Friday, August18, 2017 L-36.com


Marine Weather and Tides
Half Moon Bay, 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 6:27AMSunset 7:58PM Friday August 18, 2017 11:16 AM PDT (18:16 UTC) Moonrise 2:06AMMoonset 4:43PM Illumination 13% Phase: Waning Crescent; Moon at 26 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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PZZ545 Point Reyes To Pigeon Point To 10 Nm- 827 Am Pdt Fri Aug 18 2017
Today..W winds 10 kt. Wind waves 2 ft or less. NW swell 3 to 5 ft at 12 seconds. Patchy fog late in the morning.
Tonight..SW winds 10 kt. Wind waves 3 ft in the evening... Becoming 2 ft or less. NW swell 3 to 5 ft at 11 seconds. Patchy fog after midnight.
Sat..SW winds 5 to 15 kt. Wind waves 1 to 3 ft. Mixed swell nw 3 to 5 ft at 11 seconds and sw 3 ft at 15 seconds. Patchy fog in the morning.
Sat night..SW winds 5 to 15 kt. Wind waves 1 to 3 ft. NW swell 5 to 7 ft at 11 seconds.
Sun..S winds 5 to 15 kt. Wind waves 1 to 3 ft. NW swell 5 to 7 ft at 11 seconds.
Mon..SW winds 5 to 15 kt. Wind waves 1 to 3 ft...becoming 2 ft or less. NW swell 4 to 6 ft.
Tue..W winds 10 kt. Wind waves 2 ft or less. NW swell 3 to 4 ft.
...san francisco bar/fourfathom bank forecast..... In the deep water channel...combined seas 4 to 5 ft with a dominant swell period of 10 seconds. Across the bar...combined seas 4 to 6 ft with a dominant swell period of 10 seconds. Maximum ebb current of 0.9 knots at 01:24 pm Friday and 1.9 knots at 01:12 am Saturday.
PZZ500 827 Am Pdt Fri Aug 18 2017
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Expect increasing northwesterly winds to continue through the weekend as high pressure builds over the eastern pacific. Locally steep wind waves will also accompany the increasing winds.

7 Day Forecast for Marine Location Near Half Moon Bay, CA
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location: 37.47, -122.48     debug


Area Discussion for - San Francisco/Monterey Bay Area, CA
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Fxus66 kmtr 181729
afdmtr
area forecast discussion
national weather service san francisco bay area
1029 am pdt Fri aug 18 2017

Synopsis Look for one more day of minor warming today as a
ridge of high pressure continues to build into our region. Minor
cooling can be expected over the weekend into next week as an
upper level low and shortwave trough move into our region.

Overnight clouds can be expected especially along the coast.

Discussion As of 08:02 am pdt Friday... Only a few minor
adjustments made to this morning's forecast as the low clouds
have managed to progress inland. Livermore, for example, recently
transitioned from clear skies to overcast conditions. Additionally,
low clouds managed to make it to san francisco international
airport with bkn ovc conditions reported over the past hour. Do
expect clearing by mid late morning for most locations today with
mostly clear skies for the afternoon. With a building ridge just
offshore, this morning's 12z oakland sounding shows increasing 500
mb heights compared to 24 hours ago. At 850 mb, temps have warmed
by about 3 deg c. As a result, this will translate to several
degrees of warming at the surface this afternoon for most interior
areas. High temperatures will be generally in the 60s and 70s
along the coast and 80s and 90s for inland communities.

For additional forecast details, please refer to the previous
discussion section.

Prev discussion As of 3:00 am pdt Friday... For the first time in
quite awhile, satellite shows that clouds are fairly limited
across our region with even monterey bay cloud-free at this hour.

Satellite does show clouds finally advancing toward the coast and
with a westerly gradient nearly 3 mb, we should see them at least
advance to the coast before sunrise. Synoptically a ridge of high
pressure will move across our region today which will lead to a
few degrees of warming. Temperatures will be in the 60s and 70s at
the coast with 80s and 90s inland.

The ridge will be replaced by an upper level low and a shortwave
trough that will dive down from the north. This will lead to
cooling over the weekend and next week with most spots dropping 5
to 10 degrees. Clouds will also be likely each night especially
near the coast. Big question will be how much the marine layer
will change with the low overhead. Could be a case of the marine
layer mixing out. Regardless, next week is shaping up to be very
quiet with temperatures near normal.

Aviation As of 10:30 am pdt Friday... For 18z tafs. Stratus has
begun to burn off retreat back to the coast across most TAF sites.

ExpectingVFR conditions through the afternoon before the return
of low CIGS late tonight early tomorrow morning. Some uncertainty
in the extend of stratus coverage for tomorrow morning.

Vicinity of ksfo...VFR currently with westerly winds increasing
this afternoon to around 15 kt. Expecting stratus to return late
tonight with slightly lower CIGS than what we saw today.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals... CIGS have retreated for ksns bringingVFR
conditions. Expecting return of low CIGS this evening. Stratus
still hovering around the edge of kmry. Possible the stratus will
clear out this afternoon although confidence is low, may bounce
betweenVFR and MVFR before the deck returns tonight.

Marine As of 08:27 am pdt Friday... Expect increasing
northwesterly winds to continue through the weekend as high
pressure builds over the eastern pacific. Locally steep wind waves
will also accompany the increasing winds.

Mtr watches warnings advisories
Tday None.

Public forecast: rowe bell
aviation: as
marine: as
visit us at

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 14 mi46 min NNW 1.9 G 5.1 65°F 72°F1015.6 hPa
PXOC1 - 9414311 - San Francisco (Pier 1), CA 23 mi46 min NNW 7 G 8 60°F 1015.4 hPa
FTPC1 - 9414290 - San Francisco, CA 23 mi46 min WNW 5.1 G 8 59°F 62°F1016.8 hPa
AAMC1 - 9414750 - Alameda, CA 23 mi46 min SE 1 G 2.9 63°F 67°F1016.8 hPa
46237 - San Francisco Bar, CA (142) 23 mi46 min 60°F4 ft
46012 - HALF MOON BAY - 24NM South Southwest of San Francisco, CA 23 mi86 min W 1.9 G 3.9 60°F 62°F6 ft1016.3 hPa (+0.6)
PXSC1 23 mi46 min 61°F 59°F
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 24 mi46 min WNW 1.9 G 2.9
OBXC1 24 mi46 min 62°F 59°F
LNDC1 25 mi46 min WSW 1.9 G 4.1 62°F 1016.3 hPa
OKXC1 - 9414776 - Oakland (Berth 34), CA 25 mi46 min W 2.9 G 4.1 62°F 1016.4 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 27 mi86 min Calm G 1.9 58°F 58°F4 ft1016.6 hPa (+0.4)
TIBC1 - Tiburon Pier, San Francisco Bay, CA 29 mi59 min ESE 5.1 59°F 1017 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 31 mi46 min SW 7 G 8 62°F 1016.7 hPa
RCMC1 - 9414863 - Richmond, CA 32 mi46 min S 5.1 G 8.9 60°F 65°F1016.3 hPa
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 42 mi46 min W 6 G 9.9 62°F 1015.9 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 43 mi46 min WNW 14 G 16 62°F 69°F1015.9 hPa60°F
PRYC1 - 9415020 - Point Reyes, CA 45 mi46 min Calm G 2.9 64°F 61°F1016.4 hPa
PCOC1 - 9415144 - Port Chicago, CA 47 mi46 min W 17 G 19 63°F 69°F1015.4 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 48 mi86 min Calm G 1.9 60°F 60°F5 ft1016.9 hPa (+0.8)

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Half Moon Bay Airport, CA3 mi21 minWSW 69.00 mi63°F0°F%1015.9 hPa
San Francisco, San Francisco International Airport, CA12 mi20 minNE 510.00 miA Few Clouds68°F57°F68%1015.8 hPa
San Carlos Airport, CA13 mi29 minVar 47.00 miA Few Clouds with Haze66°F59°F78%1016.3 hPa
Palo Alto Airport, CA19 mi29 minNNE 610.00 miClear68°F60°F78%1015.9 hPa
Oakland, Metro Oakland International Airport, CA21 mi23 minN 09.00 miPartly Cloudy65°F57°F78%1016.1 hPa
Mountain View, Moffett Field, CA23 mi80 minN 010.00 miPartly Cloudy69°F59°F70%1016.7 hPa
Hayward, Hayward Air Terminal, CA23 mi22 minVar 310.00 miFair68°F55°F63%1016.7 hPa

Wind History from SFO (wind in knots)
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Last 24hrN8NW14NW15NW16NW18W20W18W14NW14NW14W12W15W13W11W10W10W9W9W7W6W6W6NE4NE5
1 day agoN8N86NW13
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W13NW14NW13NW14NW10W9NW7NW5NW6NW4W4W5S3W4CalmCalmNW4NW4NW6N5
2 days agoSW16SW14
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Tide / Current Tables for Half Moon Bay, California
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Half Moon Bay
Click for Map
Fri -- 02:32 AM PDT     -0.33 feet Low Tide
Fri -- 03:06 AM PDT     Moonrise
Fri -- 06:28 AM PDT     Sunrise
Fri -- 09:25 AM PDT     4.54 feet High Tide
Fri -- 02:19 PM PDT     2.50 feet Low Tide
Fri -- 05:43 PM PDT     Moonset
Fri -- 07:57 PM PDT     Sunset
Fri -- 08:19 PM PDT     6.38 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.40.3-0.3-0.30.2123.144.54.54.13.42.82.52.63.24.155.96.36.25.54.2

Tide / Current Tables for San Mateo Bridge, South San Francisco Bay, California Current
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San Mateo Bridge
Click for Map
Fri -- 01:56 AM PDT     -1.86 knots Max Ebb
Fri -- 03:04 AM PDT     Moonrise
Fri -- 05:33 AM PDT     0.00 knots Slack
Fri -- 06:27 AM PDT     Sunrise
Fri -- 08:32 AM PDT     1.82 knots Max Flood
Fri -- 12:01 PM PDT     -0.00 knots Slack
Fri -- 02:39 PM PDT     -0.91 knots Max Ebb
Fri -- 05:27 PM PDT     0.01 knots Slack
Fri -- 05:42 PM PDT     Moonset
Fri -- 07:57 PM PDT     Sunset
Fri -- 08:10 PM PDT     1.45 knots Max Flood
Fri -- 11:19 PM PDT     -0.01 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-1.2-1.7-1.9-1.7-1.2-0.50.51.31.81.81.50.90-0.6-0.9-0.9-0.7-0.30.41.11.41.310.3

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 (14,3,4,5)
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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.