Sunday, January21, 2018 L-36.com


Marine Weather and Tides
San Francisco, CA

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 7:19AMSunset 5:23PM Sunday January 21, 2018 10:24 AM PST (18:24 UTC) Moonrise 10:05AMMoonset 9:57PM Illumination 25% Phase: Waxing Crescent; Moon at 5 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- 821 Am Pst Sun Jan 21 2018
.small craft advisory in effect from 3 pm pst this afternoon through Monday morning...
Today..S winds 5 to 10 kt, becoming sw 5 to 15 kt this afternoon. A chance of rain.
Tonight..S winds 10 to 20 kt with gusts up to 25 kt. Rain likely.
Mon..SE winds 10 to 20 kt with gusts up to 25 kt. A slight chance of rain in the morning.
Mon night..NE winds 5 to 15 kt.
Tue..NE winds 5 to 10 kt.
Tue night..NE winds 5 to 10 kt. Rain likely after midnight.
Wed..SE winds 10 to 20 kt with gusts up to 25 kt, becoming W 5 to 15 kt. Rain likely through the night, then a chance of rain through the day.
Thu..W winds 5 to 10 kt, becoming 5 to 15 kt. A chance of showers.
PZZ500 821 Am Pst Sun Jan 21 2018
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Winds will increase and become southwesterly later this morning, especially for the northern waters, ahead of an approaching weak cold front. The cold front is forecast to pass through Monday morning and winds will switch out of the north. Small craft advisories are in place for most coastal water zones mainly due to squared and hazardous seas over the next couple of days. A new northwest swell train arrives by this evening.

7 Day Forecast for Marine Location Near San Francisco, CA
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location: 37.81, -122.44     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 211735
afdmtr
area forecast discussion
national weather service san francisco bay area
935 am pst Sun jan 21 2018

Synopsis Dry and cool conditions today will become replaced by
wet weather this evening and overnight as a cold front moves
southeastward over the area. Briefly gusty winds will accompany
this front. Rain will gradually dissipate as the front moves south.

The weather pattern will remain active this week, with more rain
likely by midweek.

Discussion As of 9:00 am pst Sunday... Chilly morning under
mostly clear skies, with several locations dropping to or below
freezing, including: petaluma, napa, santa rosa, livermore,
hollister, santa rita, san martin, and other inland valley
locations. These temperatures are generally 5 degrees below
normal, with some areas closer to 10 below. Overnight temperatures
are forecast to remain several degrees above normal and above
freezing for the next few nights as increased overnight cloud
cover should act as a blanket, keeping daytime warmth infrared
energy trapped near the surface.

The main focus today will be on a storm system currently well to
the north, centered just offshore of the british columbia coast,
and its relatively shallow surface cold front, which is expected
to sweep across the area from later this afternoon through the
predawn hours of Monday morning. Forecast models have steadily
showed this storm system weakening, with less overall rainfall
and weaker winds. Because this model continues to trend weaker,
the models are struggling to come into agreement with each other
regarding the actual strength of the system, with some weakening
the system much more than others. That said, overall, this system
should be relatively weak by mid-winter storm standards. As per
typical with systems arriving from the northwest, the north bay
will see the most overall precipitation, with up to 0.75-1.25" in
the north bay valleys, 1.25-1.75" over the wettest coastal north
bay ranges (ie near venado, tamalpais, etc). Much lesser amounts
should be anticipated farther southward and inland, for example,
downtown san francisco should expect around .25-.33", while san
jose will range from .05-.20" in part due to rain shadowing. Winds
will primarily be breezy along the coast as the cold front pushes
through, however, some brief locally gusty winds could also
accompay the frontal passage inland as well. We are eagerly
awaiting the arrival of the latest runs of our short term models
since they should be in better agreement than the older runs,
given that the system is nearly on our doorsteps at this point.

Keep an eye out for updated rainfall amounts coming out by early
this afternoon.

Looking ahead, a wetter, more organized storm system will move
into the region from the northwest around Wednesday afternoon,
through the night, lingering through Thursday. Storm total
precipitation and winds should be of higher magnitude than
today tonights storm system, so it may actually be the one to
watch this week. That said, the next storm looks like a run of the
mill mid winter system. Neither of these storm systems is likely
to help get us out of the precipitation deficit the region is in
as of today. The extended period is looking dry at this time, but
that may change as models recently broke up the potential for a
blocking rex block. This could help open the door for a slightly wetter
pattern in successive model runs, however, for now the forecast
remains dry.

Here's a look at our current water year:
site since oct01 (water yr)
obsrv normal %norm
santa rosa 11.10 18.90 59
napa 5.73 10.46 55
concord 5.58 7.93 70
dt san francisco 7.68 11.75 65
sfo airport 7.26 10.11 72
oakland 7.18 10.44 69
hayward 4.77 8.65 55
livermore 4.71 7.79 60
san jose 4.23 7.08 60
moffett field 4.39 6.71 65
watsonville 5.50 10.26 54
monterey 6.08 7.65 79
salinas 2.22 5.57 40
santa cruz 8.33 14.69 57

Previous discussion As of 5:45 am pst Sunday... Mainly clear to
clear skies overnight have allowed temperatures to cool down to
the 30s to mid 40s, including reports of mid to upper 20s in the
southern salinas valley. IR imagery indicates steadily increasing
clouds associated with a cold front 450 miles to the northwest of
the bay area. The result of warm air advection and elevated
inbound moisture can be seen on this morning's 12z oakland
sounding, a weak warm frontal inversion is near the 600 mb level.

Recent model trends have been going with comparatively less QPF with
tonight's cold frontal passage. 06z GFS focuses MAX qpf 1.25" over
coastal sonoma county to 1 2" marin county and 1 4" or less south
to southern monterey and san benito counties. Likewise the 00z
ecmwf favors these aforementioned areas as wettest to driest with
less QPF though, varying from 3 4" north to less than 1 10" southern
counties. The NAM has also cut back on qpf, by as much as 50% from
just 1-2 days ago. The models have even trended toward this being
a shallower, cold, dense modified polar air mass primarily confined
at or below the 850 mb level. When rain begins in the north bay later
today kmux will have trouble seeing it because the precipitation will
be relatively robust, but fall at a very low altitude. This front may
still demonstrate some vigor as some of the stronger fronts can be
those that are not elevated rather confined between a well developed
upper boundary (850 mb in this case with subsidence indicated above
this pressure level) and the lower boundary being ocean and ground.

Winds will still pick up and be gusty near frontal passage, but the
models have indicated less wind compared to previous output. There's
very good agreement in the model output that this front's rain band
will steadily diminish as it moves southeastward overnight. Most if
not all of the rain will be over by Monday morning's commute.

The next chance of rain will be Wednesday into Thursday. This rain
will be generated by a much more vertically developed low pressure
system in the gulf of alaska and its cold front will sweep through
the area with moderate to heavy rain. With a long wave trough in
place over the west this weather system should produce more of a
widespread soaking rain in a more robust dynamic environment; at
least a couple inches or more in the bay area to an inch or so in
the southern counties. Orographic forcing on windward slopes may
enhance rain totals with this system as well. The air mass behind
this system will be modified polar air from the bering sea alaska.

Some of the coldest air available at high latitudes is presently
emptying out across southwestern alaska. Nome to the north for
instance has been -15f to -20f this morning. Below normal temperatures
are likely in our forecast area by the end of the week. Cloud cover
will play a role in night temperatures specifically it could get quite
chilly to cold over inland valleys with a period of near freezing
to sub-freezing temperatures.

Lastly, the 00z ECMWF has backed off on the omega block solution
for eastern asia to alaska late this week. We still may have ridging
return to the west coast, but if the pattern has a chance to be more
progressive than stationary or retrogressive than it offers more of
a chance of periodic disturbances bringing wet weather to california
versus a long stretch of dry weather. We may be a little the past
climatological peak of blocking patterns too which helps.

Aviation As of 9:35 am pst Sunday for 18z tafs.VFR expected
today. Weak cold front moving in later today. Rain is expected to
begin after 00z in ksts then move through the sf bay area by
03-05z. Rain not expected to affect monterey bay terminals until
after 12z. Winds are expected to be mainly southwesterly southerly
through the forecast period, between 08-12 kt.

Vicinity of ksfo...VFR expected through this afternoon. CIGS will
gradually lower to be MVFR this evening. Light east southeast
winds this morning will turn more southerly southwesterly and
increase by afternoon.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals...VFR conditions are expected to prevail
through the forecast period, with mainly high clouds. Generally
light winds. Rain chances increase after 12z Monday.

Marine As of 09:30 am pst Sunday... Winds will increase and
become southwesterly later this morning, especially for the
northern waters, ahead of an approaching weak cold front. The
cold front is forecast to pass through Monday morning and winds
will switch out of the north. Small craft advisories are in place
for most coastal water zones mainly due to squared and hazardous
seas over the next couple of days. A new northwest swell train
arrives by this evening.

Mtr watches warnings advisories
Tday Sca... Pt arena to pt reyes 0-10 nm
sca... Pt reyes to pigeon pt 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... Sf bay from 3 pm
public forecast: drp
aviation: sims
marine: sims
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
FTPC1 - 9414290 - San Francisco, CA 1 mi54 min ESE 2.9 G 4.1 50°F 53°F1028.7 hPa
PXSC1 2 mi54 min 50°F 47°F
PXOC1 - 9414311 - San Francisco (Pier 1), CA 3 mi54 min SE 8 G 12 48°F 1027.3 hPa
OBXC1 5 mi54 min 48°F 44°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 6 mi54 min SSE 9.9 G 11
OKXC1 - 9414776 - Oakland (Berth 34), CA 6 mi54 min SSE 6 G 8.9 48°F 1028.6 hPa
LNDC1 8 mi60 min SSE 6 G 8.9 47°F 1028.2 hPa
RCMC1 - 9414863 - Richmond, CA 8 mi54 min SW 1.9 G 5.1 47°F 54°F1028.3 hPa
AAMC1 - 9414750 - Alameda, CA 8 mi54 min ESE 6 G 8.9 47°F 53°F1028.6 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 8 mi60 min S 8.9 G 11 49°F 1028.6 hPa
46237 - San Francisco Bar, CA (142) 10 mi84 min 53°F7 ft
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 19 mi54 min WNW 2.9 G 5.1 47°F 1028.3 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 21 mi94 min S 3.9 G 5.8 52°F 54°F8 ft1027.5 hPa (+1.2)
MZXC1 - 9415102 - Martinez-Amorco CA 23 mi54 min WSW 1.9 G 2.9 46°F 51°F1028 hPa46°F
RTYC1 - 9414523 - Redwood City, CA 24 mi54 min ESE 1.9 G 2.9 46°F 54°F1028.8 hPa
PCOC1 - 9415144 - Port Chicago, CA 27 mi54 min SSE 2.9 G 4.1 45°F 51°F1027.5 hPa
PRYC1 - 9415020 - Point Reyes, CA 31 mi54 min ESE 2.9 G 5.1 52°F1027.9 hPa
PSBC1 - 9415115 - Pittsburg (Suisun Bay), CA 33 mi60 min ESE 5.1 G 7 46°F 1027.8 hPa
SFXC1 - San Francisco Bay Reserve, CA 35 mi99 min SSW 1.9 45°F 1027 hPa44°F
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 39 mi94 min ESE 3.9 G 5.8 54°F 56°F10 ft1027.2 hPa (+1.2)

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, CA14 mi28 minN 010.00 miPartly Cloudy50°F43°F77%1028.7 hPa
Oakland, Metro Oakland International Airport, CA14 mi31 minSSE 710.00 miA Few Clouds48°F43°F83%1029.2 hPa
Hayward, Hayward Air Terminal, CA20 mi30 minSSE 610.00 miFair49°F37°F66%1029.8 hPa
Half Moon Bay Airport, CA21 mi29 minN 05.00 miFair with Haze52°F46°F82%1028.1 hPa
San Carlos Airport, CA22 mi37 minN 010.00 miPartly Cloudy48°F41°F76%1028.8 hPa
Novato / Gnoss Field, CA24 mi29 minNNE 410.00 miFair45°F41°F87%1029.1 hPa
Concord, Buchanan Field, CA24 mi31 minSSW 410.00 miA Few Clouds50°F39°F68%1027.2 hPa

Wind History from SFO (wind in knots)
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Last 24hrNE4NE4NE4W11NW11W12W13W10W10W10W8W5NW4W4S3SW3S3CalmCalmW3CalmSE4SE6Calm
1 day agoE6NE3NW9W11W13W13W14W12W10W11W8W8W6W3W7NW9NW7W9NW8W8NW7N5CalmNE4
2 days agoE5SE6W15W11W6W3W6W7NW8W4N3CalmCalmW8W8SW3S3W8SW5SW3CalmW4W53

Tide / Current Tables for San Francisco, California
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San Francisco
Click for Map
Sun -- 02:43 AM PST     5.09 feet High Tide
Sun -- 07:21 AM PST     Sunrise
Sun -- 07:55 AM PST     2.65 feet Low Tide
Sun -- 10:05 AM PST     Moonrise
Sun -- 01:46 PM PST     5.09 feet High Tide
Sun -- 05:21 PM PST     Sunset
Sun -- 08:11 PM PST     0.40 feet Low Tide
Sun -- 09:57 PM PST     Moonset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
3.54.455.14.74.13.32.82.72.93.33.94.555.14.73.92.81.70.80.40.61.22.1

Tide / Current Tables for Alcatraz Island S, San Francisco Bay, California Current
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Alcatraz Island S
Click for Map
Sun -- 12:49 AM PST     1.57 knots Max Flood
Sun -- 04:05 AM PST     -0.00 knots Slack
Sun -- 06:28 AM PST     -1.56 knots Max Ebb
Sun -- 07:21 AM PST     Sunrise
Sun -- 09:48 AM PST     0.00 knots Slack
Sun -- 10:04 AM PST     Moonrise
Sun -- 12:50 PM PST     1.03 knots Max Flood
Sun -- 03:21 PM PST     -0.01 knots Slack
Sun -- 05:21 PM PST     Sunset
Sun -- 06:37 PM PST     -2.21 knots Max Ebb
Sun -- 09:57 PM PST     Moonset
Sun -- 10:08 PM PST     0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.41.61.30.80.1-0.9-1.5-1.5-1-0.40.10.50.910.80.2-0.5-1.4-2.1-2.2-1.6-0.9-0.10.5

Weather Map and Satellite Images
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Weather Map
wmap_P
IR Satellite Image from GEOS
west_satellite

GOES Local Image of CentralWestCoast    EDIT
Geos

Wind Forecast for San Francisco/Monterey Bay Area, CA (13,3,4,5)
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Ground Weather Radar Station San Francisco Bay Area, CA
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weather_mapweather_map weather_map

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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.