST IN THE NORTH BAY VALLEYS AND NORTH SALINAS VALLEY. THEREFORE...MAY INTRODUCE PATCHY FROST TO THE AFTERNOON FORECAST PACKAGE. THE 0000Z ECMWF AND 1200Z GFS40 HAVE INITIALIZED WELL WITH THE CURRENT SYNOPTIC PATTERN. BOTH MODELS AGREE THAT TODAY'S TROUGH OF LOW PRESSURE WILL SLIDE OFF TO THE SOUTHEAST WITH A NEW TROUGH OF LOW PRESSURE PASSING OVER THE FORECAST AREA FRIDAY. A DIRTY RIDGE WILL THEN MOVE OVER THE CALIFORNIA COAST FOR THE WEEKEND. THIS SPELLS OUT COOL UNSETTLED WEATHER FOR THE WEEKEND. FOR EARLY NEXT WEEK BOTH THE 0000Z ECMWF AND 1200Z GFS40 ARE FORECASTING A STRONGER TROUGH OF LOW PRESSURE TO PUSH INTO THE PACIFIC NORTHWEST AND NORTHERN CALIFORNIA. THE GFS ENSEMBLE MEMBERS APPEAR TO AGREE ON THIS TROUGH AS WELL. THE TROUGH IS EXPECTED TO BRING A CHANCE OF RAIN TO THE FORECAST AREA MONDAY NIGHT TUESDAY MORNING TIME FRAME. A BULK OF THE PRECIPITATION WITH THIS STORM WILL BE IN THE NORTH BAY AREA. YET ANOTHER STORM SYSTEM IS EXPECTED BY MID WEEK BUT MODEL AGREEMENT BEGINS TO BREAK DOWN SO EXACT TIMING IS A BIT CLOUDY AT THIS POINT IN TIME. && .AVIATION...AS OF 10:00 AM PST THURSDAY...VFR CONDITIONS AND LIGHT OFFSHORE FLOW WILL PREVAIL THIS MORNING. WINDS WILL VEER ONSHORE THIS AFTERNOON...BECOMING LIGHT AND VARIABLE OVERNIGHT. BY FRIDAY MORNING WINDS WILL BACK TO THE SOUTHEAST TO EAST AHEAD OF AN APPROACHING WEATHER SYSTEM. VICINITY OF KSFO...VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. LIGHT OFFSHORE FLOW WILL TURN WESTERLY THIS AFTERNOON WITH WINDS UNDER 10 KNOTS. RAIN EXPECTED AT THE END OF THE FORECAST PERIOD AROUND 18Z-20Z FRIDAY. MODERATE CONFIDENCE. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. LIGHT OFFSHORE FLOW WILL TURN WESTERLY THIS AFTERNOON WITH WINDS UNDER 10 KNOTS. && .MARINE...AS OF 10:00 AM PST THURSDAY...SOME OF THE HIGHEST TIDES OF THE WINTER WILL OCCUR OVER THE NEXT COUPLE OF DAYS...KNOWN AS THE KING TIDES. THE HIGHEST HIGH TIDES ARE EXPECTED DURING THE MORNING HOURS OF THE 13TH AND 14TH. FOR EXACT TIME AND MAGNITUDE OF TIDES PLEASE VISIT: WWW.CENCOOS.ORG/SECTIONS/CONDITIONS/TIDES.SHTML SEAS BETWEEN 8 AND 10 FEET AT 12 TO 14 SECONDS WILL CONTINUE THROUGH AT LEAST THIS EVENING. THE COMBINATION OF BUILDING SWELL AND HIGHER THAN NORMAL TIDES WILL RESULT IN LARGER BREAKING WAVES CLOSER TO THE BEACH THAN NORMALLY EXPERIENCED WITH THIS SIZE OF SWELL. THIS WILL RESULT IN A HIGH POTENTIAL FOR PEOPLE WALKING ALONG THE BEACH OR CLIMBING...FISHING FROM ROCKS TO BE SWEPT INTO THE SEA BY A WAVE. PLEASE DO NOT TURN YOUR BACK TO THE OCEAN WHEN VISITING THE BEACHES THIS WEEK. SEAS WILL DECREASE TO 6 TO 8 FEET AT 12 SECONDS FRIDAY BRINGING AN END TO THIS POTENTIAL HAZARD. SOME ROADWAYS ALONG THE COAST DO EXPERIENCE FLOODING WITH HIGH TIDES OF 7 FEET OR GREATER COMBINED WITH HIGH SURF. SINCE WE ARE NOT EXPECTING HIGH SURF WITH THESE TIDES COASTAL FLOODING SHOULD NOT BE AN ISSUE. HOWEVER...PLEASE BE VIGILANT AND DO NOT CROSS FLOODED ROADWAYS IF YOU HAPPEN TO RUN INTO ONE. .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA FOR HAZARDOUS SEAS...SAN FRANCISCO BAR UNTIL 9 PM && PUBLIC FORECAST: LARRY AVIATION/MARINE: CW VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
The national radar mosaic for the moment the first event began.
2 coastal flood. Local standard time, as filed.
Minor coastal flooding in Marin County at the time of the King Tide caused Highway 1 to be closed at the time of high tide.
Streets in Mill Valley were flooded at the time of high tide during the King Tide.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2012Every state in 2012This day in weather historyWarnings in California, December 2012
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 426057, 426059.