One of the first winter storms of the season brought moderate rainfall amounts to the area on November 17. Only minor impacts were reported.
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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.
One of the first winter storms of the season brought moderate rainfall amounts to the area on November 17. Only minor impacts were 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 Nov 16, 9:58 PM PST, 2 hours 2 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
958 PM PST FRI NOV 16 2012
.DISCUSSION...AS OF 9:00 PM PST FRIDAY...A LOW PRESSURE SYSTEM
CENTERED APPROX 200 MILES WEST OF THE MONTEREY PENINSULA CONTINUE
TO TRACK EAST TOWARD THE CENTRAL CALIFORNIA COAST THIS EVENING.
DOPPLER RADAR DEPICTS WIDESPREAD SHOWERS ACROSS THE REGION WITH
SURFACE OBSERVATIONS REPORTING LIGHT PRECIP ANYWHERE FROM A
HUNDREDTH TO A TENTH OF AN INCH AN HOUR. MODELS INDICATE HEAVIER
RAIN IS ANTICIPATED OVERNIGHT AS THE FRONT MOVES INLAND AND ACROSS
THE AREA. AMSU IMAGERY REVEALS TPW VALUES OVER AN INCH JUST OFF
THE COAST WHICH WILL BRING A DECENT AMOUNT OF RAIN TO THE DISTRICT
OVERNIGHT AND INTO SATURDAY MORNING. PONDING ON THE ROADWAYS AND
SLICK ROADS WILL CONTINUE TO IMPACT THE DISTRICT...HOWEVER NO
SIGNIFICANT FLOODING IS EXPECTED. ANTICIPATE MODERATE STEADY RAIN
AND OCCASIONAL HEAVIER DOWNPOURS THROUGH TONIGHT AND INTO SATURDAY.
FORECAST REMAINS ON TRACK...NO UPDATE NEEDED AT THIS TIME.
FROM PREVIOUS DISCUSSION...RAINFALL AMOUNTS ARE STILL GOING TO BE
GENERALLY 1 INCH OR LESS IN THE LOWER ELEVATIONS OVER THE NEXT FEW
DAYS AND 2-3 INCHES IN THE HIGHER TERRAIN. STILL NOT EXPECTING ANY
FLOODING CONCERNS GIVEN THE ANTECEDENT DRY CONDITIONS AND THE
SPREAD OUT NATURE OF THE RAIN OVER SEVERAL DAYS AS WELL AS THE
FACT THAT THE RAIN AMOUNTS ARE NOT EXCESSIVE. THE GENERAL PATTERN
EVOLUTION OVER THE NEXT FEW DAYS WILL BE FOR A DEEPENING LONGWAVE
TROUGH TO DEVELOP ACROSS THE GULF OF ALASKA AND NORTH PACIFIC.
THIS WILL FORCE UPSTREAM RIDGING ACROSS THE INTERMOUNTAIN WEST AND
LEAVE OUR AREA IN LOWERED HEIGHTS AND WESTERLY FLOW AROUND THE
BASE OF THE TROUGH. A SHORTWAVE TROUGH AND ASSOCIATED VORT MAX
WILL SWEEP ACROSS THE AREA THIS EVENING. A SURFACE LOW AND
ASSOCIATED TROUGH WILL PUSH ACROSS THE AREA AS WELL AND HELP TO
BRING INCREASED RAIN CHANCES OVERNIGHT. THERE LOOKS TO BE A LULL
IN FORCING ON SATURDAY BY 18Z AND THIS SHOULD BE REFLECTED BY
LIGHTER RAIN AMOUNTS ON SATURDAY AFTERNOON. THEN THE NEXT
SIGNIFICANT PUSH OF FORCING WILL BE AFTER 03Z SUNDAY AS A
SHORTWAVE IMPULSE PUSHES TOWARDS THE NORTH BAY AND CROSSES THE
AREA BY 12Z.
AFTER SUNDAY MORNING THE FORCING WILL WEAKEN AS 500 MB HEIGHTS
BEGIN TO RISE. THE UPPER LOW IN THE GULF OF ALASKA WILL REMAIN
STRONG BUT ITS INFLUENCE WILL NOT BE FAR ENOUGH SOUTH TO BRING
RAIN TO OUR AREA. WEAK 500 MB RIDGING WILL DEVELOP OVER THE AREA
BY LATE MONDAY AND INTO EARLY NEXT WEEK...HOLDING ADDITIONAL
RAINFALL TO THE NORTH BAY AND HAVE ADJUSTED POPS DOWNWARD FROM THE
BAY SOUTH TO ACCOUNT FOR THIS. THE RAINFALL FORECAST TO GET
TRICKIER IN THE EXTENDED PERIODS AS MUCH WILL DEPEND ON HOW FAR
SOUTH THE LARGE UPPER LOW WILL MAKE IT. THERE LOOKS TO BE A FAIRLY
SHARP CUTOFF ACROSS THE AREA FOR RAIN CHANCES. FOR NOW THE BEST
CHANCES WILL BE CONFINED TO THE NORTH BAY BUT IT REMAINS TO BE
SEEN HOW FAR SOUTH THOSE CHANCES WILL GO.
&&
.AVIATION...AS OF 9:55 PM PST FRIDAY...AN AREA OF LOW PRESSURE OFF
THE CENTRAL CALIFORNIA COAST WILL MOVE INLAND LATE TONIGHT AND
CONTINUE TO SPREAD NUMEROUS SHOWERS ACROSS THE AREA THROUGH
MIDDAY SATURDAY. CIGS WILL BE MOSTLY VFR AND OCCASIONALLY MVFR
THROUGH THE EVENING AND THEN MOSTLY MVFR LATER TONIGHT INTO
SATURDAY MORNING. VSBYS WILL OCCASIONALLY DROP TO MVFR IN SHOWERS.
LIGHT TO MODERATE SOUTHEAST WINDS WILL CONTINUE OVERNIGHT. SHOWERS
WILL TAPER OFF AROUND MIDDAY SATURDAY AND WINDS WILL VEER TO THE
SOUTHWEST. ANOTHER WEATHER SYSTEM MOVING IN FROM THE NORTHWEST
WILL SPREAD MORE RAIN ACROSS THE REGION ON SATURDAY EVENING.
VICINITY OF KSFO...SCATTERED SHOWERS ALONG WITH VFR CIGS ARE
EXPECTED THROUGH THE LATE EVENING HOURS. CIGS AND VSBYS WILL
OCCASIONALLY DROP TO MVFR. MORE WIDESPREAD MVFR CIGS ARE LIKELY BY
LATE TONIGHT AND INTO SATURDAY MORNING. EAST WINDS 5 TO 10 KNOTS
THIS EVENING WILL GRADUALLY TURN TO THE SOUTHEAST AND INCREASE TO
10 TO 15 KNOTS LATE TONIGHT AND SATURDAY MORNING. WINDS WILL THEN
CONTINUE TO VEER TO THE SOUTH OR SOUTHWEST ON SATURDAY AFTERNOON.
SHOWERS ARE EXPECTED TO TAPER OFF ON SATURDAY AFTERNOON BUT THEN
RAIN WILL REDEVELOP ON SATURDAY EVENING AS THE NEXT WEATHER SYSTEM
APPROACHES.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...SCATTERED SHOWERS AND VFR CIGS WILL
CONTINUE THROUGH THE NIGHT AND INTO SATURDAY MORNING. OCCASIONAL MVFR
CIGS AND VSBYS ARE POSSIBLE IN SHOWERS. WINDS WILL BE LIGHT FROM
THE SOUTHEAST EXCEPT UP TO 20G25 KNOTS IN THE NORTHERN SALINAS
VALLEY. CONDITIONS WILL IMPROVE ON SATURDAY AFTERNOON AS SHOWERS
TAPER OFF.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...SCA...PT REYES TO PIGEON PT 0-10 NM
SCA...PIGEON PT TO PT PINOS 0-10 NM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM
SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 3 AM
SCA...PT ARENA TO PIGEON PT 10-60 NM UNTIL 3 AM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 3 AM
&&
PUBLIC FORECAST: CW
AVIATION/MARINE: DYKEMA
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WWW.YOUTUBE.COM/NWSBAYAREAThe national radar mosaic for the moment the first event began.
1 heavy rain. Local standard time, as filed.
Heavy rain led to two small sewage spills into creeks in the Ross Valley. More than 3,000 gallons spilled into the Sleepy Hollow Creek near Willow Way in San Anselmo. 1,000 gallons of sewage spilled into Fairfax Creek on Steven Court in Fairfax.
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, November 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: 420006.