Saturday, December15, 2018 L-36.com


Marine Weather and Tides
Belvedere, CA

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 7:16AMSunset 4:53PM Friday December 14, 2018 9:23 PM PST (05:23 UTC) Moonrise 12:19PMMoonset 11:46PM Illumination 51% Phase: First Quarter Moon; Moon at 8 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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PZZ530 San Pablo Bay, Suisun Bay, The West Delta And The San Francisco Bay North Of The Bay Bridge- 851 Pm Pst Fri Dec 14 2018
Tonight..W winds 5 to 15 kt...becoming northeast after midnight. Showers likely, mainly this evening.
Sat..E winds 5 to 15 kt. A chance of showers.
Sat night..SE winds 5 to 10 kt. A chance of showers.
Sun..SE winds 10 to 20 kt with gusts up to 30 kt. Rain.
Sun night..S winds 15 to 25 kt with gusts up to 30 kt. Rain.
Mon..N winds up to 10 kt.
Mon night..NW winds around 5 kt.
Tue..S winds around 5 kt.
Wed..NE winds around 5 kt.
PZZ500 851 Pm Pst Fri Dec 14 2018
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... A moderate west to northwest swell will build tonight and result in hazardous conditions through Saturday. Generally light winds will prevail tonight as a weak frontal boundary remains stalled over the region. South to southeasterly winds will then increase Saturday into Sunday ahead of the next and stronger approaching pacific storm system. An even larger and more powerful long period west to northwest swell will move in Sunday afternoon through Monday.


7 Day Forecast for Marine Location Near Belvedere, CA
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location: 37.83, -122.44     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 150023
afdmtr
area forecast discussion
national weather service san francisco bay area
423 pm pst Fri dec 14 2018

Synopsis A weak weather system will produce light rain across
the sf bay area into this evening. Scattered showers continue
Saturday across the north bay. A stronger wetter system impacts
the area Sunday. A very large wave train arrives late Sunday into
Monday. A return to dry weather is expected late Monday.

Discussion As of 03:00 pm pst Friday... A pair of storm systems
will bring unsettled weather to the region through the coming
days. The first of these two storm systems first arrived earlier
today bringing gusty southerly winds up to 50 mph over the higher
terrain and continues to encroach on the region from the
northwest this afternoon. A north to south line of light pre
frontal showers developed along the air mass boundary of the warm
sector earlier today, however, these high based showers promptly
fizzled upon moving over the santa cruz mountains and diablo
range bringing only spotty accumulations of a few hundredths. The
southern tail of the main frontal rain band is now moving across
the north bay, bringing reports of brief heavy at the santa rosa
airport. As of 215pm, precipitation accumulations have been
primarily confined to the sonoma coast and coastal range, with
just under half of an inch being reported near both monte rio and
gualala. Additional accumulations are anticipated through the
coming hours across the san francisco bay area.

Confidence is high that the surface frontal boundary will continue
to move towards san francisco and oakland over the remainder of
the daylight hours. From there, the surface frontal boundary will
stall out as the upper level support pulls away and lifts towards
idaho, leaving behind a stalled frontal boundary over the
northern san francisco bay and a moisture rich air mass overhead
of the broader region. The main precipitation band will rapidly
deteriorate through the evening and it is possible there will be a
few hours of little to no activity on the radar around midnight.

Short models then agree that a weak secondary pulse will pass over
the region late tonight into tomorrow morning, which will provide
just enough lift to kickstart the shower activity over the north
bay tomorrow.

A potent storm system is forecast to impact the forecast area
throughout Sunday with lingering showers into Sunday night and
early Monday. This storm system is accompanied by a fairly moist
air mass in the range of around 1.20-1.30" pwats and also has the
potential to tap into the additional lingering moisture orphaned
by tonights storm system. Thus, there is the potential for
moderate to locally heavy rainfall, primarily over the north bay
and isolated sections of the santa cruz and santa lucia ranges on
the order of up to 2.00-3.00". Elsewhere, widespread rain of 0.50
to 1.00" is expected to fall regionwide, with locally higher
amounts in the north bay valleys and locally lower amounts in the
typical rain shadowed portions of the santa clara and salinas
valley. Generally speaking, this should come as another round of
beneficial rain with only minor nuisance ponding of water and
nuisance flooding in prone paved low lying areas. In addition to
rain, southerly winds will become gusty ahead of the system,
especially along the coast and over the higher terrain.

In addition to the rain and wind, this storm system will be
responsible for bringing the largest waves so far this season to
the coast from late Sunday through Monday. A high surf warning has
been issued and is in effect from 9am Sunday through 9pm Monday.

The earlier start time accounts for the arrival of the very long
forerunner waves which present a significantly increased risk of
rip currents and sneaker waves. Please review the beaches section
for more information about the upcoming high surf event.

Aviation As of 4:15 pm pst Friday... A mix ofVFR-MVFR
conditions expected to continue as visibilities and cloud bases
remain lower in association with a weak frontal boundary
now essentially stalled over the sf bay area. Winds will continue
generally light and southerly, though locally a bit stronger and
gustier vicinity central portions of sf bay through early this
evening. Light rain and briefly lower ceilings are possible across
the san francisco bay area terminals through mid-evening.VFR
conditions are more likely to persist for the monterey bay
terminals as the frontal boundary remains stalled to the north.

Vicinity of ksfo...VFR conditions expected to generally prevail
through the evening rush, though ceilings and visibilities may
temporarily reduce to MVFR with a passing shower. Southerly
winds to 15 to 20 kt through the early evening hours, then light
out of the southeast. Moderate confidence.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals...VFR conditions to persist with mid level
cloud deck expected to continue over the region. Can't entirely rule
out the possibility of a passing shower, which could briefly
reduce ceilings and visibilities to MVFR. Moderate confidence.

Beaches As of 03:09 pm pst Friday... A potent storm system
passing south of aleutian islands will move nearly due east over
the coming days. This eastward trajectory will create a dynamic
fetch zone where the strongest winds of the storm system will
continuously increase the energy within a swell train on the
southern flank of the storm, resulting in a very large, long
period wnw wave train aimed at the california coast. Very long
period forerunners will arrive through the day Sunday and will
bring a significantly increased risk of rip currents and sneakers
waves to the coast. The largest waves are then forecast to arrive
Sunday night through Monday morning, with peak swells of 17 to 21
ft at 19 to 21 seconds currently expected. Large breaking waves of
25 to 40 ft will be possible at west and northwest facing
locations, with breakers up to or exceeding 50 ft at favored break
points along the coast. As a result, a high surf warning has been
issued from 9 am Sunday through 9 pm Monday along the entire
coastline.

Marine As of 03:09 pm pst Friday... A moderate west to
northwest swell will build tonight and result in hazardous
conditions through Saturday. Winds will become fairly light
tonight as a weak frontal boundary stalls over the region.

Southerly winds will increase late Saturday night into Sunday
ahead of the next storm system to impact the region. A larger,
more powerful long period west to northwest swell will build
Sunday into Monday and result in hazardous conditions into early
next week.

Mtr watches warnings advisories
Tngt Sca... Pt arena to pt reyes 0-10 nm
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 pigeon pt 10-60 nm
sca... Pigeon pt to pt piedras blancas 10-60 nm
sca... Rough bar advisory for sf bar
sca... Mry bay until 5 pm
sca... Sf bay until 9 pm
public forecast: drp
aviation: blier
marine beaches: rgass
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
FTPC1 - 9414290 - San Francisco, CA 2 mi59 min WSW 1.9 G 2.9 55°F 56°F1019.7 hPa
PXOC1 - 9414311 - San Francisco (Pier 1), CA 3 mi53 min ENE 4.1 G 5.1 58°F 1018.3 hPa
PXSC1 3 mi53 min 60°F 53°F
TIBC1 - Tiburon Pier, San Francisco Bay, CA 4 mi48 min Calm 55°F 1020 hPa
OKXC1 - 9414776 - Oakland (Berth 34), CA 6 mi53 min WSW 1.9 G 2.9 56°F 1019.4 hPa
OBXC1 6 mi53 min 57°F 54°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 6 mi53 min SW 2.9 G 4.1
RCMC1 - 9414863 - Richmond, CA 7 mi53 min 55°F
PPXC1 - 9414847 - Richmond (Point Potrero), CA 7 mi53 min WNW 2.9 G 4.1 56°F 1019.7 hPa
AAMC1 - 9414750 - Alameda, CA 8 mi59 min Calm G 0 57°F 55°F1019.6 hPa
LNDC1 9 mi53 min N 1 G 1.9 57°F 1019.3 hPa
46237 - San Francisco Bar, CA (142) 11 mi53 min 56°F10 ft
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 18 mi53 min NW 7 G 8.9 54°F 1019.2 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 22 mi53 min WNW 6 G 8 55°F 54°F1019.5 hPa55°F
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 22 mi43 min NNE 3.9 G 5.8 54°F 57°F1020.3 hPa
RTYC1 - 9414523 - Redwood City, CA 25 mi53 min S 6 G 8.9 59°F 55°F1019.6 hPa
PCOC1 - 9415144 - Port Chicago, CA 26 mi53 min W 7 G 8 56°F 53°F1019.5 hPa
PRYC1 - 9415020 - Point Reyes, CA 31 mi53 min 56°F1019.8 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 33 mi53 min NNW 5.1 G 5.1 55°F 1019.2 hPa
SFXC1 - San Francisco Bay Reserve, CA 34 mi98 min WNW 4.1 54°F 1019 hPa50°F

Wind History for San Francisco, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
San Francisco, San Francisco International Airport, CA15 mi27 minN 010.00 miMostly Cloudy60°F48°F65%1019.1 hPa
Oakland, Metro Oakland International Airport, CA15 mi30 minNNE 410.00 miMostly Cloudy55°F51°F87%1019.8 hPa
Hayward, Hayward Air Terminal, CA21 mi29 minN 010.00 miOvercast57°F48°F74%1020.5 hPa
Half Moon Bay Airport, CA22 mi28 minSE 58.00 miOvercast57°F51°F82%1020 hPa
Novato / Gnoss Field, CA23 mi28 minN 02.00 miFog/Mist52°F51°F100%1020 hPa
San Carlos Airport, CA23 mi36 minN 010.00 miOvercast59°F50°F72%1019.3 hPa
Concord, Buchanan Field, CA23 mi30 minN 410.00 miMostly Cloudy55°F48°F80%1018.3 hPa

Wind History from SFO (wind in knots)
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Last 24hrCalmCalmCalmS3S3CalmCalmW3NE8NE8SE4E3E6E6S17
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1 day agoCalmCalmS4CalmCalmCalmCalmCalmS3S3S3S3NE7E3CalmCalmCalmE4NE4N6NE7NE9CalmSE3
2 days agoW11NW11W8W11NW7W6NW8NE33E7CalmNE13NE8NE13NE8NE7NE35W14W10W11W10W8W11

Tide / Current Tables for Alcatraz Island, San Francisco Bay, California
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Alcatraz Island
Click for Map
Sat -- 03:49 AM PST     First Quarter
Sat -- 06:08 AM PST     5.07 feet High Tide
Sat -- 07:18 AM PST     Sunrise
Sat -- 12:23 PM PST     2.51 feet Low Tide
Sat -- 12:47 PM PST     Moonrise
Sat -- 04:51 PM PST     Sunset
Sat -- 05:28 PM PST     3.96 feet High Tide
Sat -- 11:40 PM PST     1.20 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.21.72.63.44.24.85.14.94.53.93.32.82.52.62.83.33.73.93.93.632.31.71.3

Tide / Current Tables for Alcatraz Island W, San Francisco Bay, California Current
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Alcatraz Island W
Click for Map
Sat -- 12:34 AM PST     0.00 knots Slack
Sat -- 03:45 AM PST     2.15 knots Max Flood
Sat -- 03:49 AM PST     First Quarter
Sat -- 07:18 AM PST     Sunrise
Sat -- 07:26 AM PST     -0.00 knots Slack
Sat -- 09:51 AM PST     -1.46 knots Max Ebb
Sat -- 12:47 PM PST     Moonrise
Sat -- 01:37 PM PST     0.00 knots Slack
Sat -- 04:07 PM PST     1.28 knots Max Flood
Sat -- 04:51 PM PST     Sunset
Sat -- 07:12 PM PST     -0.00 knots Slack
Sat -- 09:57 PM PST     -1.64 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-0.40.41.422.11.91.40.5-0.5-1.3-1.5-1.2-0.9-0.40.311.31.20.80.2-0.6-1.4-1.6-1.4

Weather Map and Satellite Images
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GOES Local Image of CentralWestCoast    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for San Francisco/Monterey Bay Area, CA (0,6,7,8)
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Ground Weather Radar Station San Francisco Bay Area, CA
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Disclaimer:
The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.