Thursday, October19, 2017 L-36.com


Marine Weather and Tides
Portola Valley, 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 7:20AMSunset 6:26PM Thursday October 19, 2017 7:13 AM PDT (14:13 UTC) Moonrise 6:07AMMoonset 5:50PM Illumination 1% Phase: New Moon; Moon at 29 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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PZZ560 Pigeon Point To Point Pinos To 10 Nm- 247 Am Pdt Thu Oct 19 2017
.small craft advisory in effect from this evening through late Friday night...
Today..W winds 5 to 15 kt. Wind waves 3 ft in the morning... Becoming 2 ft or less. Mixed swell nw 3 to 4 ft at 12 seconds and S 3 ft at 15 seconds. Patchy fog in the morning.
Tonight..SW winds 5 to 15 kt...becoming nw 15 to 25 kt after midnight. Wind waves 3 to 5 ft. NW swell 3 ft at 20 seconds... Increasing to 7 to 9 ft at 20 seconds after midnight. SWell S 3 ft. Chance of rain.
Fri..NW winds 10 to 20 kt. Wind waves 2 to 4 ft. NW swell 11 to 14 ft at 18 seconds.
Fri night..NW winds 10 to 20 kt. Wind waves 2 to 4 ft. NW swell 11 to 14 ft at 17 seconds.
Sat..NW winds 5 to 15 kt. Wind waves 1 to 3 ft. NW swell 9 to 12 ft at 14 seconds.
Sun..N winds 10 to 20 kt. Wind waves 2 to 4 ft. NW swell 7 to 9 ft.
Mon..N winds 5 to 15 kt. Wind waves 1 to 3 ft. W swell 5 to 7 ft.
PZZ500 247 Am Pdt Thu Oct 19 2017
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... A cold front is forecast to pass through the region later this evening. Winds will increase along and just behind the front, occasionally gusting around 25 knots at times. Showers will be possible ahead of and along the cold front, as well. A very robust northwest, long period swell will arrive late this afternoon and through the evening, generating large waves and hazardous seas through at least Saturday. Operators of small crafts are urged to use extreme caution if out at sea over the next several days.

7 Day Forecast for Marine Location Near Portola Valley, CA
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location: 37.36, -122.23     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 191150
afdmtr
area forecast discussion
national weather service san francisco bay area
450 am pdt Thu oct 19 2017

Synopsis A cold front remains on track to push through our
district later today and tonight, bringing our first widespread
rainfall event of the season, along with cooler temperatures. Look
for the most rainfall to be in the coastal ranges and across the
north bay. Along with cooler temperatures, breezy onshore winds
can be expected through Friday. Dry conditions will return on
Friday and a warming trend is forecast over the weekend and into
the first part of next week. Temperatures are forecast to be well
above seasonal averages during the first half of next week.

Discussion As of 3:43 am pdt Thursday... The marine layer
deepened yesterday and cool air filtered inland with help from an
increased onshore flow. Currently the marine layer depth is around
1000 feet per the fort ord profiler and the latest surface
pressure gradient between sfo and sac was up to 2.6 mb. Latest
temperature trends are warmer than yesterday at most locations due
to increased cloud cover as coastal stratus has spread into
inland valleys.

Satellite imagery shows the approaching cold from now along the
washington and oregon coasts. Models continue to bring the system
to our area later today, with rainfall reaching the sonoma and
marin coasts by this afternoon, then spreading south through the
greater san francisco bay area by late evening, and then down
through the remainder of the CWA around midnight and through the
early morning hours. The 00z NAM forecasts local rain totals up to
0.75" in the north bay mountains tomorrow afternoon and evening,
and up to 0.25" in the santa cruz mountains tomorrow night.

Elsewhere in the hills and north bay valleys, expect rain totals
from 0.10-0.25", while all other valley locations will likely see
a tenth of an inch or less. Rainfall is expected to end by Friday
morning with partly cloudy and relatively cool and breezy
conditions.

A warming trend is forecast during the weekend as an upper level
ridge begins to build over california. The ridge is then expected
to strengthen along the west coast early next week, resulting in
a marked warming trend. Light offshore flow is also forecast to
develop early next week resulting in warm and dry conditions
across our entire area on Monday and Tuesday, with widespread
highs in the 80s to around 90. Slight cooling is indicated by
midweek at the coast with a return to onshore flow, but warm
conditions will persist inland.

Aviation As of 4:46 am pdt Thursday... For 12z tafs. A
complicated aviation forecast over the next 24-36 hours in store
for bay area terminals. Current fog product shows widespread
stratus low clouds affecting all TAF terminals. Most sites are
MVFR ifr, with some isolated lifr CIGS right now. Clearing time is
still uncertain at this moment. With sufficient onshore flow,
it's possible some sites, such as kmry, may not clear at all
today, though CIGS may lift some later this morning. This will
have to be closely monitored and updated as the morning
progresses. A cold front will bring a chance of rain this evening
and overnight, enough to wet the runways at most TAF sites. Winds
ahead of the front will be moderate, occasionally gusty along and
behind the front, out of the SW wsw. Winds will eventually turn
more out of the W NW after the front passes.

Overall forecast confidence: low to moderate
vicinity of ksfo... MVFR ifr CIGS will prevail through much of the
morning, possibly into the early afternoon hours. Low confidence
with respect to clearing times. Wsw winds through much of the
period until the cold front passes around 06z. Rain showers
possible as early as 03z.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... Lifr ifr CIGS will continue through
majority of the morning. Low confidence with respect to clearing
times. Light to moderate wsw winds for kmry today, with winds
varying through the day at ksns. Rain showers possible as early
06z.

Fire weather As of 3:43 am pdt Thursday... Relative humidity
recoveries have improved this morning with even most hilltop areas
seeing 80-100% values. Onshore winds will continue to gradually
increase today and moderate and locally gusty winds are expected.

Models continue to move an early season cold front through the
district late today and tonight. Rainfall will begin in the north
bay this afternoon and spread across most of the remainder of the
district tonight. The models have just recently trended slightly
wetter with this system, although rainfall amounts are still
expected to be mostly light. Wetting rains are most likely in the
north bay mountains and perhaps locally in the santa cruz
mountains. Rainfall should end in most areas by Friday morning.

Friday will be a cool day with brisk northwest winds.

A warming trend will begin over the upcoming weekend as a high
pressure ridge begins to build over california. This ridge will
strengthen into early next week and result in warm and dry
conditions districtwide from Monday through Wednesday. Will need
to be wary of possible gusty offshore winds in the hills by Sunday
night and especially Monday night.

Marine As of 2:47 am pdt Thursday... A cold front is forecast
to pass through the region later this evening. Winds will increase
along and just behind the front, occasionally gusting around 25
knots at times. Showers will be possible ahead of and along the
cold front, as well. A very robust northwest, long period swell
will arrive late this afternoon and through the evening,
generating large waves and hazardous seas through at least
Saturday. Operators of small crafts are urged to use extreme
caution if out at sea over the next several days.

Mtr watches warnings advisories
Tday Sca... Pt arena to pigeon pt 10-60 nm from 5 pm
sca... Pt pinos to pt piedras blancas 0-10 nm until 6 am
public forecast: sims
aviation: bam
marine: bam
fire weather: sims
visit us at

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 10 mi43 min S 2.9 G 4.1 54°F 65°F1015.3 hPa
AAMC1 - 9414750 - Alameda, CA 29 mi43 min WSW 4.1 G 8 56°F 62°F1016.2 hPa
LNDC1 30 mi43 min WSW 6 G 7 56°F 1015.7 hPa
OBXC1 31 mi43 min 56°F 54°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 31 mi43 min SW 7 G 8
PXSC1 32 mi43 min 57°F 54°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 32 mi43 min W 5.1 G 8.9 56°F 1015.7 hPa
FTPC1 - 9414290 - San Francisco, CA 33 mi43 min W 4.1 G 7 55°F 57°F1016 hPa
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 35 mi83 min NW 3.9 G 3.9 55°F 55°F6 ft1015.5 hPa (-0.6)
46237 - San Francisco Bar, CA (142) 36 mi43 min 55°F4 ft
TIBC1 - Tiburon Pier, San Francisco Bay, CA 39 mi46 min SW 5.1 54°F 1015 hPa
RCMC1 - 9414863 - Richmond, CA 40 mi43 min SSW 2.9 G 4.1 56°F 59°F1015.4 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 41 mi83 min NNW 7.8 G 12 55°F 55°F6 ft1015.7 hPa (-0.5)
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 42 mi83 min W 3.9 G 5.8 54°F 55°F5 ft1015.6 hPa (-0.7)
46092 - MBM1 43 mi61 min NNE 7.8 52°F 55°F1015.7 hPa (-0.9)
46114 - West Monterey Bay, CA 44 mi43 min 55°F6 ft
ELXC1 - Elkhorn Slough Reserve, CA 46 mi88 min ESE 4.1 52°F 1015 hPa51°F
MZXC1 - 9415102 - Martinez-Amorco CA 47 mi43 min SW 9.9 G 12 57°F 62°F1015.2 hPa55°F
PCOC1 - 9415144 - Port Chicago, CA 49 mi43 min SW 11 G 13 56°F 62°F1014.8 hPa

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Mountain View, Moffett Field, CA11 mi77 minSE 310.00 miSmoke55°F51°F87%1016.2 hPa
San Carlos Airport, CA12 mi18 minSSW 310.00 miOvercast55°F50°F82%1016.3 hPa
San Jose, San Jose International Airport, CA16 mi20 minSW 310.00 miOvercast56°F51°F84%1015.6 hPa
Half Moon Bay Airport, CA18 mi18 minN 02.50 miFog/Mist54°F53°F100%1015.2 hPa
San Francisco, San Francisco International Airport, CA19 mi77 minW 310.00 miOvercast56°F51°F84%1015.6 hPa
San Jose / Reid / Hillv, CA22 mi26 minN 010.00 miOvercast55°F51°F88%1016.9 hPa
Hayward, Hayward Air Terminal, CA22 mi19 minWSW 510.00 miOvercast57°F50°F78%1016.6 hPa
Oakland, Metro Oakland International Airport, CA23 mi20 minWSW 810.00 miOvercast56°F53°F90%1015.7 hPa

Wind History from PAO (wind in knots)
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Last 24hrCalm--5N6N6--NW10N10NW10NW13NW14NW10NW5N8------------------Calm
1 day ago5--CalmN7N7--N6N8----NW8NW8W5NW6------------------Calm
2 days agoCalmCalmCalm44N6N6N10NW7NW10NW8----Calm------------------Calm

Tide / Current Tables for Granite Rock, Redwood Creek, San Francisco Bay, California
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Granite Rock
Click for Map
Thu -- 12:51 AM PDT     7.63 feet High Tide
Thu -- 06:59 AM PDT     1.19 feet Low Tide
Thu -- 07:07 AM PDT     Moonrise
Thu -- 07:21 AM PDT     Sunrise
Thu -- 12:12 PM PDT     New Moon
Thu -- 12:55 PM PDT     8.52 feet High Tide
Thu -- 06:25 PM PDT     Sunset
Thu -- 06:50 PM PDT     Moonset
Thu -- 07:36 PM PDT     0.22 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
7.27.67.15.94.22.71.61.21.734.86.688.586.74.92.91.30.40.31.22.74.5

Tide / Current Tables for Dumbarton Hwy Bridge, South San Francisco Bay, California Current
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Dumbarton Hwy Bridge
Click for Map
Thu -- 01:31 AM PDT     -0.01 knots Slack
Thu -- 04:39 AM PDT     -1.05 knots Max Ebb
Thu -- 07:06 AM PDT     Moonrise
Thu -- 07:20 AM PDT     Sunrise
Thu -- 07:43 AM PDT     0.00 knots Slack
Thu -- 10:47 AM PDT     1.69 knots Max Flood
Thu -- 12:12 PM PDT     New Moon
Thu -- 01:32 PM PDT     -0.01 knots Slack
Thu -- 04:56 PM PDT     -1.28 knots Max Ebb
Thu -- 06:25 PM PDT     Sunset
Thu -- 06:49 PM PDT     Moonset
Thu -- 08:12 PM PDT     0.00 knots Slack
Thu -- 11:22 PM PDT     1.85 knots Max Flood
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.40.6-0.3-0.7-1-1-0.8-0.40.21.11.61.71.40.6-0.3-0.8-1.2-1.3-1.1-0.7-0.10.71.51.8

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 (10,2,3,4)
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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.