Friday, January19, 2018 L-36.com


Marine Weather and Tides
Los Altos Hills, 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 7:18AMSunset 5:20PM Friday January 19, 2018 9:15 AM PST (17:15 UTC) Moonrise 8:58AMMoonset 7:59PM Illumination 9% Phase: Waxing Crescent; Moon at 3 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- 836 Am Pst Fri Jan 19 2018
.small craft advisory in effect through late Saturday night...
Today..NW winds 10 to 20 kt. Wind waves 2 to 4 ft. W swell 13 to 16 ft at 15 seconds. Slight chance of Thunderstorms through the day. Chance of showers in the afternoon.
Tonight..NW winds 15 to 25 kt. Wind waves 3 to 5 ft. W swell 11 to 14 ft at 14 seconds. Slight chance of showers.
Sat..NW winds 15 to 25 kt. Wind waves 3 to 5 ft. W swell 10 to 12 ft at 14 seconds. Slight chance of showers in the morning.
Sat night..NW winds 15 to 25 kt. Wind waves 3 to 5 ft. W swell 9 to 11 ft at 14 seconds.
Sun..S winds 15 to 25 kt. Wind waves 4 to 6 ft. W swell 7 to 9 ft at 15 seconds. Slight chance of rain in the morning, then chance of rain in the afternoon.
Mon..NW winds 5 to 15 kt. Wind waves 1 to 3 ft. W swell 9 to 12 ft. Chance of rain, then slight chance of showers.
Tue..S winds 10 kt. Wind waves 2 ft or less. W swell 6 to 8 ft. Slight chance of rain, then chance of rain.
PZZ500 836 Am Pst Fri Jan 19 2018
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Large west to northwest swell will continue to impact the coastal waters through today, causing large breaking waves and high surf along the central coast. Scattered showers with possible Thunderstorms will continue through the day. Slight increase in northwest winds tonight. Winds will increase and turn southerly on Sunday morning ahead of the next system. SWells will gradually decrease over the weekend.

7 Day Forecast for Marine Location Near Los Altos Hills, CA
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location: 37.35, -122.18     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 191708
afdmtr
area forecast discussion
national weather service san francisco bay area
908 am pst Fri jan 19 2018

Synopsis Chillier, unsettled weather is here for the weekend
and will last into next week. Unstable weather conditions will
cause scattered showers and a few thunderstorms to develop today.

Snow showers are likely along the highest ridge tops. A band of
rain, possibly heavy at times, moves into the north bay Sunday
evening spreading southeastward Sunday night into Monday morning.

Rain returns during the middle of next week with showery weather
lingering into late next week.

Discussion As of 09:08 am pst Friday... Current forecast
remains on track. Simply put, cold unstable airmass and lingering
moisture will lead to scattered showers, possibly thunderstorms
and lowered snow levels.

The system that brought rain to the region continues to exit to
the east. Kmux radar imagery shows scattered showers moving NW to
se across the region behind the departing system. Farther to the
west, about 200 miles or so, is a cluster of lightning associated
with more organized open-cell cumulus clouds. Utilizing nucaps
soundings shows CAPE values greater than 400 j kg near this
cluster. That being said, latest models bring this instability
over the bay area through the day. SPC updated the day 1 outlook
to include central california for a general mention of
thunderstorms. Given the lowered snow levels, any developed storm
will be capable of producing small hail.

Dry, but cool weather for Saturday. Rain chances return Sunday
evening into Monday.

No update planned.

Prev discussion As of 5:34 am pst Friday... An ongoing large scale
pattern change over the west continues to bring in chillier,
modified maritime polar air on NW winds into california early this
morning. IR satellite imagery shows a fair amount of upstream
instability with open cellular cumulus clouds with a positive tilt
500 mb trough axis accompanied by mid-upper level temperatures as
cold as -33c. Kmux radar shows scattered showers in the NW wind
flow. Several lightning strikes were detected approx 500 miles
west of the central coast at 5:10 am.

Hit or miss showers today will be the theme in a convectively driven
environment. There's also a slight chance of thunderstorms. As the
mid-upper levels cool off today this will greatly steepen lapse rates
allowing air parcels to freely move upwards. A little strange to see
differences between the hrrr model indicating instability offset by
some convective inhibition while the WRF indicates similar instability,
but virtually no convective inhibition. The 500 mb trough is elongated
and vorticity spread thin perhaps, but relative and absolute vorticity
values do tend to tighten up as the trough approaches and passes over
the forecast area later this morning and afternoon. Convection that
develops over the coastal waters could have tops to 50 thousand feet
thus indicating how vertically extensive the cold air is with this
trough. Cells that develop may have some tilt to them, possibly
generating some with hail as well. Will need to keep a close watch
on the radar. Cold air advection also has the area ridge tops in the
mid 30s this morning thus snow showers are possible on the highest
peaks this morning onward today.

A dry break Saturday into Sunday is then followed by a much shallower,
but more intense cold frontal boundary with stronger confluence and
shear along the boundary late Sunday evening; this air mass is the
next in line originating from the bering sea and alaska. The front
will be accompanying the tail end of a weak atmospheric river so it'll
have some juice with it to some extent. Cross sections of omega values
show a strong pocket of upward vertical motion at lower levels
nearing 40 microbars second over the north bay Sunday evening,
lesser amounts as the frontal boundary moves southeast Sunday night.

Leaning toward little if any hydro hazards based on the pace of
frontal movement and 00z ecmwf, 00z 06z GFS qpf between moderate and
heavy rain rates. However, the 06z nam GOES wetter specifically over
coastal sonoma county which may extend to marin county as well
before matching QPF output from the ECMWF and GFS and before the
rain band reaches a sfo-oak line. 925 mb SW winds, warm air
advection also ramp upwards for a 3-4 hour period prior to cold
frontal passage; 925 winds 40-50 knots are indicated. Best guess at
the moment is that strong upward vertical motion along the front
should preclude downward momentum transport enough to preclude a
wind advisory for now, but will monitor subsequent model output on
this. Rain rates amounts will be of primary concern with wind a
secondary concern in this particular case, but will keep a close
watch on it nonetheless.

Wet, chilly weather continues next week. Rain returns focusing in our
area during the middle of next week.

Aviation As of 4:04 am pst Friday... For 12z tafs. GenerallyVFR
across the region early this morning as CIGS slowly rise in the
wake of a fropa. Fog low CIGS in the north bay valleys is
currently affecting ksts. This fog should clear by mid morning.

Current kmux shows scattered, popcorn-type showers across the
district, moving NW to se. This will likely be the case through
the day today, per the 10z hrrr. ExpectVFR conditions, CIGS above
3000 ft, to prevail through the forecast period. However, any
shower that occurs could drop CIGS vsby to MVFR or ifr briefly.

Hrrr is suggesting shower activity picks up by early afternoon.

Westerly winds will pick up this afternoon, 10-15 kt.

Vicinity of ksfo...VFR CIGS and vsbys will prevail across area
terminals as showers continue to move across the region. However,
showers could affect CIGS and vsby briefly. West-northwest winds
around 15 kt this afternoon.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals...VFR CIGS and vsbys will prevail across
area terminals. Showery conditions will persist through much of
the forecast period, which could drop CIGS & vsby briefly. Light
winds.

Marine As of 02:30 am pst Friday... Hazardous seas from large
northwesterly swell will continue to impact all coastal water
zones today, creating large breaking waves and high surf at the
coast. Scattered showers will also continue through the day.

Northwest winds will increase slightly today in the wake of a cold
front that is currently passing over the southern waters. Winds
are forecast to switch out of the south and dramatically increase
again Sunday morning, ahead of another storm system approaching
from the northwest.

Mtr watches warnings advisories
Tday High surf warning... Caz006-505-509-529-530
sca... Mry bay
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
public forecast: mm canepa
aviation: bam
marine: bam
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 11 mi46 min 50°F 55°F1020.6 hPa
AAMC1 - 9414750 - Alameda, CA 30 mi46 min E 2.9 G 4.1 50°F 54°F1020.2 hPa
LNDC1 31 mi46 min SE 1 G 1.9 50°F 1020.1 hPa
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 32 mi46 min E 1 G 1
PXSC1 33 mi46 min 53°F 46°F
OBXC1 33 mi46 min 52°F 47°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 33 mi46 min E 2.9 G 4.1 51°F 1020.2 hPa
PXOC1 - 9414311 - San Francisco (Pier 1), CA 33 mi46 min NW 2.9 G 5.1 52°F 1019.1 hPa
FTPC1 - 9414290 - San Francisco, CA 35 mi46 min SE 1.9 G 1.9 50°F 53°F1020.2 hPa
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 37 mi86 min NNW 5.8 G 12 53°F 56°F17 ft1019.6 hPa (+0.8)
46237 - San Francisco Bar, CA (142) 39 mi46 min 53°F12 ft
PPXC1 - 9414847 - Richmond (Point Potrero), CA 40 mi46 min NW 1 G 2.9 53°F 1020.3 hPa
RCMC1 - 9414863 - Richmond, CA 41 mi46 min WNW 2.9 G 4.1 49°F 54°F1019.8 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 41 mi86 min NNW 12 G 16 55°F 56°F16 ft1019.7 hPa (+0.7)
46092 - MBM1 42 mi121 min N 7.8 54°F 57°F1019.6 hPa (+1.1)
ELXC1 - Elkhorn Slough Reserve, CA 44 mi91 min Calm 47°F 1020 hPa47°F
46114 - West Monterey Bay, CA 44 mi46 min 56°F19 ft
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 45 mi86 min NW 12 G 16 53°F 54°F14 ft1019.6 hPa (+0.7)
MZXC1 - 9415102 - Martinez-Amorco CA 47 mi46 min SSW 1.9 G 2.9 47°F 52°F1020.3 hPa47°F
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 49 mi46 min SSW 2.9 G 4.1 49°F 1019.9 hPa
PCOC1 - 9415144 - Port Chicago, CA 49 mi46 min S 5.1 G 5.1 47°F 52°F1020 hPa

Wind History for Redwood City, CA
(wind in knots)    EDIT      (on/off)   Help
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Mountain View, Moffett Field, CA9 mi20 minN 010.00 miPartly Cloudy49°F46°F90%1020.9 hPa
Palo Alto Airport, CA10 mi29 minN 010.00 miPartly Cloudy48°F46°F94%1020.3 hPa
San Carlos Airport, CA13 mi29 minN 010.00 miA Few Clouds50°F46°F88%1020.3 hPa
San Jose, San Jose International Airport, CA13 mi23 minENE 310.00 miPartly Cloudy51°F46°F83%1020.5 hPa
San Jose / Reid / Hillv, CA19 mi29 minVar 510.00 miMostly Cloudy48°F44°F87%1020 hPa
Half Moon Bay Airport, CA20 mi21 minE 47.00 miFair46°F44°F93%1019.6 hPa
San Francisco, San Francisco International Airport, CA21 mi20 minWNW 510.00 miA Few Clouds52°F45°F77%1020.1 hPa
Hayward, Hayward Air Terminal, CA22 mi22 minENE 410.00 miPartly Cloudy50°F44°F80%1021.4 hPa
Oakland, Metro Oakland International Airport, CA24 mi23 minE 310.00 miA Few Clouds49°F48°F97%1020.4 hPa

Wind History from NUQ (wind in knots)
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Last 24hrCalmSE5SE9E6W7W11
G15
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W4NW5W6W5W6CalmS3CalmW3CalmCalmS3CalmCalmCalmCalmCalm
1 day agoN6CalmN6N6CalmCalmCalmNE5NW6W3CalmNW4CalmCalmS5CalmN5NW4CalmS5S6SE4S3SE4
2 days agoN3NE3N5N9N5NW3N4NW4N5NW3CalmNW4NW3CalmW4W3CalmCalmCalmCalmCalmSE3E4N4

Tide / Current Tables for Palo Alto Yacht Harbor, California
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Palo Alto Yacht Harbor
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Fri -- 02:31 AM PST     7.18 feet High Tide
Fri -- 07:20 AM PST     Sunrise
Fri -- 08:57 AM PST     Moonrise
Fri -- 09:05 AM PST     3.15 feet Low Tide
Fri -- 02:04 PM PST     8.33 feet High Tide
Fri -- 05:18 PM PST     Sunset
Fri -- 07:58 PM PST     Moonset
Fri -- 09:22 PM PST     0.07 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
4.36.17.17.16.55.74.94.13.53.13.54.66.27.78.37.86.54.731.70.70.10.21.2

Tide / Current Tables for Dumbarton Point 2.3 mi NE, South San Francisco Bay, California Current
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Dumbarton Point 2.3 mi NE
Click for Map
Fri -- 02:55 AM PST     -0.01 knots Slack
Fri -- 06:34 AM PST     -0.70 knots Max Ebb
Fri -- 07:20 AM PST     Sunrise
Fri -- 08:34 AM PST     0.00 knots Slack
Fri -- 08:57 AM PST     Moonrise
Fri -- 11:08 AM PST     0.92 knots Max Flood
Fri -- 01:54 PM PST     -0.01 knots Slack
Fri -- 05:18 PM PST     Sunset
Fri -- 06:43 PM PST     -1.30 knots Max Ebb
Fri -- 07:58 PM PST     Moonset
Fri -- 09:19 PM PST     0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.310.6-0-0.3-0.6-0.7-0.6-0.30.20.70.90.80.5-0-0.4-0.7-1-1.3-1.3-0.8-0.20.51.1

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 (12,3,4,5)
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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.