Monday, September24, 2018 L-36.com


Marine Weather and Tides
Half Moon Bay, CA

Version 3.4
What's New / NOTES
9/17/2018 XTide broke when 1and1 "upgraded" my server. It has been esculated. I am sorry for the problem.

Sunrise 6:57AMSunset 7:05PM Sunday September 23, 2018 10:15 PM PDT (05:15 UTC) Moonrise 5:48PMMoonset 4:28AM Illumination 99% Phase: Full Moon; Moon at 14 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- 845 Pm Pdt Sun Sep 23 2018
Tonight..NW winds 5 to 15 kt with gusts up to 25 kt. Wind waves 3 to 4 ft. NW swell 4 to 6 ft at 9 seconds.
Mon..W winds up to 10 kt. Wind waves 2 ft or less. NW swell 3 to 5 ft at 9 seconds.
Mon night..SW winds up to 10 kt. Wind waves 2 ft or less. NW swell 4 to 5 ft at 9 seconds.
Tue..SW winds up to 10 kt. Wind waves 2 ft or less. NW swell 3 to 5 ft at 9 seconds.
Tue night..NW winds up to 10 kt. Wind waves 2 ft or less. NW swell 3 to 4 ft at 9 seconds.
Wed..NW winds 5 to 15 kt. Wind waves 2 ft or less. NW swell 3 to 5 ft.
Thu..W winds 5 to 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 period of 8 seconds. Across the bar...combined seas 5 to 6 ft with a dominant period of 8 seconds. Maximum ebb current of 2.2 knots at 03:37 am Monday and 2.6 knots at 04:01 pm Monday.
PZZ500 845 Pm Pdt Sun Sep 23 2018
Synopsis for the central california coast and bays including the Monterey bay..Greater farallones...and cordell bank national marine sanctuaries... Moderate to locally gusty northwest winds will continue in the overnight hours across the coastal waters. This will result in locally generated steep fresh swell. Winds will diminish into tomorrow morning with locally gusty northwest winds continuing north of point reyes through midday. Once winds subside, they will remain generally light through the period.


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 240424
afdmtr
area forecast discussion
national weather service san francisco bay area
924 pm pdt Sun sep 23 2018

Synopsis High pressure will begin to build over the region
through the first part of the week and result in a warming, drying
trend. This will will bring dry offshore winds at times and
increased fire weather concerns, especially for the north bay
hills overnight through Tuesday. Temperatures are forecast to
cool late in the week with the potential for unsettled weather
conditions during the upcoming weekend.

Discussion As of 9:23 pm pdt Sunday... No updates planned for
this evening. Skies are mostly clear with developing offshore wind
pattern. Northerly gradients down the coast are about 4 mb with
the large scale wmc-sfo having just turned offshore by about 2 mb.

Light northeast winds are already showing themselves in the hills
of the north bay, a sure sign of our upcoming critical fire
weather and warming trend. Main impact in short is fire weather so
will focus there. At first glance the 3% rh at mt tam may appear
suspect but mallory ridge in the east bay just dipped to 5% with
11% at las trampas and 4% at ben lomond in the santa cruz mtns.

This is all consistent with an established 1000 foot marine layer
along the coast and developing dry north wind pattern. Rh values
this dry at night above the marine layer combined with any wind
will be of concern. The northeast winds will continue to slowly
develop overnight, first showing in the highest ridges of napa
county. The winds wont be strong enough to break through any of
the night time inversion layers setting up around 1000 feet. So
all the winds and low humidity will stay confined to the hills.

This pattern then sets the stage for a sunny and warm Monday
across the bay area. We should expect widespread 80s inland and
even comfy 70s near the coast. The offshore winds never get strong
so we wont drive hot temps all the way to the beaches.

The models continue to show more drying and stronger winds Monday
night into Tuesday across the north bay hills. Will avoid any
yo-yo forecasting for the time being but will have to closely
monitor for fire weather watch or red flag warnings over the next
few forecast cycles. Latest NAM solution keeps winds light later
Tuesday into weds but drives a very dry airmass across nearly all
the area through midweek with above normal temps. It will be a
warm week with elevated fire weather concerns.

Long range shows cooling by the weekend. Will await the new 00z
euro before elaborating more on the extended range precip chances.

Aviation As of 04:27 pm pdt Sunday... For 00z tafs. Satellite
imagery showing mainly clear skies across the region with some
passing high clouds.VFR through the evening with patchy ifr cigs
around the sf and monterey bay area TAF sites tonight. Patchy
dense fog will possible in the early morning in the north bay and
around the monterey bay. Onshore winds will diminish in the
overnight hours before picking up again tomorrow afternoon.

Low confidence on timing and extent of stratus redevelopment.

Vicinity of ksfo...VFR. Gusty winds will continue into the early
evening. May see some brief low CIGS in the early morning.

Sfo bridge approach... Similar to ksfo.

Monterey bay terminals...VFR through the early evening. Early
return of low CIGS tonight, with patchy dense fog developing late
tonight into early tomorrow morning.

Marine As of 09:08 pm pdt Sunday... Moderate to locally gusty
northwest winds will continue in the overnight hours across the
coastal waters. This will result in locally generated steep fresh
swell. Winds will diminish into tomorrow morning with locally
gusty northwest winds continuing north of point reyes through
midday. Once winds subside, they will remain generally light
through the period.

Mtr watches warnings advisories
Tngt Sca... Pt arena to pigeon pt 10-60 nm
sca... Pt arena to pt reyes 0-10 nm until 3 am
sca... Pt pinos to pt piedras blancas 0-10 nm until 3 am
sca... Pigeon pt to pt piedras blancas 10-60 nm
public forecast: rww
aviation: as
marine: as
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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
RTYC1 - 9414523 - Redwood City, CA 14 mi27 min NNW 1.9 G 2.9 59°F 70°F1011.6 hPa
FTPC1 - 9414290 - San Francisco, CA 23 mi33 min SW 5.1 G 6 55°F 60°F1011.4 hPa
PXOC1 - 9414311 - San Francisco (Pier 1), CA 23 mi27 min WSW 6 G 8 56°F 1010.2 hPa
PXSC1 23 mi33 min 57°F 54°F
AAMC1 - 9414750 - Alameda, CA 23 mi33 min W 7 G 9.9 57°F 66°F1011.5 hPa
46237 - San Francisco Bar, CA (142) 23 mi45 min 58°F5 ft
OMHC1 - 9414769 - Oakland Middle Harbor Met, CA 24 mi33 min SW 5.1 G 7
OBXC1 24 mi27 min 58°F 54°F
OKXC1 - 9414776 - Oakland (Berth 34), CA 25 mi27 min SSW 1.9 G 2.9 58°F 1011.2 hPa
LNDC1 25 mi27 min WSW 2.9 G 4.1 58°F 1011.3 hPa
46026 - SAN FRANCISCO - 18NM West of San Francisco, CA 27 mi25 min WNW 7.8 G 12 55°F 55°F7 ft1011.6 hPa
TIBC1 - Tiburon Pier, San Francisco Bay, CA 29 mi34 min S 8.9 56°F 1011 hPa
PPXC1 - 9414847 - Richmond (Point Potrero), CA 31 mi27 min SSW 11 G 14 58°F 1011.2 hPa
RCMC1 - 9414863 - Richmond, CA 32 mi27 min 63°F
DPXC1 - 9415141 - Davis Point, San Pablo Bay, CA 42 mi27 min W 7 G 8.9 61°F 1010 hPa
MZXC1 - 9415102 - Martinez-Amorco CA 43 mi27 min WNW 8.9 G 9.9 64°F 67°F1010.3 hPa49°F
PRYC1 - 9415020 - Point Reyes, CA 45 mi27 min WNW 5.1 G 8.9 58°F1010.7 hPa
PCOC1 - 9415144 - Port Chicago, CA 47 mi27 min WSW 8.9 G 9.9 64°F 67°F1009.9 hPa
46042 - MONTEREY - 27NM West of Monterey Bay, CA 48 mi25 min NW 12 G 14 56°F 56°F8 ft1010.9 hPa (+0.5)

Wind History for Redwood City, CA
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Half Moon Bay Airport, CA3 mi20 minN 07.00 miFair46°F44°F93%1012.2 hPa
San Francisco, San Francisco International Airport, CA12 mi19 minWNW 1010.00 miFair56°F48°F77%1010.9 hPa
San Carlos Airport, CA13 mi20 minN 010.00 miFair61°F46°F59%1011.2 hPa
Palo Alto Airport, CA19 mi88 minNW 710.00 miClear0°F0°F%1011.5 hPa
Oakland, Metro Oakland International Airport, CA21 mi22 minNW 410.00 miFair56°F52°F87%1011.5 hPa
Mountain View, Moffett Field, CA23 mi19 minNNE 510.00 miFair60°F53°F78%1011.6 hPa
Hayward, Hayward Air Terminal, CA23 mi21 minNW 410.00 miFair58°F50°F75%1012.2 hPa

Wind History from HAF (wind in knots)
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Last 24hrSE3SE3S3S3CalmE3E3E3NE4E3E3S3W6W6W5W10NW10NW9NW7W6W5CalmCalmNE4
1 day agoS4S6SE4CalmCalmCalmE4NE4NE3E4CalmNW6NW3NW6W5W6W7NW6NW8NW9NW8CalmN3Calm
2 days agoCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalm--S10
G15
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G17
S11S12S10S10S7S7SE7SE6Calm

Tide / Current Tables for Half Moon Bay, California
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Tide / Current Tables for San Mateo Bridge, South San Francisco Bay, California Current
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Tide / Current data from XTide NOT FOR NAVIGATION
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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 (1,6,7,8)
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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.